Solar power help for the not so smart

[4x4Grant]

Ok I have searched and read a bit but i don't seem to grasp this so i need to ask.

Right i would like to install a solar pannel on my camping setup to charge my battery (second battery) when i am parked off.
Now the question is what size pannel do i need? The battery has not been purchased yet so i can't tell you sizes. What i need to
try wrap my head around is how to work out what size i would need for what battery.

I am a little lost on Amps and Watts at this stage so if someone here with the knowledge could kindly try explain to me in simple terms
i would be so happy and greatful.

Many Thanks
Grant

[Hoppy]

a 100a battery (i use a 658) with a 80 to 90w panel works well with a 40l engel, lights etc. and the solar controler will automaticly chose between the power sources

[4x4Grant]

Thanks Hoppy makes my life easier now

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[ThysdJ]

Its not that simple I am afraid. You need at least 100W in panels to keep a 40 liter Engel going. PROVIDED that it isnt very hot and that you have ample sunshine and that your panels are rotated to face in the right direction. That is my setup at the moment. It is hard work to use solar panels. Obviously the bigger (wattage) the panels the easier it is to keep the system going. Get the best controller you can afford and if you can afford a CTek DC to DC charger that will double up as a solar controller then it will automatically select between power sources. The thing to remember is MPPT.

[4x4Grant]

Ok so tell me how do I work out what watts I need to charge a battery?

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[subok]

An Engel 40L draws 2.8 Amps when it is running and set at 1°C. Lets say it is in about 35°C ambient temp and it runs for 30mins in each hour. So you will need 2.8 x 12 = 33.6 Amps in each 24 hours. This is line with my own experience running a 40L Engel for 48 hours using a 105Ah battery before it needs recharging. So about 67.2A in 48 hours. This is dangerously close to damaging a deep cycle battery and remember that the Engel will just suck your battery for all amps it can deliver as it does not have a low voltage cut-out.
I use a 110W panel with a cheap Phocos 10A controller on a battery box with a deep cycle which has about 70% capacity left (it is almost 6 years old). The battery receives about 4 Amps constant charge from the controller and the fridge is connected to the load side of the controller. So it receives roughly 36 Amps in an 8 hour day of full sunshine. BUT, the moment you get a rainy day or two in succession, things change and you fall behind in re-charging the battery and you will need an altetnative way of charging the battery and will involve either a 220v charger, a solenoid system or a 12V - 12V DC charger. The latter two will involve driving around as they both feed off your main battery.
In my opinion, the best solution (bang for buck) is the battery box sold by Bushpower at the moment. It has a V/A monitor, and a DC-DC charger/solar controller. All you need to do is to install a cable from the box to your main battery and connect a solar panel! Sorted.
So you will probably get by with a 120W panel for your Engel and a few lights, and then you need to take a drive when there is no sun.
Hope this answers your question? Also look at ChrisF's post titled Electrickery for camping.

[ChrisF]

Grant your battery is a "banking SAVINGS" account - you CANT take out more than what you put in.

Your fridge use a certain amount of "energy" (A.h) during a day.

your driving and your alternator needs to put this back into the battery - or your next withdrawel will show insufficient funds (PAP battery)


Thys eluded to climate in his reply. In the Cape about 25A.h is typically what my National Luna Weekender use - an 80W panel gives an AVERAGE of about 4A for about 6 to 7 hours per day. Thus if you start with a full battery you can go for a week or two without actually running out of battery power.

Now take that same rig to Kgalagadi - now your fridge use about 50A.h per day !!!!!! TWO DAYS and your battery is DEAD !! (okay that is if you dont drive)



Now add a decent dc-to-dc charger to the mix and every short trip CHARGES the battery and you need even less from your solar system. :)



now you start moving into the field of charging technology and all the options.

1) for years the Ctek 250 S was the best option - it is a good cd-dc charger, and it automatically swtiches between alternator and solar charging to get the best out of your system. pity they lost the plot and doubled their prices in the last 18 months !!

2) DCdP has some interesting chargers and solr regulators ....

3) I just finished installing (2 hours back) a HCdP Power Panel Mark 4 - http://www.bushpower.co.za/products.asp?pid=647" onclick="window.open(this.href);return false; - STUNNING piece of kit !! (I will post a project document in a few days - kitting out Ranger for bush camping, from water to power .....) IF you have the space THIS is the answer !!!!!!!!!!!!!!!!!!!




SHORT answer to your question -
100 to 130W solar panel WITH a Ctek or HCdP Mk4 system.

