You may know this, but you design your dummy load by looking at the current 
you want to draw at the nominal voltage.  If you want to draw 300 amps at 
160 volts, you use Ohm's law (resistance = voltage / current = 160 / 300 = 
0.53 ohms).

Having done the calculations I think using a water heater element isn't 
going to do it for a 300a dummy load.  You'd need a couple dozen of them!  
They're usally only 4500 or 5000 watts at 240 volts; less at 160v.

You might try another EVer's hack - a length of wire, also in a barrel of 
water, bolted to lugs on 2/0 wire.  Ideally it would be nichrome wire, but 
steel should work.  

To determine how much wire you need, you'll want an ohmmeter that can 
measure low resistance, or else the resistance per foot spec of the wire.  
Don't use too small a wire!  This value doesn't have to be exact, just 
reasonably close.  Don't let the water boil away to below the level of the 
wire.

As for the others' ideas of cold temperatures affecting your battery, I 
don't know enough about lithium yet to say how it's affected by cold, but 
that certainly happens with lead.  It's worth investigating.  But check your 
cells' internal temperatures if you can; it may be that your high currents 
are already warming up the battery during your commute.

David Roden
EVDL Administrator
http://www.evdl.org/


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