Let me start by stating that I now realize that my old current measurements were not applicable to this case. The reason is that I had forgotten to remove the ELM327 during the entirety of recent testing. So this morning I measured the current draw of the LEAF with it plugged in: 175 mA. That is 10X the quiescent draw of the LEAF without the ELM327 plugged in! On other words, our ELM327 devices have contributed to further 12V battery degradation beyond what the Nissan charger design already achieves.
But does that invalidate my belief that our LEAF's 12V battery is badly sulfated? Not at all. At 175 mA load, the battery should be depleted less than 5% of the nameplate capacity of 55 mAh overnight. Still, I have removed the ELM327 for now to reduce the overnight load.
RegGuheert wrote:O.K. I charged our LEAF's 12V battery at 15.9V for a bit over three hours this morning. It bubbled steadily during that time. After standing for about one hour, the voltage is now at 13.0V. We'll see how the voltage holds up over the next few days, as I do not think we will be driving the LEAF until at least Saturday.
I measured the voltage this morning after 19 hours of sitting (with the ELM327 still in place): 12.40V. That is a marked improvement over the tests I did last week since a higher voltage, and thus, a higher SOC, was achieved after sitting 1.5 times as long. This result represents about a 10% improvement in capacity, which is about what I would expect given that the high voltage charges have only put a total of about 6 Ah of charge into the battery. Several more of these sessions will be required to eliminated all of the remaining sulfate. I just started another desulfation charge this morning.
(BTW, I am convinced that yesterday's reading of 12.70V was erroneous. Likely the charger had just finished a charge not long before my reading. Now I am removing it altogether to prevent similar occurrences.)
Also for those with the little caps on the battery (I think '11-'12s only): CHECK YOUR WATER LEVEL!!! (I'm sure Reg has already done so
Absolutely! And our LEAF's battery's cells' fluid levels are each just slightly above the upper "FULL" line, just as they have been since we bought it. The bottom line: the LEAF's charger stays so far away from a full charge that it does not seem to electrolyze ANY of the water in the battery. As a result, it is likely that no LEAF batteries will fail from a loss of water, but that most will fail prematurely due to sulfation.
One thing I love about this battery is that the case is translucent so you can easily check the battery fluid levels without removing the caps. Simply hold a stubby flashlight behind the battery and shine it below the water level. The level can then easily be seen.
thew wrote:The car had sat long enough for the EVSE to run the Battery down.
Just for reference, all of the testing I have done to date has been with the EVSE unplugged. I believe that gives me the lowest current draw.