Considering an Alternator Delete

[crazyrog17]

I feel like I posted this in a like thread, but this ^ idea plus a micro controller.

The Geo Metro XFI incorporated a system that would electronically disconnect the alternator under low electrical load conditions, and when the battery voltage was above 11.5 volts.

An arduino would be suitable, connected to a 50 amp 100% duty cycle relay/solenoid.

[mikeyjd]

I feel like I posted this in a like thread, but this ^ idea plus a micro controller.

The Geo Metro XFI incorporated a system that would electronically disconnect the alternator under low electrical load conditions, and when the battery voltage was above 11.5 volts.

An arduino would be suitable, connected to a 50 amp 100% duty cycle relay/solenoid.

I like this option. I don't think I have enough know how yet to do it myself though.

[jason_]

Go diesel with mechanical injection.

Manual lever shut off for the pump.

All of my buddies water pumps are like that because thieves are running off with his batteries.

6cyl. 955 incher Cummins big blocks

Serious pair of welding leads for jumpers, sparks fly, fires up. Runs for the day, afterwards cuts the fuel to shut them down.

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[Tommychu]

I feel like I posted this in a like thread, but this ^ idea plus a micro controller.

The Geo Metro XFI incorporated a system that would electronically disconnect the alternator under low electrical load conditions, and when the battery voltage was above 11.5 volts.

An arduino would be suitable, connected to a 50 amp 100% duty cycle relay/solenoid.

That's a great idea in theory but you'd lose fuel economy from the 15-20 spare alternators plus tools you'd have to keep in the back for when the voltage spike from disconnecting the output lead of the alternator blows them up.

Switching at the regulator wouldn't require a 50 amp relay, and would unload the alternator a lot more safely. But letting the alternator work the way it was designed to do is already the most efficient way to operate the electrical system in my mind. If you minimize the electrical loads the alternator only works when it needs to, and isn't that big a load in the first place. Shutting it off would also mean it's going to work that much harder when it comes back on.

If I was in your shoes I would look at underdriving it personally. Festiva alternators are sourced from Mitsubishi, I bet finding a pulley to do so wouldn't be too hard.

[mikeyjd]

That's a great idea in theory but you'd lose fuel economy from the 15-20 spare alternators plus tools you'd have to keep in the back for when the voltage spike from disconnecting the output lead of the alternator blows them up.

Switching at the regulator wouldn't require a 50 amp relay, and would unload the alternator a lot more safely. But letting the alternator work the way it was designed to do is already the most efficient way to operate the electrical system in my mind. If you minimize the electrical loads the alternator only works when it needs to, and isn't that big a load in the first place. Shutting it off would also mean it's going to work that much harder when it comes back on.

If I was in your shoes I would look at underdriving it personally. Festiva alternators are sourced from Mitsubishi, I bet finding a pulley to do so wouldn't be too hard.

please explain.

[crazyrog17]

Put a larger pulley on the alternator. Fewer rotations of the alternator per rotation of the crankshaft.

[jason_]

Changing rotation speed won't make a difference.

Slower will cause activate problems. And faster the regulator will keep it from over voltage-ing, if that's a word.

It's the reason running with no battery is a no no, if regulator pukes, or goes bad in the wrong direction , alternator might over voltage and with no battery to soak extra volts, smokes electrical items.

The rectifier is the same no matter the rpm, but like I mentioned, certain rpm is needed to permit charge.

Older gm one wire with built in regulator would stop charging if turned too slow, and wouldn't continue until I bumped 12v to activate it again. I fabbed one on our ford work master, and gagging the engine with the hydraulics it's easy to under turn the alternator, and it'll stop charging.

Not to mention if it was under a heavy load, and on the verge of too slow to almost stop charging, it'll overheat

They get mighty hot when pulling load for headlights.

And do turn hard when charging heavily. I was juicing 6 batteries on our diesel loader, left jumpers on, touched they key on the Cummins, fired up. Crawled back down, jumped in car.... stalled, dashights. found out it pulled so many amps through the jumpers, alternator gagged out the engine on my aspire. Bumped car key, fired right up.



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[Tommychu]

A little research tells me that Unorthodox used to make an underdrive crank pulley for the Miata B6/BP (obviously easily adaptable to any B-motor if not a straight bolt on, though I believe the Miata was serp so you'd need Aspire or Miata alt/WP pulleys). Keep an eye out on CP and the Miata forums, they pop up once in a while. OBX still makes 'em, but they want $100 for it and that's a tad steep for a stupid little hunk of aluminum IMO. Part#58-9999-17 if ya wanna ebay it. Or if you really wanna spend some dough on pulleys you can pick up a full set from these guys for $400.
All of these are big nose only as far as I can tell though, so if you're pre-'92 you'll have to find something else.

Running a modern alternator at 15-25% under stock speed isn't going to cause any kind of big disaster. If it did, the market for underdrive pulleys wouldn't have exploded in the early-mid 2000s quite like it did. Older alternators (like the one-wire Delcos) ran the field windings exclusively off internally generated power and depended on the residual magnetism hanging around the iron core of the rotor after the last shutdown to get things started again. So you needed a good rev to get the ball rolling and then it would work as normal from there. Almost all of the new stuff will give the rotor a little zap from the battery on startup to alleviate that problem (or solve it by other means).
And it's not like we're dealing with delta-wound stators here. An automotive wye stator will still produce power down to some pretty damn low speeds. Maybe not quite as efficiently (and that's a really big maybe- every alternator is different) and definitely not as much power but remember that we're talking about absolute minimalism here on a fuel-mileage-at-all-costs build. I'm sure mikeyjd isn't about to fill his hatch with half the Rockford Fosgate catalog or try to run arena-grade High Pressure Sodium foglights.

[mikeyjd]

A little research tells me that Unorthodox used to make an underdrive crank pulley for the Miata B6/BP (obviously easily adaptable to any B-motor if not a straight bolt on, though I believe the Miata was serp so you'd need Aspire or Miata alt/WP pulleys). Keep an eye out on CP and the Miata forums, they pop up once in a while. OBX still makes 'em, but they want $100 for it and that's a tad steep for a stupid little hunk of aluminum IMO. Part#58-9999-17 if ya wanna ebay it. Or if you really wanna spend some dough on pulleys you can pick up a full set from these guys for $400.
All of these are big nose only as far as I can tell though, so if you're pre-'92 you'll have to find something else.

Running a modern alternator at 15-25% under stock speed isn't going to cause any kind of big disaster. If it did, the market for underdrive pulleys wouldn't have exploded in the early-mid 2000s quite like it did. Older alternators (like the one-wire Delcos) ran the field windings exclusively off internally generated power and depended on the residual magnetism hanging around the iron core of the rotor after the last shutdown to get things started again. So you needed a good rev to get the ball rolling and then it would work as normal from there. Almost all of the new stuff will give the rotor a little zap from the battery on startup to alleviate that problem (or solve it by other means).
And it's not like we're dealing with delta-wound stators here. An automotive wye stator will still produce power down to some pretty damn low speeds. Maybe not quite as efficiently (and that's a really big maybe- every alternator is different) and definitely not as much power but remember that we're talking about absolute minimalism here on a fuel-mileage-at-all-costs build. I'm sure mikeyjd isn't about to fill his hatch with half the Rockford Fosgate catalog or try to run arena-grade High Pressure Sodium foglights.

Thanks for that post Tom. I have a much better feel for what it would take to make it happen. As much as I'm trying to hit the absolute best FE setup I can it's being done on a budget, so this mod probably won't pencil out for me or be worth my time.