ChrisJConklin
New member
- Joined
- Mar 30, 2012
- Messages
- 3
A whole lot of interesting discussion on this forum regarding the dealer stated and expected degradation of the LEAF battery system with time. I see a general expectation of a degradation to 80% of initially rated capacity in 5 years, further degrading to 70% after 10 years...though certainly driving style and charging protocols amongst other things mean "your results may vary"...
I'm interested in the issue because I am collecting data on my 3 month old LEAF electrical power consumption (L2 home charging system, with individual TED charging circuit monitoring), with the intent of upgrading my home solar PV system to zero out my net energy use again (the LEAF has pushed us from a net generator to a net consumer....). With the price of power in Hawaii now $ 0.35 per KwH for a typical residential user on a 7% annual inflation curve, getting it right before doing the upgrade is important.
My key question, for those battery experts out there, is whether I can expect the efficiency of the battery to degrade over the years of operation - or just the battery capacity. Since our short commute doesn't make the expected degradation in battery capacity (e.g. range on a single charge) a major issue, what about efficiency? Can I expect the wall-to-wheels efficiency (currently about 4.00 M/KwH after some short use data) to degrade with time, even at a lesser rate? Some say no, but it seems that as a battery's capacity to carry power gets reduced over time, it's ability to receive that power and to convert it to mechanical power would be less than when it is brand new. Would the CARWINGs reported ratio (which is of course higher than the "wall to wheels" number because of losses with charging...), degrade, reflecting the ability of the battery convert electrical energy to mechanical power? Even if it didn't, would the Walls to Wheels efficiency degrade, reflected that the battery pack is less efficient in accepting a charge, as well as less capable of getting the full KwH of charge in comparison to a new one?
My gut tells me that I would see some degradation in the WtoW efficiency, but that it would be very unlikely to be as a high as a 30% less over 10 years. But that is not based on any real battery engineering based assessment......
thanks,
chris conklin
Honolulu
I'm interested in the issue because I am collecting data on my 3 month old LEAF electrical power consumption (L2 home charging system, with individual TED charging circuit monitoring), with the intent of upgrading my home solar PV system to zero out my net energy use again (the LEAF has pushed us from a net generator to a net consumer....). With the price of power in Hawaii now $ 0.35 per KwH for a typical residential user on a 7% annual inflation curve, getting it right before doing the upgrade is important.
My key question, for those battery experts out there, is whether I can expect the efficiency of the battery to degrade over the years of operation - or just the battery capacity. Since our short commute doesn't make the expected degradation in battery capacity (e.g. range on a single charge) a major issue, what about efficiency? Can I expect the wall-to-wheels efficiency (currently about 4.00 M/KwH after some short use data) to degrade with time, even at a lesser rate? Some say no, but it seems that as a battery's capacity to carry power gets reduced over time, it's ability to receive that power and to convert it to mechanical power would be less than when it is brand new. Would the CARWINGs reported ratio (which is of course higher than the "wall to wheels" number because of losses with charging...), degrade, reflecting the ability of the battery convert electrical energy to mechanical power? Even if it didn't, would the Walls to Wheels efficiency degrade, reflected that the battery pack is less efficient in accepting a charge, as well as less capable of getting the full KwH of charge in comparison to a new one?
My gut tells me that I would see some degradation in the WtoW efficiency, but that it would be very unlikely to be as a high as a 30% less over 10 years. But that is not based on any real battery engineering based assessment......
thanks,
chris conklin
Honolulu