# Conversion of cheap electric car



## onegreenev (May 18, 2012)

Should be reasonably easy to do. You should get a new smart controller to set voltage limits and smart charger to charge lithium and limit your charge and a set of 100 to 180ah LiFePO4 cells. Calbs come to mind. 

What is the current voltage of the system your looking at buying? 

Batteries won't be cheap but should last a good long time in a vehicle like that.


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## tomofreno (Mar 3, 2009)

You mean one of these?
http://www.topspeed.com/cars/others/2007-aixam-mega-e-city-ar136988.html
The peak 13kW power will greatly limit acceleration and top speed, but if you just want something to toodle around town in at lower speeds and want greater range through using LiFePO4 cells it should work.


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## cliftonts (May 6, 2012)

tomofreno said:


> You mean one of these?
> http://www.topspeed.com/cars/others/2007-aixam-mega-e-city-ar136988.html
> The peak 13kW power will greatly limit acceleration and top speed, but if you just want something to toodle around town in at lower speeds and want greater range through using LiFePO4 cells it should work.


That's the one, I have no idea of the battery specs. I think there are 12 lead acids in there but that's all. I'm just looking at cheap ways to get on the EV ladder and although it's not the fastest in the world it seems to me the batteries would either need replacing or need replacing soon. Either way it seems a shame to replace them and still only have a 40 mile range so...


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## tomofreno (Mar 3, 2009)

If this is a new area for you, you might start by reviewing the battery, battery charger, and bms sections of the Wiki here to get an idea of what may be required, then ask further questions:
http://www.diyelectriccar.com/forums/showthread.php?t=669

If the stock range will meet your needs it would of course be cheaper and easier to just replace the lead acid batteries with new ones with similar parameters. The same energy pack would be smaller (but more expensive) with LiFePO4, possibly creating more space inside the car, or you could opt for a larger energy pack to give greater vehicle range as you said. Be aware that at the least, you will have to use a LiFePO4 pack voltage high enough that the stock charger does not over charge the cells (generally cell V < 3.5V is safe), while ensuring it is in the range compatible with the motor controller.


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