Solutions to 12 Volt Batteries and Chargers Posted Here

[lorenfb]

Try turning "on" the wipers while monitoring the battery voltage. This is one of the undiscovered charging
modes that the Leaf enters into, i.e. mentioned up-thread that anecdotal data takers failed to find,
where it charges greater than 14 volts. What other modes exist in the Leaf's charging algorithm that have
been overlooked where the Leaf charges greater than the 13 volts normally observed?

[LeftieBiker]

Try turning "on" the wipers while monitoring the battery voltage. This is one of the undiscovered charging
modes that the Leaf enters into, i.e. mentioned up-thread that anecdotal data takers failed to find,
where it charges greater than 14 volts. What other modes exist in the Leaf's charging algorithm that have
been overlooked where the Leaf charges greater than the 13 volts normally observed?

There may well be others, but when you stop the car and the battery is 2+ AH down from full, the car isn't adequately charging the accessory battery.

How about a little input from others who use battery maintainers? How often does the maintainer go into full charge mode (usually a solid red light) when you connect it, how often into finish charge mode (flashing green or solid yellow) and how often do you connect the battery and it's either green (float) immediately, or within a minute or so?

[Marktm]

How about a little input from others who use battery maintainers? How often does the maintainer go into full charge mode (usually a solid red light) when you connect it, how often into finish charge mode (flashing green or solid yellow) and how often do you connect the battery and it's either green (float) immediately, or within a minute or so?

I have left my battery charging on two - 1 amp chargers for over 24 hours and the red light was still on - and both were very warm. I was actually surprised as I was expecting them both to go to "maintenance" (flashing green, no red) in about 1/2 that time based on the battery size (~40 AH?) and estimated SOC (from settled voltage curve). The charge voltage was 13.5 +, but I had no way of determining if the Leaf had any substantial drain during this charging - should have disconnected it.

[BrockWI]

Before I swapped out my 12v battery I would charge every Friday night with a Deltran battery tender charging at 1.25 amps and rarely would it be blinking green (absorb) in the morning 8 hours after the start, often it would take 12+ hours to get to float. Sometimes I would charge mid week as well and then it was usually about 4-5 hours to absorb.

Now that I have swapped the stock 51R for a slightly larger 34N I still top it off every Friday but usually it starts absorbing in 10 to 15 minutes and floating in less than hour.

My theory is the Leaf charging pattern drops in to float way to soon for a smaller or weak battery, which also would explain why some people have no problem if they started with a "good" battery. But even if that is the case I agree that the Leaf under charges or defect charges the aux battery in some cases.

[lorenfb]

The charge voltage was 13.5 +, but I had no way of determining if the Leaf had any substantial drain during this charging - should have disconnected it.

Right, one always needs to first check the standby current (drain) to be assured that there's no parasitic drain
(> 50 - 80 ma), e.g. the result of an ECU (controller) failing to enter its sleep mode. This is a very very common
problem with present day automotive electronics and its CAN bus technology that results in dead 12 volt
batteries. In some vehicles, it may take as long as ten minutes for all ECUs to enter their sleep mode,
thereby draining the battery with the vehicle being off. Remember, when you press the On/Off button
on the Leaf, the 12 volt battery power consumption isn't zero as was the case with non-electronically
controlled vehicles of the past.

[erichz]

Well, my 12v battery died again unexpectedly. I've now taken it to the dealership for testing to see if there's a slow drain somewhere, or (more likely) the battery itself is just not being charged sufficiently on shorter trips.

[Marktm]

Well, my 12v battery died again unexpectedly. I've now taken it to the dealership for testing to see if there's a slow drain somewhere, or (more likely) the battery itself is just not being charged sufficiently on shorter trips.

Lost track - Is this the same battery that originally failed, or a replacement? If nothing is wrong with your Leaf's 12 volt system, I'd guess you have a bad cell in your battery - which should show up in the dealer's load test equipment.

[erichz]

This is my original 12volt battery. They've actually had it for a couple days now, which worries me.

[erichz]

Got the car back from the dealer with no resolution. Their tests turned up no problems with either the 12v or a parasitic drain after 4 days of looking.

[Marktm]

Got the car back from the dealer with no resolution. Their tests turned up no problems with either the 12v or a parasitic drain after 4 days of looking.

Might want to take it to a trusted mechanic that has a battery load tester and explain what has happened. See if the battery is definitely OK.