12V Lights

[Quintin]

just an question I have. Why go throe all of this will it not work if you change the existing globs with LED globs and then just get an inverter connected to a battery and Panel. this way you can make use of existing wiring and circuits just disconnect from the DB and connect the inverter output to the light circuits. This way you don't have to let your house look like and siance experiment and it should work well. You can even should you have a problem with your battery system then switch back to normal Eskom power with out a hassle.

[pietpetoors]

You can yes.

BUT I do not like the idea of an inverter which have to run 18 hours without doing any work just so that it can power my lights for 6 hours per day. It does not sound very effective to me.

But yes, you can.

[Stef]

I received some 12 Volt lamps for the house.
They use the normal E27 screw in and B22 Bayonet fittings.

6 watt warm white, 12 volt DC.
http://www.4x4direct.co.za/led-house-li ... -p-165.htm" onclick="window.open(this.href);return false;
and
http://www.4x4direct.co.za/led-house-li ... -p-308.htm" onclick="window.open(this.href);return false;

E27-7watt.jpg

[ChrisF]

just an question I have. Why go throe all of this will it not work if you change the existing globs with LED globs and then just get an inverter connected to a battery and Panel. this way you can make use of existing wiring and circuits just disconnect from the DB and connect the inverter output to the light circuits. This way you don't have to let your house look like and siance experiment and it should work well. You can even should you have a problem with your battery system then switch back to normal Eskom power with out a hassle.

in many instances this is the only practical way to do it ....


Basically it comes down to the following - the light circuit(s) leaves the DB board and a change over switch is used. You can now power your lights from 220V (eskom) or from your battery and inverter set.


Few things to consider :

- IF you have 24 of those stupid 50W downlighters in your house, that is 1,2kW !!!!! And this is the classic modern house .... So you will need a serious look at your lighting, to ensure the load can be handled by a battery and inverter .... by the time you have this sorted your electrical load is so low you might as well use eskom when available and only use the battery and inverter during load shedding.

- since you are now fiddling with the house wiring you really should have the work done by an electrician ...

[Quintin]

Mmm that is true, I am looking at all ideas as I am in the process of getting off the grid but that is not an easy task and very costly. I almost thing the government does not want to help with the power issue in SA as it would have been very nice if they can have a zero tax figure on importing of alternate power products i.e. solar panels, wind generators etc. I mean just to convert my swimming pool pump is going to cost around R15 000. to do my house from R150 000 upwards depending on what I want to do.

At lease I go my water sorted out that is for free from the stream so now I fill my pool with stream water, converted it to a fish pond and use it to irrigate my garden. I have at least 500 000 lt water for free and my garden looks great. I am now focusing on the electrical side of things.

[ChrisF]

Quintin do speak to Meinhard about a PV pool pump solution - https://www.youtube.com/watch?v=ddq1KDV954Y" onclick="window.open(this.href);return false;


off course I met him AFTER doing my install ...

[pietpetoors]

I almost thing the government does not want to help with the power issue in SA as it would have been very nice if they can have a zero tax figure on importing of alternate power products i.e. solar panels, wind generators etc.

My blood boils each time I go through the import duty document.
Crap like TV games and Big screen TVs carries zero import tax and stuff we need to keep the economy running is taxed at 20% like all vehicle spares and of course all lights.
Clothing are taxed at 45%

[Mud Dog]

...... I almost thing the government does not want to help with the power issue in SA as it would have been very nice if they can have a zero tax figure on importing of alternate power products i.e. solar panels, wind generators etc. .....

Of course they don't. They realise full well that those who are payers are supporting the non payers whom they do not wish to upset by cutting their illegal connections because the vast majority are ANC voters.

If they make it too easy to get off the grid, too many payers will be lost. :roll:

[ChrisF]

The FUTURE of 12V lights - viewtopic.php?f=170&t=39312" onclick="window.open(this.href);return false;

[ChrisF]

...... I almost thing the government does not want to help with the power issue in SA as it would have been very nice if they can have a zero tax figure on importing of alternate power products i.e. solar panels, wind generators etc. .....

Of course they don't. They realise full well that those who are payers are supporting the non payers whom they do not wish to upset by cutting their illegal connections because the vast majority are ANC voters.

If they make it too easy to get off the grid, too many payers will be lost. :roll:

Let's see if I can reply without pushing my blood pressure into the red line ....


Municipalities are making a fortune out of the re-selling of power -
http://www.fin24.com/Economy/Eskoms-pow ... s-20150605" onclick="window.open(this.href);return false;


Now re-read the City of Cape Town (COCT) document on Small Scale Embedded Generation ... Yes it briefly mentions safety, then gets side tracked by FINANCES. Let's sum up the COCT document for people wanting to generate power at home via pv.

A single phase 60A home may not generate more than 3,5kW, or 20kW.h per day. Let's say you use 5kW.h of this during the day for the fridges etc. Thus you SELL 15kW.h to COCT, at a gracious 49,7c = R7,45 per day that you "earn". BUT at night you buy that power back from COCT for a mere R1,09 per kW.h = R16,35 per day. Thus your first 20kW.h COST you R 8,90 per day.

Ooooo, but for this privaledge you must pay R 13,03 per day, irrespective of units used !!


Thus your 600kW.h per month will cost you a nice even R 657-75 .....

Based on the COCT rates for electricity for 2014/15 you have just saved R 264 per month on a usage of 600kW.h ... this for a mere R 100 000 investment !!!!!!!



sceptics may just think that this setup does not encourage citizens to generate power ....

[ChrisF]

Powering your 12V lights

not sure if this should be a separate thread, or if we should rather keep all the info together .....

long long ago in an era before candles, in fact in a time before a uniquely african thing called "load shedding" we had the option of using transformers to power 12V light systems. Yes, many downlighters have been 12V for years already, but powered from 220V.

