Ever had a NiMHi battery repaired?

[Eugene]

If you have voltage on each cell but not the pack then I would suspect something else, perhaps the thermal fuse is bad?

Radio shack has the worst batteries, I'd bet the mAH rating on the Makita pack is much more than the radio shack cells. Also the batteries inside the Makita pack most likely are not consumer top but the spot welded connected type.

Search for places like Batteries plus who can rebuild the pack with new cells if needed, or is you determine the cells to be bad order them from someone like digikey or mouser who can spot weld them into the right config.

[Bay Area Dave]

Got an 18V nickel metal hydride Makita battery that shows the same voltage on all cells but has no power. Obviously, at least one of the cells must be bad. Ever had any type of repair facility fix one of these puppies? Makita said to "throw it out". Thanks a LOT, Makita! I can get 3,000 milliamp C batteries from Radio Shack, but then there is the issue of identifying the bad cell(s) and soldering the ends of the new battery into the circuit. Using a conventional soldering iron gets the battery pretty toasty (been there; done that before for making up phone battery packs when no replacement is available). The batteries are sold in packs of 2 for around $12-15. A new Makita 18 volt battery is about $70 the last time I checked. found one on-line for $63 just now...

dave

[Swingman]

Clunky website, best rebuild service around.

[Leon]

If all cells show the same voltage and you can get no power there is a connection problem IMHO. I know that in my Panasonic battery pack there are diodes and or resistors. Does you battery pack have these also? Could one of those be bad? When you say you have no power, do you mean there is no voltage at the battery terminals or there is voltage but not enough to run your tool?

Normally a shorted cell will show no voltage. Seems like something in the pack other than the cells may be bad. Maybe a bad connection.

I have had a family member overhaul my 2 Panasonic batteries at her electronics business.

[Leon]

Totally different thing here. I was looking at the new B&D 24 volt lawn mowers a couple of days ago. The 24 volt battery pack will power the mower long enough on 1 charge to do 1/3 acre. The replacement cost of the battery was ..... $19.95. Ever think we are being raked over the coals for our tool batteries?

[P©WÉ®T©©LMAN]

Actually Dave if all cells show the same voltage individually but have no power combined I would suspect a wiring connection problem, troubleshoot that first!

[BruceR]

Perhaps 8^)

Could also be that since the lawn mower doesn't need to be as compact as a cordless handtool, they might use a different type of cell (sealed lead-acid perhaps).

-Bruce

[Leon]

Good Point... Seems these type batteries do have a gel cells.

[P©WÉ®T©©LMAN]

Different type of battery altogether though (acid or gel cell probably), but I do agree cordless tool batteries (at least good quality ones) are way too expensive these days.

Assorted Bi-Metal Recip blades :

[Michael Daly]

You don't want to do that. If the new battery isn't an exact match to the old ones in capacity, you'll only toast another battery soon (they won't all discharge and recharge at the same rate).

If you are going to replace, replace them all at the same time.

BTW - have you opened the thing? You might find that the batteries are smooth on both ends - no bump on the + end. A standard battery won't fit if that's the case. You'll have to find equivalent "industrial" batteries.

Mike

[Tom Watson]

A young man who lacked in capacity Sought out help with his lack of ampacity

Had he looked to his shorts He'd found help there of sorts

But instead found the rocks of compacity

(burma shave)

Regards, Tom.

Thomas J.Watson - Cabinetmaker (ret.) tjwatson1ATcomcastDOTnet (real email)

[Bay Area Dave]

Leon, not enough power to cut a 1x1 when used in my 6 1/2" circular saw. It spins a little slower than normal and has very little power. No load voltage on each cell is normal. I don't have a load tester to check them properly.

dave

Leon wrote: When you say you have no power, do you mean there is no

[Bay Area Dave]

yup! which is why I bought replacement batteries for a bicycle lighting system at Fry's Electronics and the next time from Interstate Batteries. Paid less than 1/2 price.

dave

Le> Totally different thing here. I was looking at the new B&D 24 volt lawn

[Bay Area Dave]

I believe you, Michael. I once replaced an obviously bad nicad in a battery pack with a high amperage one from Radio Shack and before I knew it another cell failed.

dave

Michael Daly wrote:

[Bay Area Dave]

your little ditty added nothing of value to this thread, Egotistical TW.

dave

Tom Wats> >

[Wilson]

[Leon]

The cells probably have a surface charge that indicates the normal voltage and diminishes quickly once a load is applied. Surface charges on charged batteries normally indicate a voltage greater than the capacity of the battery or cell.