chuck wrote in news:1152046290_6185
@sp6iad.superfeed.net:

That's 100 amps SQUARED times the
internal resistance (which is nonlinear
FWIW) to get the power dissipated in heat.

Chuck



100A squared times internal resistance PLUS the heat generated by the
CHEMICAL REACTION of Sulphuric Acid eating into Lead to create Lead
Sulphate....

And, with Gellcells or AGM, there's NO INTERNAL CONVECTIVE COOLING in the
gel or guaze between the plates.

Case in point is my little dock electric scooter:
http://www.largoscooters.com/bladezxtrse.html

It runs 8 miles at 16 mph, wide open, but its 12AH, 12V (2 in series for
the 24V motor) will trip the overheat breaker wedged between the
batteries long before you do 3 miles, especially if there is any uphill
driving. The little AGM batteries, freshly charged just before you left
home, get HOT really FAST driving the 450 watt motor continuously for any
distance....too hot to touch!

450W divided by 24V = 18.75A, far more than a reasonable 10% of capacity
AH for these batteries. The idiots also put them in this "hot
swappable" carry bag, exacerbating the heating problem. I got rid of the
bag and they do run cooler, but not cooler enough for a full-power, 8
mile run. I'm considering a 24VDC cooling fan with a thermostat switch
that vents the battery/electronics compartment at 100-110F or so to help
out.

The chemical reaction happening this fast gets quite hot, too!

(It's a great scooter for long marina docks, folding flat into your trunk
or lazarette). Chain drive, smooth power from pulse-width modulation
electronic throttle. Electric braking also has dynamic braking switch
that drags on the PM motor on deceleration....small recharging going down
hill...(c;