lorenfb said:A necessary diagnostic tool for those Leaf lead-acid battery "analytical researchers".
Harbor Freight has a digital meter which measures the impedance of your battery for $80: Digital Battery Analyzer. I don't have one, but the reviews are decent. It doesn't put a large load on the battery, but rather it measures impedance using a smaller load and a four-wire measurement technique. This should be fine for the LEAF since it typically does not have a large load on it.QueenBee said:Anyone have any recommendations on a digital version of this for personal use?
I would expect a reading at least that high with a battery even seven years old in your climate (or mine).QueenBee said:I tried to measure the health of my battery by fulling charging it and then disconnecting it but it's very hard to go more than 12 hours and after just 12 hours between 60 and 50 degrees it was still at 12.72 volts which I believe is higher than expected for a 4 year old battery, correct?
Yes. I measure ~64VAC from neutral or ground to either battery terminal of my BatteryMinder 1500. But both of my maintenance battery chargers are fully isolated between the AC input and the DC output. I expect the AC is due to the small capacitance of the transformer inducing the AC waveform on the outputs due to the extremely high impedance it sees. I don't think there is anything to worry about.QueenBee said:So random question. Doesn't anyone else measure about 50 volts AC between either terminal of their battery tender and their buildings ground/neutral?
Agreed. That is my main grievance. I have no other vehicle which does not return home with the 12V battery fully charged.QueenBee said:To try to clarify my previous point of why I think there are two related problems with LEAF charging. The issue being discussed at depth here is that when the DC->DC converter is on it's not using a charging algorithm which optimally charges the battery for highest longevity. The outcome of this being that someone who never experiences a dead battery will have a shorter battery life than is possible.
Also agreed. This is more of a nice-to-have that EVs can offer because they have a zero-emissions on-board energy source.QueenBee said:Then I think the second problem is that for whatever various reasons the algorithm which decides when to automatically come to life and charge the 12v battery does not achieve the requirement of not letting the 12 volt battery go dead. Even with the first problem this automatic process could and IMO should still keep the battery at the under charged state, not letting it ever go completely dead. As has been reported in many other threads this is not always the case. So LEAF owners who leave the car parked under various specific sets of conditions come back to find the 12v dead.
And this is a third issue being discussed in this thread, as there appears to be a firmware bug in the MY2013s and beyond which causes a load to be left on sometimes, draining the battery. If Nissan has a fix, that is great news!QueenBee said:I don't think I have seen it mentioned but one resolution to this problem is there is a NTSB for I believe applie io just 2013s experiencing 12v battery issues with the remedy being a software update. Sorry I don't have this handy.
Which is why I postulate the algorithm it uses disregards voltage.RegGuheert said:...I guess it didn't think 12.40V was low enough or the fact that the battery hasn't been fully charged in two weeks was sufficient reason to warrant any further charging. :roll:
I agree it seems to be using an algorithm which is designed to replace some % of net charge lost (while ignoring the three important facts about 12V battery charging mentioned in my post above in response to QueenBee).TimLee said:Which is why I postulate the algorithm it uses disregards voltage.
Primarily looks at net current drain since the last time it applied 14.5 volts.
That would be an interesting test! I may try that someday, but not before I continue my daily monitoring test to try to see if it ever decides to charge the battery up to full as a matter of course. In my previous test two years ago, it never did in three weeks of monitoring. But this time around, I KNOW my battery can hold the charge if it decides to do it.TimLee said:Would be an interesting test to fully charge the 12V battery, then disconnect it from the LEAF, substantially discharge it with external load, hook it back up, start the LEAF charging, and monitor what the DC to DC voltage and current flow to the 12V does.
Most modern chargers hold the voltage at 14.5V UNTIL the current drops below a certain level. Unfortunately, I doubt the LEAF's current monitors can resolve current below about 1A (or perhaps 0.5A). Does anyone know the resolution of this measurement in the LEAF when measuring low currents? If the resolution is really 1A, then it may simply decide "Since the current is now below 1A I cannot measure any further change, so I'm dropping into float."TimLee said:The LEAF 12V charging may be a combination of net current it has monitored (which in this case would be zero, no monitored loss), and the current flow it observes when it applies 14.5 V.
