Flooded Battery EV System Overview
(Proposed Charger Operation / New Module Interface)
Initiated 11/5/08
After reviewing the system in its present Gen1.5 configuration, its possible to add an Interface Module (IMod) to
sense the parameters (below) and offer Flooded Battery EV Systems (6V, 8V, 12V) to the list of Can-Do EV
hardware!

The new IMod would interface to the Charge Detector, Charger and Controller. It would contain:

Maximum Pack voltage setpoint (voltage setpoint at a given ambient temperature - user adjustable)
Temperature compensation probe (placed inside the battery box or compartment)
Minimum Pack voltage setpoint (to cut back the controller power level - user adjustable)

The Charge Detector (CD) would operate in a similar fashion as before, that is, bulk charging up to when the
Maximum Pack voltage setpoint on the new IMod is reached. The CD would then sense the charging current while
reducing available current, and cycle between charge reduction and bulk charge until the pack was steadily above
the Max Pack setpoint on the IMod. Above the Max Pack setpoint, (<1V) the IMod would stay in charge reduction
mode on the CD. If the voltage continues to rise and exceed the Max Pack setpoint > 1V, the IMod will enable float
mode on the Charger and take a rest for ~10 sec, then restart in current reduction mode on the CD. If the pack
voltage again exceeds the Max Pack setpoint by 1V, it will switch to float mode again and continue to cycle between
those 2 modes until the charger is unplugged. This should sufficiently charge the flooded pack by cycling between
current reduction and float modes without expending too much gas from the cells. Likely LED indicators will be
present to indicate what the IMod is doing. The user adjustments would be trim-able to make any final adjustments to
the charging system, so that the correct setpoints will prevent overcharging / overdischarging the pack. Also note
that the 1V is arbitrary at this point, and may become user configured if need be.

This system would also eliminate individual battery monitors, offering a system cost savings. There will still be a risk
of reversing individual batteries even though the Min pack setpoint is configured above 5.4V (for 6V) or 7.2V (for 8V)
or 10.8V (for 12V) x the number of batteries (set by user). Individual monitoring is difficult to do considering the harsh
environment, but a tiny sealed LVP board for individual battery monitoring may be offered at a low cost (if desired -
TBD - to be developed).

Questions? Comments? Other considerations? Feel free to email me.