watchdoc
Posts: 138
Joined: Sun Sep 19, 2021 6:15 am
Delivery Date: 03 Jan 2022
Location: Greenville, NC

ONE long charge or TWO short charges to avoid Rapidgate

So, the last couple times I have DC fast charged to try and use up my EVgo $250 credit, I'm surprised at how much my 22 Leaf Plus rapidgates on a single charge. Each charge was approx 45 minutes and started below 20% and ended above 80%. This charger is at a Chick-fi-la restaurant so we just ate dinner. Both times charging speed slowed below 20kw and the temp guage was well past the 3/4 mark although not in the red. I drove home and the temp guage returned to normal by the next morning.

Anyway, I have some 300-500 mile trips (each way) planned for later this year and I'm trying to work on my charging strategies. Assumming you start out with a full battery and temp guage in the middle, would it be better to make two short charging stops or a single long stop?

Something like:
Leg 1 Full down to 10% (170-190 miles?)
Charge 1 10% to 90% approx 1 hour (150 miles added approx? and lots of rapidgate)

OR

Leg 1 Full down to 10% (170-190 miles)
Charge 1 10% to 70% approx 30 min or as soon as rapidgate really starts dropping the charge rate (80-90 miles added??)
Charge 2 10% to 70% again or as soon as Rapidgate knocks the charge rate down again (50-60 miles added???)

Opinions from you guys that have taken longer trips in your Leaf Plus??
22 Leaf SV+ Deep Blue Pearl
GerryAZ
Gold Member
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Delivery Date: 12 Jun 2011
Location: Phoenix, AZ

Re: ONE long charge or TWO short charges to avoid Rapidgate

If charging stations are located appropriately and you know they are working, then two "short" charges would probably cause less battery heating and minimize charge tapering. Also, tapering is sometimes caused by the charging station to minimize utility demand charges. Even in that case, tapering usually starts at 15 minutes so the two shorter charges would still be beneficial.

The only drawback to planning for two shorter charges is if the second charger is not available for some reason.
Gerry
Silver LEAF 2011 SL rear ended (totaled) by in-attentive driver 1/4/2015 at 50,422 miles
Silver LEAF 2015 SL purchased 2/7/2015; traded 8/10/2019 at 82,436 miles
White LEAF 2019 SL Plus purchased 8/10/2019
SageBrush
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Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

Re: ONE long charge or TWO short charges to avoid Rapidgate

Not all drops in power are rapid-gating. It is also part of the normal taper that occurs as SoC increases past ~ 45% of thereabouts.

I think the better question for you is where are the DC chargers located, and where would you like to spend the better part of an hour ? Your other questions can then be answered.
2013 LEAF 'S' Model with QC & rear-view camera
Bought Jan 2017 from N. Cal @ 90% SOH
Two years in Colorado, now in NM
SOL0 7/2022 @ 83% SOH
DougWantsALeaf
Posts: 3349
Joined: Fri May 10, 2013 8:21 pm
Delivery Date: 18 May 2013
Leaf Number: 407811
Location: Chicago North Side

Re: ONE long charge or TWO short charges to avoid Rapidgate

I have also noticed that some chargers will taper faster than the car could take charge. I have had a couple sessions where the charge was running at 40 something and then after ~30 minutes drops to 20 almost instantly. When I restarted the session it went back to the 30s and held it. I dont know exactly why that happens.

I have another trip to Kansas coming in a few weeks, so will be trying 2x 20-90% charges and then a 50-80% for the final leg. In my previous runs, I always get inpatient and leave early which has me arrive at a very low SoC, which increases the temp on the battery. I will post the results. My hope is to get total charge time to 2 hours for the drive...which might be a bit aspirational.
2019 S Plus (93.3% SOH) & 2019 SV Plus (89.9% SOH) Both Silver
2013 Leaf SV sold 2019 with 11 bars
100 Mile Club Member (Number 87)
Max Miles on 13 Leaf: 120 miles
Max Miles on 19 SV+: 242 Highway miles @ 4.5 miles/kWh
SageBrush
Posts: 7449
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

Re: ONE long charge or TWO short charges to avoid Rapidgate

I'll take a guess that the most useful thing a driver can do when faced with a multiple charger day in a LEAF is to drive on the slower side. Probably best to stay under 65 mph (accounting for headwind if present.)
2013 LEAF 'S' Model with QC & rear-view camera
Bought Jan 2017 from N. Cal @ 90% SOH
Two years in Colorado, now in NM
SOL0 7/2022 @ 83% SOH
DougWantsALeaf
Posts: 3349
Joined: Fri May 10, 2013 8:21 pm
Delivery Date: 18 May 2013
Leaf Number: 407811
Location: Chicago North Side

Re: ONE long charge or TWO short charges to avoid Rapidgate

Sage,

In general I agree, but would more accurately say to keep car above 4 miles per kWh efficiency (ideally above 4.5). The draw on the battery absolutely impacts the rate of temp reduction while driving much more than small differences in ambient temps.

