Help diagnosing dead 12v (as opposed to some other problem) SOLVED

[hradek]

I'm sorry, but overcharging is just about the last thing a Leaf accessory battery experiences as a cause of death. I think that you're close, though. I believe that it's all the times the 12 volt battery gets very low and is then charged up, but it isn't the charging that kills it - it's the being run nearly dead. Lead-acid batteries HATE that...

If you put a voltmeter on the battery every time you push the start button and ever time you charge, the voltage will jump above 13 volts for a few minutes. Unlike an ICE there is no energy drain when when you start a Leaf so there is not much of a load on the battery. Other reason I have for thinking we are over charging is that I have a 1 kilowatt off grid solar that I USE to charge my Leaf with hooked to a timer that cycled on and off 24 times a day. Cooked the 12 volt battery in 10 months. Not doing that any more.

 

[nlspace]

Other reason I have for thinking we are over charging is that I have a 1 kilowatt off grid solar that I USE to charge my Leaf with hooked to a timer that cycled on and off 24 times a day.

Yes You are Overcharging. You have a non-standard charging setup that nobody else here has ever used. So your experienced failures have nothing to do with a normally operated Laef.

There are numerous posts on this forum about the 12V failing due to under-charging that never de-sulfates the plates and results in capacity loss and shortens the life.

 

[hradek]

Yes You are Overcharging. You have a non-standard charging setup that nobody else here has ever used. So your experienced failures have nothing to do with a normally operated Laef.

There are numerous posts on this forum about the 12V failing due to under-charging that never de-sulfates the plates and results in capacity loss and shortens the life.

Seems like under charging is unlikely since every time you charge and use the car over 13 volts is applied to the battery. Check your self with a volt meter

 

[DavidMW]

To check whether the car's 12V battery charge system is working, it's best to monitor the voltage when driving (more precisely, when the car's in READY state - not OFF, ACC (accessories) or ON (without pressing the brake pedal)).
How do I monitor the 12 battery charge system while driving? Is this using LeafSpy or similar?

 

[gozer]

NAPA has a neat little voltmeter that plugs into the 12v port and monitors the battery and loads on it as long as the car is switched on. $23 bucks +-.
Innova is the brand. Ive had one for my last 3 cars. Wont drive without it.

 

[mrlithium]

to monitor the 12V battery anytime use an external bluetooth unit like this

 

[DavidMW]

Thanks for those excellent suggestions - I hadn't thought to use to 12 port - doh!
Ideally I'd like to be able to monitor remotely but I'm not sure if LeafSpy can report while the car is OFF?