I was in a hurry during lunch hour today and I wanted to top up the battery in my snowmobile for the coming winter season. I connected everything, powered up the charger on a 2 amp charge setting and made my way to work.

I got home this evening and checked the status gauge on the charger. It indicated that it was still charging which seemed a little long. I proceeded to disconnect the charger only to realize that I had the terminals reversed. The battery was quite warm and I was only able to hold onto it for a few seconds at a time. I was a little worried and disconnected it from the machine and placed it in the middle of the backyard. I connected a 12volt light and it lit right up. After about 5 minutes it started getting dimmer. I then took my multimeter and tested the voltage (ensuring Red on Red and Black on Black!). The voltage read -3.5 volts. Yikes. I let the light completely drain the battery for a few hours. The battery stayed warm for a long time, even though the temperature was -4 Celsius outside.

Right now the battery reads a voltage of -2 and has been sitting in my storage room for a half hour or so. Should I try charging it properly? Should I find a small 12 volt light to hook up to it to drain every last bit of power out of it first? Should I give up and buy a new battery?

The battery is identical to motorcycle batteries as well as many other small vehicles.

Thanks!
Rene

Way too late, but I definitely recommend the CTEK battery chargers. Really nice high quality ones, great for leaving connected for long periods... and they're switch-mode, so light, cool-running, etc.

They make 12v and 6v variants too, but might take some tracking down in the US... here's the UK place I got mine from, lots of boat places carry them.

http://www.vertar.com/ctek/

Hugo

The only problem I have with the CTEKs is that all the models I have seen are "too smart", and need to be put in the right mode when you turn them on - so useless as long-term maintenance chargers, as a power outage puts them in a non-functional mode.

It looks to be a nice day today so I'll probably set it up in the middle of the yard again.

The fluid level is perfect so that's no worry.

Rene

I've played with batteries for years and only had one explode (but it only takes one). It was actually more of a pop if you ask me. Anyway, it exploded when I removed the charger wires from the battery and had a spark.

To prevent a spark make sure you turn the battery charger to off when you disconnect the wires. Sometimes unplugging the charger from the wall leaves a drain on the battery which will make a spark.

If there is no ignition source it will not explode.

>>If there is no ignition source it will not explode. <<

I've heard of a number of people that had a battery blow up due to a high load. in each case the battery was near the end of its life (well, no duh), that is to say older batteries.

I'm afraid you've almost certainly bent your battery beyond recovery. Reverse-charging lead-acid cells will depolarise them, then attempt to repolarise them the other way around, which is very unlikely to have a happy outcome. An attempt at redepolarising and rerepolarising won't end well

You might get lucky, as lead-acid cells are actually pretty robust, but I doubt it. Even if it doesn't go pop in the process, it will definitely and dramatically affect it's longevity, and not in a good way.

pca

Here's my plan.

Last night I stuck a test light on the battery to drain as much juice out of it as possible. I'll leave it on until the weather clears up as it is wet and snowing outside now and I'm not gonna setup my charger in this weather.

When it clears up I will set the battery in the middle of the back yard along with the charger at about 6 feet away (the length of the charging leads). From there the charger will be plugged into an extension cord which is plugged into an outside outlet that is controlled by a switch inside the house. Safety is my big concern and then recovering the battery.

The good news is that I never hurt anything on the snowmobile. When I put it on charge the battery was still connected to the machine. I stupidly tried the ignition before I had my head straight and she spun once and then nothing. I figure a fuse saved me there. I went out after and gave her a few tugs and she started. Whew!

Worst case scenario, I'll have to buy a new battery so my fiancee can start her machine when we ride this winter.

Thanks for the advice!

Rene

One suggestion: if the battery allows, remove the cell plugs to allow any pressure to release before it builds to dangerous levels. The others are right, a lead-acid battery going pop can put a crimp in your plans pretty badly.

Also, if it does sucessfully finish charging, leave it alone to think about what it's done for a while, before picking it up.

pca

Plugs will be removed and when (if) I see the green light on my charge I will turn off the charger from inside the house and wait a while before going to see if I made a mess or not.

Rene

Just thought I'd update.

I left the test light on the battery for a week or so and then waited a few more days. I then hooked up the charger on a 2amp charge and left it.

When I went back to look (the next day as I forgot about it overnight) the charger light had turned green and there was a big mess all around the area where the battery was. The battery seems to have let some gases leave, but the fluid levels still looked good. I flicked off the charger, disconnected and tested the voltage. 12.4 Volts. Nice!

I then left it for a few days and went back to check and it was still in the 12 volt range. I hooked up the charger and let it run again on a 2 amp charge and it turned off after an hour or so. Checked the voltage and just shy of 13 Volts. I then left the battery alone for a couple weeks (we were packing up to move to a new house). When I finally got a chance, I decided to take the battery and hook it back up to the snowmobile. Turned the key and the machine started wonderfully!

Looks like I got lucky. We'll see how it holds out this winter.

i wouldn't even chance it, goto costco and get a new one.

I'm glad to hear the battery returned to 'normal' with just some simple drain & charge work!
The real test will be how long it can hold a charge- hopefully more than a week.
But, yah, if not this year, then next year is time for a new battery.