Ebay Inverter- not my best decision!
In 2017 we were in the market for an inverter since we were totally rebuilding our 34 classic Mainship and outfitting it for our future cruising needs. I researched & studied every inverter related post I could find on here and decided what the heck, most seem happy with their cheap inverter so I'll give it a go! I was already sure about wanting a true sinewave one and bought a 3500W model which was overkill for our needs but it was only a few $$ more ($325) than the 2000w plus it came with a remote on/off and was hard-wire capable, both features that I wanted.
When we received it I took it down to the boat to wire it into its respective AC & DC systems. For the 12v DC I added a Blue Seas remote battery switch for the inverter with the battery on/off to be controlled next to the inverter controls & breaker panel. While I was at it, I added a remote battery switch for the engine battery disconnect and a Blue Seas ACR to charge/combine the house bank too. But I digress.
I added a selector switch to switch between incoming shore 110v & the inverter. Simple enough. Shore hot & neutral on one side of the selector & inverter on the other with the bonding tied together at the breaker panel & the output of the selector switch running to the breaker panel 110v hot & neutral (I wanted the capilibility to have all of the boats recepticals powered by the inverter, knowing the ProMariner 1250 battery charger, water heater & air conditioner breakers would need to be manually turned off during inverter use). I had already rewired/replaced any questionable wiring & breakers on the 110v system & I'm confident everything is up to snuff regarding the AC.
So we went out & I fired up the inverter to show my wife how cool it would be to heat stuff in the microwave, watch TV, etc off of inverter power. All of that worked fine and she was happy but I noticed that while on invert power, the battery charger was pulsing on & off. Weird. The breaker was off and disconnecting the charger 110v input from the breaker made no difference either! More weird. OK then, I wasn't going to let a dumb Chinese inverter foil my dreams! I moved the charger neutral to the shore side of the source selector switch & the problem was solved! When the selector was on the inverter side and the charger breaker was off, the charger was completely isolated and no more pulsating! Problem solved! Until I came down to the boat at night and noticed the indicator light beside the charger breaker always had a faint glow in the off position. Oh well. Not a big deal.
Fast-forward a few months and while microwaving some hot chocolate underway, the microwave started pulsating along with the inverter. I thought I might have a bad battery in the bank & would check it when we returned. Well the batteries were good & I shelved the diagnostics until the 2019 season.
So here it is, the 2019 season has started and I fire up the inverter to check things out. Now, without ANY breakers on and the 110v selector on the inverter side, the microwave started pulsating on/off like the charger did. As a last ditch effort/guess, I disconnected the case bonding from the inverter case but that didn't make any dif regarding the microwave pulsing or dim charger breaker indicator light.
I officially threw in the towel and disconnected the inverter from the ships system and ran it to a designated GFCI receptacle in the galley. Yeah, I know, no breaker to protect the line but I'm thinking this inverter is going to belong to Neptune very shortly & the system will be replaced with a Samlex system.
The point of this long post is to convey the message that I've wasted a little bit of money and a lot of time on a cheap inverter and while I never have figured out what the hell was going on with all of the electrical backfeeding, I'm pretty sure the cause is internal to the inverter and more importantly, could have poised a potential danger to those onboard while the inverter was in use. Another boating-related lesson learned!