Now to power the 12V lights when eskom takes time off to count their profits .....

BATTERIES.

Never have there been a topic more hotly debated than what battery to use and how to use it.

There are just so many things that determine what will work for YOU :
Cost
Space
your system
etc etc


The cost effective load-shed-buster system may well look like this -

DSCN2296 (Small).JPG (53.33 KiB) Viewed 24934 times

This specific charger system makes it a VERY versatile solution !! You connect 220V to the charger, then connect it to the battery. But you connect the light (load) directly to the charger unit. When 220V is supplied to the unit, the light is powered from the 220V source and the battery remains fully charged. When eskom takes a brake the unit automatically switch over to the battery and your light wont even know the power went off.


The other approach may look something like this -

DSCN2254 (Small).JPG (31.13 KiB) Viewed 24934 times

100Ah battery with a 220V and/or PV charger system.


There are a number of technical bits to consider when selecting your components :

- total light circuit power draw

- battery capacity to match the former

- 220V charger

- pv charger and panel size



see you in the next post for more detail on these items.

[ChrisF]

Total light circuit power draw -

WHAT do you want to do with your 12V lights ?????

A couple of LED strips and one or two downlighters purely to provide emergency lighting ?

OR do you want to switch over a few rooms completely to 12V lighting ?


here are a few numbers from our system :

Kitchen - 1,2m of 14W/m high bright LED strip. This draws 1,4A at 12V. During winter this light is used roughly 3 hours at night and another 1 hour in the morning. The current draw is thus : (3+1)x1,4 = 5,6A.h


I live in my braai room, aka man cave. The 12V lights here draws another 5A.h per winter night

The bedrooms draw maybe another 1Ah per night.

Thus our system draws maybe 12Ah on a long winters night.


NOTE - this is for a household with TWO people. Add 1 or 2 kids and the power draw WILL drastically increase.

[ChrisF]

Battery capacity required ??


For the purpose of this thread I will be using conventional wisdom. Graphs from the following website - http://www.lifelinebatteries.com/manual.pdf" onclick="window.open(this.href);return false;

Depth of discharge vs battery life -

life cycle (Small).jpg (40.58 KiB) Viewed 24932 times

Basically this graph states the following :
- if you use 50% of the capacity each night you may reasonably expect to get 1000 cycles out of this AGM battery (this would be between 500 and 1000 cycles for a deep cycle battery)
- if you only draw 10% of the battery capacity per night you could reasonably expect to get 5 000 cycles from it, or more that 10 years !



CONLUSION - your battery capacity SHOULD be more than DOUBLE the nightly current draw. Ideally 3 to 4 times the nightly draw. Better still if the battery capacity is such that you only draw 10% per night.


Application -
IF you use the 7A.h battery - you could expect to use about 3A.h per load shed and not damage the battery. That is a constant 1,5A draw, or about 18W. This could be 6 downlighters, or about 1,5m of 14W/m LED strip (remember you CAN use a number of small strips to total up to this 1,5m). Make no mistake, that IS a lot of light for backup purposes, though you wont be reading under these lights.


With a typical 100A.h deep cycle battery you could use 50Ah over a period of about 5 hours, thus a 10A draw. To put this in perspective. Hoppy's 24 off 3W LED lights only draw 6A.


PS - once you have a deep cycle battery you will add an inverter for the tv/computer. THIS accounts for about 40A.h during a load shed !!!! Thus on load shed days use the lights sparingly or you will drastically reduce the battery life !! And THIS is why Pieter is trying to source a larger 12V battery.

One could make a bank of batteries, but KNOW that this comes with various other issues, ie keeping the batteries balanced. Buying a single large battery surely has many benefits !!

[ChrisF]

When speaking to an industry specialist he stressed the importance of the QUALITY of the charger as very important in ensuring long life for the battery.


Here we are talking of the likes of the Benton BX range. The BX2 has a maximum charge rate of 7A. This is less than 0,1C, ie less than 10% of the battery capacity (for a 100Ah battery 0,1C will be 10A). Even with a 50% discharge after a load shed this low charge rate will fully recharge the battery long before the next loadshed on the next day. Thus NO reason to even consider any of the fast chargers. And we know that a slow charge IS better for a battery, even if some suppliers now claim their units can accept a higher charge rate. We simply dont need the high speed charge in this type of application, thus rather protect your investment.


If you are going the route of the 7Ah battery, please do get one of these small power supplies suited to the smaller battery.

[ChrisF]

PV charger and panel size -

we have a range of PV chargers to choose from. Typically you can choose between PWM or MPPT.

PWM - Pulse Width Modulating - basically this unit switches the PV panel ON and let the battery see the full panel voltage, but as the panel voltage is too high it switches the panel off again, and on and off and on and off ..... The width of these pulses determine how much power flows from the panel to the battery. You can buy these for under R300. Unfortunately this cheap charger stops the charge rate at 13,9V, thus it wont ever charge the battery fully. For a full charge the charge volts needs to go up to about 14,5V for a short period.

MPPT - Maximum Power Point Tracking - looking at the V-A curve of a PV panel one can see there is a specific voltage at which the panel delivers maximum current. Bear in mind the maximum current varies throughout the day in accordance with the position of the sun. Thus the maximum power point is an ever moving target. The MPPT solar regular constantly monitors the maximum power point of the panel, and adjusts the charge current accordingly. For good measure it also measures the state of charge of the battery and further adjusts the volts and amps to the battery to ensure the best possible charge rate for both the available power and the state of charge.

understandably the MPPT units are not exactly cheap ...




PV panel size - play on sites such as these http://re.jrc.ec.europa.eu/pvgis/" onclick="window.open(this.href);return false; and you will soon realise the massive differences of the available power between Summer and Winter !! Summer time I can get near 6 hours worth of maximum power from the PV panel, my flat mounted PV panel hardly gets 4 hours worth of power in winter - IF and only if there is zero cloud cover ....

