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Discussion Starter · #1 ·
So let me kick this off by saying the data clearly indicates that if this is a factor, it's way, way smaller a consideration than say not abusing DCFC or charging to 80% (nominal) capacity-level things. I just want to get to the bottom of this mystery.

I am not an electrician, electrical engineer or even someone who you would trust to install a ceiling fan without keeping an eye on it for a year or two so that makes me not want to lean on my own understanding and want to find out more. I've seen echoed in many places over the years from people who are smarter than me that L1 is worse for your car than L2 and then people on this board really challenged me on it and some were like, "I wish I knew where this started."

Anyways, I got to Googling and the most authoritative sources I could find would only commit to price concerns at running less efficiently. When it came to battery life things were inconclusive and even contradictory.

Here are excerpts from the Leaf manual that completely contradict:

From page CH-7
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It would seem like Nissan is telling Leaf owners with these somewhat conflicting passages to use either L1 or L2 charging but then says "don't trickle if you can limit it to only when you need to." But they don't go on to explain why.

So here's the question, does anyone here at least know why some authoritative sources say this? Is it applicable to the Bolt and a general EV thing? Perhaps something less relevant depending on the car?

I'd really love to learn more about this.
 

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This review of the literature doesn't appear to draw distinctions between Level 1 and Level 2, but does advise against frequent DCFC because of the negative impact of high current charging on battery longevity. It's possible that the difference between 8-12 A vs 32 A is too small when compared with DCFC @ 150 A.
 

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I'd consider L1 to be optimum if the lowest state of the battery was not below 30%.

It is not optimum for speed considerations.
 

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My last car, a Kia Niro PHEV, had a similar statement in the owners manual. Basically, they said the 120v EVSE is for occasional use, while Level 2 is the expected "normal". As to why, I can't say. But if that statement is similar across manufacturers, one would expect some level of accuracy about it.
 

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Discussion Starter · #5 ·
My last car, a Kia Niro PHEV, had a similar statement in the owners manual. Basically, they said the 120v EVSE is for occasional use, while Level 2 is the expected "normal". As to why, I can't say. But if that statement is similar across manufacturers, one would expect some level of accuracy about it.
But it's vague. Are they telling you this because it's better for the battery or because they know most people will look at L1 charging and be like, "really?" Like in the Leaf manual the part specifically about battery longevity it says, "Yeah just don't DCFC" and later it's like, "But don't trickle unless it's an emergency" and doesn't go on to say why.

So is the accuracy they're just saying, "You will be unhappy with L1" or is there an actual connection with battery longevity?

When I did get challenged on this it was by electricians and/or electrical engineer-types on here who had sound reasoning for saying L1 charging isn't bad, all I had were these vague proclamations littered about.

So ok, there's gotta be accuracy but accuracy to what. Is it a maintenance thing or a human thing?
 

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So ok, there's gotta be accuracy but accuracy to what. Is it a maintenance thing or a human thing?
Outstanding question, to which I have no answer. Yes, it's vague. They really don't say why, just that it's not recommended. But is does seem to be consistent across manufacturers, for whatever that's worth...
 

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From what I've read over the decades. Most batteries do better when more slowly charged.

They don't recommend it because it takes all night to charge is my guess.
 

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From a purely technical point, charging slower will be better for the battery longevity because it lessens the chance of the ions getting stuck in the wrong place. However, the law of diminishing returns will be at play here. From what I gather, the difference between L1 / L2 will be minimum enough that you won't really feel it. Heck, in the case of Bolt, the DCFC charging speed is so slow (less than 1C at maximum, which isn't even sustained that long) that using that exclusively isn't likely to degrade the battery any faster than just using L1 / L2.
 

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Here are excerpts from the Leaf manual that completely contradict:
From page CH-7
It would seem like Nissan is telling Leaf owners with these somewhat conflicting passages to use either L1 or L2 charging but then says "don't trickle if you can limit it to only when you need to." But they don't go on to explain why.

So here's the question, does anyone here at least know why some authoritative sources say this? Is it applicable to the Bolt and a general EV thing? Perhaps something less relevant depending on the car?

I'd really love to learn more about this.
There is a video on Weber auto channel where prof. Kelly is comparing Leaf's and Bolt's batteries. He actually did some analysis on their differences and how those should be charged to extend their life. Surely worth watching.

 

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Discussion Starter · #10 ·
There is a video on Weber auto channel where prof. Kelly is comparing Leaf's and Bolt's batteries. He actually did some analysis on their differences and how those should be charged to extend their life. Surely worth watching.

I love how he harps on the "So you sold me this CHADEMO thing then instructed me not to use it" thing hehe.

The sad part is Nissan may deserve more praise then backlash on that one, that's not a thermal management thing and is true of CCS. I look at this more like, "at least Nissan has the balls to tell you that you're jamming your batteries full of juice in a stressful way"
 

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Here are excerpts from the Leaf manual that completely contradict:
Understand, Leaf has never implemented liquid cooling, so the advice will be significantly different than Bolt with liquid cooled systems. See the Weber Auto video posted above.
 

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Discussion Starter · #12 ·
Understand, Leaf has never implemented liquid cooling, so the advice will be significantly different than Bolt with liquid cooled systems. See the Weber Auto video posted above.
Oh I watched it before and then again from start to finish when he posted it. I'm not even saying that the Bolt doesn't do direct DC (redundant?) charging better with less damage to the batteries but it's not exactly a secret that DCFC is one of the actual ways you can shorten your battery life if used frequently.

Edit: Whooops, thought you replied to my last comment. I see what you're saying. Yes, I do understand that, is that the reason, just older worse thermal management car started this trend? I would think that it could be the opposite, perhaps the Bolt doesn't want to use like a high energy system while only grabbing 1kWh.
 

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Oh I watched it before and then again from start to finish when he posted it. I'm not even saying that the Bolt doesn't do direct DC (redundant?) charging better with less damage to the batteries but it's not exactly a secret that DCFC is one of the actual ways you can shorten your battery life if used frequently.
The lore about minimizing DCFC is probably based on Tesla and Leaf. Obvious WRT Leaf, but Tesla actually gimped DC charging speeds on older MS with a lot of SuC sessions to minimize warranty claims. Tesla tends to be aggressive WRT DCFC, so that might be part of it.

@NewsCoulomb has documented his degradation on YouTube, at 125-130K miles (lots of 500+ mile trips and DCFC), his deterioration doesn't seem too far out of line compared to other Bolts with less DCFC. So the liquid cooling and less aggressive DCFC speeds on Bolts may be sufficient for prolonged life. Nevertheless, the advice holds true that minimal DCFC MAY be a useful strategy for prolonged life.

WRT L1 vs L2, the heat and C-rate differences are probably not significant enough to make much difference. In fact, 240V at higher Amps may subject the cells to less heat due to less time exposed to charging. Overall, probably not significant enough to make a difference.
 

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The sad part is Nissan may deserve more praise then backlash on that one, that's not a thermal management thing and is true of CCS. I look at this more like, "at least Nissan has the balls to tell you that you're jamming your batteries full of juice in a stressful way"
It could be that, but also possible that Leaf has a less advanced battery cooling system so it needs more pampering to keep its battery intact. I don't know what the right answer is.
 

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I closely monitors my BMW using DC. It was had a noticeable effect. I'd assume same on Bolt so I only tested DC once.

I'd think that if a used car dealer checked each Bolt they brought in and compared ones with DC to non they'd find DC were less.
 

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Yes, capacity was reduced and I meant monitored. I had free charging from BMW for a year. Also I had to run from 100% to 0% almost everyday. I'm sure that isn't great.
 
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