RegGuheert said:Yes. I measure ~64VAC from neutral or ground to either battery terminal of my BatteryMinder 1500. But both of my maintenance battery chargers are fully isolated between the AC input and the DC output. I expect the AC is due to the small capacitance of the transformer inducing the AC waveform on the outputs due to the extremely high impedance it sees. I don't think there is anything to worry about.QueenBee said:So random question. Doesn't anyone else measure about 50 volts AC between either terminal of their battery tender and their buildings ground/neutral?
Oh! I was wondering why you measured that.QueenBee said:I noticed because my I felt tingling between my knee and license plate while using my battery minder 12248.
Well, the signal is definitely there. While the DC impedance is certainly very high on my unit, it sounds like the AC impedance may be quite a bit lower.QueenBee said:Tested a friends batterytender brand and saw the same thing. Probably rare that anyone else would ever experience this as I was barefoot, wearing shorts, and have an all metal bracket for the plate that mounts to the tow hook. You also have to just barely touch it so the current is concentrated to just a little bit of sensitive skin. Thanks for confirming that mine isn't defective.
RegGuheert said:12.87V>12.78V>12.71V>12.64V>2C4D>1C2D>12.57V>1C5D>12.44V>12.47V>12.44V
Wednesday's voltage was 12.44V: It's back down to what it was on Monday when I had the ELM-327 plugged in.That might be interesting, although I do not tend to keep the LEAF plugged in. I disabled the timers about a year ago and we simply plug it in when we want to charge.69800 said:buy the way may wife is going on vacation so the leaf will be parked for 4 days. Do you want me to record anything specific? I was thinking about 5 min interval for 4 days while plugged in.I'd be most interested in seeing a 24-hour (or less) plot with the samples at 10-second intervals including at least one charge and one driving cycle. Thanks!69800 said:What would you like to see?
Thanks!69800 said:you got it. I will do it this week
69800 said:Here is a one day charge profile. True absorbsion charging takes place at 14.3 volts and float voltage of 13.1 volt only hold the charge where it currently is at. In one day using a 10 second recording interval the 12v battery got a grand total of 120 seconds of charging at 14.3v
Yes, we can. It doesn't matter what the current is. Lead-acid batteries CANNOT absorb the charge instantly due to the thickness of the material on the plates. If you do not dwell at the absorption voltage for many hours, there will be lead sulfate which does not get recharged back into lead and sulfuric acid. What you get with a brief absorption phase as is done in the LEAF is known as a surface charge.Nubo said:We can't draw any conclusions on whether that absorption charge was adequate, since the amperage is unknown.69800 said:Here is a one day charge profile. True absorbsion charging takes place at 14.3 volts and float voltage of 13.1 volt only hold the charge where it currently is at. In one day using a 10 second recording interval the 12v battery got a grand total of 120 seconds of charging at 14.3v
Nubo said:69800 said:Here is a one day charge profile. True absorbsion charging takes place at 14.3 volts and float voltage of 13.1 volt only hold the charge where it currently is at. In one day using a 10 second recording interval the 12v battery got a grand total of 120 seconds of charging at 14.3v
We can't draw any conclusions on whether that absorption charge was adequate, since the amperage is unknown.
It really doesn't, not to full. (And if it IS putting in ~10W, then the battery is nowhere near full. If the LEAF OEM battery is close to full, the power flow at 13.1V will be significantly less than 1W.) In the case of OP's battery, 13.1V is LOWER than the resting voltage of the fully-charged battery, which was measured to be 13.3V.QueenBee said:Does putting in roughly 10 watts of power at 13.1 volts into the battery really not charge it?
RegGuheert said:It really doesn't, not to full. (And if it IS putting in ~10W, then the battery is nowhere near full. If the LEAF OEM battery is close to full, the power flow at 13.1V will be significantly less than 1W.) In the case of OP's battery, 13.1V is LOWER than the resting voltage of the fully-charged battery, which was measured to be 13.3V.QueenBee said:Does putting in roughly 10 watts of power at 13.1 volts into the battery really not charge it?
But even in the case of the LEAF OEM battery which has a resting voltage of 12.9V or lower when fully charged, the battery will NOT charge to full at 13.1V. (It will charge up to about 70% or perhaps a bit more if it is below that level.)
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