Even better to do it by average battery draw (keep it sub 8kW) but not everyone has Leafspy. Limit to 1 or just over 1 power bar. This requires a very steady foot though. I would love if Dala could rig the cruise control to be a power set instead.

Mph can be all over the place based on wind. I have had 75mph eat less energy with tailwind than 50 into a strong wind.
2019 S Plus (93.3% SOH) & 2019 SV Plus (89.9% SOH) Both Silver
2013 Leaf SV sold 2019 with 11 bars
100 Mile Club Member (Number 87)
Max Miles on 13 Leaf: 120 miles
Max Miles on 19 SV+: 242 Highway miles @ 4.5 miles/kWh
SageBrush
Posts: 7449
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

Re: ONE long charge or TWO short charges to avoid Rapidgate

DougWantsALeaf wrote: Tue Sep 20, 2022 1:10 pm (keep it sub 8kW)
That is ~ 40 mph on level ground without any wind.
15 kW is in the 60 - 65 mph range in above conditions
2013 LEAF 'S' Model with QC & rear-view camera
Bought Jan 2017 from N. Cal @ 90% SOH
Two years in Colorado, now in NM
SOL0 7/2022 @ 83% SOH
watchdoc
Posts: 138
Joined: Sun Sep 19, 2021 6:15 am
Delivery Date: 03 Jan 2022
Location: Greenville, NC

Re: ONE long charge or TWO short charges to avoid Rapidgate

DougWantsALeaf wrote: Tue Sep 20, 2022 10:04 am I have also noticed that some chargers will taper faster than the car could take charge. I have had a couple sessions where the charge was running at 40 something and then after ~30 minutes drops to 20 almost instantly. When I restarted the session it went back to the 30s and held it. I dont know exactly why that happens.

I have another trip to Kansas coming in a few weeks, so will be trying 2x 20-90% charges and then a 50-80% for the final leg. In my previous runs, I always get inpatient and leave early which has me arrive at a very low SoC, which increases the temp on the battery. I will post the results. My hope is to get total charge time to 2 hours for the drive...which might be a bit aspirational.
Doug, do you still feel that going below 20% SOC on a multi charging stop road trip just heats up the battery more?

What do you think the maximum single stop range would be? I figure it would be in the 320-340 mile range

I'm trying to develop some charging strategy road trip rules.

What do you think about these general rules???
1. Slower is still often faster to keep your Km per mile figure up.
2. For trips less than 320-340 miles, run the battery down to teens or single digits, then make a single long charging stop.
3. For trips greater than 320-340 miles, make multiple stops charging from 20%-80% to keep rapidgate at bay and keep charging speeds up.

Of course, these rules are charger speed and charger location dependant.
22 Leaf SV+ Deep Blue Pearl
DougWantsALeaf
Posts: 3349
Joined: Fri May 10, 2013 8:21 pm
Delivery Date: 18 May 2013
Leaf Number: 407811
Location: Chicago North Side

Re: ONE long charge or TWO short charges to avoid Rapidgate

If your charger is well placed, you could even do 400 miles with the smaller tires/rims on a newer battery with one charge on a summer day. You need 220 miles out of the starting charge though and will arrive in single digits SoC even with high care.

If getting a good charge rate, I would go higher than 80%, even 90% just to stretch the distance between stops. On my trip to Greenbay last week, when charging in Milwaukee, I was above 40KW into the high 70s SoC and still near/at 30 at 90%.

While any new EV owner would be utterly frustrated below 75KW, I find 30KW is kind of the tolerance limit in terms of charging speed.
2019 S Plus (93.3% SOH) & 2019 SV Plus (89.9% SOH) Both Silver
2013 Leaf SV sold 2019 with 11 bars
100 Mile Club Member (Number 87)
Max Miles on 13 Leaf: 120 miles
Max Miles on 19 SV+: 242 Highway miles @ 4.5 miles/kWh

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