On Aug 9, 2006, at 11:57 AM, Kenneth Waller wrote: >> What would you expect to see in a car of similar age with lower >> mileage? > > I don't know, that's why I posted the question. Maybe someone more > knowledgeable in battery technology might have a feel for the > effects of a > high mileage vehicle's battery condition vs a similarly old vehicle > with > relatively low mileage. I'm thinking of the possible effects of many > charging cycles vs a lot less.
You should hunt around the rest of John's website ... there are pages and links to a lot of technical information about the drive system. It's pointed out in other technical references to the Synergy Drive System that the design of the system is prioritized to preserve and benefit the battery to the greatest extent possible, as well as to mask aging issues. The control system monitors battery state, prevents as much as possible high drain as well as low charge conditions, and balances power generation using the ICE to supply current for the needs of the drive system as well as other accessories to accomplish this. The drive system is not designed to operate on battery alone: it is a relatively small capacity battery relative to a full electric car's design and can power the drive system for only a short period (up to a mile or so) before being fully depleted. The ICE and power generation control is essential to operation for anything other than limited uses. As the drive battery ages and capacity/current delivery is diminished, the control system takes this into account and uses more power generation using the ICE to compensate for the battery degradation. A battery with 10,000 charge/recharge cycles on it, even though it has (theoretically) perhaps only 80% of its original capacity and current delivery capability, should be capable of powering the car with very little to no noticeable difference in operation. The differences would show up ultimately, as the battery capacity continues to diminish, as increased fuel consumption as the ICE would be delivering more power generation required for operation of the electric drive motors. Given the sophistication of the control system at masking normal degradation of the battery over many cycles like this, I suspect that it would be difficult to see any difference between how John's car operates with its very high mileage/many cycles battery vs a much lower mileage example. You'd likely have to do diagnostics on the battery itself to see much difference, or higher resolution monitoring of the fuel economy. John provides the available data from his car on other pages on his site, as do some other users, so perhaps collating and comparing them would bear this out. I imagine that the limit of use is when the battery's capacity and current delivery drops below the threshold that will run the system without undue strain on the other components or produces severely reduced initial acceleration (since the battery and electric drive motors are the primary power source for starting from rest, the engine is geared too high to supply adequate torque at starting speeds). fun stuff. I'm enjoying learning about this car immensely. Just a few more days and I'll be driving mine ... then I can tell you from a practical standpoint of use what I think about it. ;-) Godfrey -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