[ThysdJ]

So Grant now the "Main manne what knows" came to stir up your crystal clear mud even further... Read the thread that ChrisF posted on the subject, it is very very informative. The point I tried to make is that one man's system is not necessarily going to be your best solution. And that there are many many outside factors you need to take into account.

My system is now built around a HcdD DC/DC charger, which charges the deepcycle from the main battery when the vehicle is moving, and acts as MPPT solar controller when the panels are deployed and the vehicle is stationary. The only draw-back is that it doesnt switch between these "power sources" automatically, but I actually prefer that, because it gives me the opportunity to make sure everything is working 100% when I change over to solar. (control freak me ).. I also installed 2 of 4x4Direct's little Amp/Volt gauges to monitor the in- and outflow of amps to and from the deepcycle battery.

As I said, I have 100W in panels, but I am going to increase that to at least 180W seeing as 4x4Direct has a lekker 80W panel that will work just nicely. We also follow a very strict "fridge usage protocol"... The Engel is well insulated and kept out of the sun/heat as much as is humanly possible to minimize the amount of amps required to keep the contents cold. The only other current draw on our system is for charging the odd camera battery, and running the laptop for about an hour every second day to backup photographs. Our camp lights all work on rechargeable penlites.. We found that these last almost 2 weeks, and the odd recharge while driving is not a hassle..

I know how you feel, I was there when I started with the whole solar thing about 2 years ago... If only ChrisF had posted his thread back then I would not be as grey as I am today...

[george]

Grant you just got excellent advice

Now it is to decide what your budget is and if you only want a few extra days or if you want a system that can run continuously.

This is my experience.With a 80 watt you will get a extra few days.With a 100-120w you can probably run continuously.

On the charger side I will go for the HCDP 12amp unit.Like Chris said if you have the bucks the MK4 panel is really the bees knees.
It can do so much more than the C-tek.The Mk4 is a complete solution for almost the same price.(even comes with a inverter)

My system is currently a HCDP 12Amp dc/dc R1250. Dixon Deep cycle battery. R1850 and a 100watt solar panel R1350.

The only drawback is that the HCDP 12Amp dc/dc can not switch automatically between car and solar.So if you stop you have to manually switch over to solar.For a saving of R3000 I really dont mind

[Mr_B]

Jislaaik... I just got schooled! Thanks for posting all!

[Wurmscooby]

Jislaaik... I just got schooled! Thanks for posting all!

+ 1 ...I have a headache of all the new terminology,excellent information guys.

[ChrisF]

I know how you feel, I was there when I started with the whole solar thing about 2 years ago... If only ChrisF had posted his thread back then I would not be as grey as I am today...

Now if only somebody else posted that thread a few years back I would have saved more than 10k in school fees !!


BUT, I just had the stunning opportunity to spend 10k of somebody elses money to test the Mk4 panel, the new solar panels from 4x4Direct, the new White\Yellow LED's from 4x4Direct, well basically half of 4x4Direct's inventory


We went for the 100W panel - Reason - SIZE, physical size that is. Due to space limitations in the Ford RANGER we simply could not house anything bigger.

HCdP Mark 4 Power Panel - we wanted a dc-dc charger (which can switch automatically), a 220V to 12V battery charger, power distribution board, with fuses etc etc ... These parts would cost 150% to 200% of what the Mk4 panel costs !! And then it would be BIG, and all over the show as it is a lot of loose stuff - just like in my 4x4. DAMN, the Mk4 panel is STUNNING !!!!!!!!!!!!!!!! The end user is NOT a technical person, he kept on asking when must he switch this and when must he switch that .... Did a little test last night, starting the engine, switching to 220V, all in different combinations ... nee wat daai paneel doen ALS, GEEN PROBLEEM !!


Ons maak Saterdag klaar, paar kosmetiese dinge. Sal dan BAIE fotos neem en n thread begin.

[george]

Ek moes 'n buurman soos jy gehad het Chris

[Mr_B]

Chris... please let me know when your neighbours house goes up for sale... we could make lekker profit by auctioning the property on the forum... as long as you promise not to move!

[KOBUSL]

One more thing Grant, PV panels work with light, so, if it's overcast, your panels will still produce some juice for the battery. Don't keep them indoors thinking the clouds block out everything. m2cw

[4x4Grant]

Man I love this forum.

Ok so here is what got me thinking about this. I can get 2 x 80watt panels for a very good price. (Will post specs soon) so I figured I could use them to charge my battery in the van when we parked off. So far the battery only runs my led lights and a spot from time to time. My trailer has a battery with the NL fridge in it. So the 2 x 80w should work well for this setup now.

