Hey guys I am starting this thread to see if anyone has interest in me posting pictures and info on my electric conversion. It is about 90% done and the car has driven a couple of times.

I dont want to step on toes, because i know that some people get really upset when there is talk of removing a rotary engine from an rx-7. I dont want to start trouble. I am as big a rotorhead as any. I love the rotary engine and have worked on them for years, I just thought it would be fun to convert my 1st gen to electric, as it has fantastic atributes as a donor chassis for an electric car.

If you guys think that it would be innapropriate to post stuff on this forum about the electric car, politely let me know, and I wont post it. I dont wanna start trouble.

But if any are interested I'll show you guys all the steps to my electric conversion.


By the way, it now has 300 ft/lbs of torque at the rear wheels. (i hope that will pique some interest)

 

Hell yeah show us.

I don't like pistons in a rotary, electric is fine

 

Does that amount of torque last more than 30 seconds before the batteries die?

 

SHOW ME! lol

 

Only 300? You must not be using a very big motor.

Some of these electric cars are running insane amounts of torque through their motors.

Example, the Tango T600 puts down a rubber burning 1000ft-lbs from its electric motor.

If you're interested in what I am talking about: http://www.youtube.com/watch?v=AseYg...eature=related
And the specs: http://www.commutercars.com/features600.php

 

I want to see this

 

anything other than a piston engine, agreed!!!!!!!!!!
electric engines go round and round anyway
not up and down!!!!!!!!!!!
whats the range, top speed, charge time, etc???

 

Electric is always a cool it spins and doesnt make alot of noise haha

 

There is a company with an electric drag FB. I'll see if I can find the site. POST IT UP!


BOOM!

http://www.dragtimes.com/Mazda-RX-7-Timeslip-7519.html

 

2nd line of the webpage:

More Info: Extended Warranty, Car Loans, Car insurance and Lemon Laws for your Mazda RX-7 Electric

 

 

great ok well i have some pics but not current ones ill post pics of the battery racks and barking system tomorrow.

Anyhow demonspawn67, you mentioned that im not using a big motor, and you are right. Some electric motors make huge torque. the drag cars in the thousands but this will be a fast street car. I chose a 9'' series wound electric motor from a company called advanced dc Usually overkill for a street car, but i wanted it to be quick

djessence you asked how long the power would last, well at full throttle longer than 30 seconds but not very long, youre right But driving normally in town im expecting between 30 and 50 miles range on a charge

I am using 12 kinetik hc1400 batteries 60 amp/hours capacity each They are only 39 lbs each and have monstrous output capabilities. I worked at a car audio shop at the time so I got them at cost, so the price was only about $2100 for all 12. I have them wired in series as a 144 volt pack using 4/0 welding cable. 6 where the storage bins used to be 3 behind those and 3 upfront.

Im charging the car using 12 chargers, one for each battery. This ensures that one battery does not gat overcharged while the rest undercharge, like a 144volt charger sometimes does

The car has only run a couple of times, i had to take out the motor speed controller (its like the throttle control and ship it back to the makers for mods)

 

Using 12 chargers... do you have to disconnect all the batteries before charging? Or how are you keeping the chargers isolated?

Wired in series, your ampacity (amp/hour) is not additive; you've essentially got a 60amp/hour, 144-volt battery. What's the draw curve of your motor?

Are you still using the transmission, or are you direct-driving the diff?

Really interested in your project, so post all the pics/spec sheets/ wiring diagrams you can.

 

What controller are you running? Why did you use old lead acid batteries (cost?)?

Why a DC system instead of AC (cost?)?

 

no I dont need to disconect the batteries to charge them When I have time later Ill post a diagram I'm still not sure what the draw curve wil be, and yes im using the transmission Ill probably leave it in 3rd gear full time yes its a 60 amp hous 144 volt pack


Im using lead acid batteries for several reasons. I live in a fairly small city, and most other cities nearby are about 1 hour away by highway and I rarely go to them, so its gonna be an in town car.

I dont really have the need to make it a long range car. The more battery capacity the farther it will go, the more expensive it is. I could probabalymake it go 100 miles on a charge but i never go that far in a day, and it would be expensive and the batteries would weight the car down, and the suspension may be compromised right now it weighs about stock maybe a tad bit heavier


The lead acid batteries I chose have a life cycle of 500 cycles (according to the manufacturer, and that varies with condition, like temp and stuff) now this means they can be drained 500 times to 80 percent depth of discharge (DOD) which is from about 12.9 volts to 12.0 Anyhow if you only drain the batteries say to 50 percent every day the life cycles go way up. So the batteries will hopefully last 5 years. cost me $2000 Lithium ion batteries have a life cycle range of 800-1000 cycles, but they would cost me more like $8000 to $10000 That is more than all the other parts combined. For one thing, i could not afford it, and for another thing, there is a great new battery type called lithium iron phosphate (LiFePo) coming out It would caost just a little more than lithuium ion and they have 2000 to 3000 life cycles at 100 percent depth of didscharge they are beasts probably last 15 years or more My hope are that by the time this battery pack dies the lifepo batteries will ea little cheaper, and ill be making more money so i can afford them

 

I am running a logisystems 120-144v 1000 amp controller

 

nano batteries

 

Quite interesting.

You're gonna have to do a bit more about water control/insulation, I think, before you do any rain driving.

Keep us informed - - This is a cool project!

 

The charge time should be 3 to 6 hours depending on how long ive driven

and ac motors and controllers are a bit more pricey which is why I chose the dc series wound motor.

 

Are there any weight savings? What kind of RPM does it usually spool up to? How does it idle? What about regenerative braking or solar panels? (I'm not sure the exact dollar ammounts on those...).

 

Seems like a good choice for batteries and controller based on your goals then. My only real annoyance with DC is the requirement to run a transmission (to maintain any sort of efficiency at low speed) and the difficulty in setting up regen braking (though that's just a series motor issue...with a PM or shunt you can do it fairly easily).

Looks like a decent setup.

However let me caution you about one thing: The buss bars you are using to connect your batteries WILL fail. As the batteries grow, shrink and move around the terminals will become stressed. They will crack.

 

Yeah I was just looking at that. Shouldn't it be bolted like a car battery on a GM where it has the rubber holder at the bottom of the battery?

 

It doesn't idle tard biscuit...it's an electric motor!

 

hmmm good point about the buss bars I still have plenty of welding cable left, maybe Ill switch to that

And yeah it does not idle when you let off the accelerator it just whirs to a stop

and about the regenerative braking, yeah its a shame a series motor wont do regen it makes a brute of a traction motor though i would like to eventually set up a very mild regen involving a small permanent magnet motor or big alternator on the tailshaft of the electric motor

Even though it was a huge pain in the butt to get the motor and tranny mated, i will say it is very cool to have the option of putting it into 1st gear to do the hugest burnout on the planet

 

with the batteries i chose, which are likely the smallest lightest i could get away with, the car will weigh about stock, or a bit more

5500 rpm is the top my motor is rated for, but some drag racer guys claim to spin them faster

And solar panels are large, expensive and provide so little power its not worth it

for example a $500 panel could charge the car all day and take me a couple of miles and the panle would be gigantic However a charging station involving solarpanals, a battery pack and a little wind generator would be really cool, and could likely charge the car overnight and pay for all the driving juice