Charging Ni-Cads (drill)

[Stuart Badger]

Hi PDs

I have a question for all those versed in  the black art of 'lectrics!

As some of you may know my battery charger for my cordless dril is US. My question is could I use a 6/12volt car battery charger to recharge the battery packs? or is there a potential problem with the Ni-Cads overheating?

I simply cannot afford a new drill and I (believe it or not) do not possess a hand drill other than a vicious 'drill a hole through 5 inches of steel' Bosch industrial mains one!

Waiting in anticipation

Stuart

[Eddy Matthews]

What voltage and capacity are the NiCads Stuart?

Regards
Eddy

[Stuart Badger]

Hi Eddy!

the battery packs are 12v (made up I think of indiviudual cells. I don't know the amperage but the charger says;

Output - DC 14.5v - 18.5v......1A for 10-12 cell battery.

Does that help?

Stuart

[Eddy Matthews]

Well, all I can say is that I've done it in an emergency, though I wouldn't recommend it as a permanent solution....

The charger should be okay for a 12v pack, but bear in mind that it won't shut off when the cells are charged, so you should keep an eye on them while charging - Feel the cells with your hand and if they are starting to get warm to the touch they are close to being charged. If they start to get hot then stop charging immediately before any damage occurs!

A lot of power tools have fairly small capacity cells (around 1.2A-1.9A), so at a 1A charge rate your lookin at 1-2 hours to charge from flat.... But as I said above, keep an eye on the temperature, and do not leave them to charge unattended!

Eddy

[Stuart Badger]

Thanks Eddy!

The charger says on it 12v - 1 hour. So if I make sure that it doesn't stay on for more than I hour I should be ok? I think the duff charger had a temperature sensor in it.

I'll give it a go - OUTSIDE!.

All the best

Stuart

[steamboatmodel]

I'll give it a go - OUTSIDE!.

You may want to add a resistor in series with the charger. When I first started using nicads I used to use a car charger and a length of nichrome wire and still had a few go bang.
Regards,
Gerald.

[chipmonk]

Hi Stuart.
Do you have a charger for model nicads if you can make a decent connection between the two and the charger is rated for 10 cells then you can use it. I had to do this when my battery drill charger went bang in the middle of a job. I was able to cannibalise the charger case to provide the connection and couple it up to my model charger. Battery drill packs use std high discharge cells the same as in our model packs.
Hope that this helps.
Cheers Chris M

[Stuart Badger]

Thanks for the advice guys!

Today my beautiful assistant told me to close my eyes, 'What' I thought 'Is going on, it cant be "that day" again,  and we had a cuddle only last year!' She then presented me with a 14.4 volt Bosch cordless drill complete with 2 batteries and charger. I feel the very least I can do to show my appreciation is make her a cup of tea sometime this month!

Stuart

[Eddy Matthews]

Don't ya just love em?

Eddy

[Stuart Badger]

Yup!

Stuart

[sandystrone]

When I charge cells like that, I put a 12v car side light bulb on the positive input lead to act like a resistor.

[Stuart Badger]

Thanks Sandy!

Stuart