Mod: Battery Monitor
DETAILS: Battery Monitor
Adding a battery monitor is like adding a fuel gauge for your batteries. This is one of my favorite mods!
The installation of the shunt on the battery is straight forward. Rather than explain it step-by-step here, just watch this video which details the installation of the Victron BMV-712 battery monitor.
Since the monitor is bluetooth enabled, you don’t have to go to the trouble of routing the data cable all the way to the control center, but I wanted to see the state-of-charge at a glance without having to reference my phone.
Now, on to the setup and testing.
I programmed the monitor with my total battery capacity (210ah on the Costco Interstate batteries) and set my "floor" to 50% (this allows the monitor to calculate the "time remaining" to 50%).
To test the system, I topped off my batteries via solar and waited for my solar controller to confirm 100% charge of my house batteries. I then "synchronized" the battery monitor (an option in the app) to confirm 100% charge.
Then, I turned the solar off (via a breaker I previously installed) and turned on several lights, my inverter, TV, fan, etc. Approximately an hour later, I took the first 3 photos above.
The monitor showed that I had 95.7% battery remaining.
The smart phone app (see screenshot) rounded that number to 96%. The voltage indicated 12.34V which seems accurate (see the next photo of One Place indicating 12.3).
This is one of those times where looking at voltage (under load) by itself can be misleading. My battery was nearly full, though the voltage level could make you fear that your batteries are considerably lower.
The current of -11.4A indicates the amps leaving my battery. If I was to turn on my solar, and if my solar was capturing 13Ah, then this number would indicate a positive 1.6A.
The Power and Consumed Ah are nice to have, but of most interest is the Time Remaining. In my screenshot, I have 8h 24m remaining until I hit 50% battery. This seems to add up perfectly since my usable capacity is 105ah, I had already burned 9ah, and at the rate of 11.4 amps per hour, I would indeed be at 50% battery in 8.4 hours.
Once I turned off the TV, inverter, lights, etc., my resting usage (with propane saver switch and fridge both on) is around 1 amp, so my “time remaining” jumps to several days.
The propane furnace uses 5-6 amps when running, so that will definitely affect my time remaining during cold months.
Below are links to what I purchased (I bought the BMV-712 with the temperature sensor option, though it isn't necessary to add the temp option and you can save a few bucks).
Victron Battery Monitor: www.amazon.com/dp/B07F3C7ZV7
Insulating Shunt Cover: www.amazon.com/dp/B006VELEFO
Wire Noodler Kit: www.amazon.com/dp/B01LXCJSRP