I'm still getting a reading of "empty" on my throttle, but I'm getting a full 40V out of the 36V battery. After a 14 mile ride (with a bit of peddling) the charge still read 38V so, that's good. If I measure the charge going to the throttle, what should it read?
Bart, it sounds as if you may have been supplied with a 48V throttle control instead of the 36V one. A 48V battery gauge would show empty @ 40V, because your 40V reading is similar to the voltage of a fully discharged 48V pack.
The lead that powers the battery gauge unit on the throttle read the same as your battery voltage.
The 40V you now have is considerably higher than the 29.1V your pack was producing, what was causing the initial low voltage problem, was it the battery, the charger, or something else?
With the 36V battery, 38V = 3.8V per cell, if you look at the following diagram you should be able to see that your pack is nearly 95% discharged at the end of your 14 mile ride.
Your battery should still be nearer to 42V if all the cells are fully charged and evenly balanced.
Nice video by the way.
Alan