Li-ion Laptop batteries for Panasonic toughbook used on boat

[Habebty]

Rather than pay £75-90 for a new battery, are there any techie tricks for breathing life into a battery that appears to refuse a charge (li-ion type for toughbook). I have a 12v adaptor for the lap top but would like the back-up of internal battery power.

 

[kingfisher]

I had the same problem and just left the battery out. I cut the charging cable from the adapter, fitted a 12V plug and it plugged straight in the cigaret lighter of the boat. Think of it as a laptop with an eeeenormous battery, all 95ah of it.

Leaving the battery out also saves energy: the laptop is not constantly trying to charge itself.

bad news is: you can't take it to the internet cafe.

 

[Brayman]

Aren't you in danger of blowing the power unit in the laptop with surges from the charging system and when starting the engine?

 

[AlanPound]

You could try ebay - sometimes there will be someone offering new batteries that are compatible...

Otherwise, if the battery pack is truly finished, you could try (carefully) cutting it open - ideally, don't bust open the batteries themselves /forums/images/graemlins/confused.gif

Typically, it will contain standard cell sizes, which you might well be able to replace at Maplins or whatever (although many more recent battery packs have some degree of intelligence in them that might object to this treatment...)

 

[Evadne]

Li-ion is actually quite a robust technology, they stand a fair bit of abuse and are reckoned to be good for several hundred recharge cycles but insurers etc. are so scared of the consequences of a mishap that most "batteries" have two or three levels of safety built in, which is what may have gone wrong. Their fears, though, are not entirely groundless.

If you're feeling brave, and have the knowledge then digging into the packaging and looking for fuses may yield results. Battery state monitor ICs check max and min voltage, and current flow, and prevent charge or discharge if they are wrong. A simple broken solder joint between the cells would throw these. There is, of course, the possibility that a cell has turned its toes up, e.g. been over discharged, so the battery really is dead.

It depends on how brave you are. I would say though, that if you have a worry that you may not know what you're doing then a doing, then don't. A new battery is much cheaper than taking apart the old one in the kitchen, then having to buy a new kitchen because the old one burnt down. A fully charged Li-ion holds a fair bit of energy that it will readily release at an impressive rate, should you short it out or overcharge it. It also gives off hydrogen gas when abused, which burns quite merrily. Cylindrical cells are also more dangerous than the flat pouched ones, and can explode with some force. I would do it next to a (stainless steel) sink full of water, and throw the battery in there at the first sign of smoke. And definitely when SWMBO is out.

 

[kingfisher]

[ QUOTE ]
Aren't you in danger of blowing the power unit in the laptop with surges from the charging system and when starting the engine?

[/ QUOTE ]

Don't think so: the laptop is actually rated at 19V (output of laptop adapter), but runs happily, if somewhat slowly on 12.3V. So I assume that if there is a powersurge capable of frying the laptop, all the rest on board will be dead too.

And the laptop is fairly disposable, so I'm not too worried.

 

[mikejames]

I did this as an experiment and then I realised that the current taken by the laptop will increase as the supply voltage is reduced to maintain the power.

Although the laptop under test worked direct from 12 volts, the current went from 3 amps to 5 amps plus. I realised that components may be reaching the limit of their ratings due to the current.
There will probably be components trying to unsolder themselves off the circuit board because of the extra heating effect of the higher current.(coils and capacitors)
It will work ok for a while then fail on a hot day or have a shorter life time than when running off 19 volts. Alternatively it will gradually begin to freeze up more frequently as capacitors run too hot dry out and lose the ability to stand surges caused by the PC's normal running.

When I tried it the machine in question was still leased and so I was not prepared to hand one back with an embarrassing fault that could only be caused by abuse...

You will also lose any protection from surges caused by switching other heavy loads on and off the alternator.

But as you say the laptop is disposable , please report back on how long it actually runs for.

 

[ytd]

I have some success with cutting open the original battery, removing the cells and packing the case with Ni-MH AA cells in cell holders brought from an electronics stores. I could fit 5 3 cell spring holders into the battery case giving me 18v. Two problems. The battery doesn't hold as much charge as the original one did. Good for only about half an hour. Also if you drop the laptop one of the AA cells can become loose and you need to disassemble the battery to re-fit it.

 

[Ecartar]

http://cgi.ebay.co.uk/PANASONIC-TOUGHBOO...1QQcmdZViewItem

 

[Spyro]

Panasonic toughbooks are widely used by British gas and British telecom engineers.
Find one and ask him/her to swap of their battery for a small quantity of Beer tokens. /forums/images/graemlins/smirk.gif If theirs are faulty they get them replaced free of charge. /forums/images/graemlins/laugh.gif

 

[Victoriag]

http://www.batteryup.com/Dell-Studio-Batteries/

A battery is charged with current, not voltage. But of course the voltage must be high enough.
If you don't limit the charging current then the battery might melt or blow up.