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Discussion Starter · #1 ·
Hi all.

Left my Leaf 24 2014 for over a week in some chilly weather - snowing and hard frost here in Glasgow.

Just went to take it for a spin and there is no power. Nothing. Needed the manual key to get in. Not a sign of any power at all.

I've read on other threads that the 12v battery is likely drained. So I presume the first step is to test it and then trickle charge if needed?
 

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Yep, you've got it. I religiously charge mine every month and condition (de-sulphate) it too with a fancy charger. Even here in Poole/Bournemouth we had a couple of frosts, no snow yet though!
 
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I've read on other threads that the 12v battery is likely drained. So I presume the first step is to test it and then trickle charge if needed?
No need to test as that is 99% the reason. Just buy a smart charger ( rather than a cheap dumb trickle charger ) and connect it overnight until it reports that it has gone through its full cycle of diagnosis, charge, and conditioning, and then switches itself off. That can take up to 12 hours, and sometimes longer. Then, as indicated above, do that once a month, whether it seems to need it or not, as part of the usual tyre kicking and screenwash filling routine.
 

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Discussion Starter · #4 ·
Yep, you've got it. I religiously charge mine every month and condition (de-sulphate) it too with a fancy charger. Even here in Poole/Bournemouth we had a couple of frosts, no snow yet though!
Thanks for that. Do I take the battery out to charge?
 

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Discussion Starter · #5 ·
No need to test as that is 99% the reason. Just buy a smart charger ( rather than a cheap dumb trickle charger ) and connect it overnight until it reports that it has gone through its full cycle of diagnosis, charge, and conditioning, and then switches itself off. That can take up to 12 hours, and sometimes longer. Then, as indicated above, do that once a month, whether it seems to need it or not, as part of the usual tyre kicking and screenwash filling routine.
Thanks! Can any smart charger be used or does it need to be specific for an EV battery? (I really know very little about cars, as you can see)
 

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Can any smart charger be used or does it need to be specific for an EV battery?
The 12v DC battery is just a standard unit as fitted to all cars so any half decent smart charger will be fine for this kind of low duty use. You can pay anything from £20 to £200. Mine is a Torq and it has worked perfectly.

Torq 12A Car Battery charger | DIY at B&Q

But many people swear by CTEK units.

CTEK MXS 3.8 Automatic Battery Charger (Charges & Maintains Car and Motorcycle Batteries) 12V, 3.8 Amp - UK Plug: Amazon.co.uk: Car & Motorbike
 

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Discussion Starter · #7 ·
The 12v DC battery is just a standard unit as fitted to all cars so any half decent smart charger will be fine for this kind of low duty use. You can pay anything from £20 to £200. Mine is a Torq and it has worked perfectly.

Torq 12A Car Battery charger | DIY at B&Q

But many people swear by CTEK units.

CTEK MXS 3.8 Automatic Battery Charger (Charges & Maintains Car and Motorcycle Batteries) 12V, 3.8 Amp - UK Plug: Amazon.co.uk: Car & Motorbike
Brilliant, thank you.
 

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Do I take the battery out to charge?
No need.

Not being the voice of doom, but if your battery is the original (Renault/Nissan branded and date marked) then it's reaching the end of its life. Smart charging will keep it alive for a while longer but you need to plan to replace it soon.
Out of interest is your car Gen1 or Gen2 (without or with the gap between the rear suspension towers? The earlier cars are harder on their 12v, the later ones are much better. If yours is a later car and the battery fails again then it's time to replace it, if the former then regular smart charging will have more effect.
 

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Discussion Starter · #9 ·
No need.

Not being the voice of doom, but if your battery is the original (Renault/Nissan branded and date marked) then it's reaching the end of its life. Smart charging will keep it alive for a while longer but you need to plan to replace it soon.
Out of interest is your car Gen1 or Gen2 (without or with the gap between the rear suspension towers? The earlier cars are harder on their 12v, the later ones are much better. If yours is a later car and the battery fails again then it's time to replace it, if the former then regular smart charging will have more effect.
Thanks, I believe mine in Gen2 (has nothing in the boot between the rear wheels). I'll have a go at charging and see what happens.
 

