Geo Metro Easy Hybrid or Waste of Time?

[inspiredvoltfreak]

Ok, had a thought coming home tonight that I'd like to try unless people shoot it down immediately. I'm definitely eager to follow the advice of people this time around and I'm not doing anything until I get some valuable input.

So here's how it stands. (NOTE: I Built a failed Delta Trike EV project Previously) The delta trike is disassembled into a rolling chassis with differential, the motor and electronics, and the batteries. I have the batteries up for sale on Craigslist and I've sold 1, 5 more to go. I'm looking as well on craigslist for a buyer for the rolling chassis to use for some fun project, though I'm recommending it not be used for anything that will actually see the roads. So what's left is to do something with the motor, controller etc. I'd hate to pawn them off and in fact am not willing to do so except as an extreme last resort. I had considered another bike but am concerned that it will not help me as I won't be able to commute with it. The most I could do is use it for short trips to the store. It would take a long time to pay off under that circumstance.

So here's my new idea. Put it on my 96 Geo Metro connected direct to the crank using the existing unused Poly-V belt slot (for air conditioning I think). I would gear the max Motor RPM to match the max Engine RPM, I could then team it with some small U1 batteries (free with 50% charge from scrap pile) (I.E. I can kill them with great frequency and exchange them with no ill effect to my wallet) (Unless there's potential for a thermal event!) and it would serve just to smooth out the power demand on the motor for hill climbing etc. Of course the big question here is what effect would the extra drag on the engine during off times have. Would it negate any gains?

I'm far from having all the details worked out but my initial thought is that if I didn't have the motor in regenerative mode on throttle off, (or if i can tune that regeneration to be quite small) The drag would not be that significant. In addition would there not be a way to remove the alternator and just put a step down converter to keep the car battery charged up?

My thought would be to have two throttles for the DC motor, one linked to the gas pedal and made adjustable, and a separate one that i could activate manually. (Thinking of putting my motorcycle twist throttle on the hand brake handle) Now what would happen if i gave the DC motor power without pressing the gas pedal for the engine? Would it not just look to the engine computer like I'm coasting down a hill and put itself in fuel cut until I press the gas? Would really like input on this point!

I've got so much more to say, but this is a good start for the basic idea. Looking forward to feedback.

By the way, since I've got nearly everything I'd need, I could do a trial run of this outlaying only about $60 for a pulley and a belt. Is it worth a try at that price? Anyone have a link to someone that's done this? If nothing else it would give me a 26HP boost, (on a 70HP engine i might add)

[inspiredvoltfreak]

I then had Gordo reply

1. You need a small pulley on the e-motor and large pulley on the crank. 2:1, 3:1
2. You need a good belt to handle 20HP.

To which I replied

1. Yes, I believe your right, the max engine rpm according to wikipedia is 5100 rpm and the DC motor 3400 rpm at 72V. Not that the engine is likely to ever see that rpm with my foot on the accelerator, but anyways if my math adds up that's about 1:1.5 ratio.

2. The diameter of pulley on my crank is fairly large as i'm pretty sure it's there for air conditioning and needed a big step down, so i would have a significant contact surface which I think would be sufficient to prevent the belt slipping. The belt is a poly-V about an inch wide, so question is how much power could it take before snapping? A quick search is telling me nothing, I suppose one could weld a chain sprocket onto the end of the crank pulley and do a chain drive instead. But that would be noisy and high maintenance.

And then Replied again

This looks pretty neat as well, but it's not worth it on my beat up old car.
http://ecomodder.com/forum/showthread.php/crazy-aeromodded-metro-chopped-teardropped-90.html

Just to get you up to speed!

[inspiredvoltfreak]

Actually, just ran the numbers again. Really it's 72 volts x 300 Amps peak x %90 efficiency or .9 = 26 HP Peak (for up to one minute) or 13HP Continuous. That's pretty impressive! 1/3 the HP of the stock motor.

So it seems the GM Version of this is known as a BAS Hybrid and works like so

"General Motors introduced a mild hybrid system called belt alternator starter (or BAS) in the 2007 Saturn Vue Green Line. The BAS system is also used in the Chevrolet Malibu Hybrid and Saturn Aura Green Line. It operates similarly to other mild hybrids with a "start-stop" system, in that it shuts down the engine as the vehicle comes to a stop and instantly restarts it when the brake pedal is released."

I must confess, the idea of removing the starter as well had occurred to me but I'd not thought of actually stopping and starting the engine with the brake pedal but rather just boosting the take off power moderately and using electric to do it and so conserving gas. That's Awesome!

Some more data

According to the EPA the 2009 Saturn Vue BAS hybrid garners an improvement of 32% city (19>25mpg) and 24% highway

I don't expect to get those numbers from my car without a robust control system but hey? If I could get 20% city and 10% Highway, It's worth it with my money already invested in the parts.

