dwl said:
...For the US market, where you are now covered by 8 year warranties, there is probably not too much interest in measuring capacity when Nissan provide bars on the dash which they seem to accept as enough evidence for replacement...
Nissan's policy is quite beneficial to
Nissan, and also to those LEAF owners who lose enough capacity bars to get replacement packs under warranty.
The far larger (?) number of American "30 kWh" pack owners who may find themselves in the same position as so many "24 kWH' LEAF owners (including myself) do today who were not lucky enough to receive warranty replacement packs, and whose only option is to exchange their OE packs under the unsatisfactory terms dictated by Nissan, may not be so satisfied when they face similar circumstances...
dwl said:
...Thanks for the extra links and I have seen the detailed tests on the 2013 Leafs before - it is a pity they weren't repeated for the 30kWh....
With no explanation for the abrupt termination of the AVTA testing program, this appears to be yet another victim of the current war on reality.
This is particularly unfortunate for BEV drivers, since BEV manufactures have managed to avoid many of the standards and accountability mechanisms that government agencies world-wide have established and enforced for ICEV manufacturers.
Without any independent review, BEV manufactures now can specify any BEV pack's "kWh" at essentially whatever they want to, within the uncertainty range of the customer's limited ability to determine.
And the manufactures themselves provide the less-than-fully -detailed EPA test results, the only information on pack capacity available to the public.
It is quite clear to me that my major complaint RE my own 2011 pack is not loss of capacity, which apparently has not occurred more rapidly than Nissan disclosed, but that my pack had significantly less than "24 kW" at delivery, as also appears to have been the case for every 2011-12 LEAF pack subject to testing by the AVTA.
dwl said:
...On the issue of temperature, the report at
https://avt.inl.gov/sites/default/files/pdf/fsev/2013NissanLeafElectricChargingReport.pdf suggests only a few percent difference in capacity as the temperature varies significantly which is a surprise to me. Maybe
there was battery heating which could explain the difference between the graph and table.
Exactly.
As the graph shows, it actually takes only slightly more energy from the grid to charge a hot LEAF battery pack than a cold one, even though a hot pack provide much greater energy when discharged.
Due to higher efficiency on charge
and discharge, you get significantly more of that grid kWh capacity available for traction and other on-road use, due to the higher
efficiency (a misnomer) of a hot pack over the entire
grid-to-road cycle.
How is this reality reflected in EPA tests submitted by BEV manufactures?
Are passively heated packs like the LEAF required to be tested at some standard temperatures, or can manufactures use ideal (HOT) conditions?
Are actively managed packs tested, the same standard temperatures, or their own optimum efficiency within their temperature control programs?
In testing packs with active thermal management, is the energy used in pre/post conditioning, the heating and/or cooling energy used
outside the test cycles accounted for?
I have no idea.