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I'll have a go at charging and see what happens.
Just as an afterthought. If the 12v is totally 'dead' - as in showing zero volts - a smart charger will not engage with it as the first thing it does is analyse the condition and select a charging regime to begin, either to recover it from a serious sulphidation first, or pulse, or trickle first, or charge hard initially. If it can't detect any voltage and is capable of responding to a load the smarty will do nothing.

In that case, you will need to use a dumb charger for half an hour, or persuade a local car owner to allow a jump-start connection to his 12v battery for ten minutes. Once a bit of charge is in your failed battery and some volts are detectable the smart charger will be happy and go on to condition and recover its health.

As has been said, it could well be that the 12v is beyond repair due to being totally discharged for too long but even if a new unit has to be fitted to replace it then still connect a smart charger to that new battery overnight monthly or the same situation that killed it could still occur again. I have heard of people demanding a replacement battery under warranty and then seeking another six months later as the car has killed that one as well. Regular maintenance avoids that hassle.
 

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The 12v DC battery is just a standard unit as fitted to all cars so any half decent smart charger will be fine for this kind of low duty use. You can pay anything from £20 to £200. Mine is a Torq and it has worked perfectly.

Torq 12A Car Battery charger | DIY at B&Q

But many people swear by CTEK units.

CTEK MXS 3.8 Automatic Battery Charger (Charges & Maintains Car and Motorcycle Batteries) 12V, 3.8 Amp - UK Plug: Amazon.co.uk: Car & Motorbike
I was looking at a Noco Genius 5 (5A) to charge my Fabia and Leaf. Can these chargers be connected to the Leaf without disconnectingthe battery?

 

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Can these chargers be connected to the Leaf without disconnecting the battery?
That has been the subject of much debate over the years. There is a theoretical danger that hydrogen gas can be given off by a 12v lead/acid battery in certain circumstances, and as there is a possibility of a spark happening when attaching crocodile clips it could produce an explosion. The fact that it never happened didn't deter the FUD pushers. If it was intended to leave the battery in place people were advised to connect to the positive terminal but to connect the negative to a metallic part of the cars' chassis or engine block. In theory, that removed any potential spark well away from the battery itself and reduced the explosive risk. In practice, millions have just clipped to the terminals for years and never singed their eyebrows off.

These days there is a different reason for connecting the negative of a charger to a body part. Some modern cars have a gizmo attached to the negative terminal that sends data to the central computer to control the internal charging regime. If 14v DC from a charger is attached alongside such a piece of technical equipment it can confuse the system and cause an error to be thrown up which may require a dealer visit to re-set. To be safe in such cars the charger should be attached to some metal part of the car rather than the battery terminal.

But to answer your question. Yes. A 12v battery charger can be connected without removing or disconnecting the battery. Subject to the above worry merchants warnings.
 

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@Jedispooner that is an expensive unit, but it has some extra features such as the

FORCE CHARGE: Bypass the internal battery sensing technology and manually force charging for trouble-shooting low-voltage batteries (down to zero volts).
that will get you out of the situation @Hitstirrer described without needing a friend.

If the 12v is totally 'dead' - as in showing zero volts - a smart charger will not engage with it as the first thing it does is analyse the condition and select a charging regime to begin, either to recover it from a serious sulphidation first, or pulse, or trickle first, or charge hard initially. If it can't detect any voltage and is capable of responding to a load the smarty will do nothing.

In that case, you will need to use a dumb charger for half an hour, or persuade a local car owner to allow a jump-start connection to his 12v battery for ten minutes. Once a bit of charge is in your failed battery and some volts are detectable the smart charger will be happy and go on to condition and recover its health.
Frankly being a cheapskate I use a perfectly adequate CTEK rip-off from Lidl/Aldi for less than £15 when they have them.
 

