Geo Metro plug-in parallel hybrid EV - in progress

[bennelson]

Originally Posted by MetroMPG

Nice vid. Was that an EV grin?

Nah, musta been a HYBRID grin!

I love how the video ends at the auto parts store.

All my EV trips either end up at the auto parts store or court!


About gearing:

There's two ways you can go with an EV. Gear low and spin the motor fast. This gives you lots of power, but may limit your top speed. I keeps amps down and motors happy.

Gear High - Better top speed, worse acceleration. Pulls more amps, so not as good for your batteries. It also assumes that you are NOT topping out the amps on your controller. If the motor was attached through the transmission, you would actually UPSHIFT to accelerate. The only other thing to watch is pulling away under electric mode from stops uphill!

My motorcycle (with a similar, but brushed, motor) is geared at just over 5:1. It was originally 6:1, which was insane torque (actually spun the back tire by accident!) but not quite the best speed. The 5:1 gearing seems to be a good balance of speed and power on my cycle.
The 5:1 gearing gets me 45 mph.

I believe the Prius EV mode kicks out at 28 mph, so we are already WAY past that!

Time for an Ammeter!

[Coyote X]

Yep it was not able to get up the hill with all the potholes in the road I think I need to play with the motor timing some more to tune it a bit better. It has much more power in reverse and can back up that hill easier, but I can do that later. Right now the main thing is to properly wire up the controls and get some gauges in there. The controller has an output pin to monitor the current since you cant directly measure an AC motor:

The output is a PWM, whose duty cycle represents current. 100% is max current. You can use any supply, such as 5V, 12V, battery voltage. It can drive simple electro-magnetic needle. We do provide such a meter. Just wire the meter between 5V and the output.

So I will have a voltmeter on the batteries and an analog ampmeter measuring motor current. I could also measure battery current but it won't mean that much since the controller doesn't output battery voltage all the time to the motor. It pulls about 40 amps from the batteries when starting out. I am thinking of putting a relay on the reverse lights to kick the controller in reverse. That way I push the clutch and shift to reverse instead of flipping a switch. It would be one less control in the car and keep everything as easy as possible to operate.

On the video I ran electric backing out then making a couple of runs at the hill. Then I started the motor on the bridge long enough to get over it then killed it by stalling the engine. I ran down the alley electric only till I got to the main road where I started the gas motor to pull out. Once I was up to speed I just left it in N and running in case I needed it.

with a 44 tooth sprocket it gives me 4.88:1 gearing and my mph vs rpm looks like:

rpm	359	718	1436	2154	2872	3231	3590	3949	4308
mph	5	10	20	30	40	45	50	55	60

From what I have seen online this motor can really run up to 5000 so if I limit myself to 60mph that will work out good and give me a good bit more power.

[bennelson]

I've also considered using the reverse switch as part of the EV system on the Electro-Metro.

My car is just too dang fast in reverse. I always have to remember to go real light on the pedal when backing up.

For mine, I would wire a resistor that would kick in to the control circuit when put in reverse. That way, the car would operate at "half-speed" when the backup lights are on. I have also considered a chime or beeper when the backups are on.

Usually pedestrians notice that a car is on by hearing the engine. Hybrids and electrics can and do move without an engine in parking lots. I am not a big fan of "bell the hybrids", but it does make sense to have a way to alert pedestrians that the car is about to move. Even a bicycle bell would help.

Most direct drive EVs use a Forward/OFF/Reverse swtich. BUT, since yours is a direct-drive HYBRID, I really like the idea of using the stick to control the direction of the motor.

[metroschultz]

Install a sound system (P.A.) that sounds like horse hooves on pavement for when you are in EV mode.
Then people will hear you coming and turn around to look for the horse.
I EOC a lot around town and have to use my horn occasionally to alert the kids playing in the street. I am going to get one of those Dukes of Hazard horns one day.

[Coyote X]

A friend gave me a kids 24v electric scooter today. I ended up spending half the day playing with it I took the throttle apart and the brake lever and combined them into a working throttle trigger.



And made a faceplate for the Radio Shack panel meter so it will read correctly.



And last but not least here is a first try at my dash panel for the electric controls. Once I am happy with it all that is needed is to laser print it onto a transparent sheet and glue it onto a piece of lexan painted white. On the back side of the lexan put some green leds so it will glow at night and actually look nice. The red is for the holes to drill out for the switches and stuff, gray is where the panel meter goes

[Coyote X]

Got a nice throttle for the electric drive now It works great. I will probably build the dash panel and mount it in this week. The 44 tooth sprocket should be here by next weekend and I hope I get somewhere with the shorter struts. Might be done by next weekend but the speed it is getting done lately I would not count on it. If nothing comes up everything except the shorter struts should be done at least. I might just weld a set of struts solid next weekend and put on the car so I can start driving it.




Maybe one day I might even vacuum the carpet...

[Coyote X]

The mess of wiring is getting slowly put into shape. First thing was to mount the battery charger and get the pack built up some. The voltage was a bit low so my first drive was on a not totally charged pack maybe, or I just ran it down while driving. No gauges yet so I have no idea actually how good it was charged.



Then I wired up a relay onto the reverse lights to switch the controller to reverse. So to back up on electric I have to push the clutch and shift into reverse. Not a big deal to hold the clutch down while backing up I figure.

With the batteries charged up a few hours I tried out the throttle since it is now properly adjusted and wired in. The car seems much stronger than the first drive but I bet it would still have trouble getting up the hill by my garage so I will be swapping to a 44 tooth from a 36 tooth sprocket this weekend if I have time. I have a lot of other stuff to do so it looks like it is going to be another weekend of slow progress.

[bennelson]

MARINCO! EVeryone's favorite DIY Charging Port!

Works well for block heaters too! (see Doax's Vibe)

[arb]

You will get about 2x the energy / cost density from Trojan t1275 batteries. They will last longer too. Yes, they are a wet lead-acid battery, but are the best bang for the buck. The 82 pounds gets you 12v at 150 amp hours (c/20 rate) !! Cost of about $200 each Trojan

Optima BlueTop D31M (60 pounds) gives you about 75 ah for about $200. Specs & Tech - Technical Specifications

Advanced DC motors are about the most reliable you can get. They spin very fast if need be. EVAlbum: Advanced DC Motor

Here is a great place to look for EV stuff - my cousin did an EV conversion on a Saturn. Saturn From SC2 to a EV 120 Volts DC - EV FORUM - ELECTRIC VEHICLE FORUM

[MetroMPG]

Rick: double accolades for the project...

1) You won in voting for the latest modification of the month contest. What EcoModder t-shirt size do you want?

2) AutoblogGreen just posted an entry about the project. See Geo Metro hybrid? It's already on the road [VIDEO] (And just wait for the peanut gallery to spring into action in the ABG comments - nothing yet, but it looks the piece was just posted a little while ago.)