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How do I determine what batteries I need?

kuurt

Jun 20, 2014
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Jun 20, 2014
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I have an old cordless drill that had an internal chargeable battery. The battery is dead now and will no longer take a charge. I can see online that they don't make a replacement battery for this particular drill any longer - it has become obsolete.

I don't know a lot about electronics, I just like to take things apart and figure out how they work. I was able to figure out how the electricity flows in this drill and how the two switches work. And I don't want to throw this old drill away - surely I can do something with it.

The problem is that I need some kind of batteries for it that are chargeable and I don't know what kind to get. I experimented with double A batteries thinking that 4 of them would give me the 6 Volts that the drill needs. But, I quickly realized that's apparently not how it works electrically speaking. The drill does say 6.0 Volts on it, but what happens with the double A batteries is that they drill will work for a few seconds and then stop. All my connections are good, but the ends of the batteries are getting hot. So, what's going on there? I'm guess that while the double A batteries do make 6 Volts combined, they're really not meant to run at that full capacity constantly as required by a power drill. Is that what the problem is? After all, we often use double A batteries for things that don't require much juice like a television remote. And maybe the drill actually requires more than 6 Volts and it says 6 Volts on it because that is what it charges at. I'm not sure.

Could someone explain it to me, and show me what kind of rechargeable batteries I would need for this drill? I'll put the info on my drill below, but If it all possible, I would also like to know how you would go about determining the battery specs for a particular project.

Thanks

Additional Drill Info: Black & Decker, Cat. No. TS220, Type 2, 6.0 Volt DC, 225/550 RPM
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
25,510
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25,510
The best bet is to open up the existing battery pack and see what's in it.

Depending on its age, they could be NiCad, NiMH, or lithium. However I'd place my bets on NiCad. And if it's NiCad they will be probably sub-C size and there will probably be 5 of them.

Look here and here. The second link id for the type 1 variant. It clearly shows that there are 5 cells, and they are probably sub-C with solder tabs.

The batteries should be easily obtainable. You may find that the ones you can get are a higher capacity than the originals -- that's fine. Specialist battery places can make up the pack for you and probably fit it into the plastic case

The main problem with these devices is that the chargers kill the batteries. If you replace the batteries, consider getting a charger that will keep them in good condition.
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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Oh, if you open the pack, it is important that you note which way around the cells go and in what order they're connected. Take photos and/or keep the existing pack intact.
 

kuurt

Jun 20, 2014
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Yeah they are NiCad, and there are 5 of them attached together by tabs.
I see there are some on Amazon that say subC NiCad. Looks like they are all 1.2 V - I guess that will work. But, they also say something like 2200 mAh - what is that? Does it matter what the mAh says?

How do I attach these batteries together? Would I need to get the ones with tabs and solder them together?

How do I know what kind of charger would keep the batteries in good working condition and not kill them?
 

Jagtech

Feb 22, 2014
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A local battery shop will have those individual cells with the tabs, and will "weld" the tabs for you, usually at no extra charge. And higher MAH usually means longer time between charges, but 2200 ma is pretty much the norm for sub-C size batteries.
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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Does it matter what the mAh says?

That's the capacity of the cell. As I said, this is probably higher than the originals and that's fine. As Jagteck says, it means the run time is longer.

How do I know what kind of charger would keep the batteries in good working condition and not kill them?

The good news is that the batteries are connected straight to the charging port on the drill (from what I can see from the exploded diagram). This means you can get a nicad charger and make up a cable to connect it to the drill.

You'll be looking for something that can charge at least 5 cells in series. If you go to a good battery shop to get the pack rebuilt (yeah, even I would do that because they do a much cleaner job of connecting the tabs) then I'd ask them if they can recommend something.

Here is a document that describes the charging process for cells.

I have one of these. Something like this would also be fine. Note that you may be able to use it for charging all sorts of other batteries and tools. It's a worthwhile investment. You may not be able to find these exact models, but you can see the features they offer. They're quite different to a simple chargers that are supplied with most older battery operated power tools.

Fortunately things are becoming better. Newer tools use lithium batteries. These will explode or catch fire (or at least emit lots of nasty smoke) if you don't charge them correctly. It provides an incentive for the manufacturers to provide correct charging because the side effect of not doing so is liability rather than extra sales.
 

kuurt

Jun 20, 2014
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Both of you guys mentioned battery shops. I guess those must be normal where you live. Sounded strange to me, because here in Indiana, I don't think I've ever seen a battery shop in my entire life. I guess I'm going to have to order them online and solder them myself. :)
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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Try googling "Batteries Indiana".

You'll find several specialist battery retailers. Give them a call and ask them if they can make you up a pack "Batteries Plus" is the iconic American store for this and they appear to have franchises (?) located all over Indiana.

One issue with soldering them yourself is that it's very hard to get the batteries as close together as a welded pack. This can put stress on the battery holder and (depending on the cell) can increase the risk of shorting out a cell.
 
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