Hi guys
I was wondering if anyone was using battery chargers which are not made by DJI? Inparticular the one produced by Smatree which is a double battery charger (and comes with 2 batteries). I've got other Smatree accessories for my GoPro, and don't really have a problem with any of them, so I might splash out. I need to top up on battereis anyway - I'm going back to India in October and plan of shooting tons of stuff!

I bought the double charger and batteries, my DJI battery extender never worked so I had to find another option. My charger was sent with one DOA battery and they promptly sent me another. Works great and no problems.

I have the Smatree double one and it works well with the exception of getting pretty hot, especially when charging two batteries.  

Like cellphone's battery, it's totally possible for Osmo batteries to be charged with 3rd party chargers.  You need to make sure the voltage is correct and sockets are compatible.  However, that's not recommended since DJI chargers will adjust the speed it charges the battery to keep the battery healthy.