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When I started designing and building my house power system I was heavily influenced by YouTube videos of people installing cool technology that worked seamlessly to harness the power of the sun and could be monitored with the touch of an app.
Yeah, right.
I have a Renogy MPPT solar charge controller. Its display voltage is always .3 volts too high. Forget using the documentation (or their support website) to program the device for LiFePo-it does not address some basic theory of operation needed to program, and their support line is unresponsive. Out of frustration I spent nearly a whole day on line trying to get to the bottom of all those parameters, no luck. Although it seems to work fine, if I wanted to fine tune it to get full use out of the battery I’d have to spend a lot more time fooling with the system. I just remember to shave .3 off the display to get battery voltage, and leave it alone.
I have a Daly 250A Battery Management System. Two or three times over the past year it's freaked out on me, saying cell voltages were out of range when they absolutely were not. I unplug the damned thing and after a few days it boots and operates normally again. The programming parameters are complete gibberish. There are zero online resources to properly program it-forget about vendor documentation, just a joke. Just like the settings on the charge controller I fiddled with these and hope for the best. The app seems to show accurate voltages--when it isn't busy freaking out.
I have another BMS sitting in a box in the back of the bus, just in case. I swear the next time the Daly freaks out I'm going to rip it out and put that one in. Probably won't be any different, but I’ll feel like I’m doing something.
I have a Victron SmartShunt. It has NEVER shown accurate SOC unless I am deep discharging and full charging, which I never do. Apparently it uses some algorithm to calculate SOC that is not based on charge/discharge amps. I keep it at 13.1VDC, then rely on total amps discharged to get SOC.
The exception to all of this is the DIY LiFePo battery, which works great. I carefully researched the build process and took my time. I top balanced them with a controlled power supply and hooked them up, and a year later the cells still read within 2-3 millivolt of each other without any interim balancing. That's a good thing, because as best as I can tell the Daly never gets to the point where it would go into top balance mode. I have a fifteen dollar active balancer board, essentially a series of capacitors that distribute charge between the cells. I've never used it.
As you can see my system is a mix of vendors and mid-range components. Maybe my problems are because I didn’t break the bank and buy all Victron. I've heard Victron components snap together like Lego blocks but I have my doubts. I’d love to hear if someone got over the sticker shock and did everything with a single vendor, and whether programming the system became easier-things like changing the charge parameters for various use cases, getting automatic top balancing, not having glitches that shut the system down randomly...
It’s clear the solar industry is poorly adapted to the consumer/DIY market. It is caveat emptor and you have to get down into the mud and really learn this stuff to make it work for you, never mind work well. You also can't trust online forums for help (maybe this one is the rare exception). Lots of sites regurgitate the same material and some of it is dead wrong.
Newbies with Instagram dreams and a short attention span will struggle.
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