Battery Vehicle Society

My guess is that the noise was the input capacitors in the switched mode charger charging up, as it was plugged into the mains. These little switched mode chargers have a heck of a surge current at power on.

Jeremy

Glad it's sorted. If that is a 12S pack, then the answer is that it will sit at around 39V or so when the surface charge has bled off. The nominal voltage of LiFePO4 cells is around 3.2V for most of their discharge curve, although they start at around 3.3V per cell. Hot off charge they will be aroun...

I think the net is probably at saturation point with various torque vs power arguments, particularly as so many have such firm views on the subject! Being an analytical sort of individual I did do some calculations years ago of just how much power the 998 Hartwell engine was really delivering in fir...

When looking at extra power, it's probably worth looking at the torque figure, rather than the absolute power figure (the product of torque and RPM). In essence, it's the extra torque that is going to give you the acceleration boost you're looking for, not the ultimate power of the motor as it hits ...

Glad the info was useful. I don't believe that a genuine, well-made, Briggs and Stratton Etek would take anything like 480 amps at 96V (over 46kW!!!), so I'd treat the claims for the Chinese clones with a very large pinch of salt. IIRC, the Etek was prone to fly apart at around that voltage (the Ete...

How long has it been on charge?

The BMS lights only come on at the end of charge, when the BMS starts actively shunting current across fully charged cell groups.

Jeremy

Sounds like an interesting idea. The Etek has been out of production for a fair while now though, so I doubt you'll find one, although the Mars Electric "clones" are pretty close to the old Etek specs (and beware, there is a fair bit of "passing off" going on with non-B&S Ete...

The balance resistors on the BMS get warm, not really hot, but it's best if the BMS is mounted so that it hasn't got masses of foam or other insulation over it. My Ping pack has the earlier BMS with no LEDs and I have it fitted inside a hard case that I can't easily open to take a look at. I have fo...

Yes, the light on the charger will stop periodically switching on and off and the fan will stop.

Jeremy

The first charge will take quite a long time, as the pack has to balance itself following shipping, storage etc, so you can expect the charger to cycle on and off for at least an hour, maybe longer, after the initial cut off. After the first few cycles the charge time will reduce, as these packs ten...