Bosch 10.8 battery pack Cell upgrade

Bosch 10.8 battery pack Cell upgrade
Recently i had bought Bosch GKS 10.8 cordless circular saw from Germany without battery pack. As I already own Bosch GDR 10.8 Impact driver which uses 10.8V battery I was confident that I will be able to use the same battery pack. The original battery from GDR 10.8 Impact driver were only 1.5Ah and on using them with saw they were getting very hot and discharging very quickly. So i decided to upgrade the cells in the battery pack as on inquiring locally higher capacity battery pack was not available and even if I managed to find one the price would be very high. This particular thing I noticed when comparing Bosch tools available in Germany and India the cordless tools can be bought there with or without battery(bare tool) and also the standard battery pack was 2Ah and higher capacity packages were also available. The range of tools available in Germany was updated and all the variants were available there, Unfortunately Indian market is left behind. At the time of writing this article i saw that 10.8V range is no longer available instead it has been renamed to 12V range.

This is a marketing gimmick as previously Bosh were using 18650 battery's nominal voltage that is 3.6V for computation of rating as there are 3 battery connected in series so total voltage comes to 3.6x3 = 10.8V. Now they are using fully charges voltage of 18650 battery that is around 4.2V so total voltage comes as 4.2x3 =12.6V

Bosch 10.8 battery pack Cell upgrade

There are 3 clips on battery pack. Which can be pushed inside and the case can be opened, inside the case you will find 3 cells in series with a temperature sensor attached in middle. I had to carefully cut the plates joining the cells to avoid any shorts and damaging the battery during the process.

Bosch 10.8 battery pack Cell upgradeBosch 10.8 battery pack Cell upgrade

Bosch 10.8 battery pack Cell upgrade

Nominal discharge capacity
Max. continuous discharge(Continuous)
18A(at 25), 60% at 250cycle
20A(at 25), 60% at 250 cycle
original cells are from Samsung INR18650-15Q which are 1500mAh which I have replaced with INR18650-25R which are 2500mAh that is 1000mAh increase in capacity also the discharge rating is high in new cells which was apparent as the cells were barely getting warm when used with saw.
Bosch 10.8 battery pack Cell upgrade
Bosch GKS 10.8 Saw

This is whit i did to the old battery which came out from power pack.
Bosch 10.8 battery pack Cell upgradeBosch 10.8 battery pack Cell upgrade

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