# Want to build a Geo Metro EV, just starting



## La Dignidad (Nov 9, 2012)

Hello all. I've been planning on buying and converting an older Geo Metro. What I want, or would like, is 50 -65mph speed and 50 mile range (dependable). I now live 20 miles from a small town so I would like to drive to town, get supplies, see people, and get home, mostly daytime driving.

The research that I have done so far indicates that I should do a DC system with something like 12 (72v) to 16 (96v) 6 volt golf cart batteries but I'm not sure about getting a 50 mile range with this setup. I don't need or want electrical extras like radio, air conditioning, electric windows, etc. so that may help with the range.

I can also consider lithium batteries and maybe an AC motor but I've seen a wide range of estimates for the prices and the difficulties of these systems.

I also don't much about which DC motors, controllers, chargers, or kits to buy to accomplish the best and most efficient vehicle.

Any advice or comments?


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## TEV (Nov 25, 2011)

My advice is to buy a Solectria Force and change the batteries with lithium( you would need lithium batteries,a new charger and a BMS ). There are a few of them for sale.If you don't know they're Geo Metro's with AC motors.


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## Caps18 (Jun 8, 2008)

Go with the Lithium Iron Phosphate (LiFePO4) batteries. DC motor should be fine. Could you fit 30 batteries in the car? http://blog.evtv.me/store/products.php?cat=10

Do you own the Metro already?

And you won't 'NEED' a Battery Management System.


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## evmetro (Apr 9, 2012)

Welcome fellow metro fan! I think these vehicles make good EVs. Small and light. I think for the range you are looking for that you are just a bit over lead sled range. I would look at a smaller lithium system.


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## La Dignidad (Nov 9, 2012)

Thanks. I appreciate the quick replies. I didn't know there were so many EV cars for sale. I saw several candidates for $5,000 to $7,000 for Metros and Solectrias. Most of them have AC motors. Is that a good thing? A couple had DC. Some more expensive ones already had lithium batteries. Others were "ready for lithium transplants".

It's a little worrisome to buy a car that is 1,000 miles away and then hope that it is in good shape and that the conversion was done well but I guess life is always full of risks. I there any way that anyone know of to verify the condition of the car and conversion?

I'll have to study this possibility. It would certainly be easier to buy an EV car and then do whatever modifications I might want. What might the price range be for installing lithium batteries and controller, charger, etc.?


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## TEV (Nov 25, 2011)

Solectria Force cars are factory made conversions, and AC systems are the best ( no brushes and they have regeneration).


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## dtbaker (Jan 5, 2008)

metros are a great choice... forget about lead right off the bat for your range requirement. AC might be a good thing in your case for extended highway/hills where regen will extend your range a little (like 10%). But AC motor/controller costs considerably more and you might be best off with 8" DC and a solid modern controller like Soliton jr or zilla. I used a curtis 1221c which is way less expensive, but barely sufficient for extended highway use as its thermal limit is around 200 amps even with good heatsink and airflow.

feel free to peruse my gallery on my Swift, its pretty complete step-by-step.

I can tell you from experience that you will find 100ah cell height of CALB/Sinopoly/Winstons will fit well, and 130 or 200ah cells will force you to invade cargo space. If you need your back seat/cargo area, stick w/ 100ah. I fit 38 cells x 100ah in my build, and COULD squeeze in 3 more in rear wheel well gracefully... which would yeild about 45 miles at 80% DOD


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## Ace_bridger (Nov 22, 2011)

For your modest range requirements I would suggest an Open Revolt controller (144V, 500A) if you're half handy with a soldering iron, and a small lithium pack.

I'd guess a little Metro would be 250-300 wh/mile ish?

Motor wise...a 9 inch or suitable sized fork lift motor?


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## dtbaker (Jan 5, 2008)

Ace_bridger said:


> I'd guess a little Metro would be 250-300 wh/mile ish?


 mine averages about 200-250wHr/mile consumption with 'normal' urban driving. averages 300 whr/mile 'at the wall' accounting for all charging losses, etc.



Ace_bridger said:


> Motor wise...a 9 inch or suitable sized fork lift motor?


9" is a bitch to fit, and requires moving rear motor mount. 8" ADC or Warp equiv (8" dia) is an easy fit. forklift motors are not a super idea unless you are really short on cash as they are intended for lower voltages.


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## evmetro (Apr 9, 2012)

I was able to fit a 21kwh pack of 34 200ah lithium cells in my metro without invading any interior space. Any more than that, and I think you would have to add them to the hatchback area/ spare tire well, or backseat area. 

An 8 inch dc motor is plenty for a metro, and I see many people running the ac35s and ac50s in these cars.


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## La Dignidad (Nov 9, 2012)

Thanks for all of the information. It's really helps me to get going in the right direction. I've got lots of work to do now to assimilate all of this and make some decisions.


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## Ace_bridger (Nov 22, 2011)

So, if you base your calculations on 250 Wh/mile then things might look a bit like this...and please feel free to correct or comment accordingly,

Range required - 50 miles (solid and dependable)
250 Wh/m
So this would mean that you'd need a pack that gives (50*250 =) 12,500 Kwh
Let's say you would like 20% in reserve that gives 15,625 Kwh

Now, dependent on what voltage pack you go for you'd need to choose an Ah rating accordingly.

If you ran, for example, a 144V pack then you'd need 108Ah pack using the numbers above but clearly cells only come in certain sizes so you either go for 100Ah or the next size up.

To run 144V of lithium you'd need 144/3.2=45. Based on the figues above you can now go and find out how much 45 off 100Ah lithium cells might cost. Obviously you can change the numbers relating to range and voltage dependent on your choice of controller, etc.

I hope this is correct and of use.


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## Caps18 (Jun 8, 2008)

I'm surprised that it is 250 W/mi. I thought it would be closer to 175-200 W/mi if you use lithium.

I am looking to use 45 100Ah cells (144V) and at $150 each, it would be $6750 + shipping.


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## evmetro (Apr 9, 2012)

If I could go back and start over, I would go for the 45 100ah cells. Very versatile ev, much simpler build.


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## tomofreno (Mar 3, 2009)

I also converted a Swift: http://www.evalbum.com/3060
Over the last few years it has averaged about 216 Wh/mile from the wall, around 200 Wh/mile excluding charger losses. Uses around 180 Wh/mile at 35 mph and around 240 - 250 Wh/mile at 60 mph on level ground in summer.

Range is about 75 miles with the 20.76 kWh LiFePO4 pack for 50/50 highway/secondary road driving in summer. Drops to around 60 - 65 miles in winter with the 3kW heater on around half the time.

An ADC 8" motor plus Zilla or Soliton Jr controller would be around $3500 and an AC35 or AC50 plus controller, contactor and Curtis gauge (comes as kit) would be around $4500. Batteries will be the most expensive part, as you won't hit your 50 mile range goal with lead acid. Not even close, especially in winter.

You can salvage a DC motor from a forklift or similar and use a lower cost controller to save money. IMO its better to go with quality components if you want reliable transportation.


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