Hooked my upgraded grid charger/discharger for the first time, and it didn't explode.
~
On the way home, I did my best to drain the battery, with around 12 miles of as much assist as I could manage, and then kept the car in high gear and used full assist for the 2-3 miles to the top of the hill I live on. I managed to bring the battery gauge down to 3 bars.
Ambient temperature was around 40F when I parked the car, and the battery was at 154.5v when I started discharging with a 60w bulb (3PM).
After 4 hours (7PM), I was down to 132.6v. I switched over to a 25w bulb.
8 hours later (3AM), I woke up, had a snack, and went out to the car to check on the discharge status. The voltage was at 74v and dropping rapidly, which suggests most, if not all of the cells were very near empty, and some were probably experiencing a very low-current cell reversal.
My math tells me that, in order to bring the pack down to close to zero charge from 3 bars on the SoC gauge, I removed a total of ~3.6Ah.
I switched off the discharger, leaving the 12v cooling fan running, and let it sit overnight.
This morning (8AM), ambient temperature was ~25F, and the battery had stabilized at around 120v. I turned on the gird charger portion and went to work.
Given that my charger puts out 500ma, I expect it to take a minimum of 13 hours to top off the 6.5AH battery, probably a little longer. It's pretty cold outside, so I'll probably leave it charging overnight tonight for a total of around 24 hours of grid charging.