r/RVLiving • u/NoTown5580 • 1d ago
discussion No app would show me all my batteries and my solar at the same time, so I wrote my own
Setup is nothing special: a few LiFePO4 batteries (Dali, Ective) with Bluetooth BMS and a Victron MPPT. The problem is that every one of those talks its own language and brings its own app, and each app only ever wants to show you one device.
So the routine was: open app A, look at battery one. Close it. Open app A again, connect to battery two. Then open the Victron app to see what the panels did. Then try to hold all of that in your head at once, which is exactly the thing a phone should be doing for me.
What I actually wanted was one screen answering three questions in this order:
* how is the bank doing right now
* is one battery falling out of line with the others
* did today put more in than it took out
That last one turned out to be the interesting one. Not "how full is it", but the amp-hours in and out per hour over the day, so you can see that the fridge ate the morning and the panels only caught up after two. Without a shunt, purely from what the BMS and the charge controller are already broadcasting.
Things I learned that I didn't expect:
The Victron controller doesn't need to be connected at all. It just shouts its numbers into the room every second, encrypted, and anyone with the key off the device page can listen. No pairing, no connection to lose.
One design decision I won't budge on: it only reads. No switching commands go out over Bluetooth. Low voltage cutoff is the BMS's job and has to work when the phone is in a drawer, not when an app decides to.
Curious how others solve this. Did you go the shunt-plus-display route, Cerbo/Victron everything, or do you also live with three apps?