OH NO! I left the charger ON!!!

[sanddrag]

This is possibly my worst screwup yet. At today's meeting, I put a battery on our Schumacher 6A manual battery charger like the one here http://www.polsteins.com/cen62abatcha.html When we all left at 5:00 PM, I forgot to unplug/disconnect it! There's nothing I can do. We cannot get back into the room until 8AM in the morning. What can we expect to find? I really hope it will be okay because I don't believe this model charger has a cutoff.

PS. At first I was really angry that FIRST disallowed manual battery chargers this year. Now I see why.

[NoodleKnight]

I'm not sure how SLA batteries take it, but for most other common batteries, over charging usually kills them...
Although something in the back of my head makes me believe that the battery will be fine.

[Jeff K.]

Hey, the only thing I had done with an RC Car battery when I was younger was leave it in the charger for a whole day and when I went to unplug it, the battery was really hot, but also worked really well. I wouldn't recommend doing it because the battery didn't last too long after charging/draining and only lasted just a few months more before I had to buy another battery. From looking at the website for the charger, it says it has a trickle charge mode, so I am going to assume that it actually does have a cutoff, something such as a built-in timer or something after the 6-8 hours where it will go into that mode, and *hopefully* that shouldn't burn anything down or destroy anything. But good luck for when you check on it.

[ConKbot of Doom]

Heh, it sucks how stuff like that happens. Once we had 2 batteries on chargers, and left them what we thought would be overnight. But it snowed and the batteries ended up sitting on the chargers for 7 days. Luckily they were the automatic chargers that come with the kit.

[Biff]

Originally Posted by sanddrag

This is possibly my worst screwup yet. At today's meeting, I put a battery on our Schumacher 6A manual battery charger like the one here http://www.polsteins.com/cen62abatcha.html When we all left at 5:00 PM, I forgot to unplug/disconnect it! There's nothing I can do. We cannot get back into the room until 8AM in the morning. What can we expect to find? I really hope it will be okay because I don't believe this model charger has a cutoff.

PS. At first I was really angry that FIRST disallowed manual battery chargers this year. Now I see why.

Check battery for heat when you get there. Lead acid type batteries normally charge using a constant voltage method. As the battery gets full it's voltage rises and the current drops. Gel cells are based on this technology. The worst thing that can happen if they get too hot from too much current is they will explode, next worst is they vent the "gel" and lose capacity, kind of like tipping a car battery over and letting the acid out, messy, dangerous, and will cut the capacity of the battery.
If the current meter has dropped to about 1 amp or less and the cell is not hot you should be fine.

[rocknthehawk]

I don't know about these batteries/chargers, but i know if you leave a car battery charging on one of the big ones for too long (i.e overnight), it will smell REALLY bad in the morning...kinda like rotten eggs.

[Kyle T]

If the charger has trickle down, you should be okay. If not, I wouldn't expect it to have exploded or anything, but it probably will be really hot, and I wouldn't advise touching it untill you unplug it from the AC and wait for it to cool. Sometimes they leak a little if they get hot enough, but that's about the worst I'd expect. Hope you didn't leave it on anything valuable.

[greencactus3]

Hey, the only thing I had done with an RC Car battery when I was younger was leave it in the charger for a whole day and when I went to unplug it, the battery was really hot, but also worked really well. I wouldn't recommend doing it because the battery didn't last too long after charging/draining and only lasted just a few months more before I had to buy another battery.

rc car batts. if you leave them on a charger too long they WILL explode. with a trickle charge they will not give peak performance with that charge but will not hurt them but at 6amps for too long a time will definilty blow them. even with 3300s 90min at 6amps will definitly be going too far.
well we're all happy it wasnt a lipo batt

[Andy A.]

It is unlikely that the battery will explode.

What is possible is that the vent caps on the top of the battery will open up, and electrolite will boil off. It won't be a huge toxic mess, but you will have to be careful cleaning off the battery and anything that might have electrolyte on it.

Also, if the vent caps have opened, the battery has been overheated so badly it's permanently damaged. Aside from loosing electrolyte, the plates may have warped an even shorted against each other. In any case, the battery should be disposed of if theres any evidence that the caps have opened or the case is distended.

-Andy A.

[Al Skierkiewicz]

You might be in luck and the charger will trail off sometime during the night. As others have posted, a charger of this type is designed to provide current by having a slightly higher potential then the battery your are charging. As the battery comes up to charge, the two voltages get close and the current starts to go down. Unfortunately as these batteries reach full charge, any additional current is turned into heat and that is bad for a gell cell.
When you get in in the morning, be aware of the state of the battery. First thing, don't move it, it will likely be hot. Shutoff the charger or unplug it. Look for signs of over temperature, i.e. bulging case, cracks, oozing liquid, or smoke. If none of those are present, place your hand near the case and see if you feel any heat, if so, let it cool down for an hour or so. Once cooled, then check for popped seals on the top and for signs of electrolyte on the case. If it has any stuff oozing out of it, handle with rubber gloves and clean up the rest with water and a little soap. The electrolyte is sulpheric acid which is nasty to delicate tissues, (eyes, nose, and more tender areas) can also destroy metals and clothes. Be sure everything is cleaned.
In the event the battery is not hot and maybe only a little warm, let it rest for a few hours and try it on your robot. It may be OK. Recycle a battery that was very hot, leaking or cracked. As a battery outlet like NTB or Battery America for advice on how to transport.
Good luck.

[bombadier337]

Well, what happened to the battery?

[sanddrag]

Originally Posted by bombadier337

Well, what happened to the battery?

The students said it was not even warm and no bulges or cracks. Very lucky. We have had a chance to put it in a robot yet to see if it still works well.