Cordless Drill Battery Rebuild

coL

I have an old Black and Decker 14.4v cordless drill (CP142). It came with two NiCd batteries that are now well and truly knackered. I have since bought a newer drill and rather than throw the old drill away I fancied a bit of a DIY project and am thinking of rebuilding the batteries myself.

Obviously safety is first and foremost in my mind. I don't want to do anything that isn't safe and I will of course have full respect for anything that involves working with or near electricity or electrical goods. I have a few questions to make sure I am going about things the right way and to see if this is even something I should be thinking about doing.

As its a 14.4v drill I presume that I have to stick to 14.4v total in whatever I replace the batteries with or else the motor will burn out?

The original battery says its 1.5 a/h but am I correct in my understanding that I can go for a higher a/h without any issues?

It originally had a NiCd battery but provided I stick to a 14.4v total and depending on the answer regarding the a/h can I go for a NiMh or even a litium battery instead?

The charger that came with it is very basic and doesn't have any indicator lights or any other way that I can see to tell if the charging is complete. Do I assume that this charger doesn't have an auto cut off and is constantly charging the battery (and maybe even overcharging/damaging it)?

If I did change to NiMh or Litium batteries I presume the original charger would not work and I would need to get a different one?

I have seen online that I can get replacement sub c cells (either NiCd or NiMH) easily enough that are already tagged so its just a case of soldering them together in the right sequence and connecting them to the poles of the original battery pack. Is there anything else I should be considering or aware of or does anybody have any suggestions?

I'm no expert on power tools but i think you'll find that anything with a li-ion battery has some sort of microcontroller for keeping the circuits in check.
Not just a case of an on/off switch anymore.

coL

BrownFinger wrote: »

I'm no expert on power tools but i think you'll find that anything with a li-ion battery has some sort of microcontroller for keeping the circuits in check.
Not just a case of an on/off switch anymore.

That's what I was thinking alright. I kind of knew that if I went for Li-Ion cells I would probably need a different charger but not sure what the situation would be if I go for Ni-Mh cells. I think I would probably need a different charger for those too as its not certain my current charger would work.

Bruthal

Yes I have used lithium batteries in items that originally had nicad or lead acid. But I put together microcontroller circuits to sense the state of charge and cut off power when discharged. Without that, lithium batteries will be ruined if run too low.

A charger designed for lithium batteries is also needed.

Bruthal

BrownFinger wrote: »

I'm no expert on power tools but i think you'll find that anything with a li-ion battery has some sort of microcontroller for keeping the circuits in check.
Not just a case of an on/off switch anymore.

Analogue - digital conversion setup with a microcontroller I've used to do it. Voltage reaches a certain level and microcontroller switches off a mosfet. One use was in a camping LED lantern. 1 hour to charge instead of all night with its lead acid battery. Only down side was it go off suddenly when discharged level reached. But adding in 7 seg display for charge level indication is easy enough.

whizbang

I had one of those drills up till very recently, great yoke.

First off, can you get 12 x cells for cheaper than a new drill ?

It will work with almost any voltage, I wouldnt be in the least bit worried about going up to 20v.
but whatever you decide, the Charger is the most important bit to get right.

coL

whizbang wrote: »

I had one of those drills up till very recently, great yoke.

First off, can you get 12 x cells for cheaper than a new drill ?

It will work with almost any voltage, I wouldnt be in the least bit worried about going up to 20v.
but whatever you decide, the Charger is the most important bit to get right.

I have found a uk website that will sell me 12 sub c cells with a higher a/h rating for around £35 incl postages which is less than a replacement battery or a new black and decker drill. To be fair there isn't much in it in terms of cost but I like tinkering with these sort of things. I have already bought myself a replacement cordless drill so am as happy to try this rather than throw the old one away.


I would have though voltage would be an issue, is there not a danger the motor will burn out wiht a higher voltage?

Only doing bits of DIY with it so not too pushed about the voltage, higher would be better but then I have the problem of fitting the extra cells into the old pack so might not be worth the hassle.


The website I found can sell me NiCd cells so I might just stick to those rather than mess around with trying to get a new charger if I go with a different type.

Kat1170

Just a thought, replacement NiCd drill battery and chargers for sale in Aldi. Take the battery apart and use cells to rebuild your own drill battery and charger will prevent overcharging.

coL

Kat1170 wrote: »

Just a thought, replacement NiCd drill battery and chargers for sale in Aldi. Take the battery apart and use cells to rebuild your own drill battery and charger will prevent overcharging.

Hadn't though of that, will go have a look at what they have. Thanks very much.

dathi

test the cells in the old batteries usually only one or two cells dead and you can make one good battery out of two. done it with old makita 18v had 5 duds ended up with 3 batteries for no costs except time

autumnalcore

dathi wrote: »

test the cells in the old batteries usually only one or two cells dead and you can make one good battery out of two. done it with old makita 18v had 5 duds ended up with 3 batteries for no costs except time

^this - when you run the battery too flat some cells may be depleated before others and the current flowing through those cells damages them, moral of the story charge it before it goes flat. As daithi says the other cells may still be perfect.

bcklschaps

A company called Batteryworld (they have shops around the country) will rebuild old NiCD or NiMh batteries. Think it's about €50 for an 18v....be a bit more for 24v or 36v

https://www.batteryworld.ie

coL

The drill was in storage for a few years and not used. I suspect that most of the cells are beyond recovery at this stage. How would I test them?

I saw batteryworld alright and the service they offer, but it works out more expensive than the replacement I can get from the uk. Plus half the attraction is tinkering round myself to see if I can do it.

dathi

https://www.youtube.com/watch?v=nDtV26Qwue4

bcklschaps

coL wrote: »

The drill was in storage for a few years and not used. I suspect that most of the cells are beyond recovery at this stage. How would I test them?

I saw batteryworld alright and the service they offer, but it works out more expensive than the replacement I can get from the uk. Plus half the attraction is tinkering round myself to see if I can do it.

You will need to buy replacement cells and spot weld the connectors etc. (Have you access to a spot welder?) will cost you about 2 or 3 times as much to rebuild battery yourself ...leave it to the professionals...or take your chances buying a replacement on Internet.

bcklschaps

coL wrote: »

The drill was in storage for a few years and not used. I suspect that most of the cells are beyond recovery at this stage. How would I test them?

I saw batteryworld alright and the service they offer, but it works out more expensive than the replacement I can get from the uk. Plus half the attraction is tinkering round myself to see if I can do it.

You will need to buy replacement cells and spot weld the connectors etc. (Have you access to a spot welder?) will cost you about 2 or 3 times as much to rebuild battery yourself ...leave it to the professionals...or take your chances buying a replacement on Internet.

Phil.x

I got a battery on eBay for my makita 14.4v, its original batteries were 1.3ah, the new one is 3ah and is better than ever, life in the old dog still (14years old+)

coL

bcklschaps wrote: »

You will need to buy replacement cells and spot weld the connectors etc. (Have you access to a spot welder?) will cost you about 2 or 3 times as much to rebuild battery yourself ...leave it to the professionals...or take your chances buying a replacement on Internet.

Going to buy cells that are already tagged so there will be no need for spot welding. All I will need to do is solder the connections together.

coL

Phil.x wrote: »

I got a battery on eBay for my makita 14.4v, its original batteries were 1.3ah, the new one is 3ah and is better than ever, life in the old dog still (14years old+)

Even though I haven't had any bad experiences with Ebay I don't know if I would trust buying batteries there. Seem to be a lot of fake stuff on there now and very hard to judge the quality.