Dead Nissan Leaf help!

[katie279]

Hey all,

One of my cars, a Nissan Leaf appears dead today - it looks like the internal light was left on, so I'm guessing it's drained the 12V battery (which in itself is a weird thing in an electric car).

I've tried charging it, but my battery charger is spitting an error 2 as it's only reading 2.9v after charging for a bit.

Is the battery dead or am I missing a trick with these new electric cars?!?

 

[BUDFORCE]

Hey all,

One of my cars, a Nissan Leaf appears dead today - it looks like the internal light was left on, so I'm guessing it's drained the 12V battery (which in itself is a weird thing in an electric car).

I've tried charging it, but my battery charger is spitting an error 2 as it's only reading 2.9v after charging for a bit.

Is the battery dead or am I missing a trick with these new electric cars?!?

I don't know anything about electric cars, but assuming the 12v battery works like any other car, it's it's reading 2.9v it's dead.

 

[Rroff]

If you've got a multimeter see what it reads (the charger is probably right) - if it's below about 10.3V that battery is done. Some chargers have a function to try and repair 12V car batteries which have dropped below 10V but usually it doesn't accomplish much and/or that battery will need replacing sooner rather than later anyhow.

 

[sovietspybob]

Fairly common on some electric cars to have a bad 12v battery, early ones especially seemed poor at keeping them topped up as i guess they're designed for use with an alternator and it's not quite as easy keeping them charged from the high voltage pack. It was quite common for the early Tesla model S's used to go through one every 12 months as the way the car charged and discharged it just hammered the life out of them.

Get a new 12v one in there and I'm sure it'll all be good again.

 

[katie279]

Yeah, sounds like good advice - new battery it is then!

 

[Werewolf]

A new battery would be good, but if you've got access to an "old style" battery charger (a "dumb" one) it might be able to get the current battery working.

We've got 3 battery chargers in our garage and the 30+ year old one is the one I really don't want to replace, it's battered, it's basic and it will charge a battery the two newer chargers won't consider touching. One of our neighbours routinely borowed it for years every few months, he had a sporty car that wouldn't get used much and had a tiny drain on the battery that if he didn't use it and didn't have a chance to charge it (his garage had no power) it would drop the battery below the level any of the "smart" chargers would initialise on, but an hour or so with the "olde basic" one and it could then be hooked up to a modern charger.

 

[bainbridge]

A new battery would be good, but if you've got access to an "old style" battery charger (a "dumb" one) it might be able to get the current battery working.

We've got 3 battery chargers in our garage and the 30+ year old one is the one I really don't want to replace, it's battered, it's basic and it will charge a battery the two newer chargers won't consider touching. One of our neighbours routinely borowed it for years every few months, he had a sporty car that wouldn't get used much and had a tiny drain on the battery that if he didn't use it and didn't have a chance to charge it (his garage had no power) it would drop the battery below the level any of the "smart" chargers would initialise on, but an hour or so with the "olde basic" one and it could then be hooked up to a modern charger.

Yep, my Bradex Big Eight is an analogue charger that must be 30 years old, but it'll pump power into anything.

As said above though, batteries that are that far gone need replacing, but the analogue charger can keep you mobile while you source a replacement.

 

[Bug One]

As others have said, a dumb charger should kick it back into life enough to get it moving.

Don't be surprised if you start getting more electrical gremlins. Nissan leafs are known for throwing errors when the 12v battery is knackered.

 

[katie279]

Yeah, think easier to just swap the battery - although I agree car battery chargers are a mess of non-standards - eg trickle Vs smart, work with start/stop Vs don't, jump capability Vs not. The 'smart' ones appear to have gone backwards in ability to actually charge batteries.....!

 

[Terminal_Boy]

Wait… An EV has a dedicated 12V battery?

 

[Rroff]

Wait… An EV has a dedicated 12V battery?

Yes, there are a lot of reasons but a major one is so the hazards can still function if the car needs to isolate the main battery.

 

[katie279]

Yes, I imagine it might help to buffer/smooth the voltage from the main batteries to the more sensitive components also - that said, I can't see why they aren't smarter - ie could use the main battery to trickle feed/maintain the 12V - just old fashioned thinking I suspect from petrol design days ...!

 

[throwaway4372]

Heard of this happening to LEAFs a bunch of times. Does anyone know if it also happens to other EVs, or is it just a LEAF thing?

Edit: does this also happen to PHEVs?

 

[DarrenM343]

They do trickle feed/maintain the 12V battery but how it's done depends on the model. In the case of the Leaf I suspect the car shut down after x mins of it being locked including power to the 12V battery.
Still, 12V battery failures are quite common among EV's. I was surprised when I bought one that it had a 12V too, although it makes sense when thought about it, but thought surely can do away with that. A legacy breakdown cause carried forward into EV's.
Usually I think something like unlocking the car and locking again or running the climate control will cause the 12V to start charging if it needs to, but if completely flat that's probably not going to work anyway

 

[Bug One]

The 12v battery covers the exact same things as it does on a non-EV.

Much better to knacker a regular 12v battery when you leave a light on than your HV battery.

I think the 12v battery on a Leaf only gets charged when the car is turned on, same as an ICE would.

Mine has a small solar panel on the rear spoiler to keep the 12v trickle charged.

 

[jpaul]

From a safety perspective, at a minimum need supervisor hw/sw not on hv battery supply that would fire the fuse on the hv battery if there was an incident, or, power, the internal sim emergency call , airbags ...

 

[Rroff]

Heard of this happening to LEAFs a bunch of times. Does anyone know if it also happens to other EVs, or is it just a LEAF thing?

Edit: does this also happen to PHEVs?

I think they removed it on later Leafs but as mentioned above the original had a solar panel in the rear spoiler to maintain the 12V.

It is one area, though they are expensive, a Lithium Iron Phosphate or similar battery would be useful as long as it had a decent BMS. Also lighter though doubt 10-20kg less makes much appreciable difference to range.

 

[Grim5]

Hey all,

One of my cars, a Nissan Leaf appears dead today - it looks like the internal light was left on, so I'm guessing it's drained the 12V battery (which in itself is a weird thing in an electric car).

I've tried charging it, but my battery charger is spitting an error 2 as it's only reading 2.9v after charging for a bit.

Is the battery dead or am I missing a trick with these new electric cars?!?

A friend had this happen

They could not charge it with a flat battery, the thing just refused to charge

The car had to be jump started, yes you read that right and after that the battery started charging and they drove home two hours later. It was jump started with a colleague's petrol car at work

 

[bigmike20vt]

It is one area, though they are expensive, a Lithium Iron Phosphate or similar battery would be useful as long as it had a decent BMS. Also lighter though doubt 10-20kg less makes much appreciable difference to range.

I have been getting spammed with adverts for lithium 12v car batteries.
smaller , lighter and 10 year warranty ... however Christ they are expensive.
still... I may consider it when my ipace 12v needs replacing.

 

[Bear]

I have been getting spammed with adverts for lithium 12v car batteries.
smaller , lighter and 10 year warranty ... however Christ they are expensive.
still... I may consider it when my ipace 12v needs replacing.

My M5 has a lithium ion starter battery (standard fit) and it costs a fortune. EBay are selling them second hand for £600. I can’t seem to find the cost of one new in the UK online.

Edit: Just found it’s £840!