Cordless drill battery

[nabby68]

Hi
I'm not sure if I'm posting this in the correct forum but here goes.
I have a Makita cordless drill with two spare batteries which I've had for about five years. I cane to use it the other day and it went flat really quickly, I then put both batteries in the charger and they fully charged very quickly so I used my drill again and the batteries went flat within 1minute of usage. I then measured the voltages for both batteries which both read 14.4v which is what they are supposed to read yet they are almost flat????
Any ideas please as to why this is?

 

[RF Lighting]

Your batteries are knackered. You'll get 5 years at best from a drill battery.

 

[big-all]

they should start at around 20% over volt for a 1hr charge at around 17v

you can try several charges/ discharges over several hours or days day but doubt you will have any lasting joy as at 3 years plus your battery will loose power/capacity gradually with age

 

[stillp]

If they're NiCad batteries, you might improve them by repeatedly charging and then fully discharging (watch they don't get hot) but if they're NiMH you can't do anything other than replace them.
I just had to replace the NiMH batteries on my Makita, which must be 15 years old, but then I tried a new drill with LI-Ion batteries, and was blown away by the extra power from the newer drill.
Cheapo Chinese batteries for your 5 year old drill might cost £10 each, whereas a new drill, with charger, can be had for not much more. I now have a Makita 18V hammer drill/driver for the heavy stuff, which was £130 last year,and a Bosch professional 10.8V drill/driver (£70) for general use. Only one battery with each, but I can't think of any job that can't wait for a 20 minute tea break while the battery charges!

 

[nabby68]

Thanks for all your replies

The batteries are nicad. May well try and improve them by charging and discharging to get me by for now but still don't understand why they're reading over 14v when apparently flat?


Anyone recommend a reputable site to get replacements?
Thanks

 

[stillp]

Presumably you're measuring with a high impedance multimeter, which doesn't put any significant load on the battery. If you put a load (e.g. a car taillight bulb) across the battery and then measure the voltage you'll get something much lower. This is because the internal resistance of the batter has increased.

 

[RF Lighting]

I get batteries from ITS London or screwfix. Be careful buying off eBay there's lots of fakes about.

 

[stillp]

Genuine Makita batteries for my old drill were around £80. A new drill of the same model, with 2 batteries and a charger, was £119.