# simple battery question.....



## ww321q (Mar 28, 2008)

batteries in series (hooked + to - ) adds voltage . Batteries in parallel (hooked + to + and - to - ) adds amperage . I am actually doing series/parallel . 10 parallel sets hooked in series . 12 v 85 ah batteries . That would give me a battery pack of 120 volts 170ah . 20 batteries total. J.W.


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## Little Rhody (Jun 17, 2008)

I completely understand parallel, and series. I just was unsure if the total amp a/h multiplied when run in series. This has answered my question. 

Im sure I will have many more, in the near future, as I am building an ev motorcycle. 

LR


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## e_canuck (May 8, 2008)

Hi all.

J.W. I have a questio or two.

I understand you have one string of 10 pairs. Or do you have two strings of 10?
Both systems would addup to 120 volts 170ah, no?

Could you elaborate the advantages and disadvantages?
Ease/ difficulty of connections. Better Peukert perhaps?

I was thinking of starting with one string of batteries then after vehicle trials to upgrade the pack by doubling it. Would the usage of the batteries make them to dissimilar?

Thank you for the inputs.

DP


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## ww321q (Mar 28, 2008)

I have 10 12 volt chargers I got from ebay cheap. I'll hook the batteries in 2 battery sets and 1 charger . Then hook them in a 10 battery string . The best way to charge batteries is 1 cell per charger . That way each battery gets the charge it needs . A 6 cell 12 volt is the best I can do but. I would need 20 chargers . By paralleling 2 to each charger I can keep the pack in balance a little better and still not have 20 chargers . I don't think charging in a long string is good idea with out a battery management system .
http://www.youtube.com/watch?v=5umhV_84VJo
J.W.


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## ww321q (Mar 28, 2008)

Actually hooking up batteries in parallel is good . If you had a string of batteries 1 bad one kills the hole string . By paralleling 2 batteries you can match a strong battery with a weak one and the strong battery will help carry the weaker one . With 1 string of batteries and 1 weak battery you could parallel a second weak battery with the 1 bad one making it ok . A way to use used mismatched batteries and still get some thing out . Like I said " A string of batteries is only as good as the weakest one " 2 batteries in parallel , the pack sees that as 1 bigger (higher ah) battery . J.W.


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## e_canuck (May 8, 2008)

Gotcha

Thanks J.W.

So much to know. So much to know.


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## Scorpyon (Sep 11, 2013)

I have 4 series connected 12v 18a/h gel cells connected on my e-bike...can i add a single 12v lead acid battery in parallel to one of the batteries to boost my current output? my gels are becoming weak and i have a car battery available?


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## dougingraham (Jul 26, 2011)

Scorpyon said:


> I have 4 series connected 12v 18a/h gel cells connected on my e-bike...can i add a single 12v lead acid battery in parallel to one of the batteries to boost my current output? my gels are becoming weak and i have a car battery available?


You can parallel the 12v lead acid battery with one of the 12V gel cells but it will only prop up that one gel cell. It won't fix anything and could cause other issues with charging.

Consider swapping out the four 12v gel cells with 16 40ah LiFePO4. They will take a similar volume to the gel cells and weigh a little less with effectively 8 times the usable capacity.

Best Wishes!


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## Ziggythewiz (May 16, 2010)

that would boost the current from the one buddy pair. You would still be limited by the test.


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