TNfarmboy

It is simple Power = voltage times amps. At 110 volts you don't need but 5 amps to get 550 watts but at 12 volts you would need 45.8 amps for the same power, hence the same CFM which = cooling capacity. Since Diesels have 2 batteries hooked in parallel for more starting amperage you could hook a fan up for 24 volts (series) and cut the amperage in half. Bottom line is on the road is not a problem because of the ram air effect. Sitting still in traffic the fan must make up for the air that is not flowing through the radiator. Sitting still in traffic or stop and go who cares if you use a few HP for cooling, you can't use it for anything else can you? It is going up that 20% grade pulling 8K that you need the HP.

kennyblatz

one guy at NADP with a big hp 12valve featured in last months DP mag i think has electric fans what type i am not sure but if he's got 85-90 psi he is making power