Yamaha 2000i's in parallel

BradTX wrote:
Any suggestions?

You haven't indicated whether you may also be running some make / model of EMS or surge protection device BUT whether you are or not you might want to be aware of this warning from Progressive Industries regarding the Yamaha EF2000iS genset.

Progressive Industries EF2000iS Disclaimer

What caught my eye is this key statement - "Please be advised the Yamaha Generator Model EF2000iS does not generate enough start-up current which causes the unit to overload. The generator then puts out non-true Sine Wave power." That suggests to me there could be other occasions during the genset's process of ramping up or ramping down in speed when the output signal is not consistently sine wave either. If so, perhaps your A/C is not reacting well to this brief moment of "non-true sine wave power".

Secondly, do you know or have you checked to see if your A/C is equipped with a hard start capacitor which will ease start up load regardless of whether the power source is shore power or from a generator? :@ I've installed a Supco SPP6 on my previous Coleman Mach 3+ and my current Dometic Brisk II A/Cs and in both cases getting the compressor to ramp up to speed was much improved.

Hey SoundGuy, thanks for the reply.

In my research, I'd never run across the problem with the sine wave, thanks for that information. I don't have a power management device but was considering a Hughes Autoformer.

The A/C does have a hard start and the fan comes on first, then the compressor. The units take the load, they will even reduce rpm's after the initial hit, it's when the load drops off is when the problem of overload arises. The A/C compressor will shut down normally, the fan is still running and the generators rap out. The units don't shut down, they just go off line.

I'm going to test it again tomorrow. When the A/C kicks off, the display on the microwave starts dimming so I don't know if the problem is with one generator tripping first and then the other overloading or if the whole gen system gets overloaded at once.

BradTX wrote:
In my research, I'd never run across the problem with the sine wave, thanks for that information.

Unless you've actually scoped the output waveform of an EF2000iS you wouldn't know if there's an inconsistency that in fact may be the source of the problem you're having. The commentary from Progressive suggests to me this may be a very real possibility.

Edit: I didn't read your second reply so what I posted is not applicable other than it should work with the hard start capacitor.
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I have a pair of 2000is and a PI voltage unit. I had the same issue initially with my 15k AC. I installed a $10 hard start capacitor in the AC and everything works fine.

I also found that if I first put a load on the generators, like a microwave or water heater, the AC would start and run just fine. It seems to be related to initial high current applications.

This capacitor should work for you.

http://www.amazon.com/gp/product/B000LDPI26?psc=1&redirect=true&ref_=oh_aui_detailpage_o03_s00

One more thought. I run mine with a grounded neutral and with the red plug on the outside receptacle so as to get proper polarity. Do you have a polarity checker you can use? I don't know if it will help but best to get everything right.

I run mine on full (eco off) when in parallel because that typically means I need a lot of current...the manual also suggests eco off when running high current applications.

I toiled over sending these back and getting a pair of Hondas but the Yamaha engine is so much better than the Honda that once I solved the AC problem with the capacitor I decided to keep them.

bill-e wrote:
I have a pair of 2000is and a PI voltage unit. I had the same issue initially with my 15k AC. I installed a $10 hard start capacitor in the AC and everything works fine.

"Works fine" for now but Progressive has offered fair warning that their EMS units are not to be used with the Yamaha EF2000iS. You've not been clear about what you mean by a "PI voltage unit" but if it's one of their EMS units then doing so completely voids the limited lifetime warranty you'd have on that unit. :E JMO, but I'd take that warning to heart and just not use any PI device when running on an EF2000iS. ;)

As an aside I'd sure like to know why the Yamaha EF2000iS's engine is "so much better" than the Honda EU2000i's engine, especially considering the Yamaha's is a significantly smaller displacement engine used to power an inverter that doesn't offer anywhere near the surge capability of the Honda's inverter - 20 sec vs 1/2 hr. :h

The Yamaha apparently goes into non-pure sine wave when it initially sees a high inrush current. I do have an EMS and spoke with PI about it. No mention of voiding warranty (though I have read that warning on their page) just that some Yamaha's have issues.

As far as the motor, I wasn't speaking of displacement as the Honda has the Yammy beat...hence the higher surge rating of the Honda. I was speaking of engine design. Plastic camshaft on the Honda vs push rods on the Yamaha plus the Yamaha is tested to twice the CARB rating of the Hondas. The higher CARB rating means that the Yamaha is built to tighter tolerances and wears better than the Honda. That coupled with the Fuel Shutoff (very important since mine sits a long time between uses) and the fuel gauge and I prefer the Yamaha.

BradTX wrote:
I'm going to test it again tomorrow. When the A/C kicks off, the display on the microwave starts dimming so I don't know if the problem is with one generator tripping first and then the other overloading or if the whole gen system gets overloaded at once.

Since the load is so much lower once running, maybe try pulling one of the generators out of the system while it's running. See if the problem persists with just one. That will tell you if there's simply a high load or an interaction issue between the two.

bill-e wrote:
Plastic camshaft on the Honda vs push rods on the Yamaha plus the Yamaha is tested to twice the CARB rating of the Hondas. The higher CARB rating means that the Yamaha is built to tighter tolerances and wears better than the Honda.

Some might wonder why Honda chose to use a plastic camshaft but the reality is it's proven reliable over the many years this generator has been on the market, with literally millions of these units having been sold worldwide. CARB ratings notwithstanding some who live off grid year round and and run their EU2000i 8 to 10 hrs a day, 365 days a year, report as much as 10,000 hrs of reliable service before the generator needs a rebuild so as a casual user I'm comfortable with the choices Honda made in designing the EU2000i.

That coupled with the Fuel Shutoff (very important since mine sits a long time between uses) and the fuel gauge and I prefer the Yamaha.

Conveniences for sure but adding these features would no doubt raise the cost of an already premium priced generator. I run premium non-ethanol gas treated with Sea Foam, along with Mobil 1 synth oil in the crankcase, and never empty the fuel tank or run the carb dry ... rather, I just give EU2000i a once a month run for a 1/2 hr under load (as I just did this morning) and using this protocol it starts on the first pull, every time no matter how long it's been sitting idle. :B

As to the OP's problem it sure would be interesting to see if this same A/C difficulty he's describing could be duplicated using a pair of Honda EU2000i gensets in place of his two Yamaha EF2000iS. However, knowing (via Progressive) that the Yamaha EF2000iS does produce a non-sinusoidal waveform under some circumstances seems to me to make it awfully culpable. ;)

OK, I tested them again today. No problems. I let the A/C do it's own thing through 4 cycles and all is good. I started with 125.6 volts, the fan kicked on and then the compressor, initially dropping to 115 and leveling out to 120.4 or so. When the A/C kicked off on normal stop, the voltage didn't spike, it returned to normal.

Only thing I can think of, and I don't know if I did this or not; or if it would affect the situation. I made a point of it today to hook up the parallel cables before I started the generators. I can't really say if I did so the other day or not. Otherwise, set-up and run conditions were the same.

I'll keep y'all updated, and thanks for the help. One question though, in y'all's experience, is there a power management system that would boost the voltage if I find low voltage at a park, and would also act as a surge protector, or do I need separate devices?