# CRX Conversion?



## kywardsc (Apr 7, 2013)

What's the strongest, longest lasting and powerful motor and batteries I can get for a Honda CRX? What's the cheapest?
I'm trying to find what's out there and best for this car. 
By the way, my price range goes up to $10,000.
I'm looking for a 100 mile range (at least) and I don't care what the speed is just distance. And if the price range is a bit low I can raise it. Thanks


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## jonescg (Nov 3, 2010)

I'm afraid your budget is too low for both motor/controller and batteries.

The best NMC chemistry out there is about 175-185 Wh/km, and it's in pouch cell format. 160 km range at 155 Wh/km = 24 kWh. I think it's safe to assume about $1/Wh assembled for this chemistry under ideal circumstances, which more than doubles the budget on batteries alone. If you want an efficient AC motor and controller you're also going to have to budget for at least $15k. Lots of options out there at least.

I hope to get started on my CRX conversion soon, perhaps even this year, depending on employment. 

All the best!

Chris


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## Duncan (Dec 8, 2008)

OK 
Go for the cheapest
Batteries - for 100 miles you will need - 100 x 250watthrs/mile = 25Kwhrs
Cheapest lithium (Lead Acid will NOT get 100 miles) -$300/kwhr = $8333

Motor - I paid $100 for an old forklift motor - just like a warp 11 except cheaper
Controller - OpenRevolt - $600

Charger
Really nice Open Source Charger - $1200
Or really basic DIY bad boy - $200

You will need connectors, lugs, contactors...
If you have found a forklift repair place (for the motor) - try and pick all of that up there

$10,000 and 100 miles is possible JUST - do you really need 100 miles?


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## jonescg (Nov 3, 2010)

I'd reckon 100 miles is a good number to aim for, but if the budget is tight it's an easy place to start making concessions.

By the way, I posted the most expensive option because I saw "bestest/strongest" but there is nothing stopping you from doing a much cheaper conversion using LiFePO4 cells and a DC motor/controller. I'm biased towards AC, but even I can admit it's still very expensive 

What I would suggest is to future-proof your project - build the vehicle with the maximum space left for batteries and leave that purchase decision till last. Also, try to build the battery space such that it's super-easy to access should you want to swap cells out - this is a good move on so many levels, not least general maintenance. The motor and controller can be as cheap or as expensive as you like, provided they move the car down the road to your liking. However the battery is a big investment, and its worth leaving the option for "bestest/strongest/furtherest" open as best you can. Get your car rolling on 14 kWh of LiFePO4 and see how you like it - it might even be enough. But if you did want to upgrade as funds permit, it's an easy job.

And I am always interested in CRX projects; especially ones with the cells behind the seats. I'm always worried I might cut through something structural...


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