Fried forklift batteries 1

[tkal]

At my work we have a 36v electric forklift. Recently it would not hold a charge. The batteries are leaking and some of the caps poped off. There are three 12 volt batteries, they are designed to go in semis, the only information on the batteries themself is a code, USRM-8D, google does not hit any sites with this. The batteries are inline for an out of 36v. The forklift says to use a UL listed type "EO" battery. The physcial demenions of the battery are similar to a good sized cardboard box. The lift also says it has a six hour amp rating, 1120. I dont know what voltage the charger is putting out but I do know that it has a rated out max of 40 amps, looking at it the other day it was putting out 2-4 amps in auto charge mode to the batteries.

I am 99% positive the batteries are fried. But we dont know what fried them, if anyone has any clue I would much enjoy your input. If you need more information, such as a multimeter reading let me know and I will get them.

 

[don01]

tkal,
I'm not the battery expert but my gut feel is;-
a) some how there has been a very very heavy load on the battery -check all motors cables etc.
b) your charger was pumping in a lot of current and may have failed.
I assume your water and density are checked regularly and were ok shortly before (we check weekly)
c) if not, a cell or battery may have failed and gone low ohms or short and the charger hasn't backed off.

my best suggestion is to get on to the local battery man (or even auto electrician / elec.forklift service man and get him to have a look)

regards
Don

 

[tkal]

Well, the orginal battery was very large, so I assume that it is capable of putting out a good number of amps. the new batteries are less than half the size. So I am guessing option "A".

Please explain what you mean by "to get on to the local battery man".

Thanks

 

[Crowbar1]

With the battery leaking and the caps popped off I'd say you were overcharging the battery, possibly a problem with charger. What type of charger is it?


Crowbar

 

[cbarn24050]

Hi, 2-4 amps will not charge a forklift battery.You need to find out what the amphr rating is.

 

[djs]

Hello;
The batteries you are using now are a standard battery called group 8D. These in general are starter type batteries which means that they are used to start engines (like in your car). The type of battery that should be used in an electric forklift is a deep cycle type. These are readily available in the smaller sizes, or in the large orginal size that was used in your lift truck.
The large batteries however are quit expensive. Also they don't necessarily come in standard voltages. For example it is possible that the orginal battery was 40 volts, not the thirty-six you now have. Because of this using the orginal charger is not recommended.

 

[ve7brz]

I feel the problem is definitely due to overcharging! The MAXIMUM charge rate for lead-acid chemistry is C/4. The MAXIMUM voltage is 2.4 volts per cell, or in this case 43.2 V. When the current drops to C/100 the charger should revert to a trickle charge of 2.3 V per cell. Your problem may not be with the batteries, but with the charger. Check it out or try a replacement meeting the specs. outlined above.

 

[don01]

tkal,
I have been accused of being lazy in the past and this is one of those occasions when I would be accused again.
As I said I am not a battery "expert" If I found this same scenario at my plant and I couldn't see a "for sure" cause before spending what is a real amount of money and replacing the batteries I would, as you have, seek more data.
The supplier of the batteries should be only too happy to come and look at your application and make recommendations to you. This does 2 things,
a) gives you an extension of your knowledge using what should be a person who has a lot of experience whith these issues,
b) gives you the best avenue of recourse should there still be a problem and more work is required.

Now I hope that doesn't sound gratuitous because its not meant to be. But, I have learnt a lot by calling the suppliers up and asking them to look at the situation.

Regards
Don

 

[tkal]

Here is what was wrong. The lift was sitting out side prior to being put to use, batteries were indoors. It seems that being outside has corroded some of the contacts in the lifts voltage gadge. The lift was not outside for a long time, month at most. So this must have been building prior to our shop owning it. Anywho, the lift would not turn on because it was reading too low a voltage, why it does this? Who knows, who cares. So everyone thought that the battery was dead so the kept on charging it and charging it. After cleaing the contacts of the gaudge it worked just fine. And according to the lifts manual it is 36v not 40v.

Thanks for all your input!

 

[don01]

tkal,
thnaks for putting up the end result. Now I'll extend my knowledge again and try to remember that for the future.
I wonder how long it'll stick for though.

Regards
Don

 

[tkal]

No problem.