Let's say the charge voltage is 14V, then the maximum charge current from a 100W panel is 7A.

Let's consider a clear sunny winter day - now if only we had these in the Cape - then I could get 7 x 4 = 28A.h maximum from a 100W solar panel. Now allow for the fact that my panel is mounted flat, and I would be lucky to see 15A.h during a clear sunny day in mid winter !! Dark cloud cover and I get 0A.h ! Light cloud cover would still deliver a bit of power ... But this applies to the worst two months of the year only. Summer I could easily get 7 x 6 = 42A.h .....

Way more than I need for the 12V lights.

BUT, not enough to fully charge the battery after a load shed !!!!



For now I monitor my battery voltage and use the 220V charger to suppliment the charge during extended rain days. I also use the 220V charger after a load shed. Still considering long term solutions\options ....



Well worth talking about the angle of the panel - IF you mounted your pv panel at an angle of about 45 degrees and facing North you would get significantly better charge rates than I am getting now !! But I only have a flat roof near my installation and I hate these mounting frames with a passion.

[pietpetoors]

45 degrees is not always the optimum. George and I did a test once and the degrees were closer to 30 degrees.

At about 2pm you put the panel in the sun. Put an empty toilet roll on the panel and tilt the panel until the t/roll gives no shadow. That is the correct angle.

We did it in summer, I can see now in winter the angle is bigger.

[ChrisF]

45 degrees is not always the optimum. George and I did a test once and the degrees were closer to 30 degrees.

At about 2pm you put the panel in the sun. Put an empty toilet roll on the panel and lift it until it gives no shadow. That is the correct angle.

We did it in summer, I can see now in winter the angle is bigger.

Actually the year round maximum angle is equal to the angle of latitude .....

BUT to compensate for the available hours it is recommended to use "Latitude plus 10 degrees". This certainly is NOT the maximum in summer, but it does help to get more energy in winter. As such the year round usable energy is better at 33+10=43 degrees in the Cape.


As for the absolute maximum - In Summer, in the Cape that absolute max may well be closer to zero degrees when the sun is absolutely right above us - for those few days only.



THIS is the problem in sizing a PV system, as the maximum gain is so drastically different between winter and summer. Add to this that you have easily more than 50% extra sun time in summer. Thus the summer gain is typically more than double the winter energy gain !


If you ever want to get off th grid and have a truly stand alone solar system , you need to size for the winter conditions, and have a grossly oversized system 9 months of the year.


Add the fact that we have 5 to 10 days of cloud cover at a time in the Cape .... relying solely on PV is not practical.

YES, for about 9 to 10 months of the year we can get the bulk of our energy from the sun, it certainly is not a standalone solution.

[Mud Dog]

Without any fancy calculations I figured that it would be best to angle the panel for maximum winter benefit because the days are shorter. The longer summer days would then compensate for the lack of optimum PV angle. Might not be a perfect science, but so far it's working for me, even with cloudy days.

My system uses 8 x 80W panels that charge 8 x 102ah batteries and it's all split into 4 units of two panels per two batteries (connected in parallel) - each unit having it's own controller. The draws from each unit are separated as well. One unit supplies the inverter for TV's / computer / decoder / ADSL router - another supplies interior lights another supplies part of the all night outside lights and the last unit supplies the smaller balance of outside lights but will occasionally power two 20W flood lights that are individually switched.

The outside lights and flood light units are not yet operational but according to the calculations I did, should be OK and not discharge more than 30% of the batteries per night. The proof however will be in the 'pudding' when I hook it all up.

[pietpetoors]

Busy with mine.
For the guys concerned about Voltage drop.
Voltage in garage at DB is 12.8 Volt, voltage in top front room, furthest from the garage is 12.54 Volt.

Will post pics later.

[pietpetoors]

Project completed today.

There is not many pictures to be taken as I just replaced my 220 volt lamps with 12 volt lamps.
The only light I had to convert was the Kitchen's LED Tube. It had 220 volt LED tubes.
I removed the PC board with LEDS and replaced it with 5x LED Modules per tube.
The modules are 1 watt each, thus each tube now is 5 watt per tube.
LED Tube

12volt-home-lights (2).jpg (37.91 KiB) Viewed 24864 times

Modules

Module

12volt-home-lights (3).jpg (38.86 KiB) Viewed 24864 times

The aim of my project is to have lights during load shedding. Thus I am not concerned about running the lights for hours on end on the battery, 2 hours is enough.

The battery supplies the 12 Volt and during normal times the battery charger keeps the battery full.
Phase 2 will be one day to add a solar panel to charge the battery. My house do not have a roof, it has two concrete slabs which makes playing around with lights and solar very difficult. My main problem with solar is getting the wires from the roof to the garage.

As I mentioned somewhere, Voltage drop is not as huge a problem as people think.
I measured the room furthest from the DB board (located in garage).
At DB it was 12.8 Volt and in the room at the light it was 12.54 Volt.

I got an electrician to remove all the light wires from the db, the live and neutral wires.
The neutral went via the Amp meter shunt to the 105 Ah battery.
The Live wires goes to a fuse box, each with its own 10Amp fuse and then to the battery with a 30 Amp fuse.

I connected a Benton BX2 to the battery but might replace it with a HCDP unit soon.
Problem with the Benton is it charges the battery and when done go into trickle mode. If you use the lights which drains the battery the Benton does not realize it and stays in trickle mode. Only when you switch the Benton off and on again does it realize it has to charge the battery.

Everything is working perfectly, one do not even realize that something has changed. The GU10 lamps are the same colour and brightness as the 220 volt version, so we do not even realize that they are 12 volt.

