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Solar split charging

Posted: 30 Jul 2015, 13:38
by JNW
Hi

I've patched in a solar system to my van's leisure battery-powered system. It's now charging the leisure battery.

I want it to split charge both the leisure and main battery. Can I connect it to the van's split charger (where is it?), or will that do something bad to the alternator? What would happen if the solar was connected and the alternator was running - both feeding into the split charger?

I'm trying to avoid spending another 25 quid on a dual charge relay (Maplin).

Cheers

Re: Solar split charging

Posted: 30 Jul 2015, 14:29
by ghost123uk
You can only do it the way you suggest if your split charge relay is of the "voltage sensing" type. Most are not, they are triggered by the blue wire from the alternator, in which case your idea won't work.

Also "we" can't tell you where your relay is, unless your van is a standard conversion, then "we" may be able to. (LeisureDrive / Westfalia / AutoHomes etc) but even then in the time since it was new, anything could have been changed around. You need to find your relay. Not difficult, physically trace the charging wire back from the leisure battery. If, as is likely, yours is not a "voltage sensing" relay, you could buy one and wire it in so that when your leisure battery reaches 13.xx Volts, this new relay then switches in your main battery to charge it.

Why do you want to solar charge your main battery? Is it for times when the van is layed up?

Re: Solar split charging

Posted: 30 Jul 2015, 16:49
by gypo

Re: Solar split charging

Posted: 30 Jul 2015, 17:05
by JNW
I think I just like the idea of a full charge when I'm camping. The controller has a function to turn on a light after sundown. Thought I could send this to a relay to run the fridge at night so I can turn off the gas.

Could I just wire up the batteries in series with diodes to stop them discharging into each other?

Re: Solar split charging

Posted: 30 Jul 2015, 17:12
by ghost123uk
Just popped back in to say, you can't run a fridge off batteries, it will flatten them in an hour or two. Also re diodes, you would need very heavy duty ones (40+ Amps :shock: ) they are available, but not cheap and have to be properly mounted, plus there is a .6 of a Volt drop across a diode, and that would screw up the correct charging voltages. imho not "the way to go".

To do what you want, a voltage sensing relay, wired so when the leisure reaches 13.xx, it switches on and thereby charges the main, is the way I would do it. (That is if I thought I needed to charge my main via solar, which I don't need to, but I understand, if not using the van for a while it might be useful, though again, if it were I, I would just disconnect the main while under storage)

Re: Solar split charging

Posted: 30 Jul 2015, 17:22
by ghost123uk
How about a simple "changeover" switch wired so you can manually select where the solar current goes?

Re: Solar split charging

Posted: 30 Jul 2015, 18:51
by gypo
ghost123uk wrote:How about a simple "changeover" switch wired so you can manually select where the solar current goes?
Now that's an idea, nice and simple, well done that man!
G

Re: Solar split charging

Posted: 30 Jul 2015, 19:39
by gypo
Just been looking for a changeover switch, considering the cable is not that thick from the solar charger to the battery would a 30a switch do the job?
I cant seem to find any at a reasonable price above that amp.
Thanks
G

Re: Solar split charging

Posted: 30 Jul 2015, 20:31
by ninja.turtle007
I use a simple cable with a 15a fuse to connect the starter and leisure batteries together if the camper is going to be laid up for a while. All batteries are then kept topped up from the solar panel.

Image

Re: Solar split charging

Posted: 30 Jul 2015, 21:26
by ghost123uk
gypo wrote:Just been looking for a changeover switch, considering the cable is not that thick from the solar charger to the battery would a 30a switch do the job?

Simple answer = Yes :ok

Re: Solar split charging

Posted: 31 Jul 2015, 07:44
by gypo
Ok thanks
G

Re: Solar split charging

Posted: 31 Jul 2015, 08:22
by JNW
Image[/quote]

I'm a bit scared by those massive wires. Nothing in my setup is that gauge.

Re: Solar split charging

Posted: 31 Jul 2015, 10:33
by ninja.turtle007
That's a Sterling charger.

In another van I used to link the cigarette lighter sockets as 1 was from starter and the other from leisure. Just make sure there is a fuse in between.

Re: Solar split charging

Posted: 01 Aug 2015, 15:50
by gypo
ghost123uk wrote:
gypo wrote:Just been looking for a changeover switch, considering the cable is not that thick from the solar charger to the battery would a 30a switch do the job?

Simple answer = Yes :ok
Would this one do the job?
eBay 181783065255
Sorry I can't link it, phone won't let me :(
Cheers
G

Re: Solar split charging

Posted: 02 Aug 2015, 05:49
by ghost123uk
Yes G, that would be fine.