Just testing the terminals on my e-bike battery. This is the 48v 12ah one and I'm sure the Engwe ep-2 only uses the top and bottom terminal. Maybe other bikes use the other ones. I noticed a slight discharge, 0.9v, from it when the key was turned off, not that this is an issue while off the bike, but it may be if it's travelling through the controller while stored for a while. If it is leaking voltage, I have no idea how much it would effect the stored battery voltage in time. It may be nothing, but thought it was worth a mention.