1976 Fiat Spider 124 EV Conversion

I am going to start testing the car with 72 volts supplied to the ME1003 DC PM motor. I am going to use Deep Cycle Lead Acid Group 24 batteries that I have from other projects. The purpose of the testing is to determine if the configuration will provide acceptable performance for surface street driving, stability of the car and current requirements. I am not concerned with range and the battery pack weight matches the weight of the ICE components removed. If I am happy with performance, I will move to a Lithium chemistry battery pack. At this point I am not interested in using Volt, Tesla or Leaf batteries. I would like to stay with a Group 24 or 27 physical form battery. I like their installation approach and I think they are readily available. My only concern is that they all seam to have BMSs that limit current to 1C. I expect to require short periods at time of 200 to 300 amps draw.
Can I draw more than 100 Amps from a LiFePo4 battery with a BMS? Do I have to put two batteries in parallel to get more than 100 Amps. Doing this will almost double the amount I have in the project so far. I do not want to do this at this time. Range, weight, and dollars per mile are not a concern at this time.
My whole objective of the project is to learn about DIY EVs and get a vehicle for surface street operation at the least amount of cost in the shortest time possible.

Update:
72 volt Curtis controller, DCPM brushed motor ME1003, 6Kwt, 72 volt power pack (6-Deep Cycle 12 volt lead acid batteries). Batteries repurposed from solar and RV project. Vehicle weight with batteries and no driver, 1922 lbs.
4 – 4 mile test drives over relativity flat terrain. Max current 240 amp, minimum voltage 55 (significant sag with lead acid), max speed 35 mph to date. Average of 336 wthr/mile. Need to replace studded snow tires for lower rolling resistance tires in the rear. 30% of battery charge used for 4 miles. No sign of over heating motor or controller in Colorado cool environment. Manual transmission a definite plus. Start out in 2nd or 3rd and shift to 4th based on current draw. My donor car needs lots of mechanical fixing.

Plans:
Add one more 12 v battery to present pack to help with voltage sag during further testing. Need to replace all tires, broken windshield, fix mechanical and get paint job. Replace battery pack with 84 volt 16.8 Kwthr Lithium chemistry. Provide ram air passive cooling of motor and controller if driving harder.

Cost: $3400 into project including donor car. Probably add additional $3000 to complete. $2000 for batteries and $1000 for car fix up. Time on project to date is 5 months.

What I learned:
Would never want to drive this vehicle on freeway. Would get blown away by 18 wheelers. 50 to 55 mph acceptable for surface street driving and acceleration is acceptable. For my purposes 10 mile range is ok with 50% discharge.
Creative design without using parts from a salvaged production EV is a thing of the past. It can be done but there is little interest in that approach.
Registration in Colorado is easy.
If you got the bucks, the tools and the time and want a long range performance vehicle and you want to build, salvage parts from a wrecked production EV.
If you will accept less consider a retro approach with Lithium chemistry batteries.

Waiting for a 250 amp 144 v controller. Plan to configure car with 12-12 volt lead acid batteries in three separate 48 v packs. Packs electrically isolated when off or following crash. With 84 v and the Curtis controller got 6 mile range on 40% discharge at 39 MPH max with slightly hilly terrain. Voltage sag still an issue. Expect 45 to 55 mph max speed on surface streets when running with 144 v. This would be acceptable. Do not intend to drive highway. Do not want to spend more for performance I do not need. Never planned to build a sport car, just a local computer. Expect 50% range > 15 miles. Total vehicle weight with full up batteries about 100 lbs less than ICE configuration. Battery cost projection $1100. Would like to transition to LiFePo batteries if I can find a set at a reasonable price . Still some mechanical issues to resolve on the car.

Larrybia said:

For me, with very little money up front and in a short time I have learned a lot, will have a completed project which will be upgradeable if I want to put the bucks into it.

Click to expand...

When someone has done (or seen or read) something enough times
...& then, you hear something concerning, "RED FLAGS" automatically start to appear (in our heads)
...& we (forum members) are supposed to alert folks about them "RED FLAGS"
...& maybe even discuss them

Like:
12-12V Lead Acid batteries = Unnecessarily heavy

Commuter car with ~15 mile range ("if" all goes well) = ~7 mile range (1/2 of your range is needed to get back home)

Voltage Sag is still an issue = it's only going to get worse (as the batteries age)

Total vehicle weight with full up batteries about 100 lbs less than ICE configuration = how much did that little 4 "banger" weigh?

