Monitor Solar System Battery Bank Voltage?


Hi -

New user of IotaWatt and excited to fully leverage the platform.

As of now I am using emoncms which is running on my Synology NAS. So far so good!

My question is how to measure my battery bank voltage? I have hybrid solar system and what I don’t consume at the time of production is pushed into my battery bank.

So far I have been unable to find anything that points to IotaWatt being able to monitor DC voltage. Accurate? I did come across a couple articles that point to using an emonPI type device but I am trying to limit my costs in buying another data collector.

My system utilizes a Victron Battery Monitor, BMV-712 and MPPT, both of which have Victron’s VE.can ports which reportedly can communicate with an emonPI type device. I was going to head in that direction but wanted to double check on alternatives that might work directly with IotaWatt.



Not sure if this would be helpful in your situation or not, but I have a new Tesla Powerwall and I monitor my power and energy to the battery using the IoTaWatt at the load center (after the inverter) in my panel. This monitors the flow in and out of the battery at the AC but not DC level. Not sure if this would help in your situation or not. I assume you have a tie-in to your panel or are you using a portable inverter and cable to backfeed to your panel.


Thanks for the feedback.

Looking to monitor SOC of the battery pack, ex. 100% full is 49 volts, 50% is 44.4 Volts… etc…

The victron bmv provides that today but hoping I can accomplish that with iotawatt so I can add it to Emoncms dashboard, single view.


Sorry I did not think you were looking at the percentage or battery status. I’m not sure how you would accomplish that using the IoTaWatt itself. For me, I use NodeRed to make an API query to my battery system and extract the battery status (percentage) of charge and forward that via the EmonCMS API. The IoTaWatt can only measure power using VTs and the Voltage, not status that I’m aware of.


@quella is right, IoTaWatt only measures AC voltage and power asa practical matter. The basic hardware could measure DC voltages with perhaps a few resistor changes, but the firmware has no logic to do the measurement or save the result, and that’s not in its future. Better to capture the existing status output independently.


Thanks for the feedback.