Would a higher watt hour battery kill a laptop?

HappyTorrent

Commendable
Nov 8, 2016
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This all started because I bought a Chromebook on Letgo for $15 and since I was really far from where the dude wanted to meet he threw in a free laptop. I found out the Chromebook is re-enrollment locked so I'm not even going to bother with it. The laptop he said would power on then shut off immediately. I found out that the problem was a corrupt Windows 7 installation. I also found out that it had a faulty ram stick. So I wiped the HDD with Ultimate Boot CD and reinstalled Windows. I spent several hours getting drivers for the laptop. Eventually I got it working. Now my only problem is that the battery is shot in it. It's a Durabook s15c. So a replacement battery is expensive. I have a couple of laptop batteries though that I've salvaged from other laptops. The problem is that either they have a matching voltage and a higher/ watt hour or on the other batteries the voltage is to high. I want to repair the Durabook battery (rated for 11.1v and 49wh) with parts of an hp battery (rated for 11.1v and 100wh) but will the higher watt hour kill the laptop? If so could I repair the battery with parts of a battery rated for 10.8v and 47wh or would my laptop become under powered?

Any help will be much appreciated.
 
1) I seriously do not recommend taking apart and swapping parts between lithium-ion batteries. They're very temperamental about how they're charged, and mis-charging them can cause them to catch fire or explode. If you do wish to try, consult with an expert who fixes laptop batteries for a living.

2) Lithium-ion cells are 3.6-3.85 Volts. The 11.1 V battery is just parallel groups of 3 cells arranged in series (3.7*3 = 11.1). Same with the 10.8V (3.6*3 = 10.8). There's no way of knowing if the difference (3.6 vs 3.7 V) is an actual difference in the chemistry, or just a difference in the specs on paper. Yet another reason not to try fixing this yourself.

3a) The Wh refers to the capacity of the battery. The laptop doesn't care about the capacity. In all likelihood the laptop will work fine at either 10.8 or 11.1 Volts. So if you can find a battery rated for that voltage with any Wh capacity which fits, it will most likely work. (The charging mechanism determines the charge state of the battery by measuring the voltage, which slowly increases as the battery is charged. So Wh capacity doesn't matter.)

3b) Based on the processor, this laptop was made in 2009 shortly after the spate of laptop and phone battery fires. That's unfortunate because the entire design philosophy of Li-ion batteries changed about then. Prior to the fires, the manufacturers put the charging circuitry in the battery, under the theory that you could match the charging circuitry to the battery chemistry, so it would always charge the battery perfectly.

Unfortunately, that led to a flood of cheap knockoff batteries from China which would fit in the laptop or phone, but had poorly designed charging circuitry. People would balk at the $150 price of a replacement battery, order a cheap Chinese knockoff from ebay or Amazon, and plug it into their phone/laptop. The first few charging cycles it would work just fine. But after the battery degraded slightly the simplistic charging model built into the charger would no longer work, and the battery would catch fire or explode.

Consequently, manufacturers moved the charging circuitry into the device. That way you can hook up any battery whose specs are close, and it'll charge safely. Unfortunately since this laptop straddles this transition period, there's no way to tell which type of charging circuitry it has. Thus (3a) may not apply.

If you wish to pursue this, I would highly recommend taking the laptop to a qualified repair shop and see if they can figure out if it's safe to plug "any" battery into it (charging circuitry in laptop), or if you must buy the expensive Durabook battery (charging circuitry in battery).

tl;dr - This battery may not be a simple device where you can just swap parts in and out at will. There's a high probability that doing so will result in a fire or explosion. Consult with an expert repair shop before attempting what you're trying to do.
 

HappyTorrent

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Nov 8, 2016
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I'ma hold you to that lol. Thanks man. I'll see what happens
 

mrmez

Distinguished
Aug 15, 2006
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19,010
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I just going to throw this out there and say, if you don't know what watt-hour is, you probably shouldn't be messing with repairing a battery.
Lithium batteries can and will explode/ignite if you short or damage them.
 

HappyTorrent

Commendable
Nov 8, 2016
20
0
1,560
0


I know enough about batteries to mess with them. I just never cared to learn the terms lol
 
1) I seriously do not recommend taking apart and swapping parts between lithium-ion batteries. They're very temperamental about how they're charged, and mis-charging them can cause them to catch fire or explode. If you do wish to try, consult with an expert who fixes laptop batteries for a living.

2) Lithium-ion cells are 3.6-3.85 Volts. The 11.1 V battery is just parallel groups of 3 cells arranged in series (3.7*3 = 11.1). Same with the 10.8V (3.6*3 = 10.8). There's no way of knowing if the difference (3.6 vs 3.7 V) is an actual difference in the chemistry, or just a difference in the specs on paper. Yet another reason not to try fixing this yourself.

3a) The Wh refers to the capacity of the battery. The laptop doesn't care about the capacity. In all likelihood the laptop will work fine at either 10.8 or 11.1 Volts. So if you can find a battery rated for that voltage with any Wh capacity which fits, it will most likely work. (The charging mechanism determines the charge state of the battery by measuring the voltage, which slowly increases as the battery is charged. So Wh capacity doesn't matter.)

3b) Based on the processor, this laptop was made in 2009 shortly after the spate of laptop and phone battery fires. That's unfortunate because the entire design philosophy of Li-ion batteries changed about then. Prior to the fires, the manufacturers put the charging circuitry in the battery, under the theory that you could match the charging circuitry to the battery chemistry, so it would always charge the battery perfectly.

Unfortunately, that led to a flood of cheap knockoff batteries from China which would fit in the laptop or phone, but had poorly designed charging circuitry. People would balk at the $150 price of a replacement battery, order a cheap Chinese knockoff from ebay or Amazon, and plug it into their phone/laptop. The first few charging cycles it would work just fine. But after the battery degraded slightly the simplistic charging model built into the charger would no longer work, and the battery would catch fire or explode.

Consequently, manufacturers moved the charging circuitry into the device. That way you can hook up any battery whose specs are close, and it'll charge safely. Unfortunately since this laptop straddles this transition period, there's no way to tell which type of charging circuitry it has. Thus (3a) may not apply.

If you wish to pursue this, I would highly recommend taking the laptop to a qualified repair shop and see if they can figure out if it's safe to plug "any" battery into it (charging circuitry in laptop), or if you must buy the expensive Durabook battery (charging circuitry in battery).

tl;dr - This battery may not be a simple device where you can just swap parts in and out at will. There's a high probability that doing so will result in a fire or explosion. Consult with an expert repair shop before attempting what you're trying to do.
 

mrmez

Distinguished
Aug 15, 2006
266
0
19,010
40
The basic specs of a battery are extraordinarily simple.

-Chemistry
-Voltage
-Capacity

If you don't know these basics, what do you actually know?
And that's not a rhetorical question.
 
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