Battery cost projection $1100. = ~8 -10kWh of OEM Lithium modules (weight ~200lbs., twice the available energy, probably 1/2 your Voltage sag & many more available cycles)


* TBH I often learn more from the ensuing discussions
...than, the actual original post or video

FYI. This is where I am coming from. Past posts detailed my approach.
I am not saying this is the best approach for every case. In my case it is.
This is a basic comparison of cost Lead Acid approach vs Lithium approach for my use case.
Increasing expected miles used will push to use Lithium.

Larrybia said:

Where can I get a 8 to 10 kWh lithium battery pack with BMS, charger and safety box for $1100?

Click to expand...

That IS NOT an easy question to answer
...because there are sooo many variables

Like the area that "you" have available to "put" battery modules
...the size & weight of battery "your" car can carry
...your systems current & voltage requirements etc.

The cheapest & easiest to work with (Lithium) option seem to be Nissan Leaf modules
(There's lots of conversions using them, just gotta do a search & then, some research)

FYI:
Besides being insanely heavy, Lead Acid batteries require constant maintenance (watering)
&
Then there's Peukerts Law?
(Here is the first thing that "popped up" when I Googled it)
What Is Peukert's Law and What Is Its Effect on Batteries?
&
Plus, Lead Acid batteries have to be always kept fully charged
...& immediately re-charged after every use
...& even constantly "topped off" when not in use (making you the BMS)
&
"if" not kept fully charged FWIU most Lead Acid batteries are getting/being damaged (inside)

Just some more Food for Thought

Electric Land Cruiser said:

Larry's method is perfectly fine. Building a lithium battery for a DIY conversion is as much or maybe even more work than converting a car to drive off an electric motor. There is so much more risk on the line also. Sure, the lead batteries are big hunks of junk and they cost too much for what they are, but he's driving on electric power. When the time comes to transition to lithium, he can do so. Until then, he's driving an EV.

Click to expand...

I agree 100%
...& that's basically how I started off when converting my ElMoto
...but, after running it converted, for ~5 years now, I've figured some stuff out
...& (I think) have come to understand other stuff a bit better.

* When I first started, learning about "this stuff" I had never heard of Peukerts Law
...or know about the "always keep fully charged" requirements of Lead Acid (& killed many LA batteries)
...& then, after "killing my entire pack" while in storage over the winter, I learned about "Parasitic Draw"

So now, on this DIY electric car forum, if/when I read about someone thinking about converting an old motorcycle (or car)
...& they mention that they are thinking about or planning to use (something like) Lead Acid batteries, I (personally) feel kinda obligated to (nicely) question that decision
...& then, (again nicely) try & explain (as well as I can) the pros & cons of that decision
...& then, hopefully others "chime in" with their experiences too

Electric Land Cruiser said:

As someone who's built a DIY battery pack out of a Nissan LEAF, there is not a lot cheap or easy about it. It's a lot of fiddly BMS wiring and trying to protect the HV cables from abrasion and trying to tetris all the modules in a way to fit and then the end result is super huge and heavy. They are several thousand dollars for an old worn out pack with 60% of its original capacity.

Click to expand...

Um...technically, most of "that stuff" (module arrangement, mounting, protecting HV cables etc.) should be necessary
...&/or required, whether the pack is Lead or Lithium

Complete final road test drive today. Final configuration with 10 - 12 v 80 Ah lead acid batteries, 120 v Kelly controller and full up weight 1930 lbs. Drove 10.5 mile around test test track and used 25 Ah or 2.54 KWh or 242 Wh/ mile. Fastest speed climbing hill 42 MPH. Vehicle could go a little faster but did not feel comfortable with ride and control. Front end is sloppy and convertible top has too much flapping. Poor choice of a donor car but I accomplished what I wanted. Surface street car to use to an from daughters house 2 miles away. Total cost of 6 month project $5.1k. To make this a more viable EV I would have to put in a larger motor, bigger lithium battery pack and fix front end and paint. Expect that this would required an addition $8K to $10K investments. I am not willing to do that. Would not get return on investment. Better route to go is fix up a wrecked production EV. Learned a lot about EV, especially impact of weight. Seams very inefficient to have a 1 ton vehicle transporting a 200lb person around doing chores.