Laptop battery rejuvenation

  Wilham 20:51 21 Apr 2004

My son borrowed my laptop and complained the battery only lasted 2 min. I explained it was only used as a reserve PC and then always on mains.

Later I charged the battery for several hours; the laptop ran on it for only 10 min. Repeating the cycle it lasted 22 or 23 min.

Is there a way I can program my laptop to tell me how long it runs each time before the low-volt slow down, to give me some idea about the diminishing benefit?

The laptop is a Sharp PC-GP10_CH with NIMH battery.

  computernerdiamnot 21:01 21 Apr 2004

It sounds like your battery has died a bad death the prob cause for this is running of the mains with the batt connected. Rule of thumb dont leave batt in if your constantly running of the mains.

  sattman 21:09 21 Apr 2004

I would suggest that all the indications are that the battery is no longer servicable. The specification will give you expected battery usuable time with a brand new fully charged battery. I do not think that there are is any that you can obtain the information you require without making internal modifications.

  sattman 21:13 21 Apr 2004


I must say that I was not aware that you should not run a lap top this way.

I always thought that if on the mains the battery was trickle charged.

Thanks for the info.

  Wilham 21:14 21 Apr 2004

I saw two offers on web sites to rejuvenate NIMH laptop batts, one was £25, other £45,... both + delivery and vat.
My own simple attempt shows improvement, ... how far can this go?

Does it me NIMH batteries still have some memory after all?

  wee eddie 21:25 21 Apr 2004

about what to do with Laptop that is almost constantly on the mains.

1. Remove battery when fully charged - only replace battery when you go on the road.

2. Leave battery in all the time - at least once a month - unplug and run the Laptop till the battery is totally flat.

3. Just leave the battery in.

Other unknown methods

To the best of my knowledge, no one has done any test to destruction tests yet. All batteries die eventually, I have seen reports of between 500 and 1000 recharges as expected.

  computernerdiamnot 21:42 21 Apr 2004

very rechargeble batt has a limited time life, eveytime you leave a batt in a laptop while using the mains and switch of the batt trickl charges back the slight discharge that goes on but when doing so counts it as a full charge. To look after batt if you dont really use batt power, fully charge, take it off and at least once a month put batt back use only batt run it down charge it back and take off again. As to wilham's post for rejuveated batts i cant help there as i only buy brand new for the piece of mind and warranty.

  computernerdiamnot 21:45 21 Apr 2004

Sorry for the mispelling

  Djohn 21:51 21 Apr 2004

click here for loads of useful information on Laptop battery's. j.

  Wilham 21:56 21 Apr 2004

It came as a shock to find the battery in my Sharp was not listed by most suppliers. It was said in one forum all GP10-CH models were sold only by PCWorld/Dixons group, and also that replacement batts cost more than £200.

You will see why I'm keen on batt rejuvenation.

  Wilham 21:59 21 Apr 2004

Djohn, brilliant.

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