My R/R connector burned last week and I have been doing a lot of research on this topic.  Has anyone changed their R/R from the factory supplied one to a "better" one like a Shindengen Mosfet?  I have exchanged emails with a Motorcycle guy who has sold several to kit plane builders with great success.  He was also a test pilot for another airplane manufacture for many years and knows our business.  He had to give me the obligatory "they are not designed for aircraft" but still spoke highly of them.  He recommended a 50-amp R/R even though I only have a 30-amp Stator as it will handle up to 50 amps and he says it will be easier on the Stator as well...Thoughts?

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MOSFET is the way to go to reduce heating of the R/R - esp in comparison to the SCR shunt type R/R ULPower supplies with the 30A PMA.  The ULPower R/R associated with the larger 50A PMA is a MOSFET type R/R and I recall it having a Harley Davidson part number!   I say "give it a go" - if you can make the connections I think it will be just fine.  Just for grins, run the idea through the AeroElectric forum - you will get a good response that will help you decide yes or no.

Thanks, I am leaning that way.  Regarding connections basically the only difference is that there are two connectors into the R/R one for the three Stator wires and one for the Battery, which I think is a better design as it separates and hopefully reduces the heat potential.  They are only a few dollars more than the Wicks R/R for the 30 Amp Stator

Hey Scott,

Are you looking to use something like the R/R from Amazon in the link below?  I've had some anomalies with my original ULPower 30 amp R/R and would like to replace it with something more reliable.

I just had another burned connector last week and just yesterday.  Installed a new (better) R/R (Mosfet) that I purchased from  Basically it is about 3 times bigger and heavier than the stock R/R and it has much better connectors for the Stator and Battery (they are separate and more robust)...

Scott, when I had a similar issue, I upsized my GND and BAT wires to 10 ga.  Connections were soldered versus crimped.  I typically draw approx 21 - 22 amps with fully charged batteries and everything going.  Running Pitot heat bumps it up to 29 amps when cycling.  No crispy connectors or sign of thermal stress at the RR so far...

I purchased one of Roadster Cycles R/R last week after the factory one burned for the second time.  I flew it for the first time yesterday and it was running 21 Amps on take-off with everything running.  When I landed I checked it with a thermal gun and it was only a little over 100 degrees.  Moving it to the firewall and upgrading was the right move.  Jack at Roadster was very helpful in all this...

Another source for the RR...

Thanks Scott for starting this thread ans to you too David for the additional advice.  My R/R failed on my 20th test flight so I went the Roadster Cycle route for a replacement.  It arrived in my mailbox 3 days later and two days after that I flew it on a test flight. Of note: My original ULPower-provided R/R used to vary in voltage considerably depending on electrical load and throttle setting (from 13.2V to 14.7V).  The new Mosfet R/R is a solid 14.4V at all power settings and Amp loads (typically 18 Amps with every electrical device on at full throttle).  After 4 flight hours since replacing my old R/R I couldn't be more pleased.

Glad to hear that. I am very pleased with the upgrade as well...

Can you tell me what part model/number you ordered?


I ordered the "SH847 SUPER KIT $207.95".  But it is a personal choice.  The biggest differences are in the accessories that you get with the SH847.  Contact Jack Fleming ( at he was a great help...

I ordered the "Complete Mosfet Kit FH020AA DIY crimp or solder kit" listed on the home page at  The main part you want is the FH020AA Mosfet R/R to replace the ULPower provided one.  I chose the kit I purchased because it included plugs, wires, and wire connectors for the installation.


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