How to best improve my db system

[Mud Dog]

My DB set up is very basic - a Cole Hersee solenoid, activated by ignition switch, with heavy cables running to the 2nd battery in the bin. I know this is far from ideal, but that's how it was when I got the vehicle. The obvious downfalls are that when the main battery is charged the alternator regulator 'sees' that and will only provide a trickle which means the 2nd battery never gets fully charged. The other negative (no pun intended) issue is that the 2nd battery draws charge from start-up, so on short trips the main battery doesn't get the full replacement charge used to start the engine.

To overcome this I am currently (again no pun) topping up charges to both batteries with a normal AC to DC charger and I want to eliminate this hassle.

So what and how do I go about it in a way that best suits my needs without unecessary expense?

Firstly, I was wondering if the present set up, given that there are thick cables connecting the two batteries, provides assistance to the main battery when there is a heavy current draw like when using the starter motor. If so, this may be a good thing.

Besides all that, my thinking is to mount a permanent solar panel on the canopy roof, and by way of a regulator and controller, having the panel charge the 2nd battery and once full, charging the main battery as well. This thread got me thinking about the use of a DC to DC charger. Pieter's DC charger has a solar panel input as well with MPPC, so I won't need a regulator and nor will I need a separate controller - correct?

How would I best set it up? Use the existing cables (without the CH solenoid) since they are already there? or leave it as it is to get double battery power at both ends and run new cables for the DC charger?

[Mud Dog]

Also, some questions about Pieter's DC to DC charger ..... it's set to cut off the draw from the source battery when that battery's voltage drops below 12.5 V, can this be adjusted to a higher value?

Then also, there is this footnote on Pieter's site;

NOTES
Disconnect +Car and Ign when using Solar Panel (Solar Panel and Car cannot be used together
In Solar Panel mode loads will automatically disconnected
Solar Panel MPPC (Maximum Power Point Control) ensures that the maximum power is extracted from the Solar Panel

Does this mean that I cannot have the solar panel permanently connected?, that I have to disconect when the alternator is working?

Does it mean that my fridge (the load) will be automatically disconnected while the SP is charging?

[george]

Does this mean that I cannot have the solar panel permanently connected?, that I have to disconect when the alternator is working?

Thats right only one at a time.

Does it mean that my fridge (the load) will be automatically disconnected while the SP is charging?

I dont think so.Your fridge will run from both

[ThysdJ]

That can be overcome with a "normally closed" relay Andy. The moment it gets power from the alternator it breaks the circuit of the solar panel...

Once the alternator does not supply power the circuit is closed again and the solar panel provides power.

CH solenoids are not all bad. I am also still using one.... But they are not really ideal when your aux battery is a deep cycle item... That's where the DC/DC charger comes into the picture... At the moment I am not running a deep cycle battery... But that will also change soon..

The main thing about these systems is to keep it as simple as possible. More fancy gadgets and stuff means more points of possible failure... We tend to overcomplicate things a bit from time to time..

[george]

That can be overcome with a "normally closed" relay Andy. The moment it gets power from the alternator it breaks the circuit of the solar panel...

Once the alternator does not supply power the circuit is closed again and the solar panel provides power.

On that specific charger there is also a manual switch that you have to manually change over.

[pietpetoors]

Thys, unfortunately it is not that simple, there is also a switch on the dc to dc charger where you select between car battery and solar.

I asked the supplier if they can replace the switch with a 5 pin relay but it seems that it will take a while before they do that.

[Mud Dog]

Thanks so far ... gives me stuff to ponder upon.

[ThysdJ]

Sorry, didnt read that far... then you are a bit stoofed Andy.. As am I..

[Mud Dog]

Not really .... one can change the CH to be manually switched from inside the cab and only use it when you need to, still use the 'cut out' relay as you suggested but for the best part let the panel do all the charging to the 2nd battery.

[WayneSchalk]

Andy I know of some guy's that in conjunction of ignition power use the oil pressure sensor for earth (I might have my wires crossed , please correct me if I am wrong). That way the CH closes the circuit just after starting up.

Never done it myself, I also have the HCDP 12a now, I see the bigger 30a one does have auto change over from alternator to solar.

[george]

Not really .... one can change the CH to be manually switched from inside the cab and only use it when you need to, still use the 'cut out' relay as you suggested but for the best part let the panel do all the charging to the 2nd battery.

I did this a lot of times.My SP was mounted on the roof rack and a lot of times I switch off the CH and let the SP do its thing while driving. On the 2.7 I did pickup a slight fuel improvement when not charging with the alternator.it was very small though.

[louis fourie]

Andy I know of some guy's that in conjunction of ignition power use the oil pressure sensor for earth (I might have my wires crossed , please correct me if I am wrong). That way the CH closes the circuit just after starting up.

Never done it myself, I also have the HCDP 12a now, I see the bigger 30a one does have auto change over from alternator to solar.

Wayne

Where can one get the 30A HcDP?

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[WayneSchalk]

Andy I know of some guy's that in conjunction of ignition power use the oil pressure sensor for earth (I might have my wires crossed , please correct me if I am wrong). That way the CH closes the circuit just after starting up.

Never done it myself, I also have the HCDP 12a now, I see the bigger 30a one does have auto change over from alternator to solar.

Wayne

Where can one get the 30A HcDP?

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You can buy from HCDP they are in Silverton http://www.hcdpelectronics.co.za/index.php But just check with them that I am correct in saying it has auto change over.

[Huismoeles]

Ek gaan n delay on energizer relay gebruik wat my solenoid switch
Gee hom krag van my lighter af
Dis as eknition aan kom tel die delay sy tyd af en dan switch hy eers