So I got tired of you guys thinking that Leaf is not charging battery correctly.
So I did something.
My battery is OEM Nissan-Renault 12V 50Ah battery, manufactured in the first half of 2014.
While it was at 13V float charge I disconnected EVSE.
Switched on full-beams , front fogs, rear fog, standing lights. Got a draw of 19.8A (should be 2x60W, 2x35W, 1x21W, 4x6W). Discharged my
50Ah battery SOC by 20% just be keeping that load for 30 minutes.
Average voltage during 30 minute draw was 11.5V. That means around 10Ah discharge, 115Wh
Stopped the discharge. Car started to fall asleep. Draw was getting down below 1A.
After waiting for only 2 minutes voltage got up to 12.1V. It would most likely get to 12.2V easily.
That means battery was above 50% SOC, more likely 60% after 20% (10Ah out of 50Ah theoretical) discharge.
Old battery is very likely below rated 50Ah and temperature was 7C - so definitely below 50Ah.
And now comes exactly what I expected.
I connected EVSE back.
Voltage spiked to 14.43-14.47V. Ammeter measured charge above 70Amps for few seconds.
Dropping down to 50Amps. Average charge was around 45Amps during the first minute.
Then 40Amps during the second. 37, 35, 32, 29, 26, 24, 23, 21 during 10th minute, 10.4Amps 20th, 4,9Amps 30th, 1,5-2,0Amps 40th.
During the whole charging process voltage was absolutely steady at 14.42-14.45V. I did measure every minute.
While charging rate was between 1-2A it switched to 13V mode.
Using Excel and video I took I got down to this:
During 40 minute charge cycle 9.27Ah of juice went in. At 14.4V it is 133Wh
. Process is 85-90% efficient.Leaf WILL charge the battery if BATTERY takes the charge.
I will test something else soon. I will trick the current sensor with halogen
bulb. I want to verify that switching to 13V mode happens as soon as charge rate at 14.4V drops below 1,3-1,8A, something like that.
I did notice that right after switching back to 13V mode and longer charge time there was a draw from the battery even after Leaf fell asleep (-0,4A)
This is expected as voltage after charging is always above resting voltage for a period of time.
Resting voltage should drop below 13V after like 10 minutes maybe.
Also I noticed that electrolyte was bubbling at very slow rate when battery was charging at 14.4V. This is normal but not recommended on daily basis due to loss of water.
Also we can conclude that SOC definitely stays above 70% during Leafs everyday use. Most likely it is at 80%. Which is not FULL state of charge but not low enough for sulfation to happen within few years.
Like I already mentioned, BMW-s keep their AGM battery charged specifically at 80% to have regen available on demand (3,5kW regen only).
Those batteries last for 5-7 years of heavy use. There is nothing wrong with keeping Lead acid batteries slightly discharged. Like I mentioned in another topic APC UPS's keep their battery at constant 13.5V. This kills the battery (99% guarantee) during 1-2 years of use. I've replaced them multiple times, always the same - ran out of electrolyte.
Therefore there is NOTHING wrong with Leaf charging the battery. It is designed not to charge it to 100%. And there is nothing wrong with that. Charging it to so-called 100% is stressing electrolyte and is not efficient (most likely there are additional losses). If there is a failure it is either because of battery internal defect or unplanned parasitic load. Leaf will charge the battery if it has been drained but will NOT set off an error code like 2005+ BMW-s do.
Therefore if there is a problem it will definitely kill the battery and then the user might do something (if vehicle is out of warranty, otherwise "don't care" policy)
Also Leaf keeps 12V battery at 13V voltage for hours and hours every day during vehicle lifetime! This is like keeping it trickle charging for years. Most Leafs are used daily. Older type Leafs that are used rarely might have problems as recharging happens only after 5 days while draw is more than on average ICE vehicle due to telematics.
Now we need to measure draw during sleep with 0.01A precision (clamp will not do it) 5 minutes after falling asleep and 12 hours after that to be sure (without any disconnections or touching any buttons). Please. Anybody besides me