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5th March 2014, 08:21 PM
#1
Running two different AH batteries together?
I'm going to start the wiring of adding a second battery to my camper soon. Do I need to get the second battery that of the same AH rating of the battery that I already have? What will happen say if I get a 130AH battery and my first battery is 105AH?
Cheers.
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5th March 2014 08:21 PM
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5th March 2014, 08:51 PM
#2
Patrol Guru
My understanding is that they should be as close as possible ie same battery model etc Having different capacities causes problems.
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2008 GU 3.0 CRD Auto - Life's too short to eat bad food.
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5th March 2014, 08:57 PM
#3
Originally Posted by
Drew
My understanding is that they should be as close as possible ie same battery model etc Having different capacities causes problems.
Thats what i am thinking. The lower AH battery will only limit the higher AH batteries capacity/ ability...
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5th March 2014, 09:03 PM
#4
Administrator
I think I asked this same question a while back and ET mentioned they should be the same otherwise they won't charge properly. Larger ah wont get full charge?
Assuming you'll be running them both from a single management system.
Hopefully someone can explain in more depth.
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5th March 2014, 09:06 PM
#5
Travelling Podologist
Originally Posted by
mudski
What will happen say if I get a 130AH battery and my first battery is 105AH?
Cheers.
No problem with different capacities of the same type of battery.
"There is no problem parallel charging similar type batteries of the same voltage but of widely different capacities. They look after themselves. 'Each draws a proportionate share of the available charge, and all reach about the same level of charge at roughly the same time,'(Ample Power Company 1990). They discharge in much the same way.”
Taken from http://www.caravanandmotorhomebooks....batteries.html
Note the word similar - this refers to batteries with similar charging requirements.
I have a set up with two N70 size (D31 - 75Ah) Yellow Top Optimas paralleled to two 90Ah Fullrivers without problem. The Optimas replaced ‘wet’ starter batteries which I got 5 years out of. The Optimas are now over two years old & the Fullrivers are over 8 years old, system is still working well.
Last edited by Cuppa; 5th March 2014 at 09:15 PM.
2006 4.2TDi ex-Telstra Remote area Camper. 425w roof mounted solar, 360Ah Aux batts, BCDC1240, Onboard hot & cold pressurised & filtered water, (25 litre hot water calorifier), ARB fridge, ARB freezer, Built in kitchen, heaps of easy access storage, 240v, 3” Genie exhaust + dynotune, 2” lift, 3900kg GVM upgrade, second glovebox, ROH Blaktrak steel wheels, Bridgestone D697's (now Toyo RT's), Redarc gauges/pillarpod, Hema HX-1, Icom 450 CB, dual rear view cameras, Onboard 30amp Victron mains charger, second glovebox, dual seat conversion, TPMS, Boss PX7 onboard air with 9 litre tank, 350w inverter, Steel bullbar, Harrop Eaton diff lock (front), Warn winch, Snorkel, Dual spares , 160 litre water tank, 180 litre fuel in two tanks (approx 1200km range) 2010 Tvan Tanami. (incl another 70 litre water tank) with matching wheels/tyres (& 3rd spare)
A Nomadic Life (Blog)
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The Following 2 Users Say Thank You to Cuppa For This Useful Post:
MudRunnerTD (5th March 2014), mudski (5th March 2014)
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5th March 2014, 09:07 PM
#6
Patrol Guru
Wont they be different anyway when one is a starting battery and the other is a deep cycle battery?
2010 TB4.8, 5 speed auto TI Wagon, Beaudesert ceramic coated Extractors and 2 1/2 inch exhaust, 3inch lift, BP-51 shocks, Black hawk radius arms and drop boxes, Road Runner Offroad billet alloy draglink, Boss air bags, 295/70/17 KM3s, Redarc Gauges, GME XRS UHF, Autometre fuel gauge, Alpine head unit with offroad maps, Carbon winch, Opposite lock bull bar, Light Force Strikers, Safari Snorkel, Duel long range tanks, work in progress.
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5th March 2014, 09:15 PM
#7
Patrol Guru
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2008 GU 3.0 CRD Auto - Life's too short to eat bad food.
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5th March 2014, 09:31 PM
#8
Travelling Podologist
Originally Posted by
paulyg
Wont they be different anyway when one is a starting battery and the other is a deep cycle battery?
As mentioned I had 2 wet starters (24v) paralleled with two Fullriver AGMs (deep cycles), the Fullrivers are still going strong & the wet starters lasted for over 5 years (They would probably have lasted longer if I hadn’t neglected to top them up & inadvertanly ran them dry). 5 years for starter batteries is pretty good so clearly the paralleling/charging arrangement did them no harm. You can read widely differing opinions on the net varying between ‘it’s ok’ to ‘under no circumstances do it’. My direct experience suggests ‘it’s ok’. The one issue I had with this set up, is that the wet batteries had a faster self discharge rate than the AGM’s, & if left for a few days without being charged would pull the AGMs down to the VSR cut off voltage. In practice this was not an issue as when the vehicle was in use the ‘extra’ capacity provided by the starters was used each night, & when the vehicle was not in use they were connected to a CTEK charger in ‘supply mode’ preventing any drain.
2006 4.2TDi ex-Telstra Remote area Camper. 425w roof mounted solar, 360Ah Aux batts, BCDC1240, Onboard hot & cold pressurised & filtered water, (25 litre hot water calorifier), ARB fridge, ARB freezer, Built in kitchen, heaps of easy access storage, 240v, 3” Genie exhaust + dynotune, 2” lift, 3900kg GVM upgrade, second glovebox, ROH Blaktrak steel wheels, Bridgestone D697's (now Toyo RT's), Redarc gauges/pillarpod, Hema HX-1, Icom 450 CB, dual rear view cameras, Onboard 30amp Victron mains charger, second glovebox, dual seat conversion, TPMS, Boss PX7 onboard air with 9 litre tank, 350w inverter, Steel bullbar, Harrop Eaton diff lock (front), Warn winch, Snorkel, Dual spares , 160 litre water tank, 180 litre fuel in two tanks (approx 1200km range) 2010 Tvan Tanami. (incl another 70 litre water tank) with matching wheels/tyres (& 3rd spare)
A Nomadic Life (Blog)
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The Following User Says Thank You to Cuppa For This Useful Post:
BigRAWesty (5th March 2014)
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5th March 2014, 09:34 PM
#9
Thanks cuppa. I was kinda hoping you'd pop your head in...As you da' man.
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The Following User Says Thank You to mudski For This Useful Post:
BigRAWesty (5th March 2014)
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21st August 2014, 06:15 PM
#10
just a quick note . I was told when joining batteries to have positive on one battery and negative on the other for charging as this creates the vision of one large battery
2012 gu6 dx canopy factory snorkel and bull bar new bfg all terrain, bellow style air bags, uhf, centre console, tinted windows, projecta 150 amp dual battery set up ipf super rally spotties, nitro oil shocks
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