I have a 24v nimh battery that no longer works, I have taken it apart and tested the cells and all but one seem ok, is it possible to get a replacement cell and fix this battery?
Bosch battery repair
- Thread starter catlad
- Start date
Sponsored Links
D
Deleted member 174758
You can get replacement cells, but the contacts are welded on which is where you may get problems. The cells used are commonly available from radio-control suppliers on the net. NiMH cells in cordless tools are pretty much always sub-C size, 1.2volt with various Ampere-hour ratings, such as these. Google "sub-c nimh" and you'll find loads (BTW you want tagged cells). There's a place in South Manchester does them, from memory, but sorry, I can't remember the name. Good luck!
Its a bit of an experiment really, I took it apart and put the multi metre on each cell and they all read approx 2.5-2.8v except one which only reads about 1.1v and looks slightly discoloured. So I thought if I can get a new cell for a tenner and solder it in I may be able to get it working again, my only problem is the cells have no information on as they are just wrapped in cardboard, and when I went and looked at the C.P.C electronics web site they have so many I am now confused 
The battery casing should state the type of battery chemistry (NiCd, NiMh etc) and the battery capacity in AH. What you need is a cell of the same chemistry and the same AH rating. (Note that the AH rating, say 4AH, applies to all cells in the battery, so each cell is rated at 4AH)
Sponsored Links
Thanks for your reply the battery I am trying to repair is a 24v 2.6ah nimh. does this mean the cell I need is 2.6ah and about 2-3volts, each one is 85mm long and 22mm wide.
NiMh (and NiCd) cells are 1.2V. I would expect your battery to be made up of 20 2.6Ah cells.
I have an 18v cordless hammer drill where the battery is weak, I just worked out it would cost me about £45 in replacement cells to renovate the battery if I do it myself. Not sure it's worth it.
I wonder if I could get off-the-shelf 6v batts and make up an over-the shoulder battery case with a short cord for less?
Or maybe two of these http://www.batteriesplus.co.uk/acatalog/Rechargeable_9_6_V_AA_NiCd_750mAh_Battery_Pack.html and a separate charger
I wonder if I could get off-the-shelf 6v batts and make up an over-the shoulder battery case with a short cord for less?
Or maybe two of these http://www.batteriesplus.co.uk/acatalog/Rechargeable_9_6_V_AA_NiCd_750mAh_Battery_Pack.html and a separate charger
I suspect each of your "cells" (2.5 to 2.8v) is actually two half-sized cells wired in series and encased in a single casing. That being the case you'll need to get two of the correct length.
John D this battery is approx £150 to replace so I don't mind a little pottering about in the shed. Jackrea its starting to make sense now there are 9 cells 85x22mm and 2 smaller ones. nbt that makes 20x 1.2v =24v so I think I am getting somewhere now. thanks
There are people out there that will do the job for you. I looked into it recently. There's a guy near me (Leicester) that does refurbs for about the same price as you can buy the cells for. Presumably he gets them a lot cheaper by buying 1000's.
No idea what the policy is on links, no affiliation with me, prices here:
http://www.knighton-tools.co.uk/acatalog/Battery_Refurbs.html
No idea what the policy is on links, no affiliation with me, prices here:
http://www.knighton-tools.co.uk/acatalog/Battery_Refurbs.html
Well I would like to say thanks for the replies, I have bought 2 more cells and soldered them in, and the battery is now working again after 18 months.
Apologies for hijacking this thread but I'm in the same boat with regards cordless power tools packing in.
My Bosch impact driver has served me well over the years. I'm loathe to replace if I can simply buy a few batteries.
Opening the pack I see an arrangement of 10 x 1.2v subC batteries.
The pack is rated at 12v 2.6Ah
Looking round, I can find plenty of subC batteries with everything but the correct Ah.
Presumably I don't want to buy a lower Ah, HOWEVER, if I go for the 3000mAh or even the 4800mAh, will this give me a much longer runtime???
And what effect (if any) would this have on the charger/charging circuit inside the battery pack?
My Bosch impact driver has served me well over the years. I'm loathe to replace if I can simply buy a few batteries.
Opening the pack I see an arrangement of 10 x 1.2v subC batteries.
The pack is rated at 12v 2.6Ah
Looking round, I can find plenty of subC batteries with everything but the correct Ah.
Presumably I don't want to buy a lower Ah, HOWEVER, if I go for the 3000mAh or even the 4800mAh, will this give me a much longer runtime???
And what effect (if any) would this have on the charger/charging circuit inside the battery pack?
http://www.batteriesplus.co.uk/acatalog/Sub_C_2600mAh_NiMH_Tagged_Battery.html
Didn't take long to find. They are NiMh so if yours are Nicad you'll have to swap them all out
Didn't take long to find. They are NiMh so if yours are Nicad you'll have to swap them all out
Ahhh, right thanks. I was looking on ebay.
Is it still worth looking at the higher rated ones though - will I get a longer running time? Will I have problems with the charger?
When I bought the tool, I got drill/driver, impact driver & 3 batteries. Really handy to have the spares so one can be charging whilst the others are in use. Currently not getting much runtime as the batteries are obviously nearing the end of their useful life, so wondering if I can improve on what I originally had?
Is it still worth looking at the higher rated ones though - will I get a longer running time? Will I have problems with the charger?
When I bought the tool, I got drill/driver, impact driver & 3 batteries. Really handy to have the spares so one can be charging whilst the others are in use. Currently not getting much runtime as the batteries are obviously nearing the end of their useful life, so wondering if I can improve on what I originally had?
won't the charger be wrong?
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links