Paralleling Batteries?? An important and interesting note!!

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11-23-2009, 07:55 PM

Folk128

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Paralleling Batteries?? An important and interesting note!!

So I decided to get a little crazy with some extra power in my trunk. I thought I had everything covered and then someone made a very good comment on how to properly parallel batteries. Im not going to bother to try and explain it but the picture I attached should be clear enough. The example in the picture is for a 120VDC system but the principle is the same.

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Paralleling Batteries?? An important and interesting note!!-how_to_wire_2_battery_banks_in_parallel.jpg

11-24-2009, 03:26 PM

ross_freier

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yup, when is wired that way it reduces the internal resistence of the batteries

11-24-2009, 08:22 PM

JohnVroom

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Quote:

Originally Posted by Folk128

if it was a good comment what was it, and if your point is a good one why not state what the heck it is... dont expect that image to answer any questions as it only raises questions
Why would ANYONE post a 120VDC system picture and expect to detract meaning from it in a 12 volt world

Quote:

Originally Posted by ross_freier

yup, when is wired that way it reduces the internal resistence of the batteries

how could any wiring change the internal resistance of a battery? the wiring could change the systems resistance... it could do any one of a number of things but it wont change the internal resistance

11-25-2009, 12:31 AM

Soundigital

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This is a good tip when you are wiring for the amps too.

11-25-2009, 05:07 AM

ross_freier

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i don't kno how i'm just repeating what i was told. do u ever ask how does wiring subs in parallel lower the impedence of the sub? its the same only diffence is u have the + and - on opposite ends of the battery bank

11-25-2009, 05:35 AM

JohnVroom

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Quote:

Originally Posted by ross_freier

it doesn't lower the subs impedance it lowers the SYSTEM impedance.

11-25-2009, 05:50 AM

JohnVroom

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the difference between the two illustrations is minimal in fact only one wire is physically located differently and electrically they are identical

I am not saying you are wrong as I am not following your point (though you have not actually said what the difference is so I am asking, why one is better than another). I have seen several wire their systems exotic batteries kind of odd... and I am certain if wired incorrectly one battery will do more work than the others even when in parallel. Personally I would always use bus bars and I would tap power for the amp in the middle of the bank (which I think is the point of all this).

11-25-2009, 07:49 AM

Soundigital

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This depends a lot on the cable thickness, a 0.2V difference on charging would make a substantial charge difference on the top rows.

11-25-2009, 02:22 PM

JohnVroom

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Quote:

Originally Posted by muriloalvares

This depends a lot on the cable thickness, a 0.2V difference on charging would make a substantial charge difference on the top rows.

I agree to a point, the battery layout should have equal lengths of copper from each battery to a common positive buss bar (and the corresponding - buss bar) and as many of the batteries close to the load (amplifier) and alternator/ charging point. The original image on this thread is a 120VAC system that has little to do with our hobby.