View Full Version : Laptop Battery

11-03-2002, 04:19 PM
Does anyone know where I can get my Laptop battery (NiCad)
reconditioned please? I would prefer a location within either Christchurch or Dunedin but would settle for nationwide locale if needed. It maybe a cheaper option than paying $200+ for a new one. Thanks.

11-03-2002, 04:35 PM
In Christchurch there is a battery reconditioning outfit on the corner of Gasson and Caryle Streets, right next to the rail crossing.
We have used them in the past, they do a good job and the cost is reasonable compared to a new unit.
I cannot think of the name and phone number as I am not in NZ at the moment but if I can get the number and company name and post back here later in the night if need be.

11-03-2002, 04:47 PM
Thank you Gordon...that would be appreciated if it is not too much trouble.

12-03-2002, 12:07 AM
While on the topic of recharging laptop batteries, does anyone know if it is possible to completely discharge a laptop battery safely, and if so how? My guess is that laptop batteries probably 'die' because they develop the 'memory' problem that other rechargeables (eg torches) do - their life gradually diminishes in parallel fashion. If this is correct, then presumably if one can suitably completely flatten them their life could be restored by recharging them fully in the normal way. This process works with torches and cordless phones, and may be what the 'battery reconditioners' do - for a price! Leaving your laptop on all night may not completely discharge the battery as there may an automatic switch-off mechanism that is activated when the battery voltage drops to a certain level.

Any comments, gurus?

12-03-2002, 12:21 AM
Brian, as requested, here is the contact details.

45a Gasson Street
Phone 03-3771771
Fax 03-3771228
Email - sales@batterymasta.co.nz

They are also on the internet
at http://www.batterymasta.co.nz

12-03-2002, 11:11 AM

I have had great success with NiCad cellphone batteries by discharging them via a torch bulb (on clip leads) until almost flat, then recharging, discharging again, and recharging fully for use. This got me back to virtually full capacity. They were being stuffed by sitting in my carphone holder on permanent charge and had a very short life out of the vehicle.

I used a torch bulb so that I could see when the battery was almost flat as total discharge can reverse-polarise one or more cells and damage them. I kept the discharge process nearby where I could see the bulb out of the corner of my eye and disconnected when it got dim (still orange) but not down to the 'glowing red' stage. You can automate this by adding a couple of silicon power diodes (1N4007 or similar) in series with the bulb. That will cause the discharge to stop at a terminal voltage of 1.2 volts. I was just too lazy to scratch up the diodes and solder them in.

It goes without saying to use a bulb matched to your battery voltage. Torch bulbs are best because they don't drain the battery too fast. You need patience on the second discharge which may take some hours because the capacity is up already.

You might have to fiddle about a bit to find a way to connect a bulb to your battery though I have often wondered if a load could be attached to the mains supply/charger input jack. It might be a direct connect to the battery, though on reflection there's probably some electronics in between that would prevent you using it to discharge. Worth a look though.

No improvement means deceased battery! You can't win 'em all.


Billy 8-{)

12-03-2002, 02:01 PM
BTW, a trick i have learned is you get the battery as flat as it can, then stick it in the freezer overnight. in the morning, take it out, let it warm up, then charge it.

(it works on cordless phone batteries, alway worth a shot)