Mode Zero

I have had a wonderful little Garmin gps for many years but finally the battery reached the end of it's natural life. With other "appliances" in a similar situation, rather than pay the exorbitant price of a new battery pack, I have simply disected the pack and replaced the cells. So I did the same with this one but when I got inside, yes there were Li cells that look easy enough to replace but there is also a very complicated little circuit board....... Can anyone tell me what it does please?

Its a protection board Paul, it does low-voltage-cutoff, over voltage-cutoff, over-current cut-off, and
balancing (2S). Even single-cell Lithiums often have them, sold as 'protected cells'.
If the replacement is a raw 2S pack, just connect to the PCB wires. If the replacement is a protected pack, then connect directly to the battery contacts.
Cheers
Phil

That PCB works similarly to this:

https://pt.aliexpress.com/item/2S-Li-io ... 18846.html

I have a handheld vacuum cleaner in the same situation as your GPS.

https://pt.aliexpress.com/item/18650-li ... 3ed2VqWwCq

Many thanks both....... FB, the battery you show looks to be identical to the old GPS cells but so far I have been unable to find the same thing in this country. Would I be right in thinking that, since it has this protection circuit, any 2s Lipo or Li-ion battery that will fit in the box will be ok?

Paul

Phil_G wrote: ↑29 Oct 2018, 15:55 Any with identical chemistry to the original Paul.

Thanks Phil, in fact I have now found and ordered the correct Li-ion cells on ebay but what would have happened if I had just used a 2s Lipo which I happen to have spare......?