A 226 watt only uses that amount of juice or about 340W if you supply 15V and 24 Amps at Imax and Vmax.

For 226 Watt pelt at 12V, it should draw less current at 12V and have smaller Q max. I would guess it would draw 260-280W at 12V and about 20amps.

I wouldn't use an 80 watt pelt at 12 V.

http://www.marlow.com/TechnicalInfo/...erformance.htm
EDIT: calculations

12v/16V =.8 and .8 x 24 amps= 19.2 amps/

12v x 19.2 amps = 230 Watts draw