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FalconFour
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Re: A peek at the Leaf's Charger

Tue Oct 02, 2012 12:15 pm

Thanks! :geek:

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!
Last edited by FalconFour on Tue Oct 02, 2012 12:21 pm, edited 1 time in total.
100% gas-free since September 2012
2011 LEAF SL - Sep 2012~Sep 2014 - 35,737 miles
2013 LEAF S+Charge - Jan 2014-Feb 2017 - 68,065 miles
2014 LEAF SV+Premium+QC - Feb 2017-present

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davewill
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Re: A peek at the Leaf's Charger

Tue Oct 02, 2012 12:19 pm

FalconFour wrote:... The cells look like they're designed to be air-cooled from the start: http://www.facebook.com/photo.php?fbid= ... e=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. ...
The battery case is sealed. There's no air flowing over them at all.
2014 Rav4 EV, Blizzard Pearl White
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Ingineer
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Re: A peek at the Leaf's Charger

Tue Oct 02, 2012 12:22 pm

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
Easily Learn Electricity HERE! - - - - Website: http://evseupgrade.com/[/size] - - - - Like us on Facebook: EVSE Upgrade

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FalconFour
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Re: A peek at the Leaf's Charger

Tue Oct 02, 2012 12:25 pm

davewill wrote:The battery case is sealed. There's no air flowing over them at all.
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...
100% gas-free since September 2012
2011 LEAF SL - Sep 2012~Sep 2014 - 35,737 miles
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Ingineer
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Re: A peek at the Leaf's Charger

Tue Oct 02, 2012 1:30 pm

FalconFour wrote: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.
This could actually backfire in areas with high ambient, such as Phoenix, making the cells hotter during the day!
FalconFour wrote:You have a 6.7kW charger? Is it external via the QC connector, or wired onboard? Just curious...
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
Easily Learn Electricity HERE! - - - - Website: http://evseupgrade.com/[/size] - - - - Like us on Facebook: EVSE Upgrade

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FalconFour
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Re: A peek at the Leaf's Charger

Tue Oct 02, 2012 2:16 pm

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? :)
100% gas-free since September 2012
2011 LEAF SL - Sep 2012~Sep 2014 - 35,737 miles
2013 LEAF S+Charge - Jan 2014-Feb 2017 - 68,065 miles
2014 LEAF SV+Premium+QC - Feb 2017-present

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Ingineer
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Re: A peek at the Leaf's Charger

Tue Oct 02, 2012 2:39 pm

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
Easily Learn Electricity HERE! - - - - Website: http://evseupgrade.com/[/size] - - - - Like us on Facebook: EVSE Upgrade

TEG
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Re: A peek at the Leaf's Charger

Tue Oct 02, 2012 6:45 pm

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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mwalsh
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Location: Garden Grove, CA

Re: A peek at the Leaf's Charger

Tue Oct 02, 2012 6:57 pm

TEG wrote: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?
Both installed, with the Choice of charging rates at the flip of a switch would be the way to go.
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Ingineer
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Re: A peek at the Leaf's Charger

Tue Oct 02, 2012 9:42 pm

TEG wrote: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?
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
Easily Learn Electricity HERE! - - - - Website: http://evseupgrade.com/[/size] - - - - Like us on Facebook: EVSE Upgrade

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