Chargepoint stations and less than 6.6 kWh charging

[SmoothJ]

Hello all and forgive me if this has been answered already. I was at a chargepoint station, and while doing a charge, I noticed I could not go above 6 kWh even though the station is rated for 6.6 (exact amount was 5.91). I also tried another chargepoint station with the same result. Is this normal for a MY 2016? I don't have a 240v EVSE at home yet, and I am still using the included 120v EVSE.

I do not think there is anything wrong per say, but curious as to why its not charging at the allowed rate.

 

[JejuSoul]

I noticed I could not go above 6 kWh even though the station is rated for 6.6

Hi SmoothJ,
Welcome to the forum. Thanks also for the post in the Charging Fault Error thread. From that thread you can see that MY2016 cars had their max charging current reduced from about 30A to 27.4A. The energy value you mention above is what you would get by charging for an hour at this current and 220V.

MY2015 = 30 * 220 * 1 = 6,600 Wh = 6.6 kWh
MY2016 = 27.4 * 220 * 1 = 6,028 Wh ~ 6.0 kWh

 

[SmoothJ]

Thank you for getting back to me on this JejuSoul. I did not read all the posts about the issue, but I wonder if the MY2017 would be "limited" to the same issue. Granted we are only talking about < 2 miles per hour difference however.

 

[notfred]

Yes, it seems Kia decided that the car should charge at 10% less than what the EVSE is capable of as a safety margin. They introduced this in the 2016 model year and seem to have carried it forward, also any older cars that have the charger replaced also get the 10% reduction.

 

[SmoothJ]

They should update their marketing material and manuals, or else they will have a nice law suit on their hands.

 

[SoulEV2016]

The marketing doc always indicate 6,6kW.

 

[notfred]

I suspect that the 10% is on the signal from the EVSE, so if you plug it in to a higher power EVSE then you will get the 30A draw that will give you 6.6kW.

 

[GizmoEV]

I do get 6.6kW on my 2016 EV at ChargePoint and other stations. It appears that the derating change is, as notfred surmises, based on the EVSE current signal. Another reason I have seen less than 6.6kW is on stations running at 208V because they are on commercial power and using only two legs of their 3-phase system. That is how it is at my local community college's stations which were put in as part of a new building construction project.

 

[JejuSoul]

The 6.6kW referred to as the max power of the charger is for the DC output not the AC input.

The OBC has an efficiency rating at best around 90%. You need to input about 7.3kW to get the max output.
Here's my car charging from a 32A 220V EVSE.
The DC output power (not shown - we call it Energy Draw in our Torque codes) would be about 6.25kW.
That value is used to calculate the OBC efficiency.

 

[jysl]

At my old work place Chargepoint I see max 5.91 also (this is before the new OBC)

So I think it just that CP charger. The one that was use is duel 6.6 shared so if two car is charging I am getting 2.87 one car I see 5.91

 

[SmoothJ]

At my old work place Chargepoint I see max 5.91 also (this is before the new OBC)

So I think it just that CP charger. The one that was use is duel 6.6 shared so if two car is charging I am getting 2.87 one car I see 5.91

I wish I can say it was just that charger, but I tried to two in different cities with the same result. As stated before ~0.6 kW isn't going to hurt me, but I was curious of what others were charging at.

I would need to get that BT ODB module and really test it out to see.

 

[GizmoEV]

I just finished building an OpenEVSE L1/L2 50A wide voltage deluxe kit. This gave me a chance to test out how the car behaves with varying pilot signals. On 240V the EVSE changes the pilot signal in 2A increments. Any setting 28A and the car charged at 27.5A which came out to 6.6kW. When the pilot signal was set to 26A or lower the car charged at about 10% lower than the pilot setting. I really don't understand why Kia did this.

 

[notfred]

Just to clarify what you measured
1) Max draw is 27.5A so at 240V 6.6kW
2) Car draws 10% less than what the EVSE signals up to the max of 27.5A

I think the reason why the did it is that knocking the charge power down by 10% increases the safety margins with little meaningful difference in time to charge. Electric car charging at home is one of the toughest things to do in terms of combined load and length of time. There are things that draw more current but they run for a shorter time, and there are things that run for longer but they draw less current.

There have been news stories about charging fires with Teslas, and Kia didn't want their name associated in the media with burning down houses:
http://energyblog.nationalgeographic.com/2013/12/20/tesla-model-s-owners-garage-blaze-a-fire-expert-weighs-in/
https://forums.tesla.com/en_CA/forum/forums/melted-plug

 

[acadiandad]

I just finished building an OpenEVSE L1/L2 50A wide voltage deluxe kit. This gave me a chance to test out how the car behaves with varying pilot signals. On 240V the EVSE changes the pilot signal in 2A increments. Any setting 28A and the car charged at 27.5A which came out to 6.6kW. When the pilot signal was set to 26A or lower the car charged at about 10% lower than the pilot setting. I really don't understand why Kia did this.

I had noticed similar results at L1 with my openEVSE but I hadn't taken the time to double check the pilot signal waveform. Good to know I wasn't imagining things !

 

[SoulEV2016]

With Torque Pro, now, you can view the Pilot DUTY provide by the charger point.
Pilot DUTY is the max alloyed current that the charger point provide.

Usefull to see a problem with the plug ... or the electronic of the charger point.