A peek at the Leaf's Charger

Is this thread not titled "A peek at the Leaf's charger"? People ITT keep derailing this topic so far off topic it's become IMPOSSIBLE to sift through all 14 pages without taking a full lunch break to sift through all the OT replies about 6kW charging. Completely off-topic. No grey area. I'm new here and a new LEAF owner - but not new to the concepts behind the LEAF. I've been promoting the LEAF based on its technologies long before I even dreamed of owning one - late last year was when I learned about the LEAF, but just 3 weeks ago I finally found I qualified to lease one.

That said, I've been on the internet for over a decade, and I've seen my fair share of what makes a topic a headache to read through. This topic has devolved into that. I'm not politely going to ask to get back on topic... this thread has gone so far OT since the very first page it's a poster child for OT discussions.

If you want your own topic about 6kW charging, MAKE ONE so I can AVOID IT. I don't need nor want 6kW charging - charging levels don't need to MATHEMATICALLY DOUBLE to just get 6kW from a 3kW charger. It could be 4 or 5kW and it would still be a welcome upgrade.

Now. If some mod could politely split off the last 11 pages of off-topic banter about the 6kW concept, that would at least clean up this thread so those of us interested can get "a peek at the Leaf's Charger" instead of a long discussion about a pipe dream charger.

Sorry to sound like an ass here, but... WOW. What an unacceptable reply to someone (me) trying to get this thread back on topic.

edit: And thank you, Ingineer, for that awesome photo of the charger guts. Just the techno-pr0n I was looking for. (Though I am still curious about how the liquid-cooling system works!)

FalconFour said:

Sorry to sound like an ass here, but... WOW. What an unacceptable reply to someone (me) trying to get this thread back on topic.

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Your pretty uppity for a guy with 8 posts!

mwalsh said:

Your pretty uppity for a guy with 8 posts!

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Beh. I've had lots of other discussions at my usual internet home...

And yeah, I'm sorry I get a bit abrasive. 'S kinda why I got out of the forum game years ago!

FalconFour said:

(Though I am still curious about how the liquid-cooling system works!)

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What liquid cooling? Correct me if I'm wrong but we know the battery in the 2011/2012 is air-cooled. I thought the charger was too. Ingineer?

Anyway, I think apart from Ingineer if anyone's had a nice peak at that Charger it's the UVA folks with the inductive mod. Wish they were in on this thread.

TimeHorse said:

What liquid cooling? Correct me if I'm wrong but we know the battery in the 2011/2012 is air-cooled. I thought the charger was too. Ingineer?

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The charger is liquid cooled. That's why you hear those pumps running when the car is charging.

If you go back to the first post, 2nd pic of this thread, you can see where the liquid lines are routed through the floor into the charger.

From what I've gathered from this very thread (I know, 15 pages of mostly OT replies are impossible to get through!), the reason the charger is able to fit in the car and be relatively lightweight is because the charger - not the batteries - is liquid-cooled by the car's liquid cooling system/radiator. That's why the cooling fan in FRONT runs while the charger is operating in the BACK. Also enables the charger to warm the motor/inverter/rest-of-the-car while it's charging in cold temperatures. Win/win/win design decision in my opinion, and why it's so interesting to me

An air-cooled charger that pumps 3,000+ watts through a step-up converter to charge 400-volt batteries would be comically large and probably take up the whole trunk.

Yes, it's liquid cooled. There are cooling lines running from front to the rear in the car already. Which is why it shouldn't be a big deal to liquid cool the battery pack with just a little more plumbing and small modifications to the battery case. If not by the manufacturer (because of the need for new crash testing), then at least in the aftermarket. Oops, there I go off-topic again.

Hey, at least we're still staying relevant to talking about the internals of the existing system... :lol:

But to address that one... I don't think that's practical either. The cells look like they're designed to be air-cooled from the start: http://www.facebook.com/photo.php?fbid=10151225784206203&set=o.141137487795&type=1&ref=nf" onclick="window.open(this.href);return false; - and as long as cool air is flowing over them - either ducted from the outside or forced by a fan - they should work just fine. Ambient temperature (over 110F in the affected cars) is the problem and unless you can chill the liquid below ambient temperature, the liquid "cooling" would still coat the cells in 110F+ temperature liquid due to the fact that it's a system designed to cool 200+ degree electronics...

