Renew Your Laptop Battery





Introduction: Renew Your Laptop Battery

Change Your Laptop Battery cells instead of buying expensive new battery...

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If the battery is a 2100 mhA can i use new 18650 cells of 4000mhA? will not change the output?

1 reply

It will only last longer, but make sure it has the same physical size, should be the same if both are 18650s.

Hi I've replaced cells of my 8-10 year old Fujitsu laptop with cheep cells but only got the same lifespan (45min tops). After re-soldering the pack and even replacing the original set of cells the laptop now alternates between 99% charged and 0% capacity continuously every 3 seconds or so and shuts down immediately once the AC power is shut down.

Could I have damaged the battery circuit?

If the battery is a 2100 mhA can i use new 18650 cells of 4000mhA? will not change the output?

3 replies

It's a bit late, but for anyone else wondering, there are no (true) 4000 mAh cells yet. The highest at time of writing is 3500 mAh. Anything claiming higher is a total fake.

As long as the voltage is the same as the old batteries, you'll be ok.

Excellent! Giving this a shot right now! Just what I needed...thanks!

This is a waste of money and time. I replaced my toshiba battery with new cells but buttery itself doesn't identify new cells. The problem is there is a microchip in battery which has the details of the battery. To reset the battery you have to reset the values on EEPROM of battery too. If you can find a datasheet of the MCU you maybe able to reset it by grounding the RESET| pin. Be causes!!!. Otherwise you have to use be2works software and GPIO cable. But you will not find it for free on internet. Best option is to go for a duplicate battery on ebay and replace the cells with orginal s3 battery before using it.

How can i define which kind of cell i need to replace my dead cell of my laptop battery? My product is "Dell Vostro 1540 6 Cell battery". 4400 mAh, 6 cell.

There is no mention of volt, mAh rate on the cell.

Also please tell me where from can I buy and collect these cells? My local store doesn't hav these.

nice job but would it be possible to use NiMH batteries, they seem to be able to withstand a high number of charges

2 replies

2 years is late for a reply but the answer to your question is "NO". Not unless you change the charging circuit to suit different kind batteries.

the chemical makeup of the cells should matter less than the actual maximum discharge current (measured in Amps) that the cell can withstand. As a rule of thumb, the higher the rated Ampere of a rechargeable lithium cell, the longer it's lifespan (because it takes less damage on recharging than a cell which can withstand a lower current)

Hmm I did this with my t400 thinkpad, expected 10.8A with 9 cells

Unfortunately when I connected it, it blew up the charging board. I'm glad my laptop is OK!

any clue what happened? I used fully charged cells. Too much juice I'm guessing...

1 reply

Some of the cells in the pack must have had different amperage and/or were nearing their lifespan. Happens a lot with cheap knockoff cells that are more-than-often repackaged dead cells from the recycle bin.

That's why the multimeter is a geek's best friend :I

8 Samsung batteries for $17, these days, would be Chinese "fakes"!...When the Chinese rate a cell at 5000mAh, it means 500mAh in real life.....So you could expect a capacity of about 1Ah all up..

Genuine Samsungs or Panasonics are at least $13 each..

So cheaper to buy a new battery..

Surprisingly Laptop batteries from China are quite good with reasonable capacity.

Probably worth buying a laptop battery to get some half decent cells for your torch .

So don't throw that old battery away..pull it apart and check the cells with a meter, you may find a pair of dead ones and the others are OK :)

1 reply

Not if you get them shipped str8 from the factory off Alibaba.

High-end 3100mah 20Amp Efest batteries (which have an authentication code sticker on each cell that you can verify on their site) are 4 to 6 usd per cell at most (not including shipping tho)

But yea, gotta' be careful of obvious knockoffs like those laughably tagged 6000mah batteries you might come across.

Wow, didn't even have to connect the new battery pack in parallel to the chip before desoldering the old one?!

AND the chip shows 100% right off?!!




t is only dangerous if you don't know what you are doing. Laptop batteries can take A LOT before they actually become dangerous.. Shorting them out, or deliberately placing them in a fire or anywhere hot.

good job