Alternator delete

[paintme205]

So I decided to try an alternator delete on my 91 festiva.

I bought a pulley from tractor supply and rigged it up so that I can still run a belt without the alternator pulley being used.

I got a v belt from a buddy.

I have three batteries from racecars that I am using for extra amps.

So in total, I have four batteries with a total of 415 AMP hours. With a 60% discharge rate, it looks like I could drive 3-4 hours without headlights / AC / Heater.

Does that sound right?

I'll get some pics and results hopefully tomorrow. I have a 90 mile each way drive to test it on.

[Cobb]

Belts and pulleys not driving anything still waste power.

What are racecars batteries?

If these are used, have you tested capacity?

What does your car draw or accessories you will need to use?

How about starting?

[Daox]

Are they starting batteries or deep cycle batteries? If you're going to discharge them to any real depth, you want deep cycles or they will die.

[California98Civic]

Originally Posted by Cobb

Belts and pulleys not driving anything still waste power.

Cobb is right, of course, but depending on what you have set up, a freewheeling pulley will be using a small fraction of the energy than a pulley loaded by a power-generating alternator.

[paintme205]

The batteries are not deep cycle so I am hoping to keep consumption at 20-30% max. Most of my driving is 10-15 miles in town so that seems pretty doable.

I haven't measured the draw yet but will today. I can't imagine it is very much since the car is as simple an EFI car can be with no extra accessories. Even the radio is gone.

[paintme205]

Well I drove 200 miles yesterday on 300 Amp hours of batteries. 100 was with headlights, 100 without. No issues with driving or headlights dimming. Total of 5 starts over those miles.

I determined that the range will be perfect when I add the fourth battery which puts me closer to 400 amp hours.

I didn't fill up yet but not sure the mod is worth it yet. I will say I was driving 75 MPH with 40 MPH winds so I'm not expecting over 50MPG if that.

My goal is to do an a-b-a test in the next week on a 35 mile trip I take pretty often. I want to know if this is helping at all or I'm just wasting my time.

[oil pan 4]

Try not to haul around more battery than you need.

[paintme205]

Three seems to be the sweet spot for my treks to the city. Discharge voltage was 12.4 volts. So maybe 25-30% depleted. That works for me.

I have the batteries on quick disconnects so I can remove two for the city driving.

[paintme205]

Well not too impressed so far.

I extended the boattail and finished the underbelly tray. Also deleted the alternator.

Mileage on last tank was 43 MPG. I was driving 75-80 the whole time and there was 40-50 MPH winds and it was cold (45 degrees) but still figured I would get better then that.

So the plan is to do a 30 mile trip and record gas mileage each way to see if I can get a read on the alternator delete. If I can't see any improvement, i'll hook it back up. A-B-A testing is the plan.

Wish me luck.

[oil pan 4]

The only constant around this region of the country is nearly constant wind and unpredictable extreme temperature swings.