Alternator Delete
 

I know a lot of you have spoken or want to delete your alternators in order to increase FE, but there are many logistical problems associated with that and keeping a system charged.

A while back I came up with something that could help.

How about running an alternator off your drive shaft? (For those that have one). You would mount it under the car or in the interior, with a stretched belt. Now, it would only charge while in motion, but it also would not steal engine power and may be enough to keep vital systems happy.

Or same idea but powering it off one or both of the axles for us FWD vehicles. Now it may sound crazy, but it is not impossible and with a little input you guys could probably be inspired to do something similar that could work.

Have fun with this ...

You could always hook the alt up to a turbo and run it downstream on the exhaust, :)

SVOBOY thats what i want to do how do I do that. i have an old turbo now how can i make an alternator that will stand 100K RPM?

the Kompressor produces 15 psi hot air. how can this drive an alternator at 15 to 20k RPM?

You're need some crazy gearing to do it, I should think, but it ought to be possible. Perhaps a larger turbo downstream so that it wouldn't be moving as fast...I know BMW was experimenting with it several years ago, and if you've got the guts I think it'd be worth the try.

What kind of motor uses 15 PSI air to turn at 15,000 RPM?

hey what about a super coupe kompressor to run an alternator?
Does anyone have a SC compressor lying around?

You wouldn't need to get up to 15k rpm though? My alt does fine running at 1500-2k. I'm not familiar with vane air motors...linky?

I got an old smog(air) pump. but I want to couple it direct no belt. Ok, i was thinking 3 times engine speed is the usual ratio.

why not hook a solar panel up to it, then in an emergancy have a generator u could start up.

Is it the current from the alternator you are concerned about or the mechanical power it takes to spin it? A simple shut-off switch could take care of the electrical part, but a feasible mechanical disconnect would be more complicated and would outweigh the benefits of hardly a gain in MPG in my opinion.

Sorry i kind of hyjacked the thread.
trikkonceptz suggested a possible regen. braking idea for one alternator off an axle.
While I took it a step further to add an other alternator that would use the heat in the exhaust gas and eliminate the belt driven alternator. The axle driven would operate only under braking, while the exhaust driven would operate of course only when the engine is running not during coast.

How do you turn off an alternator that is still turning, that has been a debate in other threads. Will disconnecting the big wire hurt the alternator?

This is getting out there guys, either take the alternator off the car a rig a battery charger up to the car so you can charge everytime you stop or put a relay in between the alternator charge terminal and bat + terminal that closes when you are off the gas or on the brake.

Not worth it at all. Remember that your transmission taxes the power that goes through it. You're better off getting it right off the crank than losing 20% it through the trans.

Instead look into an underdrive pulley for your engine, or have one custom made. Slowing your accessory chain by 50% would surely help fuel economy while keeping your vehicle practical. Also look into reducing your electrical load (LED tail/signal lights, HID headlights, etc).

If you pipe your exhaust into the SC compressor, will the shaft turn an alternator direct coupled to it.

The idea is to extract a bit of energy from the exhaust gas converting it to electricity that can be used for driving accessories.

Thermodynamically, it would look like a pressure drop across the compressor would lower the final exhaust temperature.

the question being would it recover more energy than the added load and friction placed on the engine?

don't know maybe it would be better to stroke the engine and sleave the bores to get more expansion the first time around in the engine.

I'm pretty sure Frank was kidding.

I'm puzzled...how would driving the alternator off the drive shaft (front axle, etc) cut energy usage? It would still have to turn to put power back into the battery. And it is still going to require as much energy to turn whether the energy is coming from the crank shaft pulley or whether it is coming from a pulley grafted onto an axle shaft.

As for cutting off the alternator output, how much gain can be derived thereby? I have driven cars with defunct alternators/generators a number of times, and while I've never quantified the gas mileage, I never noticed any significant power difference. I did, however, notice a significant dimming of the headlights...this was driving from about the midpoint between Baker and Barstow, CA, to Barstow. Had to get the battery recharged and then was able to drive home to Glendale the next day. Of course it was a very quiet trip...I was afraid to even turn on the radio...it was an old Rambler with a tube radio.

I wonder also about battery life...if the alternator is disconnected you are pulling the battery down a lot more than it normally would be...car batteries are designed to give a lot of power for starting, but not designed for continuous loads. Are you saving a tenth of a mpg or two and trading for shortened battery life?

The most logical thing would be to lose the alternator and charge a deep cycle or alternative (NiMH, Li-ion, etc.) battery at home. Use the waste heat of the exhaust to improve engine efficiency, not drive an unnecessary accessory.

- LostCause

A lot: Plug-in Blackfly: going alternator optional nets +10% mpg

AndrewJ just did that to his Civic, and noted an even larger mpg boost.

