Dual battery matters
Submitted: Sunday, Jan 22, 2017 at 13:38
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steamfire01
Hi Folks
After seven years and two under bonnet dual batteries (one deep cycle and one cranking) I have decided to move my next dual battery to the rear of my 2012 Patrol.
The seven years included an eight month lap and plenty of off road KM including some time on the Gibb RR.
I'm sure that the principal reason for the demise of the two batteries in that time is the under hood heat load in the Patrol, no doubt assisted by the nearness of the turbo.
My question is what is the smallest gauge wire that I should consider running from the terminated ends of the existing dual battery system to the new dual battery position next to the fridge in the rear.
By the way, the second battery is only used for my fridge and some very occasional lighting so there's not a major current draw involved.
All comments appreciated.
Regards
TJ
Reply By: KiwiAngler - Sunday, Jan 22, 2017 at 21:31
Sunday, Jan 22, 2017 at 21:31
I noticed similar trend with aux battery in my 2004 Patrol, especially when travelling through NT and FNQ
My "fix" has been to cut an additional scoop hole in the bonnet above the aux battery - seems to be doing the job as current battery has lasted longer than any previous battery installed prior to modification.
Air temp where i am currently during day is 35-40c hate to think what it is under bonnett whilst driving and towing my camper - I also pop the bonnet as soon as i make
camp each night to help get the heat out whilst sitting still
AnswerID:
607891
Reply By: Sigmund - Monday, Jan 23, 2017 at 07:39
Monday, Jan 23, 2017 at 07:39
My theory now about how these basic systems perform is, if measured, it's all between 50% (or less) and 70% charged. The alternator doesn't have the volts or the time or both to get to 100%.
Batteries take around 14.7 V for a bulk charge but how many alternators can produce it? The best my standard unit can do 14.1 V at the input side to the isolator (and 13.7 at the batteries).
Even if it could hit the right voltage, it would take over 30 hours to charge a depleted battery according to the 240 V charger manual (at 15 amps).
Anyway, next week I'll have a different theory!
AnswerID:
607895
Reply By: Sand Man (SA) - Monday, Jan 23, 2017 at 07:49
Monday, Jan 23, 2017 at 07:49
If you are moving your auxiliary battery to the rear of your patrol, besides wire size, you need to consider how you will secure your battery.
Have you considered a "total solution" where you don't have to worry about all the technical stuff. Just purchase a complete dual battery system.
ABR sidewinder have a good product with their "Flyer" battery box which comes complete with cable and available with or without an isolator. You will need an isolator of some kind, be it a voltage sensitive relay as available in the higher priced Flyer, or a dc-dc charger of some kind which will improve battery health by providing a multi-stage charging process.
No financial interest with Derek or ABR Sidewinder, just a satisfied user.
A practical accessory available for the Flyer is a mounting cradle which enables secure fixing while enabling easy removal when necessary.
Sidewinder Flyer
AnswerID:
607896
Follow Up By: Sigmund - Monday, Jan 23, 2017 at 09:31
Monday, Jan 23, 2017 at 09:31
Yeah, in that vein I'd also look at the Engel Smart Battery Box 2 - close to an all-in-one solution. Comes with a 12v charger, copes with Lithium, and has Engel, 240v, 12v and USB charging outlets. The specs sound like it has a VSR built-in but Engel say it's not for charging but for running appliances.
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Follow Up By: steamfire01 - Monday, Jan 23, 2017 at 12:43
Monday, Jan 23, 2017 at 12:43
Thanks Sand Man;
I have a full dual battery setup, using Redarc isolator and appropriate wiring serving the under bonnet setup. It's the heat that's killing the batteries.
I'll certainly consider the Sidewinder for my next vehicle.
Regards
TJ
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