This week I will just add some trunking and run the wires in the trunking so that it looks neater.

DB

DB

12volt-home-lights (1).jpg (34.36 KiB) Viewed 24864 times

The Volt /AMp meter and fuse box

Meter

12volt-home-lights (4).jpg (28.49 KiB) Viewed 24864 times

[Mud Dog]

Lekker! And ja, you'll have to neaten up that spaghetti a bit!

Having a concrete deck for a roof certainly has it's challenges, especially that there is no roof space in which to run wiring. So you're forced to use the existing conduits, but with the 12V replacement bulbs that are available now, it actually makes it quite simple.

Mounting solar panels on the roof should also not be a problem. Make up a frame (maybe even a second one to keep aside for when you might want to expand your PV array), using something like 3x30mm angle iron. Something like this .....

(excuse the quick rough drawing) ....

FRAME.JPG (12.2 KiB) Viewed 24864 times

Have the frame galvanised. Drill 12mm holes (they will reduce in size after galvanising) where the two red marks are to anchor it to the concrete roof slab and use two galvanised 10x60mm galvanised Hilti sleeve anchors to secure it. First drill the holes in the slab and mount the frame, then release the frame again leaving the Hilti studs in place - seal the studs at the base (Sikaflex is better than silicone) - and re-secure your frame.

Drill 8mm holes where the green marks are on the two cross members (the example assumes that you will be mounting two panels and that the frame will be sized accordingly). These holes will also reduce with galvanising but can be cleaned out if necessary with a 7mm drill bit. The holes should be spaced so that there is 8mm more between centres than the width of a panel (it will result in there being 8mm between each panel - 4mm on each side - of which 6mm is taken up by the thickness of the "J" bolt, leaving a safety margin of 1mm on each side of the bolts). To mount the panels you then just need six (three top and three bottom) 6x60mm galvanised "J" bolts with 30x6mm bonded washers. (I used wing-nuts for easy adjustment.)

Running the cables is also not a problem. You can use PVC Eggert Ducting that's surface mounted to house the cables down the outside wall (preferably in an unobtrusive position like next to a down-pipe or in a corner). Where you drill the cables through the wall to the controller / battery, one just seals it off when the cables are in.

Not difficult.

[pietpetoors]

Thanx Andy. Problem is our complex rules say you may not run any pipes or conduit down the walls, everything must be inside the walls. So i will have to grind a groove in the wall, put the wire in and plaster it again.

[Mud Dog]

There could be another way around it .... not exactly to code, but there must be downpipes to handle the water discharge from the roof. Maybe one of them is close enough to your battery position - run the wires down inside the pipe and exit at the back through the wall.

Otherwise you are left with little other option than to chase it into the wall (outside). I would not try come down through the roof slab because this leads to other complications.

[ChrisF]

Jip. Complex rules make for complex installations . . .

pieter hoe word die tv antenna draad afgebring ?

Wat maak die Benton as die ligte vir n dag of twee brand ? Hoe laag daal die battery volts voor die Benton weer oorskakel na laai ?

Ek sit nou weer met solar laaier wat te hoog laai ...... nou op soek na n laaier ....

[pietpetoors]

Die TV antenna gaan in die muur af, maar heel aan die anderkant van die huis waar die garage is, gaan dus baie lang drade benodig.

My geyser staan op die dak en is reg bo die garage, gewonder of ek nie sommer drade in sy pyp moet trek nie. Dan gaan dit seker nie vreeslike duk drade kan wees nie.

Die E27 en B22 ligte skakel af as hulle ongeveer by 11.5 volt kom. Dus as die battery onder 12 volt gaan begin van die ligte doodgaan, ek kon die battery dus nog nie onder 12 volt trek om te kyk of die Benton weer gaan aankom nie. Ek het 'n verskaffer gekry wat se ligte werk tussen 10 en 30 volt en oorweeg om die volgende batch van hulle af te kry. Dit kan nogal 'n lekker feature wees as die lig onder 10 volt afskakel want dan beskerm hy sommer jou battery ook.

Ons het 'n battery in die winkel wat ons kameras en ons vertoonkas se ligte trek en het dieselfde probleem daar met die Benton gehad, daar het ons nou oorgeslaan na die HCDP 6 Amp laaier en dit lyk of hy reg werk.

Jy sê jou solar laaier laai te hoog, watse controller het jy in?

[Mud Dog]

Pieter, pull the cables down through the geyser conduit - there should be more than enough space, the geyser cables are not that thick, a 3KW element only draws about 15A and I've seen many sparkies using 2.5mm. It's only live and neutral in the conduit, the earth is usually connected to the pipes, so the conduit is fairly empty.

The cable from the PV,s to the controller doesn't even need to be 2.5mm if the combined panels only amount to about 160W - the controller won't draw the full amps anyway. Mine are working fine on 1.5mm and my batteries are already full before midday, even on overcast days.

[Stef]

My 12V sample from Piet arrived, can't wait to test it. Did some testing last night with a crude temporary setup in the bathroom with a normal 36d eg DL and the 120 deg DL. major difference. Will be interesting to see how the 12V globe compares.

@ Chris, have a similar idea with the 7Ah batteries & chargers wired to 220V. We use to power data controllers the same way, with seamless txfer to batt power. Still have the diode circuit, very elementary. Even contemplating a central Meanwell PSU (21A) to drive multiple chargers to each 7Ah Batt.

[Stef]

handy tool for wire sizes: http://www.solar-wind.co.uk/cable-sizing-DC-cables.html

[ChrisF]

handy tool for wire sizes: http://www.solar-wind.co.uk/cable-sizing-DC-cables.html

Stef the danger with this calculator is that we dont know what the regulators are busy writing up ....


