Going to install inverter bypass in RV to stop buzzing while hooked to shore power

[corn18]

Below is my current install with my Victron Multiplus II 12/3000/120x2 50 in my RV. When I am hooked to shore power, it buzzes all the time. Not real loud but I can hear it all the time and it drives me nuts. I don't need it 99% of the time when hooked to shore power, so I want to make the buzz go away. I could move it, but it is in a great spot with good airflow (a/c) and very close to batteries (one foot). The location is right by the access panel where the old converter was, so there is a direct path into the camper for noise. I can't turn the inverter off because it needs power to operate the ATS. If I go charger only, it still buzzes all the time. If I turn off the battery feed to the inverter, it constantly buzzes on and off which is more irritating than just buzzing.



I am going to buy a manual select switch so I can bypass the inverter and then turn it off. The manual select switch will route power directly from the shore power input to the AC panel in the camper. Then I can turn off the inverter and no more buzz. I lose charging but solar handles that. I lose battery backup, but I can just turn the inverter on and not bypass it if I need battery backup. I lose power share but I can also just not bypass it if I need power share. 99% of our camping so far is at campgrounds with 50A service, so I do not need the inverter for that. If I need to charge the batteries with shore power, I can just not bypass the inverter.

This is the selector switch I bought:

This is the new diagram:



Any other ideas?

 

[schmism]

1) I'm surprised this is a "coil whine" on the input side and not just a function of the big ass transformer in the thing that will 60hz hum anytime its "on" (which is going to include any time doing its normal inverting job and not limited to when grid power is connected to it)

2) your updated schematic seems to suggest it will always have grid power supplied to it, so I don't understand how this is supposed to fix the hum, if it hums when connected to grid power.

 

[chess-equality]

Below is my current install with my Victron Multiplus II 12/3000/120x2 50 in my RV. When I am hooked to shore power, it buzzes all the time. Not real loud but I can hear it all the time and it drives me nuts. I don't need it 99% of the time when hooked to shore power, so I want to make the buzz go away. I could move it, but it is in a great spot with good airflow (a/c) and very close to batteries (one foot). The location is right by the access panel where the old converter was, so there is a direct path into the camper for noise. I can't turn the inverter off because it needs power to operate the ATS. If I go charger only, it still buzzes all the time. If I turn off the battery feed to the inverter, it constantly buzzes on and off which is more irritating than just buzzing.

View attachment 112246

I am going to buy a manual select switch so I can bypass the inverter and then turn it off. The manual select switch will route power directly from the shore power input to the AC panel in the camper. Then I can turn off the inverter and no more buzz. I lose charging but solar handles that. I lose battery backup, but I can just turn the inverter on and not bypass it if I need battery backup. I lose power share but I can also just not bypass it if I need power share. 99% of our camping so far is at campgrounds with 50A service, so I do not need the inverter for that. If I need to charge the batteries with shore power, I can just not bypass the inverter.

This is the selector switch I bought:

This is the new diagram:

View attachment 112247

Any other ideas?

Does it affect other electronics?

Mine's worse as it's on the output side, and wrecks USB ports:

5kw inverter drives speakers, USB ports, and oscilloscope-meter nuts

So here goes :( Only affects my 12v basic inverter. My 24v AIO doesn't have this issue. The setup: - 5kw 12v pure sine wave basic inverter, non-AIO, no built-in shore charger - 4 x 200Ah parallel bank - Monitored by Victron SmartShunt; batteries are good - Used only as backup; powered off most...

diysolarforum.com

Incidentally I'm considering to replace it with a Victron

 

[corn18]

1) I'm surprised this is a "coil whine" on the input side and not just a function of the big ass transformer in the thing that will 60hz hum anytime its "on" (which is going to include any time doing its normal inverting job and not limited to when grid power is connected to it)

2) your updated schematic seems to suggest it will always have grid power supplied to it, so I don't understand how this is supposed to fix the hum, if it hums when connected to grid power.

It only hums when it is on. If I can bypass it to get power to the AC side of the camper, then I can turn it off and it doesn't hum.

 

[l00semarble]

What firmware are you running? The early firmware in these units had an issue with loud and constant buzzing. I brought it to their attention after I sold a few of first batch of these to arrive in states. They resolved the issue with a new firmware.

 

[corn18]

Well, that was easy. I updated the firmware to 4.97 and it is now quiet as a church mouse. Awesome sauce!

 

[l00semarble]

Great. Glad that was all it was.

 

[RV10flyer]

I have found out...start here before getting the credit card out to buy stuff. These forum members have a lot of knowledge and experiences. Well, there will always be a use for that switch.