Alternator Delete

[ebacherville]

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!

[AndrewJ]

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.


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.

[guitarterry]

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.

[JohnnyGrey]

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.

[diesel_john]

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.

[LostCause]

Originally Posted by JohnnyGrey

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.

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

[OldGuy]

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.

[guitarterry]

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

[MetroMPG]

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).

[diesel_john]

"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.