It IS very easy to show a calculation for a specific plug circuit that will have only one bedlamp and that will only have 0,2A current draw. Thus one could come up with some very thin wire ....



HOWEVER, the regulations are clear that all plug circuits will be 2,5A and a given size CB .....


By the same token, current 220V light circuits require a minimum of a 1,5mm2 wire and a given CB size ..... BUT, with the low voltage 12V circuits the current of light circuits will QUICKLY exceed the amps we are used to for light circuits !!!!!!!!!!!!!!!



As such dont be too surprized if the new regs require 2,5mm wire for 12V light circuits ..... (it wont work to limit the fuse size as this can be changed too easily)




going to be FUN when the new regs comes out .....

[The Legend]

Hoe se hulle " if you are good you are good"



Sal nie omgee om so n setup in my huis te he nie

[Stef]

handy tool for wire sizes: http://www.solar-wind.co.uk/cable-sizing-DC-cables.html

Stef the danger with this calculator is that we dont know what the regulators are busy writing up ....


It IS very easy to show a calculation for a specific plug circuit that will have only one bedlamp and that will only have 0,2A current draw. Thus one could come up with some very thin wire ....



HOWEVER, the regulations are clear that all plug circuits will be 2,5A and a given size CB .....


By the same token, current 220V light circuits require a minimum of a 1,5mm2 wire and a given CB size ..... BUT, with the low voltage 12V circuits the current of light circuits will QUICKLY exceed the amps we are used to for light circuits !!!!!!!!!!!!!!!



As such dont be too surprized if the new regs require 2,5mm wire for 12V light circuits ..... (it wont work to limit the fuse size as this can be changed too easily)




going to be FUN when the new regs comes out .....

Undoubtedly, we're all holding our breath I suppose but very few things surprise me these days ...

What I like 'bout the calculator is that it takes wire length into account, and at least a good point to start from. House wire is 1.5sq mm simply because of the way we wire the circuits i.e 1 or 2 circuits for a entire house so the first run from DB to first point of consumption will have the most current; easier to just have one size all the way than many different sizes as the load decreases down the chain. If one were to apply the calculator with total current draw and longest distance in mind it would come closer to 6mm than 2.5

[Stef]

Ok so the 12V model from 4x4 direct arrived and I did some testing sommer in the bathroom as I had a temp setup handy..


3 Lamps tested, from left:

36deg Ellies 4W, 120 deg Uniontech 4W & 4x4 direct 6W

20150622_180039.jpg (175.61 KiB) Viewed 24980 times

The test rig

20150622_175531.jpg (91.37 KiB) Viewed 24980 times

Ellies:

20150622_175004.jpg (128.09 KiB) Viewed 24980 times

Uniontech:

20150622_175202.jpg (130.45 KiB) Viewed 24980 times

4x4 direct:

20150622_174739.jpg (103.15 KiB) Viewed 24980 times

[Stef]

Only "drawback", and that's just me, about the 4x4 direct version is the GU10 connector on 12V as opposed to the MR16 of the others. GU10 is normally reserved for 220V so it's easy to accidentally put it into a 220V wired fitting and blow it up. Benefit though is that you wont have to replace connectors if you convert the installation to 12V.

BTW Chris, read up on PELV & SELV (protected/safe extra low voltage installations) a bit in the wiring code; seems it does cater for 12V after all (actually up to 120V DC ripple free), but doesn't distinguish between lights & plugs for example, but it mentions lighting as a example of ELV....

I'll scan the pages at work tomorrow if I have a chance

[ChrisF]

Stefan we had some discussions about the GU10 12V vs staying with the traditional MR16 12V fittings ....

The main benefit of going GU10 12V is exactly for what Pieter has done - remove the 220V wire from the DB and power it with 12V. Then it is simply a matter of swopping out GU10 220V units with GU10 12V units.



I am talking under correction here - the way I understand it, the references to low voltage (12V) is primarily aimed at 12 and 24V control circuits inside of 220V systems ..... Add to this that traditionally these systems were still powered from 220V via a transformer. The concept of using PV panels and battery banks in residential installations, and then the inverters, chargers, controllers, etc are not dealt with properly. Right now the white coats are busy writing codes to deal with:
- mounting the PV panels
- inverters\regulators - to ensure that the equipment is up to par with our wiring codes and conventions ...
- battery banks .... here is a whole new can of worms ....

PS - you do know that the existing wiring code actually do provide the tables for selecting DC cable sizes.



interesting times :)

[pietpetoors]

I had the 12 volt GU10 made purely because I did not want to change all my light fittings.
You can choose, you either put a 12 volt GU10 in the existing fitting and only change your globes or you can change all the fittings and globes.
If you already have a MR16 system you can just remove the transformer and connect it directly.

You can also accidentally install a 12 volt B22 and E27 on a 220 volt circuit.

It is no big deal, it just makes one bang when it blows the circuit and then it is dead.
Happened twice to me already.
One of my lights, the electricians who initially did my house's wiring put the light on the plug circuit.
So I changed 3x GU10 12 volts and when I switched it on it just went bang and tripped the plug circuit.

[pietpetoors]

Andy, coming back to your frame;

Why must one build a frame?

The solar panels each has its own frame, why can't you just pop rivet the panels together (or screw it) .
Then on the floor I can put flat bar pieces with hinges, one end of hinge on flat bar, other end I pop rivet to the bottom end of the solar panel frame.

At the back I can make extendible legs so that I can change the angle during the year.

[pietpetoors]

O ja Chris, I see somewhere you mentioned one must get the correct charger for the 7Ah battery, so I did.

We now sell the 0.8 Amp CTEK especially for the smaller batteries.

http://www.4x4direct.co.za/batteries-an ... p-1805.htm" onclick="window.open(this.href);return false;

[Stef]

100% Pieter & Chris, it is really no big deal and has the benefit as mentioned; I have GU10's in the roof already so makes sense.

I am talking under correction here - the way I understand it, the references to low voltage (12V) is primarily aimed at 12 and 24V control circuits inside of 220V systems ..... Add to this that traditionally these systems were still powered from 220V via a transformer. The concept of using PV panels and battery banks in residential installations, and then the inverters, chargers, controllers, etc are not dealt with properly. Right now the white coats are busy writing codes to deal with:
- mounting the PV panels
- inverters\regulators - to ensure that the equipment is up to par with our wiring codes and conventions ...
- battery banks .... here is a whole new can of worms ....

PS - you do know that the existing wiring code actually do provide the tables for selecting DC cable sizes.



interesting times :)

Chris, not quite, can have up to 120VDC and 50V AC. Agree with you on the solar bit as sources for ELV are not clearly defined (unless in another standard other than 10142). In the code ELV is mentioned under section 5 as a means of protection and then again under section 7.9 where the general guidelines and installation rules are defined, but as you say, only deals with transformers for which there is a separate standard.

The only hint at anything else as an ELV actually SELV, is where it refers to sources of more than 1kg. I haven't seen any restriction to txformers as the only source.

The regs are ambiguous yes, but I believe one could under the current code use that to apply to batteries as well i.e. the 25A limit for SELV sources, so arguably a 105AH deep cycle battery is a no go, yet our UPS room at work has 160 odd of those in combinations of series & parallel...can of worms indeed.

[Stef]

Here's a scan of section 5 wrt ELV as means protection pages 77 to 80:

section5.pdf

(247.54 KiB) Downloaded 199 times

A bit of Section 7...note 7.11.4 and 7.12 between the heading & 7.12.1...deals with a bit with batteries etc but does not address the physical wiring thereof except for lighting as per section 7.9

section 7.pdf

(148.02 KiB) Downloaded 195 times

[Mud Dog]

Andy, coming back to your frame;

Why must one build a frame?

The solar panels each has its own frame, why can't you just pop rivet the panels together (or screw it) .
Then on the floor I can put flat bar pieces with hinges, one end of hinge on flat bar, other end I pop rivet to the bottom end of the solar panel frame.

At the back I can make extendible legs so that I can change the angle during the year.

I suppose a frame as such isn't really necessary - one just needs some way to secure the panels so that they aren't picked up and flung in the wind.

My roof angle was close to perfect, so I just made flat frames which assume the same angle as the roof. The frames and multiple panels with the "J" bolts worked well for erecting everything - nothing too heavy, oversized or awkward to handle when lifting and assembling it on the roof. It's also easy to remove / replace or add panels.

Just made more sense to me that way.

[ChrisF]

Stef I come from the tools and DO understand what you are saying. In fact I DO agree with you.

That said I am trying to figure out where the white coats are heading with the new regs .....


The document published by the City of Cape Town regarding PV systems makes the following comments :

regs (Small).jpg (37.42 KiB) Viewed 25019 times

Clearly they have some far reaching thoughts regarding PV installations, and DC wiring in homes ......




The requirement for a SABS mark for European inverters that already carry all the international brands ..... uhm ja .... laat ek liewer nie sê wat ek dink nie ..... may just mention that some of the best German solar hot water systems never got SABS approval "due to lack of local content" ......

[Stef]

I see what you mean

SABS also not what they used be, private test labs not any better either...
Just wonder how long b4 the update is published...fortunately municipalities up here do not seem to have caught on yet. And in my personal experience one cannot rely on the inspectors from dept of labour, contractors can get away with pretty much anything

[ChrisF]

I see what you mean

SABS also not what they used be, private test labs not any better either...
Just wonder how long b4 the update is published...fortunately municipalities up here do not seem to have caught on yet. And in my personal experience one cannot rely on the inspectors from dept of labour, contractors can get away with pretty much anything

most interesting catch 22 situation ....


right now our electrical department is going out on tender for a grid tied system for a commercial client.

We are applying all best engineering practices, providing professional sign off the whole lot .... and yet when these new regs finally gets published ......


nice to be at the cutting edge of technology and to see how it all develops and unfolds .... but it aint called CUTTING edge for nothing !

[ChrisF]

the next project -

visited friends last night .... they currently use candles during load shedding ....


we started talking, had a look at my system, talked about cost effective stop gap solutions .....


And here is the thought pattern at the moment -

12Ah 12V battery (the slightly bigger brother of the classic 7Ah battery in UPS units) : R300
60 to 100W power supply from Mantec - this is virtually a mini UPS - when 220V is available the load (lights) are powered via the power supply, when loadshedding kicks in the unit takes power from the 12Ah battery : R300 to R400 depending on the model used (HUGE stock issues!!)
Now it is a matter of a few downlighters and LED strips as the house allows .... anything from R500 to R 1000 .... all depending how much light you want.
And another couple of hundred rand for fuses, switches, and wires ....


EMERGENCY lights - we could set up something under R 1 000, but the more elaborate they want the lighting the budget can steadily creep upward ..... Fortunately with the right planning it is possible to add lights as and when the budget allows.


This would be a perfect loadshed buster system.

IF the lights are chosen and placed correctly some of the room may no longer use 220V lights achieving a minute saving in the electrical bill. But this design is NOT aimed at replacing the 220V lights, rather a cost effective loadshed buster.


PS - with a kid in high school THIS is a very good way of ensuring studies dont suffer .....

[Stef]

Exactly what I was getting at...catch 22...

One can go and convert your house, but when the regs are published you might have to spend money again.
So what does one do in the mean time? Haven't decided yet...7Ah batteries like above or 105Ah deep cycle..which I have 2 of

A plug & play setup that allows you to go back to code almost effortlessly is the way to go I think

[ChrisF]

Stef "plug and play" is probably the way to go ..... let's face it, the fun is only going to start when you want to sell your house ......


so the system that gets you back to "standard" with the least effort is the way to go, at least until the regs are published .....