You wonder correctly. This will destroy a conventional starting battery pretty quickly, as you mentioned. So unless you have a supply of free or cheap batteries (with enough capacity), this mod makes no sense from a financial standpoint.

Just a quick thought on this concept, what if you used a deep cycle battery and somehow combined an alternator with an ac compressor clutch, you could then keep your alternator in the car and simply use a toggle switch to engage/disengage the alternator drive.
Add some solar panels to the system to help with charging.
Maybe even automate the switch on/off depending on the voltage at the battery.
Just some thoughts, take them as you will. JoJotheTireMan

On a car, solar panels aren't worth their weight. The only reason I have one on our other car is because my sister goes weeks without driving it. It prevents the battery from going flat.

True the test could consume the SC turned gaseous powered motor. If however diesel's are dirty as everyone says they are then after the test it should have a very fine coat of nice lubricating lampblack sealing all the little nooks and crannies. Exhaust temperatures for the rabbit are only 300 or 400F.

Besides it would be still good to look at and sit in the living room.
A slight devaluation for the advance of science.

I'll Try it first with an old smog pump or two and see if it melts anything.

A alternator on the drive shaft type setup could act as regenerative breaking... while driving it would not charge then as soon as you hit the breaks the 12v from the break light wiring trips a relay and the alternator is energized and connects to the electrical system and starts charging, most "GM one wire" alternators have a plug on them that can be used to control the charging of the alternator , for external regulator use..

I don't know how much breaking you'd get out of a standard high output alternator, but if its capturing wasted energy its a good idea.. however I know that you can make a gas powered alternator based charger from a 5 hp lawn mower type motor.. so they do take 5hp to turn the alternator at 5000 rpm..

realize that when your motor is running at 2k the alternator is at about 5k... so at red line of 6k its probably spinning at 10+k rpm.. so the exhaust mounted turbo may be a great idea... it would add some back pressure to the exhaust also.

If some one had a spare turbo laying around this probably would not be to hard to test out. couple the shaft from the turbo compression side to the alternator run some compressed air through it.. see what happens

Happy modding!

I strongly recommend an "alternator delete." This goes doubly for those with already aeromodded cars.

Before an alternator delete I was topping out at 57mpg.
Afterwards I'm hitting 68mpg.

That's just over a 20% gain. :thumbup:


I think my results are so much higher than Darin's for two reasons:

1.) Honda D-series motors are very efficient at low loads.

2.) Low aero drag (and an HAI) make the alternator a bigger portion of the load than normal, therefore removing it gives a proportionately large gain.

I got to recap and focus.
1. altenator delete
2. solar panels
3 a braking altenator, i would run a flywheel
4 engine heat, use a steriling or steam engime to run an altenator
5 plug in a charger, especially if ur aleady pluging in a block heater.

Here's an idea...

How about removing the stock tensioner spring and replacing it with a cable or vacuum actuator of some kind? Maybe even an A/C type clutch on the crank pulley. That way you can stop and start your entire accessory chain as needed.

I was thinking deep cycle battery, I have been using them in all my light applications just because they less expensive than regular batteries. Only other accessory is the water pump want to go to an electric pump so no belt.

The A/C clutch has come up a few times, but it's generally discounted because:

1.) It takes energy to make energy
2.) A/C clutches would be oversized, so an underdrive pulley would have to be mounted on the crankshaft
3.) Keeping the alternator the same, but killing the field current scores higher on the cost/benefit ratio.

Putting the A/C clutch on the crank is a novel idea, but my biggest concern would be keeping the oil and coolant pump operational. I also have no idea what kind of torque those clutches can transmit without slipping.

The ultimate would be to lose the accessory belt altogether and just substitute critical components with motor driven ones. Electric coolant pumps, as used on drag cars, are energy intensive, expensive, and generally aren't very reliable...but it could feasibly work.

- LostCause

HI guys:

Although I have been lurking here for some time,this is my first post at this forum, so first let me tell you a little bit about me and my Geo Metro.

Im a retired 70 year old that shares your passion for improving mileage, and I am working on controlling the alternator on my 1994 stick shift 3 cylinder Metro to save gas as well.

I recently installed a Xantrex Link 10 Battery Monitor in the Metro and optima red top 44 AGM 44 amp hour battery.

Next I tore into the stock 55 amp alternator and brought out two wires which allows turning the field on by connecting the ends of the wires togather, or turns it off when the wires are disconnected.

The internal voltage regulator, and the alternator, function normally when field is on and alternator does not charge when the field is off.

I rigged up a 3 way switch on the dash, and a bit of circuitry, such that in one position the alternator never charges, in another position it charges normally all of the time, and in the final position it charges only when the fuel injectors are cut off during deceleration for regenerative braking.

With a fully charged battery and with the alternator off, when the engine is cold it uses about 7 amps, but when it warms up it drops to about 3 amps. All in daylight with no accessories on. I still haven't figured out what is on when cold that draws the extra 4 amps, not that it it matters much.

