Electronics, Lighting, & Gadgets - NiMH battery & charger help

Ever since I blew up that lamp in grade 9 shop class, I've had bad luck with all things electric.

I've used a L&M Arc NiMH for ~2 years 2-3 times a week from November to March. I'd get about 2.5 hours of light per charge until last week, suddenly I now get only 45 minutes of light.

I did some tests tonight, I plugged the battery into the charger and it stopped charging after 5 minutes. I re-plug it back in and got another 5 minutes. The third time I re-plugged it in I got about 30 minutes charge time before it quit. Every time I re-plugged it in after that I got only another 5 minutes. The battery can't be fully charged can it? It use to take over 2 hours to fully charge. Why is that? :twitchy: Is the battery Ka-Put or is it the charger? Is the temperature sensor on the battery screwed?

L & M hasn't been much help, they don't make NiMH anymore but will gladly sell me a Lithium Ion battery and charger at the discounted price of $280! Ummm....NO!. I could buy 3 Magic Shines for that price!!

So presumming that my L & M battery is screwed, I searched though Al Gore's IntraWeb and find this 10.8 volt 4500mah NiMH battery pack... is it easy to jimmy-jig this into the L & M connector? How would it work with my charger?
http://www.onlybatterypacks.com/items.asp?db=31

Any help you can give to this electronics simpleton is appreciated.

Thanks,
T.J.

I'm thinking about rebuilding my old cordless drill battery packs by sending them in to primecell.com. (http://www.primecell.com/pctools.htm) They open up the battery case and install new cells. Perhaps they can do the same thing for your pack if the connector is hard to find.

That looks like a cool option, thanks for the link. It looks like they'll rebuld my L & M NiMH 10.8 volt battery for $43. I wonder if they use AA size batterys so they can reuse the L & M batter case. I also wonder if I will get the same run times as before. I might give them a call tommorow.

That looks like a cool option, thanks for the link. It looks like they'll rebuld my L & M NiMH 10.8 volt battery for $43. I wonder if they use AA size batterys so they can reuse the L & M batter case. I also wonder if I will get the same run times as before. I might give them a call tommorow.

I use a 13.2 volt NiMH 5000 MAH battery pack made by Batteryspace.com that consists of 11 "C" cell batteries in series. They have them nicely shrink-wrap packaged with a couple of wires hanging out that I solder to my connector cables and light switch. My light switch is mounted onto a tall plastic bike water bottle, and the battery pack then slides into the water bottle. This website has dozens of battery kits that you can buy for very reasonable prices. Mine was about $50.

I use a 13.2 volt NiMH 5000 MAH battery pack made by Batteryspace.com that consists of 11 "C" cell batteries in series. They have them nicely shrink-wrap packaged with a couple of wires hanging out that I solder to my connector cables and light switch. My light switch is mounted onto a tall plastic bike water bottle, and the battery pack then slides into the water bottle. This website has dozens of battery kits that you can buy for very reasonable prices. Mine was about $50.

Hey, that is a really great idea!

Probably the easiest DIY project I've heard of thus far. I was concerned about using one of those pre-packaged battery packs because it wouldn't be water proof. I never thought about putting it in a water bottle. I can hot glue the wire to the outside of the cap to seal it because the switch is on the lamp head. Then I thread the wire through the drinking spout, go to Radio Shack and get a couple Tamiya connectors and I can get a couple battery packs that I can switch out for those long night rides or 24 hour races.

Thjis one looks good and for a reasonable price too!
http://www.batteryspace.com/airsoftgunbattery108v4200mahnimhbatterypackforairsoftmod.aspx

One question, how does my L & M charger know when to stop charging the battery?

Good NiMH battery chargers use voltage sensing to determine when charging should stop. Cheap ones, typically 8 hour charge time ones, go by time and may overcharge batteries that are only partially discharged. I would expect the L&M charger to use voltage sensing.