oli-1 avatar image
oli-1 asked

Automatically switch on Phoenix 12/500 VE.Direct on recharged battery


is there a way to turn on the Phoenix 12/500 inverter at a defined battery level (or voltage)?

I have a small island system with 240 Wp charging a 55 Ah/12V LiFePo via SmartSolar MPPT 75/12. This is running fine so far, but I often have a fully charged battery with no way to discharge it on the 12 V system (which I use to charge smart devices and notebook computers). So a lot of sun energy is wasted (charger in float mode).

So I installed a Phoenix 12/500 inverter that now runs a fridge most of the time. I also installed an automatic transfer switch, so the fridge gets landline power in case the battery is too low for the inverter. This also works fine.

But now the inverter discharges the battery completely and then it does not turn on again, when the battery is full again. But I would like to switch off at 20% battery level (so I have enough spare for my more efficient 12V system) and automatically turn on at 80% battery level (so the inverter just kicks in, when I risk to run into a 100% full battery)

Is this all possible with the two Victron devices or will I need to read the battery level with an Arduino via from either MPPT or inverter and then switch the inverter manually on and off via the remote control port of the Phoenix?

Thank you very much


Phoenix InverterVE.Directsmart solar set-up helparduino
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1 Answer
ripper avatar image
ripper answered ·

3 ways:

The Phoenix has build in voltage dependant on and off. As LiFepo is fairly stable in its voltages you should be able to use that. It obviously works as it shuts off, it doesnt go on because it is set to the wrong restart voltage. Fine tuning might be necessary if you have a heavy load which has the voltage reduced while running. Needs access via Victron Connect app, probably with a bluetooth to ve direct dongle.

A mini potential free ie normal relay, not SSR, to open or close the loop of the Phoenix remote by the load output of the Mppt. Also voltage related. Again Victron Connect app, voltages adjustable. 2 minutes delay when voltages are reached.

Purchase of a BMV, with the right adjustments it can be very acurate then charge state related via internal relay to Phoenix remote terminals.

I would go with one, maybe two. Three is expensive overkill for what you want to achive albeit a lot of fun to look at when you have it.

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Related Resources

Phoenix Inverter product page

Phoenix Inverter Smart product page

VE.Direct protocol FAQ

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