This chart lists three stages or conditions of the life cycle of the Optima battery pack in the Corbin Sparrow I electric car. These batteries are currently either Optima Blue Top or Yellow Top deep cycle 12 volt batteries.

The columns list:

• The Stage - where this pack is in the three stage life cycle
• Characteristics/measurements to determine if your pack is in that stage
• Behavior of the pack in that stage - what you can expect from it
• Information about how the pack arrived at this stage and what you can do to to keep your pack from moving to the next stage.

This is draft 1 - not final by any means!

	Stage of life	Characteristics/Measurements	Behavior and Expectations	Causes, Maximizing Life
	Stage 1	Full range available. Batteries balanced in capacity to within 2 amp hours.	This pack can always be successfully charged by the Zivan if it is equipped with the thermal probe. The Zivan should move through it's cycle, equalize, and you should end up with the charger off and a green LED on it. Since the capacities of the batteries are within 2 AMP hours of each other, the one hour equalization charge at 2 amps provided by the Zivan should always result in a reasonably equal pack. Voltage after "surface charge" has dissipated should be around 171 volts. No venting is heard during or after charging.	You don't have to do anything special to maintain a Stage 1 pack, however, anything you can do to KEEP it in Stage 1 longer (desulfation, regulation, equalization) is probably good preventive maintenance. This is how your pack should arrive from the factory. The Sparrow manual and Corbin Motors website both have information about battery care, and specific instructions about how to avoid damage and extend the life of the pack. The Sparrow EV Group is also a great resource, and is the source of much of the information in the Sparrow Battery Care Chart (thanks to all!). Be especially careful to avoid the most common causes for damage to your new battery pack, which are listed below. Problem references: Deep Discharges Batteries Too Hot
	Stage 2	Pack capacity may vary by MORE than 2 AMP hours, BUT no cells appear to be dead (dried out or shorted).	Rest voltage of batteries varies by more than .2 volts. During charge, voltage may vary between batteries by more than a volt. Some cells may vent near the end of the charge or during equalization. Range on the pack may be slightly down, like 5-10%. The Zivan can charge and equalize this pack under certain conditions. Recharging after deep discharge may not result in full equalization. Multiple equalization cycles may be required to fully charge the pack.	This pack can probably be greatly helped by equalizers. If the venting can be stopped by controlling the tendency to overcharge specific batteries, they will last longer. Some charging techniques, such as skipping one or two equalizations (when the car is recharged from shallow discharges) may reduce venting and extend life. Motivated, technical folks may want to manually equalize the pack with slow chargers periodically to pick up where the Zivan left off. Problem references: Unequalized Pack Sulfation Venting Get a piggy bank and start saving for the next Stage...
	Stage 3	One or more cells is "dead" (dried out or shorted)	Behavior: battery voltage may vary under light load (like the heater) by one volt or more, range is severely reduced, Zivan may never enter equalization phase (watch out for this! It just keeps forcing full power into the pack!), standing voltage a few hours after a charge may fall to 165 volts or lower, batteries may vent while charging (but they may be too dry to vent, so it will not necessarily happen).	Time for action. This pack cannot be properly charged or equalized by the Zivan, and even with help (equalizers, regulators, etc) the range cannot be increased. It is time to make a decision: Replace just the batteries with the failed cells Replace the pack Keep in mind that replacing individual batteries may move a pack from Stage 3 (some cells dead) to Stage 2 (more than 2 Amp hours of capacity difference in the pack). If the batteries failed VERY early, and you have no other problems with the pack, you just MIGHT get back to Stage 1 by replacing only some of the batteries. If you do a partial replacement, and your pack behaves like it is in Stage 2, you should consider replacing the rest of the pack or adopting Stage 2 preventive maintenance solutions aggressively. Problem references: Dried Out Cell Unequalized Pack Sulfation Venting Sudden Range Reduction Pack Worn Out

Other battery references, not specific to the Sparrow:

• Battery FAQ
• Battery Links

Disclaimer: It's just a personal web page! I do not work for Corbin Motors, Optima, or any of the manufacturers mentioned here. Apply the information contained in this chart at your own risk! PLEASE get second opinions before taking any action based on the contents of this chart.

If you think you have a different problem, or need clarification on anything presented here, or feel that anything is incorrect, please mail me: davidbuATwww.los-gatos.ca.us (use @ instead of AT, of course...).

Note: "Estimate" is typically another word for "Guess" ;-)

Thank You.