I always check the cell voltages before and after charging and before the ride. Any time there's an issue, I top all cells to within about .01v of each other. (They sit for a while after charging before I test them) For now, I think I'm fine riding without the cell monitor, but I am always checking draw, voltage, Ah used and such during the ride (Cycle Analyst)... Over the long term, cell monitors and a BMS... I am not going to sit here and look at a bike and wait for the rest of the stuff to arrive as I can afford it.
Had a few issues with the bike - strange noises from the rear, regen stopped working, needed to waterproof the connections and then a pedal fell off - turns out it was stripped. The bike got ripped apart again so I could fix it up.
The regen issue was clearly going to require pulling the controller apart as I had tested everything else and it passed. I had used Arctic Silver, a high quality CPU heatsink grease - bad choice. That stuff turns into cement over time. I ended up drilling out two of the bolts and then had to use a lot of force, removing a lot of skin from my knuckles in the process, breaking a few internal connections (throttle override, a ground wire and the on/off switch connections. I was going to have to open it again since I wasn't happy with my original modding effort.
I have an Infineon controller, so thankfully I figured out that I could use a Radio Shack diode, located where the original had been soldered onto the board, traced it back and found a pad labelled "SL" that I could solder the new diode through. Lots of good technical info on the controller online. Soldered the ground and power lead back onto the board, removed and resoldered a better jumper for the regen and mangled the rubber seal on on side. Finally got it back together and re-sealed it with Silicone.
The regen issue turned out to be a broken wire inside a connector, so *snip* *solder* and a little heatshrink tubing solved that one.
Connected the batteries, powered it up and it looks like I got it right.
The noise turned out to be some of the spokes had come completely undone. Screwed the caps back on, checked the true of the wheel and used a little loctite to ensure they never move again.
Replaced the front crankwheel with a Shimano kit I bought and now I'm nursing a sore finger and wishing I had never taken the front derailleur off. No matter what I do, I cannot make it work. Tried what they said in Youtube, but no luck. Thankfully the bike shops are open tomorrow, maybe I can go bribe someone to make it work for me.
It was a beautiful day here and I had hoped to get a 30mi ride in but that was just not in the cards.