alternator hp draw

[California98Civic]

Originally Posted by pete c

I think running without the alternator for shorter trips is a very good idea. Using a portable PV array to help keep it topped off is also a good idea, but, I wonder if it's worth the cost and trouble? I think it may be if you remain parked for long enough stretches to provide a substantial charging. How long that period of time is, I have no idea. Depends on the size of the array and the strength of the sunlight.

Here is an older thread on this theme, check out Ryland's post (#2) in particular): http://ecomodder.com/forum/showthrea...ons-17009.html

Originally Posted by pete c

I think a better idea is active management of when the alternator is used and use of deep cycle batteries. A simple way would be to toggle it on with the brake light signal. An accurate voltmeter would tell you when your charge was getting low enough to need to go to full time alternator use.

This is a good idea if you drive your car engine on a lot and in the city. If you do a lot of engine off coasting, using the brakes won't engage the alternator. And if you drive a lot of the freeways (not in bumper-to-bumper traffic) a brake-activated system might not be ideal or even practical.

james

[todayican]

Ive been giving this some thought as well. (another potential commercial MPG related product)

A battery bank and charger that replaces the alternator.
Assuming 10% savings, its still a bit expensive

Here is how I did the math
Added up all the accessories wattages from another post (Thanks OP)
Assumed all the ones that could be on, were, for 10 hours straight.

I believe I came up with 66a continuous (meaning one would need 66 watt hours to replace with a battery)

so something that could survive a 10 hour day would be 660ah x 12v

Using Lithium Iron Phosphate batteries that comes to 2880 just for the batteries and weighs 172 pounds.

Assuming once the charger and cord went in and the installation box (and a few bucks for profit) were looking at like 4k

If one were to be bought brand new for a new car, it would last somewhere around 350,000 miles. Assuming the car lasted 150,000 of those with the original owner, heres what he or she could save:

150,000 miles
average of 35mpg
assuming $4 for fuel (likely more over time)
They will buy 4285.71 gallons ($17,142) without the device.
Or Buy 3896.10 gallons (15,584) with the device

fuel savings of 1558 (even if they drove out the entire lifespan of the batteries, using the same assumptions they would only save 3960)

So unless I was way off with my math a "commercially feasable" (Moron proof) would be unfeasable.

No for someone taking short trips, like a shorter commute, game on! :-)

[mikehallbackhoe]

I removed my alternator belt on my crx, and the cold idle went from 2000 rpm , to 2500 rpm. I had to ride the brakes going through town! I put the belt back on. I just bought a 31A yellow top optima battery for my dumptruck, which doesn't get a lot of use. I am going to put the optima in my crx when the weather gets nice, and remove the alternator belt. It won't cost me anything to experiment. the extra power is nice, even without the mpg gains.

[ecomodded]

I like the idea of a large battery bank for a alt. delete, but It would have to be done more efficiently than todayican's example.
Here is a list of changes that can be made to reduce your amperage consumption-
Replace heater fan with 2 low watt 12v fan's in tandem that draw minimal amps perhaps 1 amp each.

replace absolutely all of the interior bulbs with LED's.
Replace all of the exterior bulbs with led.
Find lower watt bulbs for your head lights, if you wanted you could mount some bolt on led pods.

Replace car stereo with mp3 player plugged into low watt powered speakers.

Use a few solar panels to on dash and back parcel shelf to charge a auxiliary battery that powers your speakers, fans
and interior lighting.
Now the car may run on 15 to 20 amps most of the time and no more than 30 35 amps at any giving time but more than likely the car will be using 20 amps for most of its driving. A person could use a smaller /cheaper battery pack to replace the alternator, making it more justifiable to consider implementing.
You would need a solar charge station at home to top up the batteries.

[ecomodded]

20 amps for 10 hours would only draw 200 amps, which could be drawn from 3 100 hr $100. deep cycle batteries.
In all honesty a 10 hour drive is out of the normal range of most drivers, a five hour drive is more likely which would be a long commute,some people have to do it. I would bet 2 hours a day is average. I think I may of just convinced myself a alt delete is with in reason..