[Hunter26]

I am thinking of running a 2.5 x 3c ( L,N,E) wire from garage down centre of house in roof. Tap off this DC wire into a pull switch in each room corner. From this pull switch, feed into a length of strip lights mounted onto the ceiling around the existing light fitting. This 2.5 x 2c will be fed by a 12v battery in the garage connected to an intelligent charger. Further more to this as a phase 2, is to run a second 2.5 x 3c to the TV set up. This circuit will be connected to an inverter which will be fed off the same 12v battery and intelligent charger. When funds are available then a solar panel,regulator,controller etc will be fitted.

comments ,suggestions,corrections most welcome.

[Mud Dog]

Pretty much the same idea as what I have done except that I'm running multiple circuits with 8 batteries being charged by eight panels and I use ONLY my LED lighting. You're obviously just looking at a L/S solution but you might well find that one battery is not going to be enough to power your load for 2 hrs, especially if you connect more than a TV to the inverted circuit, but it's a start.

Calculate your load amps, add a little for inverter inefficiency and see if your battery A/hr rating will be sufficient (bear in mind that you should not drain more than about 40% of the battery).

[Stef]

Stef "plug and play" is probably the way to go ..... let's face it, the fun is only going to start when you want to sell your house ......

Indeed...even if it is a system that you just disconnect & swop a few connectors; new owner swops them back again

[ChrisF]

feedback time -

We had guests this weekend. As happens when you have up-country guests for the first time the usage pattern is slightly changed ...

By 17:00 the light would start fading and I switched on ALL the lights. The lights for their room, bathroom, Kitchen, Lounge, braai area were all switched on and left on until we went to bed. Thus the system was tested way beyond its design parameters !! Each time I went to the garage to get more braai wood I did glimpse at the volt meter and kept an eye on the system ....


The system was drawing about 6A for almost 5 hours !! And in the morning it was another 6A for yet another 2 hours .... the morning power consumption certainly did not form part of my design (plain and simply forgot about it, never thought we use that much power in the morning)


The light load thus got my 100Ah battery down to 60% SOC, and the 12,5V seemed to confirm that figure.


Saturday was a perfect mid winter day, with clear skies. We took a day drive and only got back by 17:00, by which time the battery was fully charged again :) :)



I am very happy to say our system is working very nicely !!

It was also a stark reminder of just how much power goes wasted when lights are left on in rooms when nobody is in the room ..... I now also understand why some people have such high electrical bills, as a result of burning way too many lights for no reason other than bad habits ...



Should we want power for the tv or computer for a two hour loadshed AND to run this many lights for the full night I would need a 150 to 200Ah storage capacity .... but with the two of us we dont use that many lights and can further monitor/manage our usage in the event of a loadshed.

[Mud Dog]

Nice Chris! I'm surprised that you get that out of a single battery. Mine run between 7 and 8 hrs every night but then I have 204 A/hr storage for each circuit (inside lights are one one of those). I've forgotten what the amp draw is, but it may be a bit more than 6A and the charge is replaced each day. The past few days have been a good test - shortest days in the year and some of them heavily overcast. No problems even though the batteries never quite reached the usual 13.8V recharge.

Our power went off at 14h00 yesterday, switched over to inverter for TV / decoder and forgot about it after the power returned at 16h00. We carried on watching till after 22h00 before I switched back to grid power - batteries were standing at 12.5V, so I think we could have gone on for much longer.

[ChrisF]

Nice Chris! I'm surprised that you get that out of a single battery. Mine run between 7 and 8 hrs every night but then I have 204 A/hr storage for each circuit (inside lights are one one of those). I've forgotten what the amp draw is, but it may be a bit more than 6A and the charge is replaced each day. The past few days have been a good test - shortest days in the year and some of them heavily overcast. No problems even though the batteries never quite reached the usual 13.8V recharge.

Our power went off at 14h00 yesterday, switched over to inverter for TV / decoder and forgot about it after the power returned at 16h00. We carried on watching till after 22h00 before I switched back to grid power - batteries were standing at 12.5V, so I think we could have gone on for much longer.

Andy I just measured the current flow - 5A with all the lights on. Thus I was drawing 30 to 35A during the night and morning cycle, as an absolute maximum. Probably closer to 25 to 30A. This from a 100Ah battery.

Our usual draw is only about 5 to 10A.h per night.


Remember this is only for lights.


On a loadshedding night I may draw another 40A.h - in which case I cut back on the power we use for the lights. And then recharge after the loadshed with a 220V charger.

[ChrisF]

the next project -

visited friends last night .... they currently use candles during load shedding ....


we started talking, had a look at my system, talked about cost effective stop gap solutions .....


And here is the thought pattern at the moment -

12Ah 12V battery (the slightly bigger brother of the classic 7Ah battery in UPS units) : R300
60 to 100W power supply from Mantec - this is virtually a mini UPS - when 220V is available the load (lights) are powered via the power supply, when loadshedding kicks in the unit takes power from the 12Ah battery : R300 to R400 depending on the model used (HUGE stock issues!!)
Now it is a matter of a few downlighters and LED strips as the house allows .... anything from R500 to R 1000 .... all depending how much light you want.
And another couple of hundred rand for fuses, switches, and wires ....


EMERGENCY lights - we could set up something under R 1 000, but the more elaborate they want the lighting the budget can steadily creep upward ..... Fortunately with the right planning it is possible to add lights as and when the budget allows.


This would be a perfect loadshed buster system.

IF the lights are chosen and placed correctly some of the room may no longer use 220V lights achieving a minute saving in the electrical bill. But this design is NOT aimed at replacing the 220V lights, rather a cost effective loadshed buster.


