One for the auto electrical wizards
Submitted: Wednesday, May 21, 2003 at 16:10
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I imagine some of you may be tired of responding to questions about dual battery setups however I am adding what may be a twist to this one.
What I currently have:
- 6mm2 wire with inline 15amp fuse connected to main battery and running to cargo area of vehicle where it is connected to a Hella outlet.
- Into this outlet I plug a 24 amp hr Blue Apple "Outback" power supply. When the vehicle is running the Outback is charged. When the vehicle is stopped the Outback will be trickle charged by the main battery. (The tech from Blue Apple said this would be OK as long as I realise that over an extended time it would discharge the main battery.) The frigde and Versa light plug directly into the Outback.
The fridge will run between 16 and 24 hours on this setup and if I drive every day the system works very
well.
What I am thinking of doing:
- installing a redarc CP12v isolater and second HCD battery (cranking type). To the second battery I would connect the 15amp accessories wire.
Effectively this would give me 2 batteries under the bonnet joined in paralell and isolated by the Redarc and a 3rd deep cycle (Outback) battery in the rear off which the fridge and lights run.
My question is, can 3 batteries be run this way or will there be too much voltage drop to power the 3rd battery (with fridge etc). In other words will the 3rd battery be redundant and will the whole setup not work?
Any advice (in very simple language) would be appreciated.
Cheers
Reply By: Tuco69 - Wednesday, May 21, 2003 at 16:38
Wednesday, May 21, 2003 at 16:38
It will work.
Just a couple of things worth mentioning:
1. Hella sockets are only rated 8 Amp - which is OK for most 12V fridges, but not enough for a 2 or 3 way like a Chestcold. An 8 amp hella plug/socket will get hot with a chestcold running from it. Any heat means that there is resistance in the socket. You didn't mention your fridge type ...
2. An easy way to establish if your 6mm wire is heavy enough is to measure the voltage at the Hella socket while the "Outback" and fridge are pluged in and running. Compare the voltage with what is available at either the alternator or main/aux batteries.
What you plan doing is similar to what many do when they have a battery in a caravan or camper trailer, and wish to charge it from the vehicle. In these cases 6mm is usually not enough.
AnswerID:
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Follow Up By: Empty - Wednesday, May 21, 2003 at 16:53
Wednesday, May 21, 2003 at 16:53
Thanks Tuco
I have a Waeco 40 ltr. Older mechanical type. Pretty effecient.
Do you think the Outback will charge fully with the 6mm? Also as the Waeco has a low voltage cutout will it be sensing when the Outback 24 amp hr battery is depleted or will it always recognise power available in the second battery under the bonnet?
I can't help thinking that the Outback will be redundant.
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Follow Up By: Bob Y. - Qld - Monday, May 26, 2003 at 13:47
Monday, May 26, 2003 at 13:47
Empty,,
Pretty sure MERIT sockets are rated at 20 amps, they are available from Piranha in
Melbourne. A friend used to send them up here for me.
The merit sockets have a positive (no pun) fit, but are easy to pull apart.
Hooroo...
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