Drill Battery Problem

[jacorb_88]

I have 2 packs of 14.4v each, one is working, the other isn't.

I tested the pack which is working with multimeter. Volt reading is between 15 to 15.5. I tested the other and it read same range as the working pack.

I'm pretty sure the terminals are free of foreign film that prevents them from connecting well.

Still the 2nd pack can't power the drill.

Any other tests to determine if I need to replace the pack or specific cells in the pack? It seems to me that all cells are still working based on the volt reading.

[bbn]

I'm no battery expert but you could try discharging the malfunctioning pack. Don't just use a piece of wire to short it. Use a car bulb. There is a article here on battery packs, maybe it can help you.

[jacorb_88]

oh yes, i've just read the discharging jig this morning.

i'll give the project a go. anyway, if discharging/recharging won't work, i would still need the jig for batt maintenance.

[jacorb_88]

ok, here it goes...

i attach the working batt pack to discharger. light lit up. i checked the volt reading while discharging, between 14 to 14.5v.

i attached the non-working batt pack to discharger. no light. i checked the volt reading while discharging, it's between 1 to 1.8.

the non-working batt seems to me is giving out 1.8v max when connected but when discharger is detached, the reading is 15 to 15.5v.

anything assessment on the above. thanks.

[JayL]

I have a Black and Decker Electric Screw Driver which works using VersaPak Batteries. The seven VersaPak batteries I have are interchangeable with the B&D cordless drill, flashlight, jigsaw and reciprocating saw that all came with the kit. All six batteries work with all the tools except for the seventh which won't work with the screwdriver (only) . I adjusted the contacts on the screwdriver side and it worked fine after that.

Based on your validations looks like the battery you have is ok. Maybe you should look at the tool also.

[jacorb_88]

am pretty sure 2nd batt is not.i just tried lighting up a 12v bulb.it did not.1st did light up.

also checked tool, terminals all ok.including batt terminals. :'(

[bbn]

OK. Now you really have to find that article here. I'm almost sure it will help you. The pack is just housing for 11 "normal" rechargeable batteries. Most likely a few cells, hopefully just one, are dead. You can replace these, saving you a lot of money. The article tells you all the details.

Good luck.

[jacorb_88]

how would you tell if there are one or more dead cells, if pack volt reading is somewhere 15 to 15.5. That's equivalent to 12 cells firing 1.2 v each (I read somewhere that a fully charged 14.4v batt pack would have a reading of 15 to 16v). Isn't it if there are dead cells, my reading would be less than that?

[bbn]

Not necessarily. If the battery goes "high impedance" then it will read 1.2v but will not deliver any current. In fact, such a cell will prevent the other good cells from delivering current too.

Bro, remember I'm no battery expert. Best is to bring the back to the battery shop and have them diagnose it. There is also a lot of material on the net about batteries if you want to DIY it yourself.

[stealthy]

if i may suggest...perhaps you could test the batteries individually. you could use those 2.4V flashlight bulbs or dc motors from toys as a load and test each battery one by one. the one that doesn't light up the bulb or run the toy motor is the "ampaw" battery.

i hope this helps.

[jacorb_88]

i tested volt reading of each cell. all firing 1.2+ v. i will try next to light up a flashlight bulb and see the 'odd' cell. hopefully, the whole bunch isn't. thanks.

keep you posted.