Then when I upgarde I can move it in the house for back up lighting.



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[Mud Dog]

My plan is actually the other way around - for a start I will also use two panels. Each panel will have it's own MPPT charger and battery (two stand alone units) - one unit will feed some permanent LED lighting in the house and the other will feed a few dedicated plug points in the house via a 1000W pure sine wave inverter. These plugs will permanently power a TV, my PC, monitor, printer and ADSL router.

Along with a 3 plate gas stove and solar assisted geyser the solar panels will also provide a contingency for power outages. Daily usage will provide a small saving on grid consumption and offset some of the cost and with a bit of luck will pay for itself over time.

Each panel will fit into some form of "clip-in" frames so that they are lockable but easy to remove. Two frames will be permanently roof mounted and I will make a third frame that will be mounted on top of the bakkie canopy).

When I want to use a panel on the vehicle, I just unplug, unclip one from the house and clip in / plug in on the canopy. I will use automotive connectors on the panels, the ones that have a shroud around the male coupling, so that both ends are safe from shorting if they are disconnected. The purpose is for when not in use on either the house or the canopy, that there can be no short / leakage on the cable from the battery.

I can also easily expand the system in increments as I want / need to.

[Johan Kriel]

Ambient temperature plays a big role in Ah demand for these small fridges, from 25 to 40 deg outside can be almost 2 to 3 times more, according Engel USA. Thus one can either try to manage the fridge Ah demand, or provide for it, or both. , depending how much time, money etc you want to spend, and obviously space you have, and how long you want to stay without external charging .

My setup is ctek 250 dual charger, 90Ah AGM battery, 3x50 watt panels, 90l and 25l fridge and can survive 2 to 3 days without driving easily in the Kaokoveld or Kalahari during December. We use the small fridge for drinks and opens the large fridge only once or twice a day.

[Mud Dog]

We are on load shedding for the past ½ hour and I am unaffected! Swambo's watching her soapies and I'm busy in the office!!

[JohanW]

Mud dog, all of the following devices " These plugs will permanently power a TV, my PC, monitor, printer and ADSL router" are DC devices by design. Why don't you change the psu of these units to run off the dc supply your batteries supply? DC to AC to DC is a wasteful exercise...

http://www.mini-box.com/M4-ATX?sc=8&category=981" onclick="window.open(this.href);return false;

[Mud Dog]

Mud dog, all of the following devices " These plugs will permanently power a TV, my PC, monitor, printer and ADSL router" are DC devices by design. Why don't you change the psu of these units to run off the dc supply your batteries supply? DC to AC to DC is a wasteful exercise...

http://www.mini-box.com/M4-ATX?sc=8&category=981" onclick="window.open(this.href);return false;

My system will not be able to run them full time, just for a few hours at a time, so unless they have a DC power input I cannot do it yet. Perhaps in time once my system has grown.

[ChrisF]

We are on load shedding for the past ½ hour and I am unaffected! Swambo's watching her soapies and I'm busy in the office!!

Andy let me start by putting my no 11 boot deep into it ...


18:00 power goes OFF ....

slim-jan smile, NOU kan hy mos daai inverter TOETS !!


Klein UPS hou die tv aan die gang, maar daai 7A.h battery is mos mo3r toe, nuwe een staan nou al n paar dae op die rak ...


RUSTIG, stap ek garage toe om die die inverter in te prop, lead uit te rol, en .... HUH !!!


O-moeder, toe ek getoets het was daar mos lig in die garage .... nou is dit donker !! Okay, gelukkig nog nie nag donker nie so ek kom darem veilig by die bakkie en skakel Elders se LED ligte aan.

Deksils, daar 175A Brad Harrison is styf om in te druk !!

Okay rol lead 1 uit.

Nou lead 2

prop die UPS in die lead in

terug garage toe


aag demmit !! te rustig !! het mos gesê ek weet daai 7Ah is klaar hemel toe, AF is die tv en dstv ...

Okay, aan is die inverter en als boot op.


Aag nee man !!!


Een of ander mak moegoe het mos Saterdag sommer twee keer daai deep cycle getrek tot 10V op n swembad pomp !! Paar kilos gery en die bakkie vir so 2 uur in die son laat staan ....


So nou wat speel tyd verby is, is die battery op 12,3V !!! Dink dit was so 12,7V voor ek die 200W las aangesit het.


