Battery Charging - Warning!

Technical Technical Discussion
#1

First of all I have a really stupid warning. If your shop has metal countertops, don’t leave your charger clips laying on them

Second, I have a fiarly stupid warning. When you are charging your batteries make sure there is no way the clips can touch at all. Besides the charger shorting (maybe about 6 amps), you’ll be shorting the battery at over 200 amps :ahh: In some instances all these things can weld themselves together and you wouldn’t be able to stop it from shorting.

Third, this is my main warning that I started this thread about. Last week, my team was charging this old battery (02 or 03) that seemed like it just wouldn’t tanke a charge because it must have been really dead. The light on the charger stayed on orange for a while, like over a day. We though maybe the charger detected the battery’s deeply discharged state and decided to trickle charge it. Apparently this wasn’t the case. After a few more days we found that the light was still orange and the sides of the battery were bulging out and cracked in three places.

Moral of the story: don’t leave your batteries charging for too long, even if the charger says they aren’t done.

#2

we also learned the hard way last year that the powersupply for the operators interface has that barrel plug on the end

if you drop that on a metal surface just the ‘wrong way’ the power supply can short out - we smoked ours last year and had to get a replacement from radio shack.

#3

please properly dispose of that battery immediatly if you havent all ready. That is an example of not only overcharging but some wheres it prob also shorted. The buldging is a sign of ruptured cells accumulation of gases, and the cracks can cause a leak of the caustic gels and will cause serious burns with contact.

#4

A great improvement over the clips is to install one of the Anderson 50A quick disconnects on your charger. Then it won’t short if you lay it down on a conductive surface and won’t have any chance of shorting when you connect it to the battery.

#5

We have one cracked battery from a few years ago. Our county dump has a special place to drop off old rechargeable batteries, but we haven’t taken our battery there yet.

And we also replaced the clips on our chargers with battery connectors. It makes battery charging easier and safer.

#6

I know that some auto parts stores and salvage yards will also take the batteries. It would be best to call first to find out and you might have to pay a small disposal fee (since your not trading them in on a new one) but you will know they will be properly recycled. That will probably be your best bet to get rid of batteries that are cracked, bulging, or otherwise pose an immediate problem. If your batteries are worn out and won’t take a charge(or full charge) but are “stable” you can wait for the recycle program many towns have. This is only true if your town has them and accepts batteries at them.

#7

if we’re going over dumb things you can do with a battery, a word of warning. if you have been testing the pneumatics for leaks and have wet fingers, dry them before holding the compressor contacts to a battery terminal! I had some pretty raw fingers from that spark…

#8

Connecting things directly to the battery is a bad idea in general, but also never do it to something sensitive like your RC. That’s why we have all those pannels and cool fuses. :slight_smile:

I second the idea of putting a quick disconnect (red thing) on your charger. That way you can just seal up the contacts on the battery and not worry about it! Good luck, as usual.

#9

Add this one to the official “Stupid Things To Do With A Battery Charger” list: never, ever, ever try to charge a 12v battery with a 18v charger because you think “it will charge faster that way.” And in particular, when you are NOT charging the battery this way, remember to NOT reverse the leads!

The real lesson learned: never let the mechanical engineer on the team play with the electrical stuff!!! (right, Meech:D ) Otherwise, a bubbling, hissing, smoking battery will result, which has to be removed from the VCU Competition premises at a dead run by the head-geek while being grappled with a long-handled pair of pliers and welding gloves!!!

-dave

#10

In the first post, you very likely already had a shorted cell. The chargers aren’t smart enough to shut off in this condition so it just tries to supply current to charge a cell that will never charge. With lead acid batteries, all excess charge current is converted to heat when the battery is fully charged. (you can only carry a chemical reaction so far.) By my calculations, the 6 amp charger will convert roughly 75 watts directly to heat. That is like having a 75 watt light bulb burning inside your battery case.
Please be careful handling batteries with cracks in the case, vented juice and/or fumes. The acid is gelled sulpheric acid, it can burn delicate tissues (backs of your hand, eyes and eyelids, inside of your mouth, etc.) and will eat holes your clothes. Wash carefully after handling a cracked battery, don’t eat, rub your eyes or pick your nose until you have thoroughly washed up. The funny thing is the holes won’t appear in your clothes until your next washing.
As to the other dumb things…Please be careful when handling these batteries. If you don’t know, ask. PM me if you think it is a dumb question and I will try to get back to you.

#11

I’m very familiar with that after a mishap with a motorcycle battery.

#12

also a word of warning for those who use the anderson quick connectors for batteries. in competition, i suggest putting a wire tie around it to keep the battery connector securely in place. our team lost a match because of this way back when…