Multiplus-II and Onan QG 5500 design questions/validation

[Togo678]

I'm savvy enough to know not to combine them. That's why I spoke up. This is today's configuration, BTW... Likely to change next time the MultiPlus acts up...

The only thing abnormal on these screenshots is that I have the inverter output voltage lowered in hopes that it would have some affect on the voltage/hz sync...

Like I said, grasping at straws....

Please excuse the over zealous safety warning, Dexter's reply was completely wrong and I have seen people get one reply to there question and just do it...

I would suggest increasing your AC in disconnect to 106v and connect to 110, disable UPS, enabling dynamic current limiter, and lowering the input current limit to 40amps. Your 10kw generator is not capable of 50amps which is 12kw.

 

[Togo678]

I'm savvy enough to know not to combine them. That's why I spoke up. This is today's configuration, BTW... Likely to change next time the MultiPlus acts up...

The only thing abnormal on these screenshots is that I have the inverter output voltage lowered in hopes that it would have some affect on the voltage/hz sync...

Like I said, grasping at straws....

What are you using to monitor your inverter? BT dongle or Cerbo?

 

[davejowen65]

No worries. I saw your frownie face on my first post. Just acknowledging and appreciating a reply.

So, I've tried all those things. I've gone as low as 15 amps just to make sure it didn't have something to do with the input setting. It will still randomly not accept input. I've swapped L1 and L2 from the generator to see if maybe I had a tired winding in the alternator (seemed to work for a while). Today I swapped them back to where they're supposed to be.

I do appreciate the help.

 

[davejowen65]

What are you using to monitor your inverter? BT dongle or Cerbo?

It's a CerboGX with DIY panel, SmartShunt has BT, but is Ve.Bus'd to the Cerbo.

 

[davejowen65]

It's all set up with Auto Generator control. I would love to just trust this system (god knows I've put enough effort into it), But I find myself constantly monitoring it, because occasionally it will start the generator and not accept an input. Would be nice if it would at least pass-thru, so my secondary charger would work, but that would be too easy...

 

[John Frum]

It's all set up with Auto Generator control. I would love to just trust this system (god knows I've put enough effort into it), But I find myself constantly monitoring it, because occasionally it will start the generator and not accept an input. Would be nice if it would at least pass-thru, so my secondary charger would work, but that would be too easy...

Would be great in the MP2 would tell us what it objects to.

 

[Togo678]

It's all set up with Auto Generator control. I would love to just trust this system (god knows I've put enough effort into it), But I find myself constantly monitoring it, because occasionally it will start the generator and not accept an input. Would be nice if it would at least pass-thru, so my secondary charger would work, but that would be too easy...

When you are monitoring the inverter how are you determining that its the inverter not accepting the power? In the cerbo do you have a voltage reading on the inputs?

 

[davejowen65]

Would be great in the MP2 would tell us what it objects to.

Ha! Totally agree. I have a whole list of things that the Victron software "should" do...

 

[John Frum]

Ha! Totally agree. I have a whole list of things that the Victron software "should" do...

That is in the next gen interface.

 

[davejowen65]

When you are monitoring the inverter how are you determining that its the inverter not accepting the power? In the cerbo do you have a voltage reading on the inputs?

I've confirmed voltage at the generator, at the multiplus, using the cerbo to read that there is input voltage being recognized. I can hear the inverter do a double clunk (like half a second worth) as it looks and then shuts off input. Generator is off right now because my batteries are fully charged, but it shows 120 volts and usually 60.1 give or take a couple tenths of hz when it's not accepting input.

 

[Togo678]

I've confirmed voltage at the generator, at the multiplus, using the cerbo to read that there is input voltage being recognized. I can hear the inverter do a double clunk (like half a second worth) as it looks and then shuts off input. Generator is off right now because my batteries are fully charged, but it shows 120 volts and usually 60.1 give or take a couple tenths of hz when it's not accepting input.

If you are reading 120v and 60hz in the cerbo than the multiplus has connected to the generator. Is it not charging?

 

[davejowen65]

If you are reading 120v and 60hz in the cerbo than the multiplus has connected to the generator. Is it not charging?

Nope, it’ll read the voltage and hz in the screenshot I just showed you and clicked on and off every minute or so rejecting power. Then I get upset after about 15 minutes, sometimes an hour when I don’t notice. Proceed to turn on and off settings randomly (that we already talked about) and after about 2 wasted hours of turning the generator on and off, inverter on and off, disconnecting batteries, changing settings, it’ll just start working like normal for another month.

 

[davejowen65]

The ONLY factor that keeps coming up is that it usually happens when it is a cold morning and the generator is running rough for the first 30-40 seconds. My ATS is bypassed right now because, I thought it may have something to do with that.

Clearly doesn’t.

I’ve tried to set Virtual Assistants to ignore ac input for about 2 minutes while the generator warms up, but that’s a whole other story. Didn’t seem to help anyway. It’s a mostly random occurrence that seems to mostly happen on cool mornings (but not always)

 

[Togo678]

The ONLY factor that keeps coming up is that it usually happens when it is a cold morning and the generator is running rough for the first 30-40 seconds. My ATS is bypassed right now because, I thought it may have something to do with that.

Clearly doesn’t.

I’ve tried to set Virtual Assistants to ignore ac input for about 2 minutes while the generator warms up, but that’s a whole other story. Didn’t seem to help anyway. It’s a mostly random occurrence that seems to mostly happen on cool mornings (but not always)

How old is your generator and does it only happen when running on the generator? I'm not exactly sure what's going on but my last guess would be the ground neutral bond on the generator. You'll have to consult ONAN for exact location and configuration but the ground and neutral should be bonded at the generator. If there is a poor connection and the bond is being lost and re-established several times a second, i.e. when the genset is shakin like a dryer with a boot in it, the ground relay tech in the multi may be overwhelmed.

 

[davejowen65]

How old is your generator and does it only happen when running on the generator? I'm not exactly sure what's going on but my last guess would be the ground neutral bond on the generator. You'll have to consult ONAN for exact location and configuration but the ground and neutral should be bonded at the generator. If there is a poor connection and the bond is being lost and re-established several times a second, i.e. when the genset is shakin like a dryer with a boot in it, the ground relay tech in the multi may be overwhelmed.

This actually makes the most sense, but I have checked it with a tester. Might be an intermittent thing. I thought about making one of those jumpers that basically has a wire jumping the neutral and ground. Think I should try it?