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Li-Ion battery pack

Nigel Goodwin

Super Moderator
Most Helpful Member
There's been a lot of discussion recently about Li-Ion batteries, and as I've said all along it's pretty essential to include a protection board. So as I've just been building a battery pack, I took some pictures to show the method I used. I first align the batteries in a jig, and apply a little hot-melt to hold them together. Next weld the terminals together, add insulation under the board, and fit the protection board - lastly a piece of heat-shrink round the pack.Batt8.pngBatt7.pngBatt6.pngBatt5.pngBatt4.pngBatt3.pngBatt2.pngBatt1.png
 

Reloadron

Well-Known Member
Most Helpful Member
Really a nice job Nigel and thanks for posting the images and the board source.

Ron
 

rjenkinsgb

Active Member
For info, there are (at least) three classes of "protection board" available in ebay.

The commonest ones only provide overvoltage / undervoltage protection.
Some only provide balance without overall protection.
Some provide both.

Also, the balance provision is often so low current it's impractical as the main balance if the cells are being even moderately fast charged. However some are rated at eg. 100mA balance current...

Few provide any charge control; you still need a voltage regulated and current limited charger.
Unless the board has decently rated balance capability, the external charger also still needs to be a balance type.

The one Nigel links to does NOT appear to have any balance capability at all, so should only be used in conjunction with a balance charger or additional balance board in the battery pack.

[I fell into that trap of just a "battery protection board" when I first started building lithium battery packs & it cost me quite a few expensive cells....]

Device datasheet:
https://www.ablic.com/en/doc/datasheet/battery_protection/S8254A_E.pdf


This would be a suitable balance board to pair with the voltage limiter board:
https://www.ebay.co.uk/itm/4S-16-8V-18650-Lithium-Battery-100mA-BMS-PCB-Protection-Board-Balance/283358540286?hash=item41f97c31fe:g:D0QAAOSwdGZcUVeJ
That's only balance so still needs the other board for voltage limiting.
 

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