[California98Civic]

Originally Posted by todayican

Here is how I did the math
Added up all the accessories wattages from another post (Thanks OP)
Assumed all the ones that could be on, were, for 10 hours straight.

I believe I came up with 66a continuous (meaning one would need 66 watt hours to replace with a battery)

so something that could survive a 10 hour day would be 660ah x 12v

I think your estimation of the power requirements is high, maybe very high. I think Brucepick estimated his Civic drew 10amps for operation. Reducing loads through LEDs and HID headlights and such is also significant (my car has HID headlights and LEDs in almost all the esternal sockets now, and it's a big improvement).

Originally Posted by todayican

No for someone taking short trips, like a shorter commute, game on! :-)

Agreed. My experience suggests a confirmation of this, at least in part (though I use a deep cycle lead acid battery from Odyssey). My commute is 11/12 miles each way.

Originally Posted by mikehallbackhoe

I removed my alternator belt on my crx, and the cold idle went from 2000 rpm , to 2500 rpm. I had to ride the brakes going through town! I put the belt back on. I just bought a 31A yellow top optima battery for my dumptruck, which doesn't get a lot of use. I am going to put the optima in my crx when the weather gets nice, and remove the alternator belt. It won't cost me anything to experiment. the extra power is nice, even without the mpg gains.

On the freeway, engine-on pulse and glide, I have noticed idle RPMs in the 800s with the alt switched off and in the 700s with the alt switched on. But if you drive accordingly, using the "driving with load" technique with a vacuum gauge for your Civic, you should be able to get significantly better MPG from the belt-off alt delete mod. Thanks for this. Please keep us posted on your experiences. BTW: doesn't this suggest you saw maybe a 25% power gain?

Originally Posted by ecomodded

Find lower watt bulbs for your head lights, if you wanted you could mount some bolt on led pods.

I love the heater/ac fan mod idea you mention. I wonder how difficult it might be to do. For the headlight suggestion, of course, HID systems are available for lots of cars, and I cut wattage by almost 2/3 (to 70watts total for headlights) with a HID system ($70 I think it cost). There are LEDs too. I've seen them, but couldn't find for my car when I was looking. But I think you could get the draw down to 15 or 20 watts with LED headlights. I'd love that.

[mikehallbackhoe]

rather than make a lot of changes, I am only going to use it during nice weather. If I have to drive at night, it is probably 1 hour or less. I will carry the alternator belt with me just in case. On my crx, the alternator belt is the only belt I have, so it is fairly easy to remove/ install. if it seems to be saving me money, I might start replacing bulbs .

[mikehallbackhoe]

I would think the smaller the engine, the more effective this would be. My crx is 1300 cc and puts out maybe 60 hp @6000 rpm. I do most of my driving @2000 rpm. this would be probably between 15 and 20 hp tops.

[drmiller100]

Originally Posted by mikehallbackhoe

I removed my alternator belt on my crx, and the cold idle went from 2000 rpm , to 2500 rpm. I had to ride the brakes going through town! I put the belt back on. I just bought a 31A yellow top optima battery for my dumptruck, which doesn't get a lot of use. I am going to put the optima in my crx when the weather gets nice, and remove the alternator belt. It won't cost me anything to experiment. the extra power is nice, even without the mpg gains.

your idle changed because the computer was reading voltage, reading alternator, and the alternator was saying it wanted to charge like crazy.

so the computer raised the idle with iAC to compensate, but the alternator never got to charge.

So, when done, you hurt your battery by running it down, and you got worse gas mileage because your idle was higher and never came down.

[mikehallbackhoe]

1. I have no computer on my 1984 car. 2. I only drove it less than 2 miles, which didn't hurt the battery, I checked with a meter when I was done, and 3. the gas I used in my 2 mile test run won't hurt my average mpg very much. I now have an optima battery designed to run without an alternator, and be recharged without hurting it, and I lowered my idle speed to compensate for the lighter load on the engine. there are advantages to driving 28 year old technology (: