Rebuilding a laptop battery pack

[Shrek]

Why not just buy the replacement battery?

I have (a 6 cell version), but was wondering about rebuilding the old 9 cell version.

 

[caroline!]

As said, it's doable. I know how they're built but my work usually involves the opposite, disassembling in order to get the 18650s out of them. That's how I got ~40 cells for my various projects, they're versatile, the voltage is perfect for anything involving lights (name torches, emergency lights, decorative LED stuff...), they've proven fine for other devices such as radios, portable speakers, keyboards, and so on. Could probably drive a super low power computer and LED monitor for a while with a pack of them too. It's only a matter of coming up with ideas around them.

My love goes for 14500 and 26650s as well, sometimes you need one to fit into an AA slot, sometimes the extra juice for more demanding contraptions. I get a lot of power outages so I'm interested in anything with batteries and retrofitting designs to accept them.

 

[Mussels]

As much as its possible, the rapid explosions caused by a punctured cell mean it's not worth it unless you have reason to believe yours is easy to replace the cells in


I'd freaking love that with a laptop battery, with replaceable 18650s

I'm trying to upgrade an RC car with them, the hard part is connecting/soldering them together safely IMO

 

[silentbogo]

I'm trying to upgrade an RC car with them, the hard part is connecting/soldering them together safely IMO

It's hard if you don't know what you are doing.
1) You don't solder naked 18650s, you spot-weld them. Soldering naked cells - that's what may cause explosion. On the + terminal you can easily slip a bit or drop a tad of solder under the Teflon ring and cause a dead short. Also overheating a "+" terminal may trip a protection valve and make your battery dead-dead(it's a "pressure valve", and even though it should recover in theory - it only happens 50% of time).
Spot welders are cheap nowadays. I bought myself a battery-powered one for ~$50, and just in the first week it paid itself off 5 times over.
Full charge is enough to repackage something significant, like a 48-cell battery pack.
2) If you don't want to buy a spot welder - buy solderable cells with nickel tabs.

Lithium Ion Battery - 18650 Cell (2600mAh, Solder Tab) - PRT-13189 - SparkFun Electronics

This is the same 18650 Lithium Ion Cell that you know and love, but now includes pre-attached solder tabs! These round high capacity cells have been mainly

www.sparkfun.com

I have (a 6 cell version), but was wondering about rebuilding the old 9 cell version.

Which laptop do you have? If it's an older thinkpad - then you may be in luck. They have a recalibration tool.
I did it a couple of times on T540/W541, all it needs is carefully replace old cells with new ones, hook up power in the correct order from "-" to "+" one by one(so you won't trip the built-in protection), and do a full calibration cycle(it does a full discarge-charge routine and save the new capacity).
De-soldering also needs to be done in the correct order, from "+" to "-".

 

[Shrek]

Which laptop do you have?

An ancient Dell Latitude E5400

I hadn't thought about price, even at $3 each, 6 cells match the cost of the ready made battery pack for the laptop.

I also didn't realize the massive 18650 capacity variations; some are 2600mAh and others 9900mAh

Which begs the question; why are quadruple capacity battery packs not on sale?

 

[LabRat 891]

An ancient Dell Latitude E5400

I hadn't thought about price, at $3 each, 6 cells match the cost of the ready made battery pack for the laptop.

I also didn't realize the massive 18650 capacity variations; some are 2600mAh and others 9900mAh

Which begs the question; why are quadruple capacity battery packs not on sale?

You have stumbled into a rabbit hole.

First off, "Legitimate" 18650 cells are something like 2000-3500mAh.
(Yes, the technology has improved greatly since the era that laptop hailed from.)

Secondly,
It's become much more difficult to get legitimate 'bare cells' since the media put attention/responsibility on manufacturers for fires/explosions of 'vapes' and other 'DIY devices'.
Basically, the big battery manufacturers are 'at war' with re-sellers the world round; purposfully spreading FUD, and trying to get sale of bare cells barred/banned.

Some resellers even put 'CYA stickers' on their cells, thanks to the change...

Thirdly,
'Legitimate' resellers sometimes end up w/ 'fakes' or used and abused cells; salvaged en-masse out of consumer/professional eWaste.

Sadly,
the 'safest' way to get reliable 18650s, is to buy something 'new' (like Bauer battery packs), and salvage the cells. (Also, keep an eye on slickdeals, etc. for when lawmower, etc. battery packs go on clearance.)
It's a shame, and a waste but, such is life in the 21st century world.

 

[Shrek]

Amazon sell the following; as usual not here to argue, but learn. These are fake?

 

[LabRat 891]

Amazon sell the following; as usual not here to argie, but learn. These are fake?

View attachment 321190

Very.

Esp. on Amazon, treat cylindrical cells like SD cards: They're all fake, and even the 'good' sellers have crap mixed-in.
If you were rebuilding an old power tool's NiCad pack, it'd be a diff story (eBay's cheaper for NiCads, anyway)

 

[Shrek]

Good to know.

 

[caroline!]

No way a single 18650 can output 9.9 Ah, that's super fake, not even 26650s are at that level. Good ones are around 3 Ah brand new with no use.

Tried to power up a 40 watt 12 volt light bulb with a few (3 in series) of them once and at 100% load they didn't last for more than 20 minutes. I'm sure a bigger pack would work better but I just wanted to see if the cells were working fine after a fast discharge. Not the greatest cells but still offered a pretty good performance considering I took them out a dumpster laptop battery.

 

[Shrek]

All this fake stuff is disturbing; my Crucial RAM that was not programmed for the rated speed was troubling enough.

 

[R-T-B]

All this fake stuff is disturbing; my Crucial RAM that was not programmed for the rated speed was disturbing enough.

