Sounds like a bad controller or maybe you're actually looking at the wrong thing... If you're looking at the voltage in the settings page, that's not actually monitoring battery voltage; that's just telling the controller what battery you're using. This is the "nominal" battery voltage and doesn't change (unless you change the setting). The ACTUAL battery voltage can be monitored on the display screen in place of the odometer, which is what the display defaults to when you first power up the bike. (Short presses of the on-off button is how to change what's displayed there).
If, on the other hand, you were actually looking at the voltage MONITOR (get to that with short presses of the same button used to turn on the bike) and it wasn't changing as you ride then the controller is likely bad.
Did you try monitoring current, time, or trip odometer (the other display options that replace ODO with short presses of the on-off button)? Did they all display correctly?
Actually, the energy bars at the top of the display screen are just displaying battery voltage - each bar corresponds to a specific voltages - from 1 bar = 40v to 10 bars = 49v. (If you want the actual voltages, see my post "XP Display Hack" in another thread). A fully-charged 48v battery will be over 50-51v, so you'll ride for a good while before the voltage goes below 48v and the highest bar extinguishes. And since the low-voltage cut-off is 40v, the bike will shut down before the lowest bar extinguishes. Knowing this I rarely look at the voltage monitor; I normally monitor the current - that way I can see both voltage (energy bars) and current on the same screen.
Hope this helps
-Bud
