I have one of these motors that i want to use as a wind turbine generator. http://www.ebay.com/itm/181392138415?_trksid=p2057872.m2749.l2648&ssPageName=STRK%3AMEBIDX%3AIT

I want my setup to be fairly inexpensive so ive searched for ages without any result for a charge controller that accepts high enough DC voltage for my 120v DC motor, and doesnt cost a fortune....

All cheaper wind charge controllers seem to run directly of AC and the once that do run of DC cost waaay too much.

Is there any chargers that fit my needs? If not, how high voltage should i expect from the motor? Could a simple 60V buck converter be enough? http://www.ebay.com/itm/200W-15A-DC-DC-8-60V-TO-1-36V-5V-12V-24V-Buck-Converter-Step-down-power-module-/181849944290?hash=item2a5719f0e2:g:COAAAOSw3ydV4L2I

I hope you can help me


1 Answer 1


First off, remember that voltage on a generator is often expressed as 'open circuit voltage.' While this generator is listed as a 120VDC unit, it's only rated for 65W total, which is only 0.64A @120V; any higher amperage draw will necessarily lower the back-EMF. However, you would still need your components to be rated for the 'static' 120V if you ever expect it to be generating power that you don't use (Unless you add a 'dump circuit' to expend any overvoltage before the back-emf damages your lower-rating device[s]).

Also, according to the specs in that eBay ad:

Power parameters:
50v 1000 RPM
100v 2000 RPM
150v  3000 RPM

So, if you keep it running @ or below 1K RPM spindle speed, your 60V buck-controller should be a le to handle it alright. ;)

  • \$\begingroup\$ I see... I find it so strang, everyone is recomending a high voltage motor yet there are no charge controllers that pairs with them... @Robherc \$\endgroup\$ Commented Feb 15, 2016 at 14:45
  • \$\begingroup\$ @Pellepuffin define 'everyone.' I know there's and advantage to using higher voltage to minimize current-per-watt (which is why we use 500KV mains transmission lines), but arcing, dielectric breakdown, component cost, insulation thickness, etc. can be compelling reasons to stay with lower-voltage primary generation equip. At least for project of this small size. A 12V gensrator is perfectly usable for applications where expected capacity is 60W or less. \$\endgroup\$ Commented Feb 15, 2016 at 15:04
  • \$\begingroup\$ i see what you mean. To my experiance most sites on the internet will tell you to get a high voltage motor so that it will produce the 12+ volts for the charging to begin. \$\endgroup\$ Commented Feb 15, 2016 at 15:11
  • \$\begingroup\$ so your advice would be to step down in voltage? :) \$\endgroup\$ Commented Feb 15, 2016 at 15:12
  • \$\begingroup\$ I'd buy a lower-voltage motor for this project, as long as you haven't already started building around the high-voltage one; then use a boost, or buck-boost converter topology charge-controller, so you can commence charging at, say 1.5-3V by boosting the output voltage. This will allow the use of lower-cost, more readily available components. \$\endgroup\$ Commented Feb 15, 2016 at 15:38

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