Thread: Dual battery system or Solar panel

Originally Posted by PhilipA

I have a dual battery controller from ABR which cuts at 12.4 volts which I personally feel is safer than 12.0 volts like Drivesafe's In my application.

I have already covered why my isolators would NOT be dangerous in your application, as you implied.

I'll put my 0.02 in (no fire added!).

My previous P38 ran an SC80 and I'll back that thing until the cows come home. My reasons are many and varied, but one that applies to most campers on this forum is the back-feed. I'd guess many here would have some sort of solar running to the aux battery, which I do, and in my case it worked two-fold by also charging the crank battery as well. Never an issue starting the (auto only) P38 after a week at camp.

My current P38 - decked out very well. Has a BCDC charger (redarc). Aux battery is unable to sustain running a smaller fridge than I used with previous P38 unless I have the solar plugged in. Case in point was just yesterday - parked at camp at midday, thought id leave the solar off until the next morning. My battery was dead flat by nightfall. On my SC80 setup on a summers day with my bigger fridge I'd get until midday the next day before I desperately needed the panels.

Cheers
Keithy

I should add to the above, the reason the SC80 setup was better then the BCDC setup is

A) The SC80 charged from the alternator and current to aux battery was much higher. BCDC chargers don't give high current charge to your battery in short drives (even though the battery was on a 240v Ctek charger before I left and the fridge was pre-chilled).

The extra AH capacity provided by the lower cutout voltage on the SC80 was enough to run the fridge overnight and half of the next day, once the solar is hooked up it maintains both batteries (provided they are still linked - easily sorted by starting the engine for a minute if they are not linked).

Cheers
Keithy

Originally Posted by Keithy P38

I should add to the above, the reason the SC80 setup was better then the BCDC setup is

A) The SC80 charged from the alternator and current to aux battery was much higher. BCDC chargers don't give high current charge to your battery in short drives (even though the battery was on a 240v Ctek charger before I left and the fridge was pre-chilled).

The extra AH capacity provided by the lower cutout voltage on the SC80 was enough to run the fridge overnight and half of the next day, once the solar is hooked up it maintains both batteries (provided they are still linked - easily sorted by starting the engine for a minute if they are not linked).

Cheers
Keithy

I think most DC-DC chargers operate at between 20 and 30 Amps, for example the Matson one I have in our camper operates at 20 Amps. However, a Traxide unit with the correct wiring can carry much more than that. My set up has heavy wiring with 60 Amp fuses at both ends, for example, but I've heard of people going higher than that.
So, more power equals faster charging.

I've managed to fit an 80Ah battery next to the turbo on a bulkhead mounted tray. Isolated using a Traxide USI-160. Been there since 2014 and so far no problems.

Which 80Ah battery fits there ?

Originally Posted by simonmelb

Which 80Ah battery fits there ?

This one Super Start Batteries > Products > Product List. it is actually marked as 80Ah on the battery.

Had to trim the under bonnet ribbing slightly, but the black sound proofing can stay in place. I'll get photos later.

EDIT Photos added.

Originally Posted by PhilipA

1 12 volts is <= 50% SOC, and the draw from ancilliaries like opening doors etc could reduce this further over a few days, after the batteries have separated. My fear on a D2 is that this could become marginal for starting as the ECU cuts off at AFAIK about 11.5 volts and the house battery will probably be that low anyway.. As one is "up the creek without a paddle with an auto with a flat battery" I prefer to be conservative.
Regards Philip A

FWIW IME.

if you have more than 10.5v the ECU will let you attempt a start, so long as the voltage stays over 8.5 it will keep trying, below 10.5V it shouldn't attempt to have a go however some will. Trying to start with under 11.5v showing prior to the attempt and you are going to get error codes, more with the auto but they should all be soft faults and should go away after 5 start events without the fault logging.