Deep cycle battery setup

jono2912, May 4, 12:47am
Hey guys. thinking of setting up van with a couple deep cycle batteries to power an inverter.

My idea was to set them up in parallel with the 'engine' battery with a few relays in between, so it would only use the deep cycle battery power while vehicle is off, but would still charge when vehicle is running. As well as maybe a alternator with a larger amp output, just to speed up the charging process.

Anyone got any other ideas! Are there packages you could buy, or just easier ways to do it!

intrade, May 4, 1:15am
solar cell on roof to charge the battery when its parked.

tmenz, May 4, 1:26am
You need a diode battery isolator to allow the alternator to charge both batteries but each can be drained separately.

bantam3, May 4, 4:17am
U need a smart charger mounted inside van. Just plug into mains at nite to charge batterys. 6volt dc are better than 12. What are u powering!:

jono2912, May 4, 4:18am

So simple.

Thanks for that!

jono2912, May 4, 4:19am
Small tools. (All under 600w) anything bigger goes on the gen.

Also used for holidays away (freedom camping)

bigfatmat1, May 4, 4:36am
I wouldn't use a diode use a vsr . A larger alternator will do squat to charging of the batteries. Would only help power inverter when engine running

jono2912, May 4, 5:20am
How would you go about charging them!

bigfatmat1, May 4, 5:31am
Vsr.maybe if ya need them charged quicker dc to dc charger smart charger at night solar panels take ya pick. depends on ya budget really

canuk73, May 4, 10:57am
VSR (voltage sensitive relay). You would connect one terminal to your alternator, one to your main battery, another to your house(deep cycle) battery and the last terminal is just an earth.

The VSR will first charge the main battery and when its fully charged, it will automatically switch and charge your house battery.It would not allow your house battery to drain your main battery but there is an option where you can jump your main battery from your house battery with a flick of a switch.

I would suggest you do some research on deep cycle batteries, maybe google your battery model and try to find out what charge rate it requires as they do require longer deeper charging than a normal lead acid battery before you invest in solar panels.

clark20, May 4, 11:06am

richms, May 4, 12:30pm
Yeah, you need the relay. If you just parallel them once you have started as a friend tried to do, you end up with a flat starting battery as it dumps what it has into the flat deep cycles and then the alternator cant really do anything to get them all back to a decent level in a short journey. The proper voltage switching one will cut the deep cycles in and out as the engine is able to charge them, and disconnect them when you are idling so would be a burden on the starting battery.

huffpuff01, May 4, 12:41pm

bigfatmat1, May 4, 7:15pm
slightly incorrect a vsr connects to main batt and house batt only not alt. also it doesnt charge one batt then the other. It joins the two batteries together once the voltage is a 13.7 disconnects them at 12.8.

aslo rule of thumb for charging on a smart charger rate the charger to %10 of the amp hour minimum.

canuk73, May 4, 9:20pm
Different type VSR mate.
And you above comment is correct regarding the newer VSR which seems to be the only one now available.

bigfatmat1, May 5, 12:29am
hella, bep and projecta vsr only connect to batt and and house batt.

hella and bep one projector

still available both of these and since a alternator nor vsr could tell if ya battery is fully chargedI find it highly unlikely they would work in the way you describe they simply sense terminal voltage. which equates to is the drain more than the alternator is putting out.

If you could post a link to your 'newer' type vsr I am curious