250 HQI vs 400 PS

[rm41400]

I have a 400 watt PS ballast made by PFO. On the ballast box it says it is 400 watts @ 3.8 amps.

I just bought a 250 watt HQi ballast and it is stamped 250 watts @ 5.5 amps.

I am confused about this. If the voltage supplied is fixed @ 110 (or 120) the output wattage should be as follows:

250 watt HQI 110volts x 5.5amps = 605 watts

400 watt PS 110 volts x 3.8amps = 418 watts.

Is this just the peak wattage at start up?

The main reason for this question is in regards to the heat generated by these lights. I assumed that my new 250 watt HQI ballast may be a little less intense and definately run cooler. However, I have observed just the opposite of this. They look brighter and the tank seems to be a little warmer than normal.

thanks

I posted in the lighting forum but got no response

 

[gflat65]

I'm thinking peak wattage, but maybe one of the local EE's will respond. I know commiphora or easttn would be able to help out on that.