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Motor Speed Controllers

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48v motor speed controllers

Because of 4QD's designs, most of our controllers can be made in 48v versions. This generally involves upgrading several components to higher voltage devices and the use or higher voltage MOSFETs and capacitors, as well as increasing the overvoltage clamping.

Modifying individual controllers is not commercially viable, and the demand for 48v versions is generally low, so only certain models are generally available as -48 versions.

Operation above 48v

A 48v battery on charge may be around 56v. If regenerated power is fed into such a fully charged battery, it will not accept more charge and it goes into overcharge. If you look at the overvoltage specification on most controller this is around 68v to allow overcharge.

However the maximum safe working voltage of the capacitors in 48v models is 62v and this should not be exceeded for any significant time or the capacitors will overheat and explode. One of the reasons why we don't make higher voltage controllers is that the next voltage capacitors (100v) are of significantly lower capacitance in the same can size, so most controllers would need a lot more capacitors. That generally means a complete redesign.

Available 48v controllers

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© 2005-2012 4QD
Page's Author: Richard Torrens
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Page first published 28th June 2005
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