tomcon
Posts: 11
Joined: Mon Jan 07, 2019 1:08 am
Delivery Date: 30 Oct 2018
Location: Seattle, WA

Re: If charge tapers near the end, why doesn't watts/amps draw drop?

Thu Jan 10, 2019 12:28 pm

My location is Seattle. I just updated it, but it does not show up in this thread. Perhaps it will only show up in future posts.

tomcon
Posts: 11
Joined: Mon Jan 07, 2019 1:08 am
Delivery Date: 30 Oct 2018
Location: Seattle, WA

Re: If charge tapers near the end, why doesn't watts/amps draw drop?

Thu Jan 10, 2019 12:29 pm

My location is Seattle. I just updated it, but it does not show up in this thread. Perhaps it will only show up in future posts.

tomcon
Posts: 11
Joined: Mon Jan 07, 2019 1:08 am
Delivery Date: 30 Oct 2018
Location: Seattle, WA

Re: If charge tapers near the end, why doesn't watts/amps draw drop?

Thu Jan 10, 2019 12:32 pm

My location is Seattle. I just updated it. Hopefully it will start showing up. Thanks!

DaveinOlyWA
Posts: 13557
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 16 Feb 2018
Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: If charge tapers near the end, why doesn't watts/amps draw drop?

Thu Jan 10, 2019 12:36 pm

tomcon wrote:I am charging my new 2018 Leaf at 120V. have a plug-in meter that plugs into the wall plug and then the charger is plugged into the meter. When i start charging, it reads about 12A and about 1150 Watts draw. Right near the end of charging to 100%, like the hour or two before the charger goes off, it is still reading the same Amps and Watts. I had expected those to drop near the end, since it seems like you are not charging the battery as much near the end (tapering) and so why is it drawing the same power? Like in the old days when you charged a 12V battery you could see the Amps drop to near 0 at the end, and then you knew charging was done. Whey doesn't charging the Leaf battery have the same behavior? Thanks, if you understand this issue and can reply!


It actually does. Look at any declining charge curve and then take the last 2%. That rate you see there is where your 120 volt 12 amp feed runs all the time. What that means is you still have the ramp down but its like the last 2% of the charge curve unlike a DC Fast charge where its the last 40% of the curve or L2 charge where it the last 5%.
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 deceased. 29,413 miles. 2018 S40; 15,000 miles, 478 GIDs, 37.0 kwh 109.81 Ahr , SOH 94.61, Hx 120.15
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

tomcon
Posts: 11
Joined: Mon Jan 07, 2019 1:08 am
Delivery Date: 30 Oct 2018
Location: Seattle, WA

Re: If charge tapers near the end, why doesn't watts/amps draw drop?

Thu Jan 10, 2019 5:32 pm

I'll see if i can actually see it. Sounds like it is going to be difficult. I was thinking if the plug keeps reading 1350 watts but the charge is tapering, maybe that is where alot of waste is, near the end. But, its looking like that is not the case. But, i'd like to actually see it if i can, just for personal satisfaction! Thanks again for all the comments!

DaveinOlyWA
Posts: 13557
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 16 Feb 2018
Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: If charge tapers near the end, why doesn't watts/amps draw drop?

Thu Jan 10, 2019 6:42 pm

tomcon wrote:I'll see if i can actually see it. Sounds like it is going to be difficult. I was thinking if the plug keeps reading 1350 watts but the charge is tapering, maybe that is where alot of waste is, near the end. But, its looking like that is not the case. But, i'd like to actually see it if i can, just for personal satisfaction! Thanks again for all the comments!


The reading will not stay at 1350 watts or whatever your rate is. It will drop. The issue you have is that the rate is so slow. On a fast charge, the rate is constant (like yours) until it hits the knee which is when the current starts to drop. (voltage ALWAYS stays the same)

Its this curve that illustrates the maximum rate at which the batteries will take a charge under that given condition. As the SOC rises, the amperage continues to drop and will eventually drop to the rate of your level one charge. the slower the rate of charge, the higher the SOC when the knee occurs. This is quite literally near full in your case. You are talking the difference between taking 40 hours on level one to 90 minutes on DCFC. If you are part of the Seattle LEAF FB group, keep an eye out. I will be posting a pix of a curve that goes pretty low but still does not get down to level one speeds.
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 deceased. 29,413 miles. 2018 S40; 15,000 miles, 478 GIDs, 37.0 kwh 109.81 Ahr , SOH 94.61, Hx 120.15
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

User avatar
Nubo
Posts: 4993
Joined: Fri May 28, 2010 11:01 am
Delivery Date: 31 Oct 2014
Location: Vallejo, CA

Re: If charge tapers near the end, why doesn't watts/amps draw drop?

Thu Jan 10, 2019 8:31 pm

tomcon wrote:I'll see if i can actually see it. Sounds like it is going to be difficult. I was thinking if the plug keeps reading 1350 watts but the charge is tapering, maybe that is where alot of waste is, near the end. But, its looking like that is not the case. But, i'd like to actually see it if i can, just for personal satisfaction! Thanks again for all the comments!


LeafSpy will let you graph the charging session, assuming it still works with 2018 model. I personally would not recommend unattended long-duration use of "kill a watt" type meters in conjunction with vehicle charging.
I noticed you're still working with polymers.

specialgreen
Posts: 225
Joined: Sun Mar 26, 2017 1:21 pm
Delivery Date: 26 Mar 2017
Location: Minnesota

Re: If charge tapers near the end, why doesn't watts/amps draw drop?

Thu Jan 10, 2019 9:52 pm

tomcon wrote:I am charging my new 2018 Leaf at 120V. .... When i start charging, it reads about 12A and about 1150 Watts draw. Right near the end of charging to 100%, like the hour or two before the charger goes off, it is still reading the same Amps and Watts.... why is it drawing the same power?


My 2017 30kwhr Leaf does taper a bit, even when charging at 120v 12A. Below is a picture of my whole house power use. The car is sucking 1440 watts all night. The little 100 to 300 watt steps up and down all night are refrigerator & freezer. The big 1kw jumps from 6:30am-9am are the furnace fan heating the house up. The 1200 watt spike at 9:30 is a toaster. You can see that the Leaf tapers from 10am to 11:15am, as the pack is balancing. Then the Leaf has three bounces at the very end of the charge cycle (I'm not sure what that is, but I see it often). Then it's done at 11:45am. Then the house returns to its base load (about 150 watts, plus 100 to 300 as the fridge & deep freeze cycle).

(ignore the green stuff, that's the solar panels)

Image

Oilpan4
Posts: 210
Joined: Wed Jan 09, 2019 10:51 pm
Delivery Date: 10 May 2018
Leaf Number: 004270

Re: If charge tapers near the end, why doesn't watts/amps draw drop?

Thu Jan 10, 2019 10:01 pm

I have the 10kw sectec home CHAdeMO it doesn't even start to taper below 8kw until above 90% SOC. Then it slows down to 3 to 4kw. Then it usually shuts off between 90 and 96%.
So you may be able to charge at 1.4kw until it cuts off.
2011 white SL leaf with 2014 batt.
Chargers: Panasonic brick moded for 240v, duosida 16a 240v and a 10kw setec portable CHAdeMO
Location: 88103

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