Battery dramas?

Burnsy

Well-Known Member
Mar 26, 2012
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Newcastle
Hi all,

Just got back from a 3 week holiday, had a great time but thats another story. I have a redarc dual battery system in my Pajero with a 100 amp deep cycle as the aux battery, I also run a waeco in the back (from aux) and power the 186L fridge/freezer in the van while travelling (draws 22 amps) On 2 occations while away i flattened my starter battery (2 year old factory 10") while playing cd's and each time only got about 1/2 hr playing, so maybe time for a new one which i can live with. The waeco will be lucky to run for a day off the aux 100 amp battery which i think is not right so i'm thinking it's a charge problem and the talk on here about "smart alternators" has got me thinking.

I checked the charge output from alternator and it was about 13.4V and also thought that was a bit low, this was when engine was running before i connected my compressor to pump up tyres. As i was pumping up tyres i noticed the compressor suddenly increased in rpm so i checked the voltage input again to find it increased to about 14.4V, so when it sensed an extra load it increased output so it seems to be doing what it is suppost to but i still don't think both my batteries are charging fully. Another thing i have noticed is when the van is plugged into car with 12 pin plug running fridge i hear a noise like a relay clicking in and out from the intake vent on van, this is with engine running, would this indicate not enough voltage at the fridge end? I have not checked voltage there yet, however when we return from a trip all is still cold and frozen.

I was going to get a auto sparky to check over the system but seem to think either an alternator upgrade or possibly a dc-dc charger in tug?
One of my mates runs a ARB fridge (same compressor as waeco) in his Prado on dual batt with no dramas using isolator like me and no dc-dc.

Appreciate any advice or opinions providing it's not about buying a Prado...no offence. :D

Cheers.
 

Burnsy

Well-Known Member
Mar 26, 2012
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Newcastle
One thing I didn't mention is the aux batt has a state of charge indicator on it which is always black indicating it needs charging.....don't know how accurate this is?
 

Feldty

Member
May 31, 2012
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Wangaratta, Vic
Hi Burnsy,

I have had a little experience with this issue of late with my Navara and Smart Alternator.
(disclaimer, I am no expert and am happy to stand corrected)
I had my setup exactly like yours and my dual battery was never fully charged. It in fact sulpherized my AGM and probably halved its life according to a local Auto Electrician. I needed to put it on a rejuvenation charger to get a decent capacity back which touch wood seems to have worked. Deep Cycle Batteries do not like to be charged at funny voltages and also like to be fully charged most of the time.
The really hard thing for me to understand was that every time I pulled over and had the vehicle idling, it would be charging the dual battery at 13.4v ???? it was only when I checked it while driving that I noticed a drop back to 12.2v. The local Nissan dealer did not even have any specs on the alternator etc that could help me with the problem.
If you have a smart alternator (I think you do) then your dual battery would be lucky to be charged to 50% by my experience if it charges similar to my Nav. This will kill your dual battery in a fairly short time.
While the coin was frustrating, I am very happy with my setup and in particular the DC-DC charger. It simply take the guess work out of it. You need to ensure that you purchase a Low Voltage DC-DC charger, or you will find that the controller will fail to charge your battery once the alternator backs off. The low voltage units work on an ignition wire rather than relying on a voltage sensor to determine when the vehicle / alternator is running.
Finally, I have been told that even the old fashioned alternator and dual battery setups could only charge a battery to 80% of its capacity due to issues that I do not understand, yet a DC-DC charger can charge them to 100%, so if capacity is the main issue for you, then the DC-DC charger may be the better option over an alternator upgrade.

Hope this helps a little.

PS. a link to a thread that may help.

http://www.expandasdownunder.com/showthread.php/1658-2011-D40-Navara-2-5-Dual-battery-system

Kev
 

crackacoldie

Well-Known Member
Jan 8, 2013
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Newcastle NSW
Have been advised that with the smart alternator in the Ranger, the only thing I can use is dc-dc charger, that a normal isolator will see both batteries fail.

Cheers

Craig
 

Burnsy

Well-Known Member
Mar 26, 2012
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Newcastle
Thanks guys, looks like I'm ripping out the redarc isolator and installing a redarc 1220!

Cheers.
 

Feldty

Member
May 31, 2012
129
7
18
Wangaratta, Vic
Redarc are very helpful and actually answer there phone in Australia with a technician. If you give them a call, they will help advise you on the unit that will best suit your application as well as advise on placement and wire sizes etc. Well worth a contact if you are going down the BCDC Route. The 25amp and 40amp units also have a built in MPPT Solar regulator.

Kev
 
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Hubble80

Well-Known Member
Nov 22, 2012
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Moranbah, QLD
Burnsy, I would suggest checking voltages on your aux battery with the vehicle off and when running. When the deep cycle is 100% you should see around 12.7V. Depending on your alternator and engine temp you should see between 13.4 and 14.2V when your VSR is sending charge to your deep cycle.

If your starting battery is all but dead, maybe your VSR isn't closing allowing your aux battery to charge. I would put your two batteries onto a GOOD smart charger to let them have a good charge and get to 100%. Remember to disconnect the negative from the VSR so you only charge one battery at a time and the VSR doesn't charge.

PS Also sheck any fuses you have in the system!!!
 
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