Gidday, newbie here. Been fully off grid for about 2 months now, and with abundant sun, havent needed to use back up power yet.

However, bought myself a good Honda gennie to cope with the cloudy days. Deliberately ran the batts down to 60% to test.

The inverter will only accept 150W approx from the gennie. And switches back and forth, 2 seconds accepting charge, 10 second pause, rinse and repeat.
Grid voltage showing as 254V dropping briefly to 240V when inverter accepts charge.

Tried disconnecting the PV. No change.

Played aroung with utilty charging current, 10A up to 40A. No change.

BUT.....If  I apply a load, (1KW heater), Gennie grunts down and and inverter shows +350W.
BUT...If I switch the heater to full, (2KW), the gennie goes to max, and very quickly trips it's breaker to protect itself.
(Gennie is 2.2Kw max, 2Kw continous).

Does anyone have any idea what is going on here?

Cheers, Baz


 

 

 

 

 

(6 x 250W Poly PV. 4 x 200A Ritar batts. MUST 80A 5000W Inverter/Controller. Victron BM700 monitor, Honda EP2200CX).

Edited November 3, 20186 yr by Bazza

5 hours ago, Bazza said:

(6 x 250W Poly PV. 4 x 200A Ritar batts. MUST 80A 5000W Inverter/Controller. Victron BM700 monitor, Honda EP2200CX).

I see you have a MUST inverter which is an Axpert clone.

Try setting program 3 to APL instead of UPS. If that does not work try and fiddle with the AVR on the gennie (there are enough videos on the net not to have to repeat the information here- Basically there is a pot that you can use to fine tune the voltage and with a pump inverter I have found this setting critical.

Thanks fo reply Chris.
I currently have the inverter on:  [02] GEN.
Just put the Watt meter on the gennie output and it read 253.4V @ 60Hz with no load. And same voltage  but 50Hz with 1Kw load.
Makes me nervous changing settings I don't understand...

Edited November 4, 20186 yr by Bazza

...Ok. No input at all from gennie on either UPS or APL.
I found the info on altering the AVR. Would you advise dialing it down to 230/240V?
Cheers.

It seems your gennie's voltage is too high. Axpert inverters (of which Must is a clone)seem more sensitive to frequency than voltage per se Remember that the gennie has to carry both the inverter load and charging so you should limit your AC charging to 1500W (30A) and only have 200-300W as a load.

Since you can get it to work if you have a moderate load why don'y you apply a 700W load to the gennie charge at 20A and then wean the moderate load off after a few minutes. It seems that the gennie's voltage is too high until a load is applied.

If this doesn't work dial the AVR back a bit so that your no load voltage is 240V.

Remember you getting advice from a sheep farmer halfway around the world. There must be someone knowledgeable in the State of Victoria. 

 

Just spoke to supplier of my inverter. He seems sure that 60Kz from the gennie is too high for the inverter. Generator specs say it should be rated at 50Kz, so will get that fixed first.

You can get digital Hz meters which are useful to see if the genny is at the correct RPM.

Chris, you would be suprised at the dearth of knowledge about solar in this country, or perhaps not the dearth but the surfeit of conflicting 'knowledge'.
DeepBass, I put my watt meter on the gennie, 253.4V, 60Hz, no load.
Am getting the gennie adjusted this morning, will report back.

34 minutes ago, Bazza said:

I put my watt meter on the gennie, 253.4V, 60Hz, no load.

I think on APL setting it will accept up to 280V, but 60Hz is a real problem unless you are a Yank (in which case 253V is even worse!) You may need a better quality gennie with a good AVR which will maintain 50Hz unless the supplier can sort that out.

On 2018/11/04 at 1:29 AM, Bazza said:

The inverter will only accept 150W approx from the gennie. And switches back and forth, 2 seconds accepting charge, 10 second pause, rinse and repeat.

So the problem is that the inverter will auto-sense 50/60Hz - when you connect the gennie with no initial load the inverter senses 60Hz input, then when it starts to draw a load it sees input dropping to 50Hz which it feels is a problem and so stops accepting power, then the gennie returns to 60Hz because the load has dropped so the inverter accepts input again ....

Connecting an initial load drops the gennie to 50Hz, the inverter accepts this and start accepting input power - your gennie AVR now can maintain 50Hz so it continues to accept input until the gennie CB trips.

You may need to get an inverter type gennie that maintains 50Hz electronically, or a bigger gennie with a flywheel that can carry the load variations without frequency fluctuations.

Makes sense Mr Fish. But the inverter should be smart enough to handle that dont you think?
I have spent hours/days searching for this scenario...nothing.

I must be the only person on the planet who cant charge their batteries with a gennie...

I tested an 'Inverter' gennie today. It also shows 60Hz unloaded. I am pretty sure the inverter is faulty.

Cheers, Baz

PS: Specs from Honda attached, beyond my ken...
Also spec label of the inverter.

 

I did some tests whith gennie and voltronic inverter. 

At the end i realizad that the problem was the slew rate of the gennie. That is the frequency variation of inverter under load changes. I remember there was something in MPP Solar Website.

https://www.mppsolar.com/v3/catalogs/PIP-HS_MS genset requirement.pdf

 

I found it. 

What firmware version does your inverter have?

Hi Silver,
Re; Firmware, I dont know and not even sure it can be accessed. 
Suppliers of inverter assure me they have not had this issue before.
I have advice from two gennie suppliers that the gennie is not supposed to run at 60Hz unloaded. (One sent photo to prove it).
My gennie supplier says 60Hz is normal. no load.
But to confuse things, I have personally tested 3 gennies and they all show 60Mz no load.
I dont know who to believe...
...Sitting here in the dark in the moment after 3 cloudy days, hoping the batts will hang out til morning.

On 2018/11/16 at 10:25 PM, Javi Martínez said:

https://www.mppsolar.com/v3/catalogs/PIP-HS_MS genset requirement.pdf

 

I found it. 

Sorry Javi, missed your post. By 'Slew rate' do they mean fluctuation of frequency over time? In your quoted case:   "< 0.3Hz/sec". That seems a very narrow range if I understand it correctly...

Yes, as you say it is a narrow range. I think that is the reason why small gennies doesn´t suit with Axperts.