Dual battery charger install help

[Robsrod 58]

Hi,
I wonder if anyone could help. I wan't to install a dual battery setup comprising of 5 x 20ah deep cycle agm batteries in parallel in a nice little spot behind my drawer setup, to power my fridge and a few lights. My question is should i go to the trouble of doing a full battery isolator setup, or just use a DC to DC charger out of the provided power socket in the rear to keep cost and hassle down.
Advice appreciated.

Rob

[gregie84]

Hi Rob,
I have a 2nd battery in my p38, 120ah AGM in rear load space...
I utilised the Piranha DBE140 near the main battery and a cable snuck in a gromet under the rear right seat when I set mine up...
Only been on 1 trip but beer was as cold as it needed to be the whole time.

[RoverHse]

Hi,

I have the National Luna unit installed charging my 120Ah in the rear load space.

The system kicks in to charge the deep cycle after a few seconds and isolates it when the ignition is switched off.

The override link system on the remote battery monitor has saved me on a few occassions when I've left the headlights on, and I was able to link the back battery at a push of a button.

The remote monitor indicates deep cycle and cranking battery charge levels

[Benz]

If your worried about cost there is nothing stopping you from putting a simple relay in there connecting the main and aux batteries which can be switched by the ignition.

still might be a bit of a hassle but at least you know they can be charged quickly

[Robsrod 58]

Thanks for the replies. I've just completed my setup in the boot, took me ages but I'm pretty happy with the results and it is open to mods at a latter date. Basically a 100a/h AGM battery via a redarc 6amp charger triggered by the aux output. It will only be used for fridge and led lights, I hope its enough!!

Rob

[Hoges]

very neat job!:BigThumb:

[ytt105]

Excellent work, but how do you get the spare out?

[ytt105]

I've got a second battery next to the LPG tank, instead of the spare wheel, and use a simple solenoid to do the change over.

However, instead of switching via the ignition, which means you are actually starting off both batteries, mine is switched from the 'exciter?' wire on the alternator.

This isn't powered until the car has started.

I've had 1 classic and 2 P38s wired this way and they have been faultless.

PS. On 1 classic it wouldn't work that way, don't know why, so I had to wire it off the LPG changeover solenoid which also didn't operate until after the car started.

[Robsrod 58]

Spare goes on roof as LPG tank is in his hole. The left hand drawer comes out revealing the jack, some spares and access to the CD stacker. The charger is off the aux, probably not a perfect solution but it will do for the time being.

Rob

[glenhendry]

You want as close to 14.4v chargin a 12v battery as possible. If the voltage drop on your aux plug is significant (because its a long run and a small wire), you can get a small automotive step up transformer to make sure the battery is kept at optimum.

[Robsrod 58]

You want as close to 14.4v chargin a 12v battery as possible. If the voltage drop on your aux plug is significant (because its a long run and a small wire), you can get a small automotive step up transformer to make sure the battery is kept at optimum.
What I meant to say was the trigger for the charger is off the aux, not the charge cable itself. It is 10sqmm cable off the battery.

Rob