Welcome to the 2020s my dude.

 

[P4-630]

I use 12 Sony vtc6 18650 3000mah flattop batteries, used them for about 5 years now for vaping, they are still as good as new even after many times of (slow) charging over the years.

These Sony's last much longer then the LG 3000 ones I had before.

 

[Tahagomizer]

That's a good learning experience, if anything. Get a cheap spot welder and have fun, lithium batteries are not as dangerous as some make them out to be. However, if you feel something's wrong - one starts to suddenly heat up or swell - throw it info a metal bowl you should have nearby, put it outside. If it catches fire, you won't be able to put it out. Lithium fires need to be waited out in a safe distance.
Get the cells from a reputable source, I found a local battery refurbishing company, wrote an email to them and they agreed to sell me a few Samsung 20S cells. Those should be the best for your purpose too, they're considered the safest 18650 cells and are often used for laptop battery rebuilding because they don't get hot. Samsung 25R cells are also popular for having a good balance between capacity and weight. As others mentioned, everything on eBay, Amazon or Aliexpress is cheap, low quality chinesium.

 

[R-T-B]

I use 10 Sony vtc6 18650 3000mah flattop batteries, used them for about 5 years now for vaping, they are still as good as new even after many times of (slow) charging over the years.

These Sony's last much longer then the LG 3000 ones I had before.

In general I think the japanese brand cells are regarded better than their korean or chinese counterparts, sort of similar to capacitors.

Of course that's a generalization, but it's usually right.

 

[Bill_Bright]

As a side note,

Brooklyn fire that killed 3 family members caused by lithium-ion battery, FDNY says

Officials said a dangerous lithium-ion battery was charging ... and ... exploded

 

[Shrek]

Yesterday my Wife's iPhone got screaming hot and would not run, but strangely recovered; I don't trust it and had her leave it in a ceramic bowl.

I ended up ordering a ready built battery pack for the laptop.

 

[Bill_Bright]

I have one of those Samsung Z Flip Phones which I really REALLY like - for the most part. It seems the trend in smart phones these days is to get bigger and bigger. More and more are the size of a small tablet. I like to stuff my phone in my pocket. I don't want to carry around a purse, fanny pack or tote bag just to bring my phone along.

Anyway, I also have a "skin" cover over my phone in case I drop it, it [hopefully] will survive.

To the point - when it needs more than an hour to charge using the wireless charger, if the phone is closed, the phone gets hot and will stop charging. I don't like that. It is not "screaming" hot, but as a technician, it is hot enough to get my attention, and not in an appreciative way.

I have to remember to "flip" it open when charging to let most of the heat to escape. Or I need to take the skin cover (rubber "blanket") off - which is a pain because it is really tight fitting. Charging with the cable is not a problem I assume because there is no wireless charging platform generating heat too. Plus, it is much faster with a cable so it may just not have enough time to build up too much heat. But of course, a cable is less convenient than wireless charging.

Anyway, like you, and going by the 4th line in my signature, I don't trust it when it gets that hot.
BTW, I like that ceramic bowl idea!

 

[dgvvfhhhfgxvchg]

To savage old 18650 cells, it will need tools to measure the cells' internal resistance, voltage, capacity...Check them first to ensure they are safe and working well.
https://cellsaviors.com/blog/how-to-salvage-18650-cells
https://cellsaviors.com/blog/testing-and-grading-lithium-ion-cells

 

[de.das.dude]

one more reason why i hate li-po
more like li-poo. Hate them. All the li-po i have come across go bad so quickly compared to li-ions of the old days.

 

[Nike_486DX]

IF the battery is older stile (built with 18650 modular cells) - then yes its absolutely worth it! Especially considering that 18650 is still being used and updated to this day (some years ago the max capacity was 2500mah per cell, but now there are 3000 and even 3500mah cells by samsung/lg/panasonic), so you can not only replace the cells, but actually get better battery life as well. Make sure you get genuine cells tho, not some knockoff crap.

On the other hand if its a newer style planar cell battery, then hell no.

 

[Mussels]

It's hard if you don't know what you are doing.
1) You don't solder naked 18650s, you spot-weld them. Soldering naked cells - that's what may cause explosion. On the + terminal you can easily slip a bit or drop a tad of solder under the Teflon ring and cause a dead short. Also overheating a "+" terminal may trip a protection valve and make your battery dead-dead(it's a "pressure valve", and even though it should recover in theory - it only happens 50% of time).
Spot welders are cheap nowadays. I bought myself a battery-powered one for ~$50, and just in the first week it paid itself off 5 times over.
Full charge is enough to repackage something significant, like a 48-cell battery pack.
2) If you don't want to buy a spot welder - buy solderable cells with nickel tabs.

Lithium Ion Battery - 18650 Cell (2600mAh, Solder Tab) - PRT-13189 - SparkFun Electronics

This is the same 18650 Lithium Ion Cell that you know and love, but now includes pre-attached solder tabs! These round high capacity cells have been mainly

www.sparkfun.com

Which laptop do you have? If it's an older thinkpad - then you may be in luck. They have a recalibration tool.
I did it a couple of times on T540/W541, all it needs is carefully replace old cells with new ones, hook up power in the correct order from "-" to "+" one by one(so you won't trip the built-in protection), and do a full calibration cycle(it does a full discarge-charge routine and save the new capacity).
De-soldering also needs to be done in the correct order, from "+" to "-".

I used a nice little container doodad.

For a laptop battery you'd need it to match the original container, however it held them together. Soldering, plastic wrap etc.
No idea what NACCON is, i assume its a brand.

OG battery went flat in about 15 minutes, new ones done 2 hours and hasnt stopped yet.
Yes i used gel caps meant for phone lines, it's what i had on hand. *shrug*