Rucksack alternator delete (portable DIY power pack to reduce alternator load)

[MetroMPG]

Just discovered this thread, jakob.

Building a portable rechargeable "power pack" to reduce alternator load is on my to-do list also.

Any updates?

[jakobnev]

Any updates?

Well i made a little 3p helper pack that i use on the way back, it keeps the current over 6A. Previously current on the way home was very low because the voltage of the main pack had sunk to not much above the cars regulated voltage.

[redpoint5]

Originally Posted by jakobnev

But i think someone tested it and found that the additional saving from taking off the belt is only 3%, so even if i reach 100% i may keep the belt on because it is less hassle.

I read somewhere that the alternator delete is good for around 10% improvement in MPG. Are you saying that leaving the belt on but disabling the alt would net 7% improvement in MPG?

Of course the results of an alt delete will vary from car to car and be affected by many variables, but is there a "typical" or average percent improvement?

[TXwaterdog]

It's going to be interesting to see your results. But before you heavily mod anything you can test your theory buy simply unplugging your alternator. You can perhaps install a kill switch that only engages the alternator when you feel it's nessisary. Why not just buy a portable jumpbox?

Personally, I wouldn't do this. I've had alternators fail and I need one, that's certain. Here in TX I use my AC 90% of the time. The number one main reason that I bought my new car is because my AC was going put on the old one. Second being swapping from 17mpg to 33mpg.

[deathtrain]

I just went this summer without using my AC. I hated life...

[TXwaterdog]

As I just drove an 80+ mile trip each way I noticed if I used my hill assist on climbs I suck less gas. I was also thinking I could tap into the system and do an alternator off on climbs in addition to the AC. If i could automate this id be even happier. Btw, I averaged 39mpg according to my onboard computer for the 160 mile trip driving through TX hill country.

[brucepick]

Originally Posted by TXwaterdog

As I just drove an 80+ mile trip each way I noticed if I used my hill assist on climbs I suck less gas...

What's a hill assist??
Is this a feature that kills the a/c compressor during hill climb??
An original feature of the car or ??

[oil pan 4]

I am considering building a few 12 AA cell stacks of NiMH batteries to simulate using solar panels to lessen alternator load.
It will take a few stacks since I think each run of NiMH cells only puts out about 2 or 3 amps (if I remember correctly). Then it takes 2 amps just to hold the two massive batteries at 14.5 volts.

[brucepick]

Originally Posted by oil pan 4

I am considering building a few 12 AA cell stacks of NiMH batteries to simulate using solar panels to lessen alternator load.
It will take a few stacks since I think each run of NiMH cells only puts out about 2 or 3 amps (if I remember correctly). Then it takes 2 amps just to hold the two massive batteries at 14.5 volts.

Consider using Li Po or even better, Lithium Iron Phosphate. With NiMH, the output is typically the AH rating. That is, a pack rated 1 AH can provide one amp. With Li Iron Phosphate, a 2.5 AH cell or pack can provide 70 amps. Of course if the load is only 2.5A, a fully charged cell or pack will last a full hour. The point is, for higher current draw, Li based cells will meet the need more easily.

[oil pan 4]

Originally Posted by brucepick

With Li Iron Phosphate, a 2.5 AH cell or pack can provide 70 amps.

Why do I need 70 amps?
I am trying to simulate the effect of a solar panel that puts out 4 to 6 amps at 14.5 volts. I have 12 AA cells rolling around and I bought 12 more tonight for about $30. Its a pretty cheap test as opposed to custom making a 20 OCV panel and finding out it doesn't do anything.