[Shop-talk] Rebuilding a Battery Pack vs Buying New Generic

[Bob Spidell]

I'll offer a general observation: Chinese batteries are crap, and a lot, 
if not most, of the 'name brand' batteries--Duracell, Energizer, 
etc.--you see on the Brazilian rainforest site are counterfeit (although 
you'll occasionally get a Chinese battery that is reasonably good). I 
got a 'tip' off Reddit that DigiKey sells legit batteries, and I just 
ordered some Panasonic CR2450s from them (both my welding helmet and 
Mustang key fobs use them).

I have an old Makita 9V drill that I don't use, but can't bear to chuck 
(pun intended). I bought knock-off batteries and they barely hold a 
charge, so there it sits, full of memories but useless. I'm all in on 
DeWalt, but you even have to be careful buying DW batteries as there are 
a lot of deceitful websites that advertise 'DeWalt' but sell Chinese crap.

I think best you can do is buy some of the counterfeits and hope for the 
best, or put your miter saw in your personal museum (like my Makita).

Bob

On 6/25/2025 6:00 AM, Jim Stone wrote:
> Thanks, David.  I hadn’t noticed that the Amazon replacement was 
> Ni-MH.  I know a little bit about Li-Ion and Ni-Cad batteries but 
> nothing about Ni-MH.  Does the fact that the replacements would be 
> Ni-MH have any impact on my rebuild vs. buy decision?
>
> Jim
>
>> On Jun 25, 2025, at 7:48 AM, DAVID MASSEY <dave1massey at cs.com> wrote:
>>
>> I used to have an old Makita drill that came with Ni-Cad a battery 
>> that eventually stopped being usable.  I bought a pair of 
>> lithium-based replacement batteries.  On the surface they looked like 
>> a much better option with double the capacity and they worked with 
>> existing drill and charger. But (there's always a but, isn't there?) 
>> to make Lithium batteries work in a Ni-Cad environment required a 
>> electronic circuit and this circuit was always on and drew enough 
>> power to deplete the battery overnight.  I could charge them up in 
>> the evening and the next morning they would be close to dead.
>>
>> But I see these are Nickel-Metal Hydride batteries.  Ni-MH batteries 
>> have characteristics more similar to Lithium - at least with regards 
>> to the charging regime (I've designed a battery charger for Ni-MH so 
>> I am familiar with this) but are less susceptible to abuse.  I also 
>> see the bullet point about no self-discharge - which was my problem.  
>> This is a $45 gamble (as it is with most no-name stuff from the 
>> Pacific rim) but YMMV.  This might be a good one.  Let us know.
>>
>> BTW I bought a pair of Milwaukee 12V tools and never looked back.  I 
>> pitched all my Ni-Cad drills and recycled the batteries.
>>
>> Dave
>>
>>
>>
>>
>> On Tuesday, June 24, 2025 at 01:36:47 PM CDT, Jim Stone 
>> <1789alpine at gmail.com> wrote:
>>
>>
>> I have an old Bosch 24v miter saw that I would like to be able to 
>> continue using for quick, non critical cuts.  The only problem is 
>> that the NiCad batteries won’t hold a charge long enough to be 
>> useful. And, I don’t think there is a way to utilize other, e.g. 
>> Milwaukee M18, batteries in a 24v system.  Besides, there don’t 
>> appear to be any adaptors available.
>>
>> So, that leaves me with two choices: rebuild my current batteries or 
>> buy new ones on Amazon.  I’ve taken one of the battery packs apart 
>> and can see that it just uses standard Sub C 1.2v batteries - 20 of 
>> them!  I’ve never rebuilt battery packs but it looks pretty straight 
>> forward; just time consuming.  20 Sub C batteries would run me about 
>> $40-50.  (Having it done professionally looks to cost at least twice 
>> that.)  Or, I could just buy a Chinese-made replacement pack for just 
>> a few bucks more. 
>>  (https://www.amazon.com/Exmate-Replacement-Battery-Compatible-BH-2424/dp/B073Z9QHXS/ref=sr_1_17). 
>>
>>
>> I’m sure the replacement batteries are also made in China, but is 
>> there any reason to assume that rebuilding the packs myself will 
>> result in a better, longer lasting battery?  Any advice from those 
>> who have done this before will be much appreciated.
>>
>> Thanks,
>> Jim
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