# AC50 question please...



## mizlplix (May 1, 2011)

1. if a motor is rated at 108 volts, is this 108 DC pack voltage or 108 AC controller voltage?


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## brainzel (Jun 15, 2009)

108 volts is the battery pack voltage.
The AC50 is used by some converters up to 120 volts DC f.ex.:
http://www.evalbum.com/3661
http://www.evalbum.com/3660


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## frodus (Apr 12, 2008)

the cutoff voltage is 130V max for the 1238-7501 and 7601 controllers. The 1238-6501 is 108V max. 

So after a full charge, your batteries should not be at or above that voltage or the controller will cut out. If it's hig, but not at the max, and you regen, the controller may fault.

So if you use 32 thundersky Lithium batteries and charge to 4V, you're at 128V and it's close to the cutoff. If you have batteries that charge to 3.7V, you could do maybe 34, but I'd still do 32 and go with higher current batteries.

Curtis is coming out with a higher voltage controller this year, hopefully.


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## tomofreno (Mar 3, 2009)

I'm running 36 CALB cells with the 1238-7501 Curtis controller. They, and TS cells as I understand it, relax to about 3.4V per cell shortly after full charge, so I suppose you could use 37. You need to program the User_Overvoltage parameter in the controller software to avoid overcharging the cells or exceeding the max controller voltage (130V) with regen. Mine is set to 129% of Nominal_Voltage (96V), or 124V. I don't get much regen after a full charge when I roll down the hill from my house, but after an acceleration and about 2/10 mile of flat ground it gives full regen at the stop sign.


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## cruisin (Jun 3, 2009)

The User_Overvoltage percent that you program into the controller
should depend on how much energy you would use before using regen the first time out of the barn. The controller will prevent regen if set too high.
A good number would be about 130%.


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## mizlplix (May 1, 2011)

Thx. For the insight. Mix


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