High Output Alternators

[markopolo]

I've been looking into High Output Alternators.

Does anyone know what the mpg impact would be if I went from a stock alternator to a something like a 200 amp, 120 amp at idle alternator?
I'm just trying to figure out real costs. I'd have to upgrade my isolator. Might have to upgrade some wiring.

My van has a 6.5l Turbo Diesel and from memory, it gets 17-18 mpg now.
If the MPG impact is too high then I'd probably not bother.

[booster]

Originally Posted by markopolo

I've been looking into High Output Alternators.

Does anyone know what the mpg impact would be if I went from a stock alternator to a something like a 200 amp, 120 amp at idle alternator?
I'm just trying to figure out real costs. I'd have to upgrade my isolator. Might have to upgrade some wiring.

My van has a 6.5l Turbo Diesel and from memory, it gets 17-18 mpg now.
If the MPG impact is too high then I'd probably not bother.

A high amp alternator may have slightly lower efficiency at lower outputs than a standard one, but I seriously doubt you would see it in fuel economy. You would need to upgrade any wiring and components that could possibly see the higher amperage.

Under normal conditions, the alternator is going to run at a set voltage, and the amperage will be determined by how much is being used. If you are going down the road with full batteries, no lights on, no accessories running, the amp draw will be very low, and the same as a lower maximum output alternator would be. The higher amps would only show up when needed.

As a point of reference, our Chevy 6.0 gas engine has a 145 amp alternator IIRC, which will do about 80 at idle. We have the 200 amp separator, and the wiring to the coach batteries is fused at 80 amps. To this point we haven't tripped the breaker.

[markopolo]

Thanks for the info.

In the 1997 Savana brochure it shows two alternator options: 100 amp and 124 amp
According to my vans RPO codes ( http://www.classbforum.com/phpBB2/vi...hp?f=17&t=1825 ) I have KW2 GENERATOR 124 AMP which would be the 124 amp alternator.

So do you think maybe 70 amps at idle now?

My thinking is that 120 amps at idle would give me 80 to 90 amps for the microwave oven or toaster oven or Coleman Polar Cub A/C plus 30 amps for the van. If I'm going to do it maybe I should go for 150 amps at idle to be sure. I have to shop around a bit.

It's looking like $1,000+ for the high output alternator, a new 250 amp isolator, 2,000 watt sine wave inverter and automatic transfer relay. That is about the same as a Honda EU2000 generator........