Battery life - Charge rate 3.3 or 6?

So the "Battery life - Charge to 80% or 100%" thread got me to thinking. Is there any evidence that charging at 1.2, 3.3 or 6 is better one way or another? Ignoring the speed of charge or the ability to pre-heat / cool the cabin in the equation, in other words if you had any options available and time and climate control wasn't an issue, which is preferred to extend battery life? I know in the lead acid world, charging to slow eventually causes the plates to sulfate and charging to fast can warp plates and off gas requiring the need to add water. Or are these rates all well within the "normal" range for the Leaf's batteries?

Just thinking out loud, but would charging at a lower rate would reduce battery heating and extend battery life?

Both charging rates are at such a low C that it makes no difference.

charge rate vs battery life is a non issue at the rates you mentioned.

You will waste more electricity to the EVSE the slower you charge.

Look at it in KW divided by the KWh of the battery. Charge rates below 1 are slow enough to be a complete non issue. Charge rates above 1 require more cooling and or degrade the battery depending on how high you go.

(0.06C) 1.44 KW Nissan Leaf on 120v / 12a
(0.16C) 3.84 KW Nissan Leaf on 240v using evse upgrade 16a (2011 and 2012)
(0.2C) 4.8 KW Nissan Leaf on 240v using evse upgrade 20a (2013 and 2014 assuming they have the "6.6 KW charger")
(0.25C) 6 KW Nissan Leaf with "6.6 KW charger" on a 27a or higher j1772 charger.
(1.83C max) 44 KW Nissan Leaf quick charge port (Chademo) but it varies because not all chargers offer the max charge rate.


9.6 KW Tesla Model S on UMC 240v 40a (0.16C for a 60kwh, 0.11C for a 85kwh)
~20 KW Tesla Model S with dual chargers on a HPWC (0.32C for a 60kwh, 0.23C for a 85kwh)

Supercharger charge rates in terms of C vary but they run big loud fans during the supercharging process so they don't overheat the battery pack while charging that fast

90KW / 85 KW (90 KW supercharger on model S with 85 KW battery) is only 1.05C
120KW / 85 KW (120 KW supercharger on model S with 85 KW battery) is 1.41C
90KW / 60 KW (90 KW on model S with 60 KW battery) is 1.5C
105KW / 60 KW (120 KW supercharger limited to 105KW on model S with 60 KW battery) is 1.75C

They may run big loud fans to cool the superchargers themselves but it has nothing to do with the battery pack as it is liquid cooled internally as part of the cars TMS.

dhanson865 said:

Supercharger charge rates in terms of C vary but they run big loud fans during the supercharging process so they don't overheat the battery pack while charging that fast

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TomT said:

They may run big loud fans to cool the superchargers themselves but it has nothing to do with the battery pack as it is liquid cooled internally as part of the cars TMS.

dhanson865 said:

Supercharger charge rates in terms of C vary but they run big loud fans during the supercharging process so they don't overheat the battery pack while charging that fast

Click to expand...

Click to expand...

not talking about the superchargers, I'm talking about the big* loud fan(s) inside the Model S. Plenty of videos on youtube by islandbayy / KmanAuto (same guy)
showing how loud his car gets while supercharging.

* and by big I mean big vs the 80mm, 92mm, 100mm, 120mm, 140mm fans I'm used to in the PC world.

As to liquid cooled, afaik the liquid cooling loop is tied into the AC system and receives cooling from it and thus the fan is wherever the radiator for the AC / cooling loop is. When the car is traveling at high speeds the passing air masks the noise of the fan(s) but sitting at a supercharger with no airflow due to movement the system has to force airflow for the radiator and thus it gets loud.


edit: here is a direct quote

My Pack Cooler, including the Air Conditioning Compressor DID KICK IN! AND HOLY CRAP! FULL BLAST AS WELL!!! Sounded like a Circular Saw going. Both cooling fans and both radiators + the AC compressor...... WOW

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http://www.youtube.com/watch?v=ZYPeequUD4s" onclick="window.open(this.href);return false;

the video is over 1 hour long, recording the entire supercharging session so I'm not going to bother to watch it again to tell you a time stamp but I remember him moving the camera around inside and outside the car and discussing the sound the fans made during different stages of his charging session.

