Now that I have my GPR-S back, with its new "MiniBMS" system, I can provide a few comments, based upon installing the system and riding around for a few miles, between rain storms.
For a BMS, the Mini seems like a good value. My cost for the 24-battery system that I have in my bike was around $350, including shipping. For someone like me, who has experience bolting together stuff, but little skills at wiring, the MiniBMS was a good selection. All you do is to fasten the individual boards to the top of each battery and connect a small wire between adjacent boards in a daisy chain. There is one small master board that connects and controls the system and it is easy to wire up by following the detailed. down-loadable, instructions on CleanPowerAuto's web site.
I recommend that anyone wanting to buy the MiniBMS read the installation instructions on Clean Power's website to verify that it will do what you want it to before purchase. The system is simple, but may not be as sophisticated a system as you might need or want.
One recommendation that I have is to purchase an extra BMS board, as it is easy to blow one up when hooking up the last power wire and BMS board. I managed to do that when my hand shook as I was trying to hold the power cord to the battery terminal, while also connecting the BMS and two other wires on to the same terminal. I momentarily disconnected the power cord from the battey terminal, causing a spark, which toasted the battery's BMS board and required my to purchase a new one (which results in a flat $20 shipping fee - which is why you should buy an extra board). BTW, the installation instructions tell you to be very careful when connecting that last power wire.
In operation, the MiniBMS performs a little different than did the Modus BMS that was originally on my bike and that failed. Some of this may be because some of the batteries in my pack are tired and not holding up their end of the program. Immediately after returning from a ride, the charging will only occur when the ignition is on and left on (which you should not do). If you turn off the ignition switch, the charging stops. I believe that is because at least one battery somewhere has sagged below 2.5 volts, causing the BMS to prevent charging. After about 30 minutes (about the time it would take to remove the bodywork and find the offending battery), the offending battery must have recovered and charging will start.
To initiate the charging process, you must first turn on the ignition, turn it off and then plug in the charger's cord. At that time it will commence charging. Oddly, the charging rate is higher than it used to be. The charger's power consumption during bulk charge used to be 7.5 amps, but now seems to be just over 8 amps. Also, the charger bulk charges until one battery reaches 3.6 volts, at which time the charger receives a hard cut-off. With the original factory BMS, it would start turning on and off, at 1.5 amps, until the pack was balanced. It no longer does that. Once it is off, the charger will not come back on, even when the voltage drops in the pack. In order to get it to charge further, you need to disconnect the power cord, turn on the ignition, turn it off, plug in the power cord and it will commence charging again, but typically only for a short time, before it shuts off again. No doubt this is caused by one or more of my batteries having a faster voltage rise than the others.
Each board has a small green LED that lets you know that the board is receiving voltage from the battery. If the voltage on a single cell goes too high or too low, a red LED will come on. When the voltage on the cell returns to the specified range, the red light will go out. However, sometimes one of my cells will drop below 2.5 volts when riding and then all of the lights will go completely off and that seems to cause the problem with the starting of the charging system. After the adjacent cells bring it back up to 2.5 volts the green light will come back on and charging will start again.
Right now, it looks like I can get about 15 Ah out of my pack before at least one cell gives up.
The MiniBMS does perform a level of cell balancing, but the process seems rather slow, compared with the Modus system when it was working properly.
All in all, I am happy with the MiniBMS system, mostly because it is cheap, easy to install, will fit just about any prismatic battery size and if something goes wrong, it is easy and cheap to replace the offending part, rather than having to replace the entire system. However, it does just provide a basic LVC/HVC and some cell balancing, but not much else. It seems to work for me, but you might want more.
