NiMH battery problem

fishhead · #1 12/11/07, 01:42 PM

Does anyone else have problems with NiMH rechargables? I can't seem to get them to hold a charge or maybe my charger is bad but it's as new as some of the batteries.

I charge them until the lights on the charger go off but when I go to use them they aren't charged fully.

Danaus29 · #2 12/11/07, 06:19 PM

Dh says the batteries are bad. Something about the charging memory in the battery. He says you may be able to totally drain the batteries then maybe get them to hold a charge. Sometimes works, sometimes doesn't. How old are they and what are they in? If they are in a Craftsman tool, that's the way they are programmed. About the time Craftsman stops making that battery, the old batteries will no longer hold any charge, so you have to buy a new tool.

fishhead · #3 12/12/07, 08:35 AM

These are AA and AAA batteries.

They are maybe a year old but really haven't worked well from the first charging. I sent another email to Ray-O-Vac. When I contacted the company last year they sent me new batteries within days.

WayneR · #4 12/12/07, 09:37 AM

Ni-Cad and NiMH batteries have different charging characteristics. Harbor Freight has a combination charger for both types. DO NOT mix battery types or chargers !

Batteries are usually damaged by overheating or overcharging them. A timer on chargers is a valuable addition to prevent such damage.

If you are so inclined, the Craftsman battery packs can be rebuilt with new cells (no experience with 19.2V, yet). Other packs assembled with screws can also be rebuilt. Purchase new packs at HF,for "donor" cells.

There are some tool brands that use special size cells, which are smaller than the usual 1.2V sub C NiCad.

Not intended as an advertisment, but HF caries a variety of both types.

fishhead · #5 12/12/07, 09:40 AM

My charger is a combination alkaline and NiMH charger.

Danaus29 · #6 12/12/07, 12:09 PM

WayneR, the Craftsman battery problem was solved. Drill was replaced with a Makita. 7 years old and the batteries are still available.

fishhead, I've never had good luck with any rechargeable regular batteries. Just past the warranty period and they'd leak, never would hold a charge, things wouldn't work as well, sometimes brand new and they wouldn't work at all. I ended up just tossing all the stupid batteries and the charger. The only things I use rechargeable batteries in now are things that are designed for and come with their rechargeables. BTW, some electronic should not be powered by rechargeable batteries. You might want to check the voltage on what you have them in and compare that to the voltage put out by the rechargeables.

wy_white_wolf · #7 12/12/07, 01:06 PM

Get a cheap multi meter and test the battery voltage after charging. Then if it is low try a different charger. If they are still low I'd say the batteries are bad.

fishhead · #8 12/12/07, 01:12 PM

I'd never thought of using my new voltage tester on the batteries. That should answer the question of whether they are charging for certain. Thanks!

Blu3duk · #9 12/12/07, 08:49 PM

The neat thing about Nickel metal Halide [NiMH] is they have no memory so when discharging and recharging they do not have to be completely discharged to receive the new charge..... so if some of your batteries are not fully charged and others are it is the battery itself not the charger, if they are all similar then it could be your charger or procedure. Most all the new NiMH chargers have an automatic shut off so they will not over charge. Even a cheap multi-meter will tell you right off if the batteries are ful strength or not, and if you get a set of new batteries to use as a bench mark then you should be pretty sure which it is.

The NiMH will eventually wear down, and like all things manufactured there are most certainly duds among the good product, my mother bought a set of ratshack NiMH and they only lasted about a year in her digi camera, while the cheap back up set will hold nearly 4 times the length for picture taking in the same circumstances...... But I also have a set of ratshack batteries that are just as good as her cheap set [cheap as in $12 vs the $20 for the 4 from ratshack.

If they did not wear out then the comapany would not be able to make enough dollars to keep in bidness, and would have to tell their stockholders why..... talk about a lawsuit waiting to happen eh?

William