Inverter ON while connected to the grid - Lesson learned

[rotateclockwise]

We recently camped for 9 days with water and electric services. Our Escape has solar and inverter with the transfer switch. I also installed a Victron battery monitor to learn about our power usage.

During our stay we used the microwave twice, and when we did, the Victron would beep indicating I hit my pre-established battery level alarm of 60%. I could watch the battery level drop on the monitor while the microwave was running and then it would jump back up once the microwave stopped.

This was our first trip since installing the battery monitor, so I was puzzled as to why the microwave was causing the alarm to sound when I was hooked up to the grid. I remember checking the inverter before we left and thought it was turned off (no lights).

I’m now realizing I accidentally turned the three-way switch (On-Off-Remote) to “Remote” instead of "off" and we somehow hit the button on the solar monitor (remote) to turn on the inverter and power the outlets. The inverter was on (lights) when I opened the bench to put tools away after returning home.

I'm not sure if this caused any problems, but be aware the inverter has a three-way switch and not a two-way. It seems obvious in hindsight, but then again, that's how you learn sometimes. The "hard way" as my father would say.

[Ian and Sue]

Originally Posted by rotateclockwise

We recently camped for 9 days with water and electric services. Our Escape has solar and inverter with the transfer switch. I also installed a Victron battery monitor to learn about our power usage.

During our stay we used the microwave twice, and when we did, the Victron would beep indicating I hit my pre-established battery level alarm of 60%. I could watch the battery level drop on the monitor while the microwave was running and then it would jump back up once the microwave stopped.

This was our first trip since installing the battery monitor, so I was puzzled as to why the microwave was causing the alarm to sound when I was hooked up to the grid. I remember checking the inverter before we left and thought it was turned off (no lights).

I’m now realizing I accidentally turned the three-way switch (On-Off-Remote) to “Remote” instead of "off" and we somehow hit the button on the solar monitor (remote) to turn on the inverter and power the outlets. The inverter was on (lights) when I opened the bench to put tools away after returning home.

I'm not sure if this caused any problems, but be aware the inverter has a three-way switch and not a two-way. It seems obvious in hindsight, but then again, that's how you learn sometimes. The "hard way" as my father would say.

I am puzzled as to why your battery showed 60% when you were plugged in? Are you sure your trailer was receiving voltage from the shore power? Do you know if your batteries were charging from the shore power? They should be much higher than that after one day of being plugged in even with dual 6v batteries.

[rotateclockwise]

Originally Posted by Ian and Sue

I am puzzled as to why your battery showed 60% when you were plugged in? Are you sure your trailer was receiving voltage from the shore power? Do you know if your batteries were charging from the shore power? They should be much higher than that after one day of being plugged in even with dual 6v batteries.

Power was being received from the pole when we plugged in. The surge protector was reading 120 and glowing the entire trip. I didn't receive any error messages, so I assume we were receiving power the entire time. The event occurred on day 6 and immediately after the microwave stopped, the battery monitor went from ~12v to ~12.5v. My assumption is that when the inverter/transfer switch is on, power to the outlets comes from the inverter and not directly from the grid.

[Brian B-P]

With the inverter turned on the transfer switch presumably selects power from the inverter, even though shore power is available. That's not necessarily what I would want, but that seems to be how it is behaving.

If that's the case, then when the microwave runs and takes about 1000 watts, the inverter will take about 90 amps from the battery. The converter/charger can only provide about 55 amps, so it will not be able to maintain its target voltage, the battery will make up the difference (net 45 amps out of the battery), and I would expect the voltage seen by the battery monitor to drop until the heavy current draw stops.

[padlin]

My non ETI install has a relay that puts the inverter on line only when city power is not available. I do not see any voltage drop if I turn on the inverter when connected to city power and run the mw. Might have someone wit b the ETI install give it a try. My DC stays at 13.3v the whole time.