Generator and Surge guard

gatorcq wrote:
so, why the disclaimer only really on the yamaha?

Obviously only Progressive would know the real answer to this question. My own guess is they saw an unusual number of EMS failures, were able to link those failures to use with a Yamaha EF2000iS generator, and upon further investigation found unusual waveform characteristics from this particular generator that could damage their EMS units. Keep in mind that Progressive's official position is that their EMS units are designed to protect RV electrical systems when being fed by a conventional campground power source and not specifically from a generator, despite the fact that in reality many owners do want to sometimes power their rig with a genset. Regardless, for the company to officially take a position on this by posting an online disclaimer that voids the lifetime warranty on any of their EMS units if used with this particular genset is significant. In one of my emails to the company I had asked about using my Honda EU2000i with my new EMS-HW30C and received the following reply -

"Concerning the use of a generator with an inverter, our EMS are designed to be used in the RV environment using a commercial power source. The hazard to our device when using an aftermarket generator, is that some provide a modified sine output, which can cause damage. Others provide a pure sine wave at all times, and others will switch to a modified sine wave under heavy loads. The portion of our units than can be damaged is the surge protect and is not bypassed using the bypass switch. Since there are many brands of generators on the market and numerous models I can not offer specific guidance on which one to select."

Based on this I'm guessing they found that the Yamaha EF2000iS was one of those models, and although designed to output a pure sine wave signal this particular model does under some circumstances output some version of modified sine wave that doesn't sit well with their EMS units. What I can definitively say now - because I've done it - is that if I bond the floating neutral output of my own Honda EU2000i my new EMS does pass voltage to it's output and on to the trailer whether the genset is running on ECO, full speed, or anywhere in between, loaded or unloaded, and therefore as far as I can tell it's safe to use this combination to power my trailer. Unfortunately, unless any prospective owner is aware of this Progressive / Yamaha disclaimer, they could well go ahead and use an EF2000iS anyway and blow out their new Progressive EMS, with no recourse because the company has made it clear they will void warranty on the unit.