Geo metro EV

[james.lafrance]

I'm another one of those crazy guys with a metro trying to make it electric. I've follow as many of the 1000+ treads of forums with geos, and basically it's gets off topic quickly or is filled with A LOT of info, some of which...well is over my head or pertains to circumstance. I've been trying to get to the bottom of this for a little while now. I'm sure there's a few people like me out there that have a hard time with forums, and would like an easier info access. Could there be a post of motor choices, controller options, and a few details for each. I'm a plumber with partial knowledge of electronics and electric, the confusing part is when I see 48v motor or a 72v motor, but they can be over-volted? or the motor is rated for x-amount of amps, or it weighs at least 100lbs it's a good one? how about fork lift motors? And controllers that one is fuzzy, which one's more efficient or which one will match speed....I think we can all agree that the transfer plates and couplers are a machinist's job or come from a kit, they are hard but are custom, so that subject hardly needs to be touched I believe. Contactors for what I've seen are near the same boat. but in short a reference (perhaps I haven't found it yet) for motors ranging from forklift to high end would help as well as for controllers. I think we needn't discuss batteries as well, that seems to be the one topic that is easy to find.

[Weather Spotter]

well a simple way of thinking about voltage and amps is this:

Watts (measure of energy without any time attached) = volts X Amps

or look at it as a circle, the top half is watts and the bottom half is spit into volts an amps.


think of volts as the pressure in a pipe, and Amps as the amount of water passing through. If your pipe (motor) stays the same, and you double the pressure, you half the Amps needed to get the same work done.

Example:
a 48V motor with a rated amps of 100 will do 4,800 watts of work.
a 96V motor with a rated amps of 50 will also do 4,800 watts of work.

hope this helps you figure out what you need.

[MPaulHolmes]

Here's my understanding: The voltage on the motor doesn't mean much. My 24v motor is run at 72v with no problems. Other people on here run their 36v or 48v motors at up to 144v. The 1 hour amp rating is pretty important. The higher, the more torque you can use. Mine is rated for 102amp for 1 hour, and it works fine for around town. It weighs 60 pounds.

For controllers, they get more expensive above 72v. Heck, they get more expensive above 48v. Curtis and altrax are the most common at low voltages, at least on Ebay. For a controller, apowers on here got a control board and power board from me, and used the spacing on the power board to drill the rest of his parts locally. I don't know what his total cost was, but it wasn't anywhere near the cost of a Curtis 1231C.

As for a contactor, I recommend the kilovac EV200. They can be had on Ebay for around $65, and work very well.

[james.lafrance]

Your help is much appreciated folks, I'm still a little fuzzy. If i find a 36v motor from Joe Smoe's forklift, and the info plate still happens to be readable, I'm gonna want to look for how many amps it can handle for a set amount of time(hour)? Would I be able to have 10-6v (or 8 or 12v)batteries then when i get more cash throw in a few extra batteries to get it to 72v? All the voltage of what ever size bat-pack i have would work on a 24/36/48v motor?

Now the brief electrical coarse I believe i understand, as a plumber i install water heaters.... a heater with two 1100 watt heating elements running on 220v AC is going to draw 10 amps. Ohm's law and stuff is within my comprehension, I've also constructed solar panels from individual 3"x6" cells, so I got a relatively good grasp on some basic electronics. From the cells to the charge controller to the inverters, some of which can and does translate to these EV projects.
IN THEORY
So if i find a 24V motor rated at 200amps/hr it will handle 4800 watts
or if i find a 48v motor rated at 110amps/hr it will run at 5280 watts
so I want on that can handle the most amps possible correct?

I've built charger controllers for solar panels, would building a good EV controller be feasible?

And how about matching speeds? that seems to confuse me a bit. I understand the fact that the engine isn't spinning so you don't need a clutch to shift, but once you shift from neutral to 3rd or 4th gear wont the transmission spin the motor if you don't give it 'gas'?

Thanks again for your time and help folks, I really do appreciate it!

[TomEV]

One thing to consider when you decide what voltage to use... You will need a charger (one of the more expensive items IMHO) and if you start out with 48v and then go to 72 or 96v, you will need to replace the charger, or manage multiple chargers.

For unusual voltages (such as 60 or 84 volts) chargers can be difficult to find. Possible, but your choice will be limited.

[jmygann]

Jim Gann's 1990 Geo Metro

[james.lafrance]

ok... I've seen the one guy's car and he had built individual chargers on each batt, is this feasible or practical? why not charge each one individually instead of getting one big costly charger? what do you mean by 'managing' multiple chargers? can I make this car 48v now then in a few months get more batteries and step it up to 72v? Will whatever motor I find be capable of this as well as the controller & contacter? Thanks again for all your help and patience

[vpoppv]

Originally Posted by james.lafrance

ok... I've seen the one guy's car and he had built individual chargers on each batt, is this feasible or practical? why not charge each one individually instead of getting one big costly charger? what do you mean by 'managing' multiple chargers? can I make this car 48v now then in a few months get more batteries and step it up to 72v? Will whatever motor I find be capable of this as well as the controller & contacter? Thanks again for all your help and patience

I run a charger for every battery. It's easy, cheap, and gives each battery individual attention rather than just "hoping" each cell is balanced. It probably doesn't matter as much if you use new batteries, but since I use other people's rejects, it's very important. As to voltages, you can go from 48v to 72v without too much to worry, but if you want to get up to the highway speeds in the 96v and up range, you'll need to advance the brushes on your motor to prevent arching. Here's a GREAT set of videos explaining the procedure:

http://www.youtube.com/watch?v=_deNn...os=YiNZouH0IG4