a question re dual battery setup
Submitted: Tuesday, Sep 02, 2008 at 14:50
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Jeelan
hi guys..
just want some advice on setting up a dual battery system.
i've recently changed both batteries in my rig from wet cell to AGM. the main battery is a 100ah/700CCA AGM (absorbed Power) and the aux batt is a 75ah/600CCA absorbed power battery.
the previous hook up worked fine but my aux was only a 55ah wet cell which was not really good for any extended stays.
Sooo,... what id like to ask about is as follows:
1) Can i swap functions of the batteries by making the 75ah AGM the Cranking batery? The factory battery is 620CCA. The guys at Absorbed Power reckon it would fine but i'm not sure. I've got a 3.2L Diesel (Mitsu Pajero NS Auto)
2) in any event, the battery posts on these new AGMs are in a different position to the original batteries so is there any easy way of extending the battery cables, particularly for the main battery?
3) When running earthing the cable from the (-) terminal of the battery - can i run the setup so that both batteries are using the 1 earth point ie run a cable from the (-) of the Aux battery to the (-) of the main battery which is then earthed through the normal factory setup? Or am i better off earthing each battery individually?
For your info, i've got a 3.2L diesel Pajero Auto
cheers
Jeelan
Reply By: Robin Miller - Tuesday, Sep 02, 2008 at 15:13
Tuesday, Sep 02, 2008 at 15:13
Hi Jeelan
1/ Should be ok , I would also make sure you
could fit either batteries into crank position as an emergency.
2/ You can buy little extension battery straps and just bolt
to old one and insulate, but I'd get a new longer one
3/ You can but I'd always go for two cables and not rely on one earth point connection.
The start battery should have best earth if you have to choose.
AnswerID:
323453
Reply By: Ted G - Tuesday, Sep 02, 2008 at 16:13
Tuesday, Sep 02, 2008 at 16:13
Jeelan
I have a Prado that is set up with a solenoid and a button on the dash if the main battery is flat then you can press the button which brings the second battery to start.
It can only be used for starting not running.
There is a marine three way manual switch for power to the rear that connects either or both batteries for aux power.
hope this helps
Ted
AnswerID:
323458
Reply By: Jeelan - Tuesday, Sep 02, 2008 at 16:20
Tuesday, Sep 02, 2008 at 16:20
hi guys
thanks for the responses.
i should have mentioned that i am running the dual battery system with a Project electronic isolator so i can do an emergency crank from the aux battery etc.
my questions were geared more towards knowing about extending the battery lead and also sharing the earth point.
thanks again
cheers
Jeelan
AnswerID:
323462
Reply By: Mainey (wa) - Tuesday, Sep 02, 2008 at 18:03
Tuesday, Sep 02, 2008 at 18:03
(1) yes, if you can notice any (negative) difference between the 600cca and the (OE) 620cca I will be very surprised
(2) The simplest and safest way is to replace the short cables with a new cable, you may be able to simply replace the shortest cables with the longer ones and then you will only have to buy one new set ??
(look at your local wreckers for cables)
(3) I would earth each battery at the closest strongest earth bolt available, if that is at the same bolt so be it.
Look at any large truck and you will see the two negative cables both connected to the same earth bolt, but the two batteries are side by side too.
Mainey . . .
AnswerID:
323483