Grin Satiator: Any way to force battery recognition'?

I stupidly left my ebike on all night and, this morning, found the battery totally flat.

Hooked up the Satiator but, even after being connected for 3 hours, it is not recognizing the battery as being connected.

Is there any way to force the charger to start charging?

My guess is that the BMS has shut off.
If the battery voltage isn't too low you should be able to revive it by bypassing the BMS until the cells charge to 3v or above.

First tell us about the battery what voltage what kind do you have access to the BMS ?

First check battery voltage. What voltage ?
If you have proper voltage put a load on it a 100 w light bulb a hair dryer on low ect. Does it work ?

The satiator has a force-start function by holding one of the buttons on the display; I can't remember which one.

But all that does is force it to turn on the output even though no voltage is detected from the battery. It won't make the battery itself enable the charge port, which is probably turned off from overdischarge of at least one cell group (probably one of the most negative ones, if the BMS is powered from just one or a few, rather than the whole thing).

Do you have a vote meter
What chemistry ?