Bosh GSR cordless screwdriver

[Mr Pounder Esquire]

I have a Bosh GSR 12v Professional cordless screwdriver. It must be well over 10 years old now, mainly used for employment work. I've never been too impressed with the battery life. I'd put the batteries on charge and when the green light on the charger stopped flashing I took the batteries off charge - as in the instruction manual. It lives in the garage. I don't use it much these days, but try to keep the batteries charged. I charged them a few days ago and was disappointed that I could grip the chuck with my hand and the screwdriver REALLY slowed down on both batteries. I could have stopped it. Aww well, time for a new one. Anyway, I shoved both batteries back on charge and left overnight. Now the screwdriver blasts away with a speed I've never seen before, no way can I hold the chuck. When the green light was flashing the batteries were warm. Cold when the light stopped flashing. Has the green light on the charger been lying to me for all of these years?

[Bill Wright]

Often people with disability scooters think they have a faulty battery when in fact they are misinterpreting the charger's green light. Often it means 'good enough to use' not 'fully charged'. I always advise that people leave the machine on charge overnight even if the green light has come on. The problem is that batteries develop quite a high voltage a long time before they are fully charged. Incidentally some of the cheaper machines come with a small non-intelligent charger that takes an inconveniently long time to fully charge. For instance one machine that has a 15A battery has a basic 2A charger with a rather low off-load voltage. Fine you might think but because the charge starts at 2A but then tapers off very rapidly an overnight charge is not sufficient.

Bill

[Mr Pounder Esquire]

Cheers Bill. The manual (long ago chucked out) did say that when the green light is solid the battery is fully charged. Bastards!

[Brian Gaff]

Probably also of course cold batteries do not hold the charge that well. Is it old enough that these are in fact Ni-cads? Half the trouble is self discharge as they age, so unless its left on charge it discharges. Older chargers were not that smart. This was probably why they said take it off charge then so you did not over cook them. Brian

[Tim Watts]

Pretty sure none of the GSRs (I have an early model) were anything other than lithium based.

[Bill Wright]

It might be telling the truth, but I know that with a lot of scooters and their supplied chargers the green light is misleading. Of course the whole situation is messy because sometimes the scooters arrive at the retailers without batteries. The retailers fit batteries of varying capacities and qualities. Sometimes they also supply a charger that they buy as cheap as poss from elsewhere. Then there's Li-ion...

Bill

[Mr Pounder Esquire]

A mate on email told me that when the green light becomes solid the screwdriver is "fit to go". Hmmmmm. Yeah it went, but not for too very long. The batteries are NiMH ..............whatever they are ........ Both batteries have been on charge for a good 24 hours and the screwdriver goes like a house on fire. On ebay the batteries are pushing 20 quid each, I can get half a decent cordless screwdriver for that, and that these days is all that I would need. I have suspicions about the honesty of the recharging instructions. I was once told that all batteries are chipped, this to give them a limited life.