Battery exploded at work!

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Earnest Tilley
Earnest Tilley Solar Expert Posts: 56 ✭✭✭✭
I work for a company that builds replacement parts for power plants, and FM boilers. We use man lifts to get on top of boilers and various other things. We plug these in each night and charge them. The ones with old batteries charge quickly and discharge just a quick. The people in maintenance decided to replace just one of the 6 6v batteries in one of the lifts. They plugged the lift us to charge and left. Someone started cutting a piece of metal with an air saw near the man lift and KA-BOOM. Acid spilled out everywhere luckily the batteries had a 1/4 inch plate between them and the person cutting. Thing is i had learned on here just a few months ago not to add new batteries to old ones it causes excess gassing which our maintenance department found out the hard way. Not to mention that was $600 wasted.

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,477 admin
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    Re: Battery exploded at work!

    It is hard to tell from behind a computer if the one of six battery change was responsible for the problem--But the sparks from the cutting operation could have cause the problem near any charging battery bank.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
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    Re: Battery exploded at work!

    Charging a large battery bank at relatively large currents will produce significant hydrogen gas. Ever notice the warning to keep open flame and smoking away from batteries?

    Sounds like everyone got lucky!

    Tony
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
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    Re: Battery exploded at work!
    BB. wrote: »
    It is hard to tell from behind a computer if the one of six battery change was responsible for the problem--But the sparks from the cutting operation could have cause the problem near any charging battery bank.

    -Bill

    One explanation would be that the new battery was not fully charged before being installed, and as a result it did not come up to full charge voltage while the old batteries did. That would lower the voltage of the string as seen by the charge controller and cause it to keep up a high current through the string, leading as you said to excessive gassing.

    Mixing old and new batteries either in series or in parallel is a bad idea, but it would be made worse in this situation by starting with a less than fully charged new battery.

    On the other hand, a fully charged new battery would start gassing heavily while the rest of the string was still coming up to voltage.

    You lose either way.....

    Which battery or batteries blew up? Old or new?
    SMA SB 3000, old BP panels.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: Battery exploded at work!

    my guess is that the new battery was already charged when they plugged in to charge the whole bank. some gassing would be present on the old batteries during charge, but the new one would've been overcharging and causing lots of outgassing. this is bad no matter what way you look at as they never should've used welding equipment anywhere near charging batteries. hydrogen gas is very flammable and explosive when ignited in a battery case. if they allow smoking at that place then they better put an end to it near the batteries as even residual gas could be in the case that could ignite and explode.

    if they go to replace a single battery in a battery bank they need to bring all of the batteries back up before inserting the replacement. this gets tricky as most chargers will dump too much voltage into the good batteries with a failed battery inline and also cause lots of outgassing.
  • Earnest Tilley
    Earnest Tilley Solar Expert Posts: 56 ✭✭✭✭
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    Re: Battery exploded at work!

    That man lift had not been working when we plugged it into the wall it would say it was charged in about 10 min and would only run for about 5 min. The other man lifts take almost 3 hours to fully charge. I had maintenance come out and check the water in the batteries which they found was almost completely gone in all the batteries. They went right over to a sink and filled up a bucket with water ( not distilled ) and put it into the batteries. The man lift worked ok for about 2 days then was doing the same thing. They took the lift back to the maintenance area and put 1 new battery in it. When they brought it back it worked for a few hours then they went and plugged it up. Then he started cutting with the saw that threw sparks near the battery and BOOM.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,477 admin
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    Re: Battery exploded at work!

    That is what I have seen with batteries that die/are killed. You can get them working for a few days or a week--Then the die hard again. If I have car with a dead battery--I just replace it. Not worth the hassles of it failing while I am out driving around.

    That bank, maybe made even worse with the one new battery, was generating mostly hydrogen rather than stored capacity at that point.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
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    Re: Battery exploded at work!
    I had maintenance come out and check the water in the batteries which they found was almost completely gone in all the batteries. They went right over to a sink and filled up a bucket with water ( not distilled ) and put it into the batteries. The man lift worked ok for about 2 days then was doing the same thing. They took the lift back to the maintenance area and put 1 new battery in it. When they brought it back it worked for a few hours then they went and plugged it up.

    When the electrolyte actually gets below the tops of the plates, the dried out areas can be permanently damaged. If most of the plates were exposed, the battery should not have been re-used, even with water added. It was already too late.

    An interesting question is whether the initial electrolyte loss was solely the result of poor maintenance, or the result of the batteries losing capacity to the point that they already were gassing off electrolyte at an unusually high rate during charge. Once some of the battery plate surface is taken out of action, a charge current that would be OK for a normal battery will be excessive and will cause heating and gassing with more electrolyte loss. So it becomes an ever accelerating problem.
    SMA SB 3000, old BP panels.