Nou ja, wat kan mens doen, Saterdag se mak moegoe is mos weg en sal nooit erken hy het self die battery leeg getrek en dit nie weer gelaai nie.


En so kyk vroulief en die peetkind vir Night rider, JA vir Night rider.

en terwyl my invertertjie sy ding doen, raas die buurman se genny in die agtergrond. Nie seker wat die ander bure die meest pla nie, die genny se geraas OF die feit dat hulle nie kan saam tv kyk nie ...



My invertjie idle rustig voort, dood stil. :)


1 uur later - battery lê nou al hier by 11,4V !! Maar die invertertjie hou die tv mooi aan die gang.


Aag wat, kan nou maar net sowel KYK wat maak die inverter as die volts laag raak. All in the name of science, of so iets.


Nou ja, ek kan nou vir jou vertel, teen 10,5V begin daai inverter n alarm maak wat my dowe oorle ouma sou kon hoor. Rooi EN blou liggie flikker, kompleet soos die blitspatrollie wat oppad is, hulle sirene is net nie so hard nie.

My buurman kyk vir my of ek van my kop af is - HOE kan ek daai battery so leeg trek ? "HOE gaan ek WEET wat daai inverter doen as ek nou staan en in meng ?"

nou sak daai volts VINNIG !! My maag draai, maar ek staan sterk - vandag TOETS ons die dem ding !!


9,9V volts voor daai inverter vir my vertel hy het nou GENOEG gesuffer, en daar sit hy AF - net sy rooi liggie wat nou brand. Skielik skyn Elders se LED strip sommer weer helder soos die battery se volts herstel na bo 11V. Uur later het dit herstel tot bo 12V


Nou ja. Nou WEET ek.

Eksperiment oor en als word uitgeprop. Sommer gou die nuwe 7A.h ook ingesit, vat mos net 50 sekondes.



Maar die twee uur is nog nie verby nie. Kyk NOU praat ek en die buurman soos ou pelle wat geen elektroniese goeters het wat ons aandag aftrek nie. Sommer n lekker koffie op die gas stoof. MENS, die load shed ding is nogal lekker. Jy kan sommer in jou huis kamp.

En dan onthou jy daar is nog n epos of drie wat gestuur moet word ... nee, die storie is sommer net n blerrie gemors !!


Maar so gesels ons voort en ontwerp die wereld se beste alternatiewe krag bronne. Ek vertel vir jou, as eksdom nou vir ONS twee aanstel, is als more uitgesort !



en na twee ure kom die krag aan. Ek kry die DStv aan die gang, sit die nuwe Topgear aan, en net soos ek gaan sit besluit daai wetters mos dis nou n goeie tyd vir nog n half uur sonder krag !! Nou dink ek nie meer so erg oor ander krag bronne nie, net kragtige gedagtes jeens die wetters wat ons tot hier gebring het .....

Gelukkig het die laptop se battery darem nog ietsie oor, so ek darem hier kom kuier ...

O-ja, die lectric is weer aan, so die kamp liggie met die pap batterye kan afgesit word. Ek moet tog onthou om die penlights wat op die werksbank lê in te sit, net voor ek nou weer in die donker moet sukkel. Maar miskien moet ek n plan maak om Elders te RY, dat daai battery kan laai wat daai anner moegoe so leeg getrek het !! En as ek NOU daai flatscreen aansit is Topgear ook net mooi klaar, net so klaar soos die bure se gennie wat na 90 minute stil geraak het.

Darem lekker om so op die klein Saterdag so bietjie te kan kamp by die huis ... properly met die kriek wat raas in die agtergrond. Lyk my die bure het vroeg gaan slaap, NIKS lectric klanke daar buite nie !! Vader behoede my dat ek tog nie vir eksdom dankie sê vir die gemors nie, al geniet ek dan nou die stilte so baie.

[Master]

Thank you for this excellent thread, also thanks @ ChrisF for the other one. Very very useful information and overview. Confirms what I already "knew" (~1 Ah/day/liter for a fridge) and gives a lot of helpful advice. Highly appreciated.
Going to KTP & CKGR in Nov/Dec and I think this will/could be quite useful...

Could anyone recommend a workshop/dealer around Gauteng who would supply & install everything within reasonable time (1, max. 2 days)? Dual battery system & 40l-engel fridge is already present.

[mossie89]

Ek weet maar min van die gevorderde inligting maar dis wat ek gebruik vir my 60L Weaco en beligting en dit werk Die battery is n 105 Deep cycle