How to hook up two Batteries

[bfrank]

So I have them wired in parallel and all seems to be good.

[ajholt7]

You will be fine. I bet you don't have any problems.

[bfrank]

Yea I agree, didnt mean to start a huge debate!

[Iwndr]

glad it worked out B!

[talltigeguy]

I do think it very important to have the same type, size and age of battery hooked up if you just put them in parallel. Putting 2different types of batteries may cause one to be chronically undercharged and one to be chronically overcharged...leading to premature failure of both of them.

[chpthril]

For all that have been reading this thread with much interest, I have just tested the "2 batteries wired in parallel will not charge" theory noted on page one.

To take a page from Adam and Jamie............This Myth is BUSTED

I've got pics and data to sort out and post later.

[talltigeguy]

For all that have been reading this thread with much interest, I have just tested the "2 batteries wired in parallel will not charge" theory noted on page one.

To take a page from Adam and Jamie............This Myth is BUSTED

I've got pics and data to sort out and post later.

I have been charging two batteries together for a long time...I think to call this a mythbusting opportunity is exaggerating a bit. 10th grade Physics class would teach us the same thing. It is the reason your Perko switch has a 'both' on it.

I too have put parallel batteries on a charger and also checked voltages before, during, after, and long after to see what happens. No need for data to convince me.

[chpthril]

Will 2 Batteries Wired Parallel Charge?

if you wire pos to pos and neg to neg, your alternator will not charge both

Some say no, so I wanted to find out.

Test: To see what to batteries wired in parallel would do as far as being charged, as well as if they are combined while being at a different state of charge.

Equipment:
Interstate 24M-XDH Lead-Acid Wet-Cell Cranking battery
Interstate SRM-24 Lead-Acid Wet-Cell Deep-Cycle battery
Schumacker 2/10/50 Shop Charger set on a 12V/10A charge
Fluke-88 DVOM
Attwood Tsunami T1200 pump.

Setup:
Charger hooked to Cranking battery and Deep-cycle wired in parallel by 6GA cables with alligator clamps. This made it easy to disconnect in order to isolate the two batteries from each other. I went with a typical lead-acid wet-cell marine cranking and marine deep-cycle, as these make up a very typical boat setup.

1) Cranking battery static charge


2) Deep-Cycle static charge


3) Cranking on 10A charge for 30 minutes


4) Starting after 30 minute 10A charge


5) Deep-cycle after 5A load for 30 minutes.


6) Deep-Cycle after wired in parallel with cranking battery


7) Cranking battery after wired in parallel with Deep-cycle


8) Both after being wired in parallel for 5 minutes


9) Both wired in parallel with 10A charge. It took >60 seconds for the two batteries to equalize to 14.10V. Reading taken on the Deep-cycle with charger connected to the cranking.


My conclusion, which I felt from the beginning, is that when two batteries are wired together, either in series or parallel, they will act as one large battery.

I started with 2 batteries that where only .02V different. I charged one for 30 minutes with a 10A charge and on the other, I placed a 5A load for the same 30 minutes. Once I combined the two batteries, each with a different voltage level/state of charge, it only took 5 minutes for the two to equalize.

After charging the cranking up again and loading the deep-cycle down. I combined them and then turned the charger on. It took less then 60 seconds for the two to equalize. This voltage level was higher then both of the batteries' static charge before the charger was turned on. This indicates that two batteries wired in parallel will be charged by the source.

Blue sea does not list a voltage drop for the 7610, so I presume it is 0V's. So, if this setup was done in a boat/car with an ACR, then I have no doubt that the same results would be experienced.

[adamsjstt]

Some say no, so I wanted to find out.

Test: To see what to batteries wired in parallel would do as far as being charged, as well as if they are combined while being at a different state of charge.

Equipment:
Interstate 24M-XDH Lead-Acid Wet-Cell Cranking battery
Interstate SRM-24 Lead-Acid Wet-Cell Deep-Cycle battery
Schumacker 2/10/50 Shop Charger set on a 12V/10A charge
Fluke-88 DVOM
Attwood Tsunami T1200 pump.

Setup:
Charger hooked to Cranking battery and Deep-cycle wired in parallel by 6GA cables with alligator clamps. This made it easy to disconnect in order to isolate the two batteries from each other. I went with a typical lead-acid wet-cell marine cranking and marine deep-cycle, as these make up a very typical boat setup.

1) Cranking battery static charge


2) Deep-Cycle static charge


3) Cranking on 10A charge for 30 minutes


4) Starting after 30 minute 10A charge


5) Deep-cycle after 5A load for 30 minutes.


6) Deep-Cycle after wired in parallel with cranking battery


7) Cranking battery after wired in parallel with Deep-cycle


8) Both after being wired in parallel for 5 minutes


9) Both wired in parallel with 10A charge. It took >60 seconds for the two batteries to equalize to 14.10V. Reading taken on the Deep-cycle with charger connected to the cranking.


My conclusion, which I felt from the beginning, is that when two batteries are wired together, either in series or parallel, they will act as one large battery.
I started with 2 batteries that where only .02V different. I charged one for 30 minutes with a 10A charge and on the other, I placed a 5A load for the same 30 minutes. Once I combined the two batteries, each with a different voltage level/state of charge, it only took 5 minutes for the two to equalize.

After charging the cranking up again and loading the deep-cycle down. I combined them and then turned the charger on. It took less then 60 seconds for the two to equalize. This voltage level was higher then both of the batteries' static charge before the charger was turned on. This indicates that two batteries wired in parallel will be charged by the source.

Blue sea does not list a voltage drop for the 7610, so I presume it is 0V's. So, if this setup was done in a boat/car with an ACR, then I have no doubt that the same results would be experienced.

I will never call you out..lol

[talltigeguy]

I will never call you out..lol

As others have said...CHP is my HOME BOY!!!!! Hahaha.

Well done, Chp.

[Ewok]

Well done, very informative for someone without EE experience.