Midnite classic with an engine driven PMA

Deveak · March 2017

I have an extra midnite classic 150. I want to hook it up to a belt driven, engine driven PMA. I am fairly certain voltage wise it has absolutely no chance of frying the charge controller. Its a windblue power dc-500. At 10,000 rpm the voltage is 100 volts open circuit. Problem is at any rpm that produces voltage high enough to charge my batteries it puts out more power than a midnite classic can handle. Would this damage the midnite classic? Would likely run it in hydro mode. Most likely a very linear power curve. Likely to be direct drive at 2700 rpm giving me 26-27 volts and 125 amps. 3375 watts. I charge at 14.8 and 96 amps so 1420 watts max. Anyone ever do anything like this or happen across someone who has used a pma hooked up to a midnite? Wind, hydro engine whatever. So far this seems the safest voltage wise.

mike95490 · March 2017

I'm not sure if the Classic is rated for Hydro usage. For use with wind, it requires a Clipper.

The way a MPPT controller works, it loads the source down till the voltage drops. Then it backs off a bit to find the Max Power Point.
That will never happen with an engine driven PMA. There is no MPP to track. You could use it as a straight DC-DC downconverter but you have to tweak the settings a bit for that, change the MPPT mode to a % of voltage, which I would guess would be 100%
As the Classic approaches it's thermal limit, it wlll reduce power, reducing the load on the PMA., which will allow voltage to spike, which could be fatal to the Classic. You have to test to make sure you don't overvoltage the classic when the thermal regulation kicks in,

Deveak · March 2017

Well the voltage will never exceed the classics max voltage limit. Not even close. I know the classic supports current limits so I would likely only set it to charge at 80 amps to keep it cooler. Just the input would far exceed the possible output.

Deveak · March 2017

http://www.fieldlines.com/index.php/topic,148426.msg1030639.html#msg1030639
Here is a thread of a guy doing it in wind mode but with a standard AVR honda generator.

jonr · March 2017

In terms of current, there is no such thing as overloading the input of a buck (aka MPPT) charge controller. If the input voltage is always acceptable, then the charge controller is fine.

I like the idea of using a solar charge controller with a slowed down (ie, more efficient at low loads) generator. But not clear that it's cost effective.

Midnite classic with an engine driven PMA

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