FalconFour said:

Ambient temperature (over 110F in the affected cars) is the problem and unless you can chill the liquid below ambient temperature, the liquid "cooling" would still coat the cells in 110F+ temperature liquid due to the fact that it's a system designed to cool 200+ degree electronics...

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You know, I had been thinking all along that there was a refrigeration unit in the LEAF to cool the electronics like in the Volt, but I bet you're right. It's probably just a normal radiator system. No wonder the lines get so warm!

Thanks for pointing that out! And welcome!

FalconFour said:

Hey, at least we're still staying relevant to talking about the internals of the existing system... :lol:

But to address that one... I don't think that's practical either. The cells look like they're designed to be air-cooled from the start: http://www.facebook.com/photo.php?fbid=10151225784206203&set=o.141137487795&type=1&ref=nf" onclick="window.open(this.href);return false; - and as long as cool air is flowing over them - either ducted from the outside or forced by a fan - they should work just fine. Ambient temperature (over 110F in the affected cars) is the problem and unless you can chill the liquid below ambient temperature, the liquid "cooling" would still coat the cells in 110F+ temperature liquid due to the fact that it's a system designed to cool 200+ degree electronics...

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The pack (or rather the case holding the cells) is sealed, like a can of Tuna (thanks to EVDriver for that analogy). So any airflow is around it rather than the cells themselves and the cooling inside the case is conductive in nature. It's also passive (no fan). So I can't see a scenario where running cooling lines around the case exterior wouldn't be beneficial.

Thanks!

And yeah, the liquid coolant is just that... coolant - the manual says it needs to be replaced just like a regular car, but at MUCH longer intervals... talking like, 10 years down the road, kind of life, I think. (OK, my last car, an '87 Fiero that got stolen, needed coolant about every 6 months... hah!) But it's definitely just plain ambient-temperature coolant. Wouldn't make much sense to me to bathe the cells in ambient-temperature liquid instead of ambient-temperature air when the cells don't really make a whole lot of heat to begin with

The Volt is a different story. The lower capacity of the pack (what, 40 miles?) means the cells are prone to higher-speed discharge/recharge cycles, which actually do cause lithium cells to produce excess heat. The closer you get to "1C" charging rate - that is, charging in 1 hour, which is the documented "recommended" highest speed to charge lithium cells - the hotter the cells get. So the Volt with its lower-capacity battery charges cells at a higher rate-per-cell than the Leaf does, simply because there's less capacity to charge. It probably needed a liquid cooling system to ensure the cells stay in a good range near ambient. They'll still be affected in Arizona, I'd imagine... unless it actually uses a chilling system, which would definitely be interesting to see.

But knowing the LEAF uses a sealed pack? Yikes. It could benefit from both a fan inside to move air around and conduct it to the outer casing quicker and more evenly, and something to cool the casing during quick-charges. That's probably why Nissan doesn't recommend QCing more than once a day - it'd cause the pack to stay hot for too long!

FalconFour said:

... The cells look like they're designed to be air-cooled from the start: http://www.facebook.com/photo.php?fbid=10151225784206203&set=o.141137487795&type=1&ref=nf" onclick="window.open(this.href);return false; - and as long as cool air is flowing over them - either ducted from the outside or forced by a fan - they should work just fine. ...

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The battery case is sealed. There's no air flowing over them at all.

Yes, the factory charger is liquid cooled. The battery modules are not. My 6.7kW upgrade charger is air-cooled for simplicity, but could be hooked into the existing liquid cooling system. (It's more efficient then the existing one, so it wasn't worth the hassle)

Now adding cooling for the pack is a whole different problem! Most cars have used the A/C compressor, because using a standard liquid to radiator system cannot cool the pack below ambient. So a liquid cooling system without a refrigerant cycle of some sort would be of little gain to a system in Arizona. It would also have to be isolated from the the charger's system, otherwise it would actually ADD heat!

