Inverter question

[whitebear47]

I was dumping tanks the other day and heard this buzzing sound behind tanks. Crawled in basement from other side and finally located the source. Sound was coming from one of the inverters. I can't say I've noticed that before. Charging light was blinking green on and off. Both inverters were absorb charging about 14.4. That's unusual on shore power but all power was off at park during the night but I don't know for how long. I don't know if it was coincidence or not, but hit main power switch, waited a few minutes, turned it back on, went to basement, buzzing stopped, inverter charging light was solid green. Checked inverter read outs and both read 13.4 or something close. About 10 min later one inverter showed full charge, and the other one followed suit a short time later. I guess I don't remember hearing the buzzing sound before, but I could be wrong. Anybody noticed this?

[BFlinn181]

Is your RV protected by an EMS? (Electrical Management System) It sounds like during the night you had an interruption to shore power. This could have included a surge, or drop in voltage, off then quickly on again, etc. Whatever it was, your inverter wasn't able to handle the changes and didn't reset properly until you turned off power and turned it on again.

I would not be without a Progressive EMS to filter power and only allow it into my RV after being checked. It also has a built in delay when restarting, to prevent trying to restart compressors in A/C or refrigerator units until the pressure has equalized in a timed delay. It's surge protection and low voltage monitoring protects all electronic gear in the RV, like your inverters. Very much worth the money.
Surge Guard makes a similar unit, but compare warranties. SG is one year. Progressive Industries is a Lifetime repair or replace warranty. If you call for technical help, you'll likely end up talking to the CEO. (I did) They'll talk you through tests of your system and suggest repair options. NO CHARGE for time or parts.
Others can argue whether to get the hard wired or portable unit, mine is hard wired into my shore cable. Here's a link to their website:
Progressive Industries RV Surge and Electrical Protection industry lea

[voltdoc]

Buzzing, not that I recall on mine, but may not be unusual under certain load conditions. I do hear the cooling fan often however. What year and model coach? Some with two inverters have one pure sine wave and one modified sine wave, which are yours? PSW have white case, MSW gray I think.

According to 2000 series manual, when connected to shore power, slow blinking status light on inverter means charging in float, medium blink (1/sec) means absorption mode, solid means bulk.

The Magnum's are pretty bulletproof, but as suggested if you did have power fluctuations perhaps one or both got "stuck" and when you cut and restored the mains you reset the inverters back to normal. You can also do a reset by holding down the button on the inverter for 15 seconds.

[whitebear47]

Always forget to add model. We have a 2013 Anthem. We have a surge protector (EMS) between shore power and coach. Power was off during night but t don't know for how long.
Thank you for the replies.

Mike

[MRUSA14]

If you mean a low soft buzzing, that is a characteristic of MSW. I hear it all the time from my outlets when the inverter is inverting. If your shore power was interrupted, your inverters would have started inverting. When you restored shore power the buzzing would stop. PSW interters don't seem to make this buzzing noise, but I think this may be normal behavior for the MSW inverter