Help with Makita battery problem

[Amp David]

I have a pairof 24 volt 3.3ah NI-MH batteries and yesterday I put one to charge. Within 10 minutes the charger had said it was fully charged. Put it onto the drill and there was almost no speed with the drill.

Checked the voltage today and its showing 24.6 volts, but when used its like a flat battery. Anyone know of whats causing this.

 

[J@mes]

Measuring the battery voltage with no load on is a bit worthless really as it doesn't really give an idea of the battery condition.

how old are the batteries?

 

[Amp David]

Fair comment. They are probably 41/2 years old, but not had that hard a life in regards number of charges

 

[rocker]

Still pretty old for NIMHs..... may just be getting knackered from old age.

Apparently you can flash them with a welder which will give them a few more months of use. I have never tried this, by the way, but I'm sure there's a post about it on here somewhere.

 

[Marvo]

Are you using the correct charger that was supplied with those specific batteries? I came across a Mactec charger which fitted certain Makita batteries but it didn't charge them properly. If you did it the other way around and put the Maktec batteries in the Makita charger they overheated.

 

[Amp David]

Alls been well until yesterday with no gradual loss over a period of time. Is this how they fail?

Been told to use the welder method, but not to confident in trying it TBH.

Its the same Makita charger i've been using since day 1

 

[oldtimer]

These batteries are only good for 5 years it is the same with burglar alarm batteries your 4 1/2 comment says it all to me yes you have voltage but what you dont have is capacity so if the battery is a 24v 3 amp hour unit that lasts 2 hours then after 5 years or a hard life it bcomes a 24v 0.5 amp hour that lasts 10 minutes

Forgot to add go to the Yuasa web site and you will get more info on a batteries lifespan

 

[Amp David]

Its decision time now then, 2 new batts at 100 quid each or a nice new Bosch 36 volt jobbie. Decisions decisions

 

[oldtimer]

Pros and Cons says you would be cheaper getting a jobbie with a 1 year parts and labour warranty

 

[rocker]

Well if you're scrapping the batts why not try the welder method anyway? I read somewhere you can crack it open and do the same thing on the individual cells inside with a car battery.

 

[rocker]

Ooh ooh I just had a thought, you didn't try charging them right after you used them, did you? Could be thermal issues making the charge stop short. And is the same thing happening to both of them all of a sudden? If so, I'd try another charger 1st. Mind you, at 4.5 years you're near the end of their life anyway.

 

[Amp David]

They had been left overnight before charging. Another battery of the same model charges ok so ruled out the charger.

Giving it a go with a welder anyway, like you say if they are dead might aswell try it. Will it work with a MIG welder or does the current only flow through the welding wire on those?

 

[pennywise]

Go with a new Bosch 36v makita are micky mouse wood butcherers tools no better than Dewalt

 

[Amp David]

Anyone know the cheapest place to get a 36 voly Bosch with the 3ah batts instead of 2.6 ah?

 

[electricians]

time for a new gun