Battery: Where did we go wrong?

[the_42nd_parado]

Hello everybody,
I am sorry for my ignorance on what happened. One of our lead acid batteries is scaring us, no one on our team has any idea what happened. All we know is that in the morning there was something definitely wrong. The sides of the battery are bulged, as though there was a reaction that created pressure. Yet oddly it seems to only be affecting one side. It seems that the top (the black part) is separated from the battery. Also when we entered it smelled as though there was a gas leak in our shop. Though this may be a separate event. If anyone has any ideas on what happened I would love to know, and possibly save our remaining two batteries.



Thanks,
The_42nd_Paradox

[Mike Marandola]

I can't comment on what caused it but I am surprised the vents didn't pop up. We had a bad battery and the vents popped up and stunk up the whole hallway.

[mrmummert]

We had two of ours do that recently too. I've read that it can be caused by being over charged but the charger we use is supposed to prevent that.

I'm wondering if it might have something to do with the batteries having been used laying on their side while in the robot. None of our 2015 batteries did it, but a 2014 one did and i think a 2012 battery might have been the other one.

[ebarker]

That battery needs to be sent to be recycled. It is bad. Either a cell shorted out or it was charged with the wrong high rate charger.

Make sure the max charge rate is 6 amps, 2 is better. Microprocessor controlled 3 or 4 stage charging is best and make sure it is compatible with AGM / GEL batteries. Liquid cells like in auto batteries have a different charge profile.

We have had maybe 3 or 4 failures in 12 years ? We keep 14 batteries in service, so altogether we have not had a real problem.

[MrForbes]

If you want help figuring out what went wrong, you might need to provide some clues. Like, what was done to the battery? was it just sitting in a nice dark cool room all by itself? was it connected to a charger? was it exposed to temperature extremes? was it shorted out? How old is it?

As mentioned, it doesn't really matter for this battery, but if you have others that might be mistreated some how, it would be helpful for you to tell us all that you know about what was done to the suspect battery.

[marshall]

Originally Posted by ebarker

That battery needs to be sent to be recycled. It is bad. Either a cell shorted out or it was charged with the wrong high rate charger.

Make sure the max charge rate is 6 amps, 2 is better. Microprocessor controlled 3 or 4 stage charging is best and make sure it is compatible with AGM / GEL batteries. Liquid cells like in auto batteries have a different charge profile.

We have had maybe 3 or 4 failures in 12 years ? We keep 14 batteries in service, so altogether we have not had a real problem.

Listen to this man! He knows his batteries. A lot of our battery process has been taken from 1311. Including our cart.

[the_42nd_parado]

Originally Posted by mrmummert

I've read that it can be caused by being over charged but the charger we use is supposed to prevent that.

I'm wondering if it might have something to do with the batteries having been used laying on their side while in the robot. None of our 2015 batteries did it, but a 2014 one did and i think a 2012 battery might have been the other one.

The charger we use is also designed to prevent overcharging as well. As for the batteries being laid on there sides, I do not not think so, the rest of our batteries have laid on there sides and have not done anything like this.

Originally Posted by ebarker

That battery needs to be sent to be recycled. It is bad. Either a cell shorted out or it was charged with the wrong high rate charger.

Make sure the max charge rate is 6 amps, 2 is better. Microprocessor controlled 3 or 4 stage charging is best and make sure it is compatible with AGM / GEL batteries. Liquid cells like in auto batteries have a different charge profile.

We have had maybe 3 or 4 failures in 12 years ? We keep 14 batteries in service, so altogether we have not had a real problem.

Ok one of our mentors is taking the battery to a hazardous waste recycling center. Also when I get back into our shop I'll try to find out weather the charger is 6 or 2 amp, also if it is Microprocessor controlled. However I am fairly certain it is 3 amp.

Originally Posted by MrForbes

If you want help figuring out what went wrong, you might need to provide some clues. Like, what was done to the battery? was it just sitting in a nice dark cool room all by itself? was it connected to a charger? was it exposed to temperature extremes? was it shorted out? How old is it?

I know we were charging the battery in preparation for a demo tomorrow. Though our charger is designed (as stated before) to prevent overcharging. As for possible temperature shifts there is a high possibility as our shop is not air conditioned. Shorted out I do not think so, the connectors were fine. If there was a short it would be in our charger. Also as stated before the battery was given to us in 2010 for frc. I guess it may have run its life.

