This post is going to deviate a little bit from my typically long-winded format and present a list of observations and measurements so far.  In short, I’m very pleased:

• The charger charges at a constant rate until it reaches the upper voltage shutoff
• After shutting off the charger, voltage drops by less than 0.2V  (in 48) over the next several hours with no load.  This suggests that the surface charge effect is small.
• When the charger is on, there’s no immediate spike in battery voltage.  Turning the charger on/off only influences the voltage by about 0.1V, meaning that even if it is on, we can still use voltage as an indicator of state of charge.
• At each of several measurements, all cell voltages stayed within 0.01V of each other.
• The self-discharge rate is (for all practical purposes) zero.  After 2.5 months in storage, the voltage was unchanged.
• Charging or discharging a 4kW module at 1500W results in no noticeable heating of the battery pack, cables, or connectors.

Coming soon (not necessarily in this order):

• Overall system objectives
• Discussion of battery management/monitoring systems
• High and low voltage disconnects
• Over- and under-temperature disconnects