battery theory question

glennster

Well-known Member
so the coffee clutch discussion here this morning was batteries. say you have something like an electric golf cart that ran on 24v dc. you have 3 identical car batteries, 500 cca each 12v and you wanted to put all three in the cart. you wire 2 in parallel pos to pos, neg to neg, and then wire the 3rd bat in series to get 24v. would it work? would you have the amp hours from each battery available? any downsides?
heres the diagram
+ + -.......to ground on cart
- - +.......to plus on cart
general consensus was that it should work, should run a little longer than just 2 12v in series.
 
Glennster YOU ALREADY KNOW THIS I BET!!!!!!!!

YOUR QUESTIONS: would it work?

ANSWER Sure it will "work" you have 24 volts

YOUR QUESTION: would you have the amp hours from each battery available?

ANSWER NOOOOOOOOOOOOOOOOOOOOOOOOOOO

Amp Hours is additive if in paralell NOT if in series. The amp hours you would end up with is basically (subject to other variables of course, never say never) that of the lowest of: Those two 12/s in paralell (which net is the sum of BOTH those batteries Amp Hrs) orrrrrrrr that single 12, and assuming the single 12 is surely less then two 12's in paralell (cuz their amp hrs adds) YOU END UP WITH THE AMP HRS THAT SINGLE 12 ALONE HAS

YOUR QUESTION: any downsides?

ANSWER: YESSSSSSSSSSSSSSSS

When you start mixin n matchin and summing up battery combinations, YOU want them IDENTICAL is size and type and brand and CCA and age and Amp Hrs and if not the weak suck off the strong and thats a very very wicked thing........

Okay got it????????????

In series VOLTAGE adds,,,,,,,,,but NOT CCA or Amp Hrs

If two same voltage in paralell, voltage stays same, but CCA and Amp Hrs is additive

John T
 
Yes it would work but your not likely to get any more out of it then you would with just 2 12 volt batteries because the single battery will run down faster then the pair so your still not going to get any more out because the single one will discharge faster then the pair leaving you with less then the 24 you need
 
(quoted from post at 16:47:04 01/04/13) so the coffee clutch discussion here this morning was batteries. say you have something like an electric golf cart that ran on 24v dc. you have 3 identical car batteries, 500 cca each 12v and you wanted to put all three in the cart. you wire 2 in parallel pos to pos, neg to neg, and then wire the 3rd bat in series to get 24v. would it work? would you have the amp hours from each battery available? any downsides?
heres the diagram
+ + -.......to ground on cart
- - +.......to plus on cart
general consensus was that it should work, should run a little longer than just 2 12v in series.
ike everything, it depends.........depends on how you wish to define work.
Bad idea as far as I see. The single battery will be the first to reach discharge, after which the parallel batteries will have plenty of capacity remaining to try to reverse charge that single battery.... a bad thing for that battery. Of course, as I said, it all depends.........could employ circuitry to prevent the reverse charging????
 
You gave the long winded way me I cut it short but I guess that is your nature since you are a Lawyer and seems they can never say things with out being windy LOL. Plus we where both typing at the same time you just get it posted a tad bit before me LOL
 
glennster
If you read up, golf cart batteries have thicker plates, more room at the bottom and more surface area than a car battery. A car battery is designed to be used for only a short time. Golf cart batteries are made to supply current longer time. I've never seen a golf cart use 24 volts. The older ones use 36v and the newer used 48 volts. Not to say there weren't 24 volt models, just never seen one.

If I had free 12v batteries, I would put 2 in series and make 24 v. Then put 2 more in series, again 24v. Then put the 2 series strings in parallel. You could add as many 24 volt strings you wanted. Going to guess you would run out of space very soon. On the other hand, if you had to buy batteries, you would be better off getting 4 6v golf cart batteries.

I know of a golf course that sold all their electric carts and went to gas. In the long run they think it will save them money.

A true redneck would put a gas powered generator on a golf cart, use a couple of golf cart chargers to power the cart and not use batteries. Then drive the cart to Wal-mart so people would post a pic on "People of Wal-mart'." web sight:)
George
 
whoopps john, i feel bad i let you down, i was figuring that 1000 amp hrs would of been available from the parallel batteries. guess i gotta go back to school some more!!
 
Dangerous and doesn't work.
The lone 12V battery will run dead while the other two have half a charge.
The two half charged batteries will cause the lone battery into cell reversal.
That's about the time an hydrogen explosion blows the top off the battery. And sprays everuthing down with battery acid.
 
Yep if you had 2 in paralell each of 500 amps you could now deliver 1000 amps,,,,,,but in series the combo still cant deliver more amps then the weakest can. Two of 500 amps each in series still can only deliver 500 amps IM SURE YOU KNEW THAT HAD YOU THOUGHT IT OVER!!!

Take care Glenster

John T
 
No problem Rich, yep as they say great minds think alike maybe??????? The ONLY thing a lawyer has to sell is words so if they charge big bucks they gotta use a ton of words to justify the cost lol Actually its the combination of Engineer (lots of tech writing) PLUS an Attorney that makes me sorta just kinda possibly LONG WINDED LOL

John T
 

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