Search found 363 matches

by Jeremy
Wed Jan 05, 2011 7:03 pm
Forum: All things battery related
Topic: New Ping battery reads 10 volts!
Replies: 2
Views: 4951

Re: New Ping battery reads 10 volts!

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...
by Jeremy
Wed Jan 05, 2011 12:47 pm
Forum: Hybrid's Corner
Topic: Contactor-based Power Assist
Replies: 10
Views: 23842

Re: Contactor-based Power Assist

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...
by Jeremy
Tue Jan 04, 2011 8:10 pm
Forum: Hybrid's Corner
Topic: Contactor-based Power Assist
Replies: 10
Views: 23842

Re: Contactor-based Power Assist

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 ...
by Jeremy
Tue Jan 04, 2011 5:54 pm
Forum: Hybrid's Corner
Topic: Contactor-based Power Assist
Replies: 10
Views: 23842

Re: Contactor-based Power Assist

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...
by Jeremy
Tue Jan 04, 2011 3:37 pm
Forum: All things battery related
Topic: My new ping- lights on BMS not working
Replies: 15
Views: 14277

Re: My new ping- lights on BMS not working

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
by Jeremy
Tue Jan 04, 2011 3:32 pm
Forum: Hybrid's Corner
Topic: Contactor-based Power Assist
Replies: 10
Views: 23842

Re: Contactor-based Power Assist

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...
by Jeremy
Tue Dec 28, 2010 11:50 am
Forum: All things battery related
Topic: Ping Batteries in cold weather
Replies: 49
Views: 40005

Re: Ping Batteries in cold weather

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...
by Jeremy
Wed Dec 22, 2010 6:01 pm
Forum: All things battery related
Topic: Ping Batteries in cold weather
Replies: 49
Views: 40005

Re: Ping Batteries in cold weather

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

Jeremy
by Jeremy
Wed Dec 22, 2010 5:23 pm
Forum: All things battery related
Topic: Ping Batteries in cold weather
Replies: 49
Views: 40005

Re: Ping Batteries in cold weather

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...
by Jeremy
Tue Dec 21, 2010 10:29 pm
Forum: General
Topic: New toy.........
Replies: 19
Views: 17092

Re: New toy.........

These motors are pretty light. The 7kW ones I have are around 1.6kg, so compare very well with the heavy industrial motors that have been adapted for EV use. I'm planning to use two of these on a common shaft to drive my motorcycle conversion. This'll give me around 14kW peak for a motor weight of a...

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