Obviously, these systems use NIMH or LI-ION batteries that are small and fairly light but I should still get reasonable results with small Lead Acid Gel batteries. I would use U1's which are 23lbs at 31ah. for 6 totalling a 72v 31ah 138lb battery. Of course these batteries will be used with maybe 50 to 80% capacity left.

I already removed my rear seat tonight which shaves 20lbs off my vehicle weight. The motor is 30lbs so it almost covers that. If I could remove my Alternator and Starter that's gotta be another 20lbs. Then I'm only up 98 lbs Plus maybe 10 more for wires, controller etc. Actually, I could go to a smaller deep cycle battery for the vehicles electrical systems as well and probably save another 10lbs. It would be good enough for proof of concept anyways. I could always upgrade the batteries later to shave weight.

Another added benefit of this is the ease of moving it over to another car down the road, Super easy!

Just a thought, If I were to put my Mars motor in place of the Alternator, I could possibly swap out my crank and waterpump pulleys and add an idler to increase contact on the motor and engine pulleys and put a wider belt on to handle the horsepower. (Assuming the water pump could take the additional stress)

F.Y.I. I spend an average of 20 minutes in very slow moving traffic approaching a tunnel each day. Stop and go Traffic is where this could shine!

Quotes in this post are from Wikipedia "http://en.wikipedia.org/wiki/BAS_Hybrid"

Please tell me the honest truth, Do you think it's worth the effort?

[amberwolf]

The Metro is a popular car to convert, in various ways.

I see no inherent reason it wouldn't work the way you want, though I don't know how much power the belt can take. You might need to switch to a different belt (and maybe different pulleys) or a chain.

You would definitely want to ensure the engine can never over-rev the motor, under any conditions, or else it is possible the motor could grenade it's commutator. That's nasty.

The one thing to consider is "will the battery and motor weight be so much that it overcomes any advantage of having the electric added in there". The metro is a light car, so it's tiny engine can pull it easy. If you use lighter batteries (not lead) then it might be worth it. If you have to use lead, it may not be; you'd have to work the numbers out.


This project converted it to a hybrid, with a motor in the engine compartment like you're thinking of, though I am not sure how he connected it to the engine
http://metroxfi.com/geo-metro-xfi-hybrid-project-page/
and it hasn't been updated with any final results.

EVAlbum may have better info:
http://evalbum.com/type/GEO
though I haven't looked thru the listings there to see which are hybrids like you want to do.


DIY Electric Car forums has had several Metro conversions, but I cant' remember if any of them were hybrids. I know for sure some were full electric, replacing the entire engine.

[inspiredvoltfreak]

The one thing to consider is "will the battery and motor weight be so much that it overcomes any advantage of having the electric added in there". The metro is a light car, so it's tiny engine can pull it easy. If you use lighter batteries (not lead) then it might be worth it. If you have to use lead, it may not be; you'd have to work the numbers out.

This project converted it to a hybrid, with a motor in the engine compartment like you're thinking of, though I am not sure how he connected it to the engine
http://metroxfi.com/geo-metro-xfi-hybrid-project-page/
and it hasn't been updated with any final results.

EVAlbum may have better info:
http://evalbum.com/type/GEO
though I haven't looked thru the listings there to see which are hybrids like you want to do.

Yeah, already figured out the gear ratio and that shouldn't be a problem.

As to your first link I read through it last night. It was Scary! He actually welded a chain sprocket onto one of the cv shafts and turned it via chain drive over a right angle with a jack shaft. Not surprisingly he had problems with the chain skipping! Imagine the flex on the cv shaft under a heavy acceleration. He discussed possibly locking the suspension on that side because it would dip down and pull steer under acceleration. Still, I've done stupid things as well. Just saying I don't particularly envy that build. I'll check out the EV album and get back to you.

[Geebee]

Try this site http://ecomodder.com/ , go to the forum, just about every variation of a Geo electric or hybrid has been done.

[inspiredvoltfreak]

Reconsidering my idea. The metro I have is the 96 4-cyl automatic version weighing in at 2000lbs. I can get a standard, 3 cyl manual weighing in at 1650 lbs for under $500 I could sell my car for around the same. In the mean time between buy and sell I could convert the standard to a hybrid which would be able to drive in full electric mode in 1st and 2nd, possibly even third. My ideal metro would be the 3 cyl convertible variety so I could easily play with a custom roof line, putting dump in the seat to get a lower line, and perhaps even boat tail it. Unfortunately, their quite uncommon. There's only one on Craigslist right now, and they want $2000 for it. Ouch! Probably will have to settle on a hatchback type.

