Test: Alternator vs. no alternator = 10% MPG gain @ 70 km/h

[RacerX]

[QUOTE=RacerX; Has anyone ever made an altenator spin just from air/wind speed?[/QUOTE]

An Automotive altenator that is....

[MetroMPG]

Assuming it's turning at the same speed as when driven by the engine, it'll use the same amount of fuel regardless of hooking it up to a wheel or a turbine (which won't work - it would require a really big swept area). There's no free lunch.

The wheel-driven idea would cause it to be under-driven at low speeds, so battery voltage may drop and you may save fuel at those times, but the load on the alternator will be higher as the RPM increases and it puts the lost energy back into the battery, so fuel consumption will go up. I can't see any real savings from that approach.

Also worth emphasizing again: discharging a starting battery will dramatically shorten its life. Going alternator-less may be an effective efficiency mod, but it's definitely not a money saving mod unless you have a source of free or cheap batteries.

[larryrose11]

MetroMPG,
there is an existing thread here in EM:
http://ecomodder.com/forum/showthrea...roof-4097.html
AndrewJ also did a similar thing, and he saw a similar 10% gain in FE, on page 8:
http://ecomodder.com/forum/showthrea...ics-312-8.html

Larry

[MetroMPG]

Hi Larry - thanks for posting the links. I've participated in both those threads.

It's worth noting that Andrew also found a source of cheap used deep cycle batteries before he started driving with the alternator disconnected.

[blackjackel]

Bad news for me, apparently I have a "serpentine belt" that goes through EVERYTHING including power steering, water pump, air pump, yadda yadda so I can't take that out

I wonder if I can buy a smaller belt and take off just the alternator...

[Daox]

You could buy a shot alternator and tear the guts out to make a sort of idler pulley.

[MetroMPG]

blackjackel: my alternator is not physically/mechanically disconnected, it's just electrically disconnected. The stock belt is still turning the alt pulley.

When I originally wrote this thread in 2006, I had removed the belt entirely and fashioned a replacement to turn the water pump because I wanted to remove ALL alternator losses including bearing and pulley fan. This time, I just disconnected the alternator wire.

[RacerX]

Battery's aren't a problem.....Thank's for the info MetroMPG

[BBsGarage]

As far as a switch is concerned take a look at these.

Battery Cut Off Switch - Compare Prices, Reviews and Buy at NexTag - Price - Review

[MetroMPG]

Good stuff, thanks. That gives me some ideas of what to look for. I'm just headed out to see what's at the local auto parts store. I want a non-energized, manual switch / disconnect like some of those, rather than a relay/contactor setup. I won't be switching the thing on/off very often, so I don't need the convenience of a remote dash mounted solution. Opening the hood and flipping a simple switch is fine.