insndrvr
Posts: 1
Joined: Fri May 12, 2017 11:11 am
Delivery Date: 06 Oct 2016

Drawing less than 6.6kw while charging

Fri May 12, 2017 11:29 am

When I got my leaf 7 months ago, it would charge at 6.6kw as measured by the ChargePoint charging stations I use at my work. After about 2 months, it dropped to about 6.3kw or less and I have seen it go below 6 well before the battery is near full capacity. I see the car ramp down the power during the last 2% of the charging cycle, but this happens throughout the whole charge regardless of how low the battery is when I start.

I have tried multiple charging stations around town with the same result. Now it will only charge at 6.3kw or less. The decrease in charging rate coincided with the weather getting colder, so I assumed it was a function of things being cold and slowing down. But now the temps are back in the 70s and the charge rate has not come back up. The dealer checked the vehicle yesterday and said it did not have any stored codes, so they do not see a problem.

Has anyone else experienced this? Is this an indication of a potential problem or is it within the tolerance of the on board charger?

Car is a 2016 SV with a little over 3,000 miles on it.

cwerdna
Gold Member
Posts: 7063
Joined: Fri Jun 03, 2011 4:31 pm
Delivery Date: 28 Jul 2013
Location: SF Bay Area, CA

Re: Drawing less than 6.6kw while charging

Fri May 12, 2017 11:51 am

At my work, apparently the supply voltage is 208 volts, which is common for commercial power, per a Chargepoint tech that came out a few years ago.

So, most of the time, per Chargepoint graphs, it's usually 5.9 to 6.1 kw, at max. The range can be 5.7 to 6.2. This is including other Leafs I plug in and both my current and former Leaf.

Some stations inherently seem to have lower voltage than others. Perhaps there's some other load on that circuit or a voltage drop due to greater resistance?

The ramp down near full and bounces (up to 3) at the end of charging to 100% is are normal.

The Tesla Model S at work usually seem to max out at 6.2 kw. 208 volts * 30 amps = 6240 watts = 6.24 kW. I hear Tesla's app shows you the supply voltage.
Last edited by cwerdna on Fri May 12, 2017 2:16 pm, edited 1 time in total.

'13 blue Leaf SV w/premium package (owned)
'13 blue Leaf SV w/QC + LED & premium packages (lease over, car returned)
'06 Prius

BenTheRighteous
Posts: 62
Joined: Tue Feb 14, 2017 5:36 am
Delivery Date: 14 Feb 2017
Location: Raleigh, NC

Re: Drawing less than 6.6kw while charging

Fri May 12, 2017 1:45 pm

I dunno, I always thought it was battery-temperature-related. My Leaf has recently started doing this:

Image

Sometimes it ramps down, sometimes it doesn't. Seems to correlate with how hot it is outside. Personally, I'm not worried about it. (Obviously I'm referring to the drop around 2:30, not the tail-end jumpiness, but I'm not worried about that either. I trust that the car is managing its charge correctly.) :)
2017 Leaf S
OpenEVSE P50-D WiFi Kit
Raleigh, NC
USA

cwerdna
Gold Member
Posts: 7063
Joined: Fri Jun 03, 2011 4:31 pm
Delivery Date: 28 Jul 2013
Location: SF Bay Area, CA

Re: Drawing less than 6.6kw while charging

Fri May 12, 2017 2:15 pm

I've never seen that weird drop to 5.x kW that BenTheRighteous is seeing. Perhaps he and the OP have a problem water pump and the OBC is ramping down to protect itself?

viewtopic.php?p=490435#p490435 is what mine typically looks like when charging to 100%. (Yes, I know that's very old Chargepoint UI.)

'13 blue Leaf SV w/premium package (owned)
'13 blue Leaf SV w/QC + LED & premium packages (lease over, car returned)
'06 Prius

BenTheRighteous
Posts: 62
Joined: Tue Feb 14, 2017 5:36 am
Delivery Date: 14 Feb 2017
Location: Raleigh, NC

Re: Drawing less than 6.6kw while charging

Sun May 21, 2017 4:50 pm

Just to follow up, I had a chat with the dealer this weekend and just like OP, their attitude was "no code = no problem." Let's just say I was less than satisfied with that answer, but at least they were willing to give me documentation of my concern and the car's current mileage, in case things got worse in the future.

(Side note: If you have a dongle plugged into the car for LeafSpy, remove it before the dealer sees it, they will make a stink about it.)

However in my case I think I've found the culprit - OpenEVSE has an internal thermometer and will ramp down the current when it passes a certain temperature.

https://openev.freshdesk.com/support/solutions/articles/6000113537-openevse-safety-features
Temperature Throttling

OpenEVSE Actively reduces charging current during high temperature events in several steps. If temperature drops full current is restored. Charging will be halted if temperature exceeds a critical level.

This is probably not what OP is experiencing, but I wanted to share what I found in case it helps others.
2017 Leaf S
OpenEVSE P50-D WiFi Kit
Raleigh, NC
USA

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