18650 laptop battery rebuild

[sammovde]

I did a few laptop battery repair a few years ago so I know it's not that difficult. At that time the capacity for each was around 2000mAh if I recall well.

Now I have no idea which brand and model to choose. Would any one give me some advice for choosing 18650 li-ion battery? I heard that there are so many fake on ebay and battery. Can I check if it is a counterfeit with the model number printed on the plastic shield?

Thanks in advance

 

[SilverFox]

Hello Sammovde,

Welcome to CPF.

If you are diligent in searching, I believe you can find some Sanyo cells with tabs that would work great as a laptop battery pack. I looked at some 2400 mAh cells and they were quite good. I don't know if they have gone much higher in capacity than that.

Tom

 

[LLCoolBeans]

sammovde,

When you start your project please post photos and details as I am interested in doing a similar project.

Thanks

 

[LEDAdd1ct]

I, too, would love to see and hear about your project!

 

[BoarHunter]

One month ago, I rebuilt a battery pack for my 3 years old HP portable. Not beeing able in the EU to get brand name 18650 I had to rely on TrustFire TR 18650 2500mAh 3.7V Batteries (2-Pack) SKU 6979 from DX, as they are the only one with a flat top.

The flat top is mandatory because of the cramped space.

When dismounting, use a sharp knife to cut the spot soldering and scavenge the strips. Use a good soldering iron at least 30W to be able to work quickly and tin both the battery terminals and the strips.

I would not recommend first timers to carry on with this rebuilt and old timers can figure out by themselves the best way to do it !

I cannot comment on the quality of the Trustifre in the long run but it was worth it as battery pack are expensive and besides you don't know when they have been manufactured. If they are a few years old, they are almost dead.

I suspect PC manufacturers not to standardize their battery packs on purpose, to force to get a new PC.

As for the 18650, I wonder how long they will use this format as more and more are using Lion polymer.

 

[sammovde]

Hello Sammovde,

Welcome to CPF.

If you are diligent in searching, I believe you can find some Sanyo cells with tabs that would work great as a laptop battery pack. I looked at some 2400 mAh cells and they were quite good. I don't know if they have gone much higher in capacity than that.

Tom

There are quite a lot of sellers of 18650 li-ion cell on taobao. But I am not sure if they are trustable. There are capacity even as high as 2900 or 3000 mAh. I would avoid choosing the no-brands. After some searching in this forum I realize that some high capacity samsung/sanyo/lg/panasonic on ebay and taobao may be fake.
I am still considering whether I should buy a new battery pack replacement

sammovde,

When you start your project please post photos and details as I am interested in doing a similar project.

Thanks

I, too, would love to see and hear about your project!

Yes, I will post photos and details. But first of all I need to find a trustable dealer which doesn't sell fake cells.

One month ago, I rebuilt a battery pack for my 3 years old HP portable. Not beeing able in the EU to get brand name 18650 I had to rely on TrustFire TR 18650 2500mAh 3.7V Batteries (2-Pack) SKU 6979 from DX, as they are the only one with a flat top.

The flat top is mandatory because of the cramped space.

When dismounting, use a sharp knife to cut the spot soldering and scavenge the strips. Use a good soldering iron at least 30W to be able to work quickly and tin both the battery terminals and the strips.

I would not recommend first timers to carry on with this rebuilt and old timers can figure out by themselves the best way to do it !

I cannot comment on the quality of the Trustifre in the long run but it was worth it as battery pack are expensive and besides you don't know when they have been manufactured. If they are a few years old, they are almost dead.

I suspect PC manufacturers not to standardize their battery packs on purpose, to force to get a new PC.

As for the 18650, I wonder how long they will use this format as more and more are using Lion polymer.

Thanks for the suggestion.

I cannot find any local stores which sell 18650 lithium ion cells. The only way is to order from the internet. I IM the dealers on taobao and surely they insisted their stock are real and original. I cannot find much information on the internet about 18650 li-ion cell. The data sheets from samsung/sanyo/panasonic seems out of date
For example,
http://www.samsungsdi.com/contents/en/product/battery/type01.html
It says the maximum capacity is 2400mAh. But samsung ICR18650-28A 2800mAh does exist on Dell and HP's sites.
http://www.dell.com/downloads/global/corporate/environ/6cell_KM742_WU843_MT187.pdf
http://www.hp.com/hpinfo/globalciti...roductdata/pdf/ba_sdili-ion2800_us_eng_v1.pdf

 

[BoarHunter]

The issue is to find these "brand" unprotected 18650 !
Once found, the total cost, shipping included must be far cheaper than a brand new battery pack to justify the pain to fix an old one.
DX ships worldwide at no additional cost.
I fixed it for 1/3 of a pack.
If I had to buy a new pack, I would have bought a new PC instead.

 

[SilverFox]

Hello Sammovde,

You may want to contact CPF member LEDite. Larry used to have Sanyo 2400 mAh cells for sale, and they are very good cells.

You may be interested in this thread where the 2800 mAh Samsung cell came in at around 2500 mAh.

Tom

 

[razirafi]

Hello to all, I do not mean to hijack this thread but I just would like to ask for advice from people with more knowledge and experience with 18650s than I do. I have a laptop battery pack that died because I stupidly left my laptop on the rear seat of my car under the blazing heat of the sun for a whole day. I opened up the pack and measured each battery and found out that five out of the six cells inside were dead. I tried searching for the exact battery pack but I cannot find one. A lot of replacements can be found but the capacity is way too low than the original so I decided that I will just rebuild this pack. The pack is rated at 11.1 Volts and about 5800 mAH. The individual cells inside is the UR18650ZTA.

The type of cells that I wish to use for the rebuild are these. http://www.ebay.ph/itm/281813726367?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649
Would I be alright to use these cells or should I use the same ones as what was inside the battery pack?

 

[sbj]

The UR18650ZTA are High Voltage Ion batteries. The charge voltage is 4,35Volt!. As a replacement, you may only use such batteries with also a 4.35V charge voltage. Normal batteries with 4.2V charging voltage would be totally overcharged (such as you wanted to take)! :shakehead

So you must specifically search for batteries with 4.35V charge voltage. If you find some with more capacity, you can use them.

 

[razirafi]

Thank you for your reply, I will follow your advice. To add more info about my pack, it is a Toshiba PA3931U-1BRS (PABAS251) rated at 11.1V and 5700mAH. I have seen replacement packs online with the same model number but rated at 10.8V and rated at 5200mAH and some are rated at 5800mAH. Does Toshiba offer two different voltages for this battery pack model (10.8V and 11.1V)?

Is the PA3931U-1BRS the same as or equivalent to the PA3929U-1BRS? Each model for different regions perhaps?:thinking:

 

[azzido]

I did a few laptop battery repair a few years ago so I know it's not that difficult. At that time the capacity for each was around 2000mAh if I recall well.

Now I have no idea which brand and model to choose. Would any one give me some advice for choosing 18650 li-ion battery? I heard that there are so many fake on ebay and battery. Can I check if it is a counterfeit with the model number printed on the plastic shield?

Thanks in advance

I know that this thread is very old but I am very interested on how did you repair the laptop batteries. In most of the cases, if you replace the cells inside of a laptop battery you need to reprogram the chip battery to reflect new cells. Most of the chips are sealed.