# Golf cart batteries - mix and match?



## 101589dpm (Jul 9, 2008)

I'm a college student that is essentially broke but attempting to begin an EV conversion on a budget... I think I've found a decent donor car (1991 Mercury Capri?) and there are a few golf courses around that have said they have some batteries I can have. My question is: is it possible to mix and match different types/brands of batteries? I have only begun to glance over the theory and calculations and such but I figured I would try to get a handle on some of the basic parts first. I haven't been to the golf courses yet to see what they have (heading over next week during my spring break) but is it possible to mix and max batteries as far as the brands go? Do the voltages of each battery need to match? Can I just throw together every working battery I get my hands on and make the car move? Thanks in advance for any insight.


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## TheSGC (Nov 15, 2007)

You want to match voltage and amp hour ratings of the batteries. Usually golf carts use 6 volt batteries, and those are good for EV use. Don't expect anything great from used batteries, but if they are free they would be great for starting out.

Usually it's not a good things to mix/match batteries, but if they are free, I see no harm it in. Just try to keep the batteries the same voltage and amp hour ratings.


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## speculawyer (Feb 10, 2009)

Well . . . why would they be giving away free batteries? I guess they might put in new ones on a regular basis and get rid of the old ones. But you don't want to try to build something using batteries having dead cells. 

But then again, I guess you can always take them, then test them, and if they have dead cells just drop them off at the closest recycling center.


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## rfengineers (Jun 2, 2008)

speculawyer said:


> Well . . . why would they be giving away free batteries?


Sound's fishy to me. Lead-Acid batteries are close to 100% recyclable.

If they are free, take them. If they are no good and you need to buy a few new ones you will save $$ by having a core to trade in.


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## rmay635703 (Oct 23, 2008)

If you are going to mess with used batteries be sure to bring the following items

1. Digital Multimeter
2. Battery Hydrometer aka battery bulb
and if they are real nice, bring along a cheapo 500amp battery discharge tester like they sell at harbor freight and other places along with a battery charger.

Make sure the batteries you take have a voltage at least equal to their rating AKA a 6v battery should have 6v or over, the more you go below that the more likely you are to find a shorted cell. You can test each cell with the battery hydrometer, if one cell tests poorly while others are good, its best to avoid that battery if you can, though it may be possible to recover.

Once you get the batteries it is a good idea to have a cheapo 500 amp discharger like I listed above, a trickle charger, distilled water, some garbage cloths you care nothing about, some acid proof containers, and some epsom salts.

Some good information on cheap battery recovery methods
http://ysuusy.com/Lead_Acid_Car_Battery_Repair.html
http://www.dallas.net/~jvpoll/Battery/aaDesulfatorSurvey.html
http://www.alpharubicon.com/elect/3dollarbattggn.htm

Before you mess with the battery adding chemicals, dumping acid or doing anything else charge them up slow and check to see if they test out at anywhere near the Ahr they should, if some are weak you might consider building a battery desulphator or if that isn't practical adding dissolved epsom salts to the battery or EDTA from JC Whitney or others, additives DO HAVE NEGATIVE SIDE EFFECTS but also can make a more or less useless battery into a usable one with the side effect of either weaker acid or an increased self discharge rate.

Good Luck, I wish I could find working used batteries, the last batch I paid $40 each and they still had blasted bad cells that the disreputable owner covered up by adding too much acid to raise the voltage


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## speculawyer (Feb 10, 2009)

rmay635703 said:


> If you are going to mess with used batteries be sure to bring the following items


Meh . . . don't look a gift horse in the mouth.

As long as their is a recycling place near you where you can dump them, just take the batteries and then test them at home. If they are no good, take them to the recycling place and drop them off. 

Now that I think about it, I don't see why they'd give you totally crap batteries just to fuck with you.


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## rmay635703 (Oct 23, 2008)

speculawyer said:


> Meh . . . don't look a gift horse in the mouth.
> 
> As long as their is a recycling place near you where you can dump them, just take the batteries and then test them at home. If they are no good, take them to the recycling place and drop them off.
> 
> Now that I think about it, I don't see why they'd give you totally crap batteries just to fuck with you.


Around here, at least lately it costs you $5 to drop off a bad battery, nobody will pay you unless you are buying another battery to trade on.

On that note I would take a few batteries as gift horses but in a previous life I used to get computers for free and most were moderately new, in fact I could get hundreds of them at a time, at that time I could just drop them off or give them away but now 

I wouldn't want him to get in over his head if the QTY is large, though he probably could find some around here to take them anyway.

In fact the company I used to work for throws out about 70 12 military storage batteries a day, about 75% were good working another 10% were under 6 months old, I could never find out who was recycling them. 

Even though they were starting batteries, they were not much like an auto start battery and would be usefull if one could get one.

Ah well.


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## speculawyer (Feb 10, 2009)

rmay635703 said:


> Around here, at least lately it costs you $5 to drop off a bad battery, nobody will pay you unless you are buying another battery to trade on.
> 
> On that note I would take a few batteries as gift horses but in a previous life I used to get computers for free and most were moderately new, in fact I could get hundreds of them at a time, at that time I could just drop them off or give them away but now


That sucks. Well, that is why I put in that caveat of requiring a recycle place that will take them. I have a place nearby where I can go and just drop off batteries for free. 

Actually, I think I could just put them on my curb on recycling day and they'd take them. Check the web site of you local garbage/recycling company. There will often be limits on how many you can put out though.

Lead-Acid batteries have a really good recycling system now . . . they do re-use the materials.


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