PS - with a kid in high school THIS is a very good way of ensuring studies dont suffer .....

UPDATE -

best laid plans and all that nonsense ....


And as we struggle to get another of these small power supplies I start asking more and more questions ... and the more the suppliers duck and dive the more I start wondering ......


now you know me by now - when I get curious I do an experiment .....



So here is the kit we started with:
7Ah battery and a 36W power supply -

DSCN2296 (Small).JPG (53.33 KiB) Viewed 24867 times

but 36W is 3A at 12V ..... now we know that the rate of charge should not exceed 10% of the capacity ..... would this unit really pump 3A into the battery ?? Surely not ......


and so we draw about 2,8A.h out of a 7Ah battery. Get the meters ready and connect to eskom .... time to check the charge current -

DSCN2378 (Small).JPG (67.8 KiB) Viewed 24867 times

DSCN2380 (Small).JPG (56.46 KiB) Viewed 24867 times

PS - a few LED's were still drawing current.

Pumping 2,5A into a 7Ah battery ..... would be interesting to see how long this battery lasts if you keep up this charge rate day after day ....




Now here is a real conundrum !!

Use the baby Ctek, and the charge rate is such that the battery wont get hurt ..... BUT, now you can only use 2 or 3 LED's during normal usage, or your battery will get drained each night .....

But now the question is WHAT do you want from your cheap light setup ??????


If it is only to deal with loadsheds - by all means get the SMALL charger, keep the battery in pristine condition, and get a 12Ah battery to run enough lights for a typical 3 bedroom home during a loadshed.

DSCN2382 (Small).JPG (62.58 KiB) Viewed 24867 times

and this is the type of charge current (0,8A) that will keep a small battery in good nick for many years -

DSCN2387 (Small).JPG (69.38 KiB) Viewed 24867 times

and slowly the picture unfolds .... you have two options

1) LOAD SHED only - small battery and small charger (and virtually no use of the lights during normal operation)

2) 12V light system for normal use - get a 100Ah battery, 7A charger, and provide a small house with 12V lighting night after night, and also during loadsheding.




now if I could custom design my ideal unit .... 60W load output from the power supply, and a selectable charge current to the battery ....


EDIT - a good nights sleep and I am looking at this differently ..... dual approach with a change-over switch :
1) Battery with proper charger for load shedding.
2) Under normal conditions, flick over to the power supply and run a few LED's for basic lighting and reduce the electrical bill ....

Leave ONE LED light on the battery to ensure there is light to get to the change over switch during load shedding .....

[Stef]

Chris, I've also been mauling over a solution similar to that edit of yours for a while now. Concept is easy enough, the implementation is another story so many ways to skin a cat

Also looked at that Meanwell backup supply...you just saved me R386 LOL
There is another supply I'm after @ mini-box.com, but landed in SA $29 will become R700+ !! http://www.mini-box.com/s.nl/it.A/id.78 ... &fromsla=T

To me this is almost ideal plug & Play because one could run a 12V light circuit from your PSU hooked up to 220V, and run from multiple 7AH batteries (1 per room for example). Catch here is that your light switch in the wall must switch 12V not 220v otherwise the light will never switch off

[ChrisF]

My friend got the change over switch and is now busy with the wiring - including the change over switch .....


now to SEE this in action ..... :)


will let you know how it plays this out.

[pietpetoors]

en?

[ChrisF]

en?

hehehe .....


Dare I say that eskom has not provided us with an opportunity to USE this system ... TOUCH WOOD !!



It is installled and provides the emergency light levels they want.

The practical aspect of switching to the battery is not a problem. Remembering to switch back is the issue we are still talking about ...... thinking of a "pilot light" that would only be active when the system is switched to the battery side ..... would love to hear your thoughts on this.

elec (Small).jpg (20.82 KiB) Viewed 24821 times

[Family_Dog]

I connected a Benton BX2 to the battery but might replace it with a HCDP unit soon.
Problem with the Benton is it charges the battery and when done go into trickle mode. If you use the lights which drains the battery the Benton does not realize it and stays in trickle mode. Only when you switch the Benton off and on again does it realize it has to charge the battery.

Meant to reply earlier, then forgot.

Pieter, my setup with a 105A battery, 1500W PSW Inverter, is permanently connected to a Benton BX-2. After 4 hours loadshedding, the BX-2 senses the battery being low immediately and commences charge once power is restored. I don't have to reset it at all.


-F_D

[pietpetoors]

Eric, now that I used the system a while I experienced that;
I keep the Benton on all the time.
If the battery falls it will keep it at 12 volt and all the lights on the Benton will be on, showing that it is fully loaded.
It will not fall under 12 volt unless we use more than 7 Amp.
If we use more than 7 Amp it falls under 12 volt and then the Benton does not charge it even if I switch off all lights, all the indicator lights on the Benton is still on.
If I then switch the Benton off and on again all of the sudden only one indicator light on the benton is on and the volts jumps up to (I think) 13.4 volt.
If I do not switch it off and on, that won't happen.

Chris
Why don't you use a 5 pin relay?
Transformer activates relay.
and Transformer power is on normally open.
Battery power is on normally closed

If power fails, transformer switch off and relay switch the battery on at the normally closed position.

[ChrisF]

Pieter not an elegant solution ... but use a normal 24/7 wall plug timer unit .... set it such that once or twice a day it goes off for a short period. When it comes back on the Benton will wake up :)

Our Benton is left off, and only manually switched after a loadshed. For the rest all charging is done from the PV panel.




Pieter the 5-pin relay certainly will work .... I just dont like the idea of using a relay such that it is energized 99% of the time ...... I know there is an electronic circuit which picks up the loadshed and then does the switching ..... maar ek bly maar weg van pc borde ....