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Hi all.

Left my Leaf 24 2014 for over a week in some chilly weather - snowing and hard frost here in Glasgow.

Just went to take it for a spin and there is no power. Nothing. Needed the manual key to get in. Not a sign of any power at all.

I've read on other threads that the 12v battery is likely drained. So I presume the first step is to test it and then trickle charge if needed?
Out of interest when the car was left for a week was it plugged in or unplugged?

Apparently when the car is turned off and not plugged in it will give the 12v battery a 4 minute top up once every 24 hours but will not do this if the car is plugged in.

So if the car is being left unused for a long time its best for the 12v battery to leave the traction battery between 50-80% or so and not leave the car plugged in.
 

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@Jedispooner that is an expensive unit, but it has some extra features such as the

that will get you out of the situation @Hitstirrer described without needing a friend.

Frankly being a cheapskate I use a perfectly adequate CTEK rip-off from Lidl/Aldi for less than £15 when they have them.
Is this the one you're referring to?

140162


About £15 from Lidl and I've had this one for several years.

It looks simple with one button but it is actually fairly intelligent, certainly for the price. It does an initial test to determine the condition of the battery and starts one of several different charging programs based on the condition and can even recover a very low battery. (From as low as about 9 volts)

Once fully charged it stops charging but periodically will do a maintenance top up, then let the battery fall back to a neutral voltage again. (Meaning it isn't constantly trickling the battery at a high voltage)

So it can be left on a battery permanently and will keep the battery conditioned. I haven't driven my ICE car for nearly a month (nowhere to go apart from work - which the Leaf can do just fine!) so this has been sitting on there for several weeks and does a great job of maintaining the battery.

I've used it many times both for preventative maintenance of the battery in a rarely used car and also charging a battery that has accidentally gone flat due to interior light etc..

Maximum charge rate is about 5 amps so it's an overnight job to charge a deeply discharged battery.
 

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It is - I have one from each of the shops with different branding and they both do an excellent job. One has a few more lights but is no more/less effective.
 

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Out of interest when the car was left for a week was it plugged in or unplugged?

Apparently when the car is turned off and not plugged in it will give the 12v battery a 4 minute top up once every 24 hours but will not do this if the car is plugged in.

So if the car is being left unused for a long time its best for the 12v battery to leave the traction battery between 50-80% or so and not leave the car plugged in.
I've noticed once or twice the far right (facing the car) charging light flashing when I walked up to to the car to leave (unplugged) and realised it was charging the 12v - Does that mean I shouldn't ever have to worry about charging it if the traction battery tops it up every 24 hours?

This is probably a dumb question but if it tops it up every 24 hours what is the need for what you've fitted? Is it because it's doing a set amount (4 minutes) which may not be enough to keep it topped up?
 

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Discussion Starter · #18 ·
Out of interest when the car was left for a week was it plugged in or unplugged?

Apparently when the car is turned off and not plugged in it will give the 12v battery a 4 minute top up once every 24 hours but will not do this if the car is plugged in.

So if the car is being left unused for a long time its best for the 12v battery to leave the traction battery between 50-80% or so and not leave the car plugged in.
Thanks. The car was unplugged. It has a solar panel for the 12v but either it wasn't sufficient or the battery is dodgy (or something else).
 

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Discussion Starter · #19 ·
Just read in the owner's manual that they recommend jump starting off an ICE car. Anyone have experience of that?
 

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Just read in the owner's manual that they recommend jump starting off an ICE car. Anyone have experience of that?
Not directly but lots of people on here have done it successfully. The key is that the other car's battery allows the HV to switch on at which point your car's DC : DC charger kicks in and keeps the car running. You need to leave the car powered on for a while for the 12v to be recharged this way and it is pretty brutal to the 12v charging it at around 100 Amps initially. Unlike an ICE there is no benefit to actually driving the car as there is no advantage in running the engine faster to spin the alternator faster etc.....
 
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