Well thanks everyone for your replies.
The_42nd_Paradox

[Mark McLeod]

Other ways of mistreating a battery include:

• Grabbing a battery by it's wires instead of the built-in grips (the battery terminals are not mechanical supports and pressure on them will crack the internal plates)
• Dropping a battery onto a hard surface, also rupturing or cracking internals (can inspect for dented corners)
• Very deep discharging maybe >80%
• Sensitive to over-charging (a bad battery can give confusing feedback to a good charger)
• Overheating (hot storage, hot surface)
• Not maintained in a charged state (leaving them to slowly discharge all summer will damage them)

But just age will eventually lead to deterioration and then overcharging even with a smart charger can occur.

[techhelpbb]

I often see people using chargers that make lots of claims about overcharging this and that but I have lots of experience with batteries (built electric vehicles and computer room battery backups). I rarely trust a battery charger I either haven't got extensive historical data or at least a complete schematic and source code for.

I have lots of wet maintenance free batteries around. I check them for temperature and any signs of leakage and if possible collect any data I can for their behavior often. The real important thing is to not have these things spraying acid everywhere because that might just be the start of your troubles.

All in all after doing FIRST on and off for 20 years I think the battery selection for FIRST is adequately safe. Though it wouldn't surprise me to see an occasional issue here and there.

As others have pointed out, once you recognize you have a battery in a bad state it is important you dispose of it not leave it laying about. You don't want someone happening upon it later and compounding the safety issue.

[MrForbes]

Originally Posted by the_42nd_parado

Also as stated before the battery was given to us in 2010 for frc. I guess it may have run its life.

That is as long as I would ever expect a battery like this to last.

[philso]

Originally Posted by the_42nd_parado

the battery was given to us in 2010 for frc. I guess it may have run its life.

Yes. The UPS' manufactured where I work use tons (literally) of Enersys batteries from the same family as the FRC legal models. We recommend that our customers replace them after 3 years. The charge and discharge rates our UPS' subject the batteries to are not as "abusive" (especially discharge) as in an FRC robot so I would expect less than 3 years of life when used in an FRC robot.

[FrankJ]

Don didn't say no lead. He said nominal lead. Nominal lead is the lead normal people use. . The recycle stream for lead is very good. You return your battery to a recyler, as you should, it will get ground up and made into a new battery. Near zero impact on the environment.

Yes there are AGM batteries that are FRC legal

[Ari423]

Originally Posted by FrankJ

Don didn't say no lead. He said nominal lead. Nominal lead is the lead normal people use. . The recycle stream for lead is very good. You return your battery to a recyler, as you should, it will get ground up and made into a new battery. Near zero impact on the environment.

At first he said "no" then he changed it to "nominal". If I would have realized it was a typo I never would have said anything.

[FrankJ]

Originally Posted by Ari423

At first he said "no" then he changed it to "nominal". If I would have realized it was a typo I never would have said anything.

I missed that. Nominal is a funny word anyway. It can mean approximately normal like all readings are nominal or it could mean insignificant. One the oddities of the English language trying be all things to all people.

In any case FRC legal AGM batteries are lead acid batteries and have sufficient lead in them for the reaction to work.

[Al Skierkiewicz]

AGM batteries actually may have slightly more lead than previous gel cell types. The glass mat allows for closer plate spacing which may allow manufacturers to add one more plate in the same space as previous designs. This gives a little higher energy density and/or available peak current. The reason FRC went to AGM batteries (namely the MK series) came from a donation by MK to supply batteries to every team that year. The AGM design also keeps maximum contact between electrolyte and full plate during the battery's lifetime. This AGM series also lightly reduced the weight of batteries. Previous gel types could be up to 14 lbs when new. As the electrolyte evaporated, the weight went down but so did the available current and energy density.
Batteries used in safety light service are designed to be on trickle charge 24/7 so they have a tendency to outgas and remain at higher temperatures. Many jurisdictions also require safety lighting to provide light for a specific minimum time period. Older batteries in this service will meet that spec. Many building maintenance managers will replace all batteries every three years or sooner, depending on environment.