1000 watt Yamaha generator?

I'm sure you meant 60a converter. At 780 watts, it should be fine.

I would shop converters before getting a larger generator.

2oldman wrote:
I'm sure you meant 60a converter. At 780 watts, it should be fine.

Please explain how a 900VA gen can supply 1383VA or so.

Kill-A-Watt on a 55amp converter set to 14.8a output, powered by a Honda gen:

124.7v, 11.06a, 980w, 1383VA, PF 0.7 with DC output at 56.8a

To repeat for the zillionth time :( It is the VA not the watts!!!

I wish I had bought a 1000 watt generator instead of the 2000 for those rare days the sun doesn't shine enough for the solar. I believe you will be ok.

It will be borderline.

60amp at 12v is 780w but when you account for losses or variations in voltage as the system isn't 100% efficient at converting AC to DC, you need to feed it more than 780w.

The 1000w Honda is only rated at 900w continuous duty. That leaves you only 120w to cover losses. This also assumes you have isolated the AC circuit feeding the charger. Doesn't take much to eat up 120w.

If you dropped back to around a 50amp charger, I would say it's a safe bet that it will work.

Since you are on the edge, you may run into issues where one day it works and another it doesn't...if you are at higher altitude or it's very hot, the power output will vary a bit.

valhalla360 wrote:
It will be borderline.

60amp at 12v is 780w but when you account for losses or variations in voltage as the system isn't 100% efficient at converting AC to DC, you need to feed it more than 780w.

The 1000w Honda is only rated at 900w continuous duty. That leaves you only 120w to cover losses. This also assumes you have isolated the AC circuit feeding the charger. Doesn't take much to eat up 120w.

If you dropped back to around a 50amp charger, I would say it's a safe bet that it will work.

Since you are on the edge, you may run into issues where one day it works and another it doesn't...if you are at higher altitude or it's very hot, the power output will vary a bit.

Another one that doesn't know about VA. :(

BTW, efficiency ratings for these things are in watts, not VA, which can be misleading. If there is a PF, that makes it worse than it looks using just watts. Typical advertised efficiency for converters is around 85%. In the above example with the 55a converter:

Watts out-- 56.8a x 14.8v (set) = 841w
Watts in--- 980w, so efficiency is 841/980 = 86% BUT,

If you use the actual input required in VA, it's 841/1383 = 61%

Which is why they advertise the efficiencies using the watts. It also shows how PF can get mixed up with "efficiency" when looking at all this.

Most generators are rated in VA but advertised in watts. Converters give their specs in watts. Unless the converter is power factor corrected (most aren't), it's draw in VA is in the ballpark of 30% higher than its draw in watts. I've never seen a converter advertisement or spec sheet that mentions this. When the real numbers are run, a 1,000 watt generator has no chance of running a 60 amp converter at its full output. It needs close to the continuous output of a typical 2,000 watt generator.

In order for a three thousand watt generator not to die when starting a power factor corrected 135 amp "charger" I had to design a circuit that allows only the charger capacitors to charge, minus -any- load then go online 10 seconds later*.

To see what I mean, try it yourself -- Disconnect your converter from the battery. Disconnect from generator vac. Let the converter capacitors discharge. Then plug the converter into the generator. Hear the hiccup? It's minor when connected to a large RV generator... it's anything than minor when coupled to a borderline small generator.

Now add battery loading to capacitor charging and for those milliseconds a heck of a lot more power is being sucked up by the converter. Is the converter power factor corrected? No? Grab more paper, sharpen the pencil, wipe off the calculator.

Reserve generator power is not calculated by gradient when starting a threshold overload. The instant the motor slows down. you a screwed pooch.


*This is switched between the power supply and a 200 amp relay. It's purpose is to -verify- the power supply voltage setting and allow adjustment before going online. Capacitor loading windup is included and it is absolutely necessary.

mike-uswest wrote:
Now I have a TT with a 60 watt convertor. Will my generator give this some power if the solar can't handle the clouds, or will it just shut the 1000 watt generator down? If it does, I will have to go generator shopping, and I like that Yamaha.

Not necessarily. At the risk of offending PD aficionados you could simply keep the EF1000iS you like so much, turn off the PD, and instead invest in a stand alone charger like this CTEK Multi US 25000 which does do a proper 14.4 volt bulk charge, offers temperature compensated charging, and won't overload your EF1000iS. You haven't indicated the size / type of battery or batteries you have but that would obviously determine just how long you may have to run your genset for sufficient recharge when the sun isn't co-operating as you would prefer.

I did mean 60 amps, sorry, that is how screwed up I am. I do have a B&D stand alone charger, but storage can be a problem. Thanks for the answers. It gives me options. I have 2-6 volt deep cycle batteries.

Mike