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still needs to deliver enough amps to close the main breaker to the EV battery pack ....
you could fit a disconnect with a remote, i have used a garage remote on / off for similar
you could power the remote from the 12V and latch it on / off
but if it fails your car stops obviously, depends how you rate all the risks
a manual switch by the 12V battery would be more reliable, IF you remember to use it :)
 

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Thats what I am thinking about, a manual one. Not remote. Yes it still needs to be able to provide enough current to operate - that is taken as a given.
 

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No M8, I will simply pop the hood and press a button - thats my plan anyway. It just saves me from having to use a spanner.
 

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The only issue with pulling the battery all the time is all the stuff that needs reset afterwards? Radio presets, electric window setpoints, clock, trip computer etc etc.

Fair enough for the odd time your leaving the car for a month, but otherwise i think that'd get really quite annoying!
 

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The only issue with pulling the battery all the time is all the stuff that needs reset afterwards? Radio presets, electric window setpoints, clock, trip computer etc etc.

Fair enough for the odd time your leaving the car for a month, but otherwise i think that'd get really quite annoying!
That seems not the case with my car - I don't know if there is a time to drain, but the only thing that requires setting is the dash clock and the satnav one soon syncs. I have not tested it over night yet.
 

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Technically if it is suffering from sulphation it is currently "bad" and not simply discharged - it won't perform normally after a single "normal" charge due to the high cell resistance. I guess what you mean is that it is potentially recoverable with the right charging/rejuvenation regime.

I'm skeptical that it is sulphated though as that doesn't normally happen until you get below about 11 volts and leave it there for a significant period of time.
Please excuse me for saying but I think you are reading a lot of what is scattered around the internet by armchair engineers.

You get two types of lead sulphate on the plates, there is a 'spongy' lead sulphate, which is an oxy-hydroxide, and therefore actively transfers charge, but if it is not cycled 'properly' the hydroxide will recombine into water and leave the crystalline lead sulphate behind.

You are quite right that if a battery is heavily discharged and left then the lead sulphate crystals will grow and effectively lock away the active conduting parts of the plate.

But well before that, while the battery is still in daily use, you will get small lead sulphate crystals forming. In fact, I do not know but I dare say you will always have such crystals present, I expect it is just a simple fact of chemical equilibrium. The question is whether the presence of crystallised lead sulphate has the effect of increasing internal impedance and reducing capacity.

This will happen if the battery routinely has current drawn and recharged (i.e. in an active duty circuit) while the voltage is below the float voltage. That is what the float voltage is, it is the electropotential of the spongy lead formation. Less than that and you can get crystals forming, which, if you leave it long enough, will be the seed crystals for the sulphation to come.

This is my understanding of the electrochemistry at work.

So the problem for Leafs is that they are routinely held below the elctropotential to avoid crystal formation. This reduce capacity over time, but is usually fully reversible at that point with a proper charge every so often. That's why I recommend Leaf owners put their battery on charge for 48hrs at least once a month. It is not merely to recharge the battery but to dissolve out the crystals at a higher electropotential.

You can take my advice, or leave it. My advice helps those that help themselves, so to speak! If you wish to be a victim of poor Leaf battery management software and Halfords batteries, go right ahead.
 

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Discussion Starter #68
There are a lot of examples of desulphating batteries. Apparently they all work and none of them work. There is a vid here that seems to give a good explanation. It seems to be a lot of faffing about for an intangible result. Much easier to bung on a new battery every 2 or 3 years. It is the cheapest thing to go wrong.
 

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There are a lot of examples of desulphating batteries.
The issue I am trying to get to is to not let your battery get near the conditions for sulphating. Resolvating the crystalline lead suphate while it is still microscopic is the thing you can do to avoid worse.
 

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'So the problem for Leafs is that they are routinely held below the elctropotential to avoid crystal formation'

+1

disconnecting the battery is not going to fix that. a higher longer float charging voltage is needed.
 

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'So the problem for Leafs is that they are routinely held below the elctropotential to avoid crystal formation'

+1

disconnecting the battery is not going to fix that. a higher longer float charging voltage is needed.
The problem with Leafs is that they have the wrong type of batteries fitted. The traction battery has no active thermal management and the 12v battery is designed for cranking an ICE.
 

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You can take my advice, or leave it. My advice helps those that help themselves, so to speak! If you wish to be a victim of poor Leaf battery management software and Halfords batteries, go right ahead.
Umm, I don't even own a Leaf! ;)

Nor does anything I've said contradict your advice to Leaf owners, so err, yeah...
 

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Umm, I don't even own a Leaf! ;)

Nor does anything I've said contradict your advice to Leaf owners, so err, yeah...
I have mislead you! 'You' was just meant to be a general 'you', not you necessarily!

I should have used the pronoun 'one' to avoid confusion, but it is so unfashionable!
 

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Well, I took @donald 's advice two years ago. These weird 12v DC events back then were often reported in here and Nissan dealers were unable to diagnose the cause. They found it more expedient to ask Nissan UK for permission to issue replacement 12v batteries under warranty and hope it didn't happen again. Perhaps that was a cost-benefit decision as many hours of investigation would be more expensive than a £30 stock item.

In my case they recovered the car, charged the 12v up and found all well again. But the chat in here made it clear that the problem was deeper than that. I'm still not sure whether it's a car issue, or a drive pattern, or a combination of both. What I do know is that a few quid invested in a smart charger and a few minutes a month have solved it for me. And I now don't worry that I might be stranded again at 1 am on a rainy Monday.
 

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recon its an EV issue as these 12V battery issues are on all the EV forums
parasitic drain / not being left of charge / dud inbuild chargers take your pick (n)
 

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Discussion Starter #76
Just an idea, not sure if this is at all practical. If you leave your car plugged in to the charger which gives you 240v entering the car, can you tap off at the socket a spur to run a small 12v charger. Or would this upset the wall charger?
 

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Just an idea, not sure if this is at all practical. If you leave your car plugged in to the charger which gives you 240v entering the car, can you tap off at the socket a spur to run a small 12v charger. Or would this upset the wall charger?
Wouldn't work.

The car will only request 240v from the EVSE when it wishes to charge the traction battery, or perhaps during pre-heating. At other times even though plugged in there will be no 240v entering the car.
 

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'So the problem for Leafs is that they are routinely held below the elctropotential to avoid crystal formation'

+1

disconnecting the battery is not going to fix that. a higher longer float charging voltage is needed.
It does though... There must be more to this than running the battery below a certain amount. I was seeing voltages of 7v and thats got to be a drain.
 
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