SuperCharging my new Tesla S at the chilly recent temperatures, with the
climate control off, was quiet as the proverbial (very quiet) church-mouse.
Perhaps SuperCharging in a Phoenix summertime would be different.

I have yet to try using the LEAF's Nissan-included (pre 2013) portable EVSE
(even updated for 240 volt operation) with the Tesla S, but it is rumored to
not work, apparently rejected by the Tesla because it lacks the minus 12 volts
in its Pilot signal.

If anybody is returning or trading their leased 2013 LEAF, and has their EVSE
modified for 240v and charging rates greater than 12 amps, please contact
me by PM. Apparently the lease contract says that you do not need to return
the EVSE to the dealer, and I would really like one to use on the Tesla.

Apparently Low voltage charging (at 120v AC) is both slow and inefficient on the LEAF,
and terribly slow and very inefficient in the Tesla S. The chargers inside the cars seem
to work much more efficiently (waste less energy) when running with 240v AC input.

The QC can put about 110 DC amps into the battery pack, and the SC can put in over
twice that into the Tesla pack, but both taper down significantly after approximately
10 or 15 minutes.

In comparison, the 6 kW LEAF internal charger puts in a maximum of approximately
16 amps DC to the pack, a relative "trickle". The precious "C" comparisons are correct,
and charging at a rate that would fill the pack in 1 hour is a "one C" rate, charging the
pack in 2 hours would be a "half-C" rate, and a rate that would charge in 4 hours would
be a slower "quarter-C" rate. The "C" stands for Capacity (of the pack being charged).

See http://avt.inl.gov/pdf/energystorage/DCFC_Study_FactSheet_50k.pdf it is a very well done government test fleet summary where 4 2012 Leaf's were driven to 50k miles with 2 of those getting exclusive DC fast charges, while the other 2 are getting level 2. The upshot was that the DC fast charge only cars saw about 2% more degradation (~27% vs ~25%) over the couple years and 50k miles.

In short, DC fast charging is barely worse than 3.3 KW Level 2, so I seriously doubt you will find any significant difference between 3.3 and 6.6 kW.

More good stuff can be unearthed if you look though their other Leaf reports:
http://avt.inl.gov/fsev.shtml

Deleted.

TimLee said:

garygid said:

... the 6 kW LEAF internal charger puts in a maximum of approximately
16 amps DC to the pack, a relative "trickle".

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27.5 amps from the wall.
16 amps is the original 2011 / 2012 or LEAF S models without charging package that is 3.3 kW into battery / 3.8 kW from the wall.

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I think the point was that the output of the charger is ~400V DC at ~15A is there is ~6 kW going into the pack. 15A into a 55-60 Ah battery is pretty much a trickle charge.

Moof said:

I think the point was that the output of the charger is ~400V DC at ~15A is there is ~6 kW going into the pack. 15A into a 55-60 Ah battery is pretty much a trickle charge.

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Thanks for correction. Deleted.
He did say DC.

dhanson865 said:

charge rate vs battery life is a non issue at the rates you mentioned.

You will waste more electricity to the EVSE the slower you charge.

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you won't be wasting electricity or $$$ to the EVSE... you'll be wasting it to the onboard inverter.

Charge as fast as possible with AC as you can on the Leaf, it's the highest conversion rate of energy into the pack (besides DCFC) and doesn't nothing for degradation rates... I don't have CHAdeMO and charge pretty darn fast!

JasonA said:

... you won't be wasting electricity or $$$ to the EVSE... you'll be wasting it to the onboard inverter.
...

Click to expand...

The loss in efficiency is from the relatively fixed overhead power consumption of the LEAF being in use for a longer period of time.
The bigger cost is pump operation but also includes power overhead for the LEAF electronics and the battery contactor being closed and the power overhead of the on board charger.
All the extra inefficient power use comes from the wall through the EVSE.