3s battery charger

[artag]

I've used the TP4056 boards for charging and protecting 3.7V lipo cells but am looking for something similar for a 3S pack.

So far I've found BMS boards which balance the pack and can be used with a constant voltage / maximum current supply for charging. However this combination doesn't do charge termination - it only drops to the current taken by the pack at max charge voltage and won't detect faults.

Is there an off-the shelf solution (ideally using cheap ebay components) to handle the whole charge and protection for a built-in battery pack ? I don't want to remove the pack so I can't use a standalone packaged charger like those used for model aircraft.
 

[IDEngineer]

Is there an off-the shelf solution (ideally using cheap ebay components) to handle the whole charge and protection for a built-in battery pack ? I don't want to remove the pack so I can't use a standalone packaged charger like those used for model aircraft.

I think you're close to your own solution here. There are very small "standalone packaged chargers" for 3S packs available on eBay... how about removing the PCB from its enclosure and putting that into your device? It's unlikely you'll be able to one-off anything smaller or cheaper. Just a thought.

[artag]

That's a option, I guess. There do seem to be some that accept 12VDC in, which I'd want.

Unfortunately they are only chargers : they don't implement the other functions of a battery pack, notably cutoff when at low voltage. So I'd have to add that circuit.