Fast Charging in Winter Experience

[DonDakin]

Hi mike,

Thanks for the details. Looks very similar to sandys who charged at much colder temps.

If it ws - 1 deg c and you had been driving your car for awhile before quick charging the battery should have been above zero for sure. I would have thought the charge would be faster. It looks like the car limits the charge alot in colder weather. You charged 60 % of you battery in about the same time as sandys 40 % at colder temps.

I agree the price is to high compared to residential rates. But to put this in perspective its about the same price as a gas car to run. Still expensive but in a pinch if you need the quicker charging times as least you can do it and continue on you way.

I hope that these prices discourage use of the chargers in winter and they cut the cost in half at least in winter. That would be the right thing to do. But i think cars with better battery temp. Management like the chevy spark or perhaps the kia soul ev can still accept the charge quickly in cold temps. I dont know.

If i have the chance i will visit this charger with canion and video the charge and document and post it and blow ten bucks also.....

Don......

 

[DonDakin]

Well I decided to check out the quick charger that was giving Sandage and Mike some grief. I have been interested in what effect the battery temp has on operation of

the car for awhile now so I thought I would post some of my findings. Things are pretty much inline with what others experianced but I have some canion data also.


It was pretty cold -12 deg c outside when I visited the charger but my battery avg temp was + 11 deg c lowest cell was 4 deg highest one 16 deg.

Started quick charging with 55.5% battery with a RR of 54 km.

The charge Current started out at 49.3 amps (17.6 KW) on canion but the reading on the charger was 54 amps. Not sure which one is the accurate reading but that's a

little more data for everyone to ponder Canion amperage readings.

At about 67 % charge the current had dropped to 33 amps and kept dropping. I charged to 71.5 % and power was down below 9 kw. At that point I stopped the charge on

the charger. Total time was 8 minutes total kwh in as per canion 2 kwh. The emailed charge report from the charge company said it was 2.4 kwh delivered and 8 minute

58 sec. I may have started canion a little late. Or perhaps the 5% disagree between the canion ampmeter and the charger caused this discrepancy.

Here is a few shots at different points of the QC from canion, note the state of charge and current.

(I forgot to get a screen shot of current just after charging so I took one when I got home.

http://imgur.com/a/IWglQ/


Total cost was $1.50 for 16 % charge. And 19 kms added.

Couple of things I noticed:

The A/C did not come on at all niether did the blower as it did during a summer QC.

I could not turn on the fan blower during the charge. Even with the key in the acc position. This is different behaviour from L2 charging. On L2 charging you can turn

the key on and get the blower working. It means there is no way to get any heat into the cabin with the diesel heater during a QC. Sandange I think also noted this.


I found it weird that my battery was above zero but the initial current was low. This charger can deliver 122 amps in the summer.

I checked my summer time quick charge video and at 73 % battery the current was 46 amps.

The car must cut the initial charge current down to 50 amps or so with the lower battery temps. It would be interesting to try again with a warmer battery and see if

the start current would be higher.

Maybe if I have the time I will try another quick test on the charger went the temps are higher. I would like to find the magic battery temp that enables full 125

amps out of the charger.

One thing I noted is that the coldest cells have lower voltages in normal operations but during quick charge the coldest cells seem to have the highest voltages.

I did not get a screen shot of cell voltages at the start of the quick charge.

So perhaps the QC current is governed by the lowest cell temp in the pack 4 deg in my case. Additionally perhaps those colder cell voltages shoot up faster during

quick charge and also govern how much the current is throttled back to prevent cells going too high in voltage during charge.

It's clear that the colder it is the slower the charge. Still much faster then L2 but about 4 times the price or more.

It looks like the charge curve is the same shape at cold temps It just does everything with lower currents.

Using canion you can stop the charge when the current starts to drop, If I only stayed on the charger for 4 minutes It would have cost only .75 cents and I would have

got perhaps 10% charge in that time. I wonder if I stopped the charge unplugged and then restarted it again would I get another 4 minutes at 50 amps......

Things to ponder...

Don....

 

[sandange]

Hi Don
Thanks for sharing your results .

So in layman's terms so far - cold temperature fast charging
sucks -
it's expensive,
not as fast as we hoped for
&
unless you have a coffee shop right there and you can see your car while charging - you freeze your @zz off staying inside the car in case the charger decides to cut out and/or others are waiting in line to use it.


Now to decipher at what temperature does it become feasible (cost and time) to use fast charging.

Just guessing here
Consider that 80% charge from 0 charge @ -20 C, ( -4 F )
if it takes
4 1/2 - 5 hours on L2 @ $1/hr = $ 5
1 hour Fast charge @ $10/hr = $10

Consider that 80% charge from 0 charge @ 10 C, (50 F)
4 hours on L2 @ $1/hr = $ 4
1/2 hr Fast charge @ $10/hr = $ 5