[jmygann]

http://evalbum.com/994

both 48 volt and solar charged

[parajared]

I considered this build when my 96 Suzuki Swift (same thing as Metro) engine went out.

EV's aren't as awesome as you would hope.
It all comes down to price and weight. Too much weight and you can't brake, steer, handle. You need something like a pickup truck to handle all the weight. And to push all that weight you need big expensive electronics. Go with the lighter lithium based build and you are talking about cash. Getting 2-4000 cycles on that $5000 battery bay isn't doing anything to save you money, not to mention the price to charge the thing up every night.

If you want to do a small build (ie geo metro, ford festiva, vw rabbit) just save yourself from blowing huge amounts of bucks on a EV conversion and just get a golf cart. Carts can be driven in 25mph zones legally, if you license and register them. You can throw a ton of batteries in the back if you need to go far, and they are already pre-built. Small car builds can go far, or go fast, but not both. Most demonstrate the same specs a run of the mill golf cart can do.

Best EV at the moment = e-bike build. You can't drive a golf cart down the highway shoulder, bike path, or sidewalk, but you sure can on an e-bike. You can fly right under the radar of all the rules, regulations, and government imposed crapola. You can build the things for less than a grand, and if you build them right you can do impressive distances. My personal record is 50miles on a 20aH battery, but I'm sure others have take theirs even further.


Other alternative builds I have done:
Veggie oil was my most successful alternative build before it became popular. I mean it's free fuel just waiting there to be picked up. Restaurants loved offloading the stuff.It meant changing fuel filters, evenings spend doing the impressively dirty job of pumping veggie oil and rebuilding fuel injectors and pumps on occasion, but it was free fuel if you were willing to work for it. No-one is giving up their grease these days though.

Waste transmission fluid was great, it never froze, it always stayed viscous, easy to pump out, and even when the veggie oil craze hit, transmission shops were happy to let the stuff go. Only problem was unlike veggie oil where you could scrape the crud off your oil refining filters, they would just clog up. I could never get the stuff to filter out properly and lost an engine once trying to use 10 micron filter rather than my usual 5 micron.

[spinningmagnets]

Chevrolet felt there was not enough interest in an AWD version of the Geo Metro to sell and support them in the US, but...in Canada they sold under the name of the Pontiac Firefly / Suzuki Cultus.
http://en.wikipedia.org/wiki/Pontiac_Firefly

At one time I toyed with the idea of building a back-yard hybrid, though I knew it was unlikely I'd ever build it. A used Firefly from Canada was my best shot. For those with more money (enough to risk experimenting) I believe the best DIY option is an AWD / 4WD vehicle that comes from the factory as a Front-WD (Toyota RAV / Honda CRV / Ford Escape / etc?). If you disconnect the shaft that connects the transmission to the rear differential, it "seems to me" that it would be fairly easy to add a motor there. Since many appropriate motors turn at around 3,000-RPMs, it "might not" need a belted gear-down to run, possibly just an adapter plate to mate the two.

Look for the smallest engine that the donor car had as an option, since you will now have a motor to add boost. I don't know if there are any glaring problems with this idea that I hadn't considered, but...that is my personal "back of the envelope scribble" for what its worth.

[inspiredvoltfreak]

Wow, I'd forgotten I ever started this topic. I have decided to go ahead with the hybrid conversion and it is in process. First step was to sell off my newer 96 Geo metro and buy up one of the older 94 ones. This also got me behind a stick shift again and knocked one cylinder out of the equation. I am happy to report that before modification I'm up from 28mpg average to 42.85mpg average. I just got a wheel alignment and have changed my driving style a bit and hit a high of 47.09mpg recently. Best ever in the old one was 32mpg. Considering I bought and sold the cars for $500 each it only cost me $114 for transfer fees and tax.

But the desire for greater fuel efficiency is driving me on. I have bought a used transmission from the scrap yard to start modifying, I took off the cover for the 5th gear set and welded a #40 sprocket onto the gear (VERY CAREFULLY). I am currently working on the adapter plate that will mate my mars motor to the transmission. I need to do a trial fit to make sure of my positioning and clearances. Basically the gear is on the opposite end of the input shaft so I will get to use all 5 gears. I will be able to use 1'st and 2'nd for sure and maybe 3'rd in full electric mode. The ratio for motor to trannie is 1:1 and I checked with the president of Mars electric who said the max safe rpm for that motor is 5,000. This matches up to the engine top speed but I never rev that high anyways.

I am currently busy with life so this project is on hold but if I make a successful test run I will post back up here.

Project cancelled. I've moved before i completed it and the car i had turned out to have a whole lotta rust under the paint and wasn't worth doing the work on. I'm now only 15 min from work so the long range commuter thing is out. May finally build an ebike of some sort.