I am really surprised that the the injector, fuel pump, and ignition together use only about 3 amps, but that is what I am observing.

With the switch set to charge only while decelerating, giving regenerative braking, the amount of charging, and braking, depends on the state of charge of the battery during deceleration. When the battery is full maybe 10 amp or so, rising to a full 55 amp as the battery nears full discharge.

If you are going to do regenerative braking, you must leave room in the battery for the generated charge to occupy by running with a partial charge in the battery normally!

I read somewhere that BMW uses 80% charge on their new system.

Also there is the old rule of thumb for charging lead acid batterys that says that a safe rate of charge, in amps, is equal to the number of amp hours out of the battery.

Thus if my 44 amp hour battery is half discharged, a safe rate of charge is 22 amps, and I am exceding that rule. Probably ok for short periods, but it is clear that for big alternators and heavy regenerative braking, big heavy batterys are needed.

Another interisting rule of thumb used by those who sell 12 volt alternators is expect 1 horse power to be required for each 25 amps of alternator output.

With my present set-up and my normal driving around Tucson, regenerative braking only does not keep the battery from becoming more and more discharged.

At present I am considering a solar panel to supplement it.

Anyway, thats my two bits worth for tonight. Take care All.

how did you wire the alternator, espesially the regen braking.

Hi OldGuy, welcome to the forum. Sounds like you've set up a nice system.

First question that comes to mind: how much of an improvement have you measured?

I assume you are using a 12v charger to top up when you get home. On the return leg, knowing you're close to a charger, and knowing the battery's state of charge, you could use your switch to shut the alternator down completely and arrive home for a fresh recharge. That strategy would net measurable gains (assuming you're not discharging the battery so deeply as to damage it or dramatically shorten its life, negating the financial savings).

"With a fully charged battery and with the alternator off, when the engine is cold it uses about 7 amps, but when it warms up it drops to about 3 amps. All in daylight with no accessories on. I still haven't figured out what is on when cold that draws the extra 4 amps, not that it it matters much."



during cold startup many cars have heated 02 sensors which draw more current, as well as the injectors draw more when cold because they are open longer, and their resistance is lower. the mass air flow goes thur a burn off to clean the wire sometime during startup. the idle air control is open further during startup. the ignition coil is cooler and has lower resistance. the fuel pump is cooler. all the relays are cooler and have lower resistance.

Great insight Diesel John, I wouldn't have thought of that.

Are you shutting the ignition off when stopped at lights?

First Question:
how did you wire the alternator, espesially the regen braking.

Answer:I broke the connection between the voltage regulator and the rear brush within the alternator, then soldered a wire on each side of the break and brought those wires out of the alternator. Connect them togather, it charges, disconnect them it dosen't.
Regenerative braking occurs when you turn the alternator on.

Darin wrote:
Hi OldGuy, welcome to the forum. Sounds like you've set up a nice system.

Actually it is all experimental at present, made from stuff in my junk box, and taped in place. I haven't had it on for very long, so i don't have any results on gas saving. Also I have been recharging the battery by just turning the switch back on to normal charge, and burning any gas I might have saved up to recharge the battery. I don't even own a battery charger.

I have decided just today to order a solar charger and mount it on the hood permanently.
The panel that I am now looking at is 30 watt, 24.64 x 17.44 by only 0.3 thick, so I doubt that it will hurt the aerodynamics much. Here is a link to the panel:
http://www.nationalsolarsupply.com/i...ROD&ProdID=900

I think Solar is a real option here in Tucson, so we will see.

Good thinking on the guess about the heated sensor Diesel John, but my metro has a two wire oxygen sensor so i don' think that is it.

In answer to Duffman's question, no, I was not shutting down the engine at stop lights.

It will be awhile before I get the panel, and I will keep you guys up to date as this experiment continues.

This a great place to exchange and share ideas & results. Take care all.
Gordon.

Since you are idling at lights I have a suggestion for you:
Add a microswitch to your accelerator pedal that closes when the pedal has not moved from its rest position. You can put that in line with your #3 option to charge the battery. This way you get charging every time that you are off the pedal, both decelerating and while idling at lights. It might give your battery that extra charge that will help it keep up to your draw and while your engine is idling its doing nothing towards productivity for the fuel used, at least now it could charge the battery and the load will be pretty negligible.

Actually, all these mods are old hotrodding tips- underdrive pullys, alternator cutout, driveshaft alternator (saw it in Hotrod magazine back in the early 80's- essentially youre spending less energy turning since youre using the drive ratio of your tranny to your advantage.

I think the "less-is-more" move here would be to go with a lighter battery (Get a BCI book...what percentage of your laden weight is that group 24?), turn the alternator slower since it would extract less power off the line in traffic, which is a reality in the big city, and use the alternator cutout.