There is almost no noticeable difference in pack temperature when I charge at 6.7 vs 3.3, but I can adjust the charge rate through LEAFSCAN™ if I need to reduce it for some reason, such as limited current available.

-Phil

davewill said:

The battery case is sealed. There's no air flowing over them at all.

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I, uh, yeah... so I read. But that's why there should be a fan inside the case to move the static air around inside (recirculating within the sealed case), as well as something outside the sealed case - road air, coolant pipes, forced air from a fan, etc - cooling the casing. That should be more than enough to cool the pack internally.

@Ingineer: (dangit, I was about 1 click from buying an EVSE upgrade, but I still can't bring myself to load anything more up on the credit card. Less than a month and I can afford it, just gimme time )
You have a 6.7kW charger? Is it external via the QC connector, or wired onboard? Just curious...

FalconFour said:

I, uh, yeah... so I read. But that's why there should be a fan inside the case to move the static air around inside (recirculating within the sealed case), as well as something outside the sealed case - road air, coolant pipes, forced air from a fan, etc - cooling the casing. That should be more than enough to cool the pack internally.

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This could actually backfire in areas with high ambient, such as Phoenix, making the cells hotter during the day!

FalconFour said:

You have a 6.7kW charger? Is it external via the QC connector, or wired onboard? Just curious...

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It's on-board. While it is possible to do this externally, it would be significantly more expensive, as well as being cumbersome and a hassle to use. On-board it's automatic, and you don't have to do anything more than you currently do, just plug and go. Externally it would require lugging the "box" around, which would have to be built to handle this, (read: Heavier) along with the expensive and bulky CHAdeMO connector. Then you'd still have to provide power, which means you'd now have 2 power cords. I can see the logic in making it off-board when you get around 10kW or higher, but as long as you can easily power it from J1772, it's more sensible to have it on-board.

The only argument I can see for off-board is the fact that it has to be installed. While the process is easy, (and makes no permanent modification to the Leaf) it's nonetheless still something not everyone will be able and/or willing to do.

The 6.7kW upgrade is mainly targeted at fleet operators.

-Phil

Wow... being installed on-board is the one thing I'm surprised could be done. Not to mention being air-cooled AND using the same charge-port (wiring) as the original charger.

My argument for an off-board charger would be a cheaper "fast-charge" solution for property owners that want to put a faster charging option on their grounds in place of a standard public station. Something that runs on unmodified, standard 220v (or 240v, is there a difference in terminology there?) wiring that could run a standard J1772 charger could also work for "semi-fast charging" a LEAF. Expensive, maybe... but ChargePoints already cost 10 grand, don't they?

The upgrade uses the existing J1772 charge port, but not the existing wiring that runs to the back, as it's inadequate. It's small enough to mount in the front under the hood without impacting the operation of any existing systems. The entire install can be completed in under an hour and uses simple hand tools.

It's how Nissan Should have designed it in the first place!

BTW, it's 120v/240v (208v in some cases where 3-phase wye-connected commercial power exsits) and has been for the better part of a century. 110v/220v is a holdover from a time before most of us were even alive, when our power standard was lower than it is now.

Japan uses 100v/200v, which is what the Leaf was originally built for.

-Phil

Is your 6.6kW an additional 3.3 kW parallel to the existing on-board (2x3.3), or do you replace the existing charger with one 6.6kW unit?

TEG said:

Is your 6.6kW an additional 3.3 kW parallel to the existing on-board (2x3.3), or do you replace the existing charger with one 6.6kW unit?

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Both installed, with the Choice of charging rates at the flip of a switch would be the way to go.

TEG said:

Is your 6.6kW an additional 3.3 kW parallel to the existing on-board (2x3.3), or do you replace the existing charger with one 6.6kW unit?

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It's an additional 3.4kW unit for a total of 6.7kW. The existing charging system in the Leaf is left untouched, and the add-on respects the tapering instructions from the Battery ECU (LBC).

-Phil