20+ kWh to charge the battery

[ken wells]

After a long, hot (90+F) drive and parked in a 100+F garage, the wall energy required to completely recharge was 20.168 kWh. Normal full recharge is 14.1-14.5 kWh. Yes, you could hear the AC running at least 50% duty cycle, cooling the battery for 5 hours. Nearly 6 kWh of cooling!

Moral of the story: after a long, hot discharge, if your schedule allows, you can save significant energy letting the battery cool until late at night to start charging. Time to learn to use the delayed charge feature.

 

[fotomoto]

Time to learn to use the delayed charge feature.

Yeah same temps here, I have mine set to midnight; car usually gets home around 5:30pm with zero EV miles. I have a 240v 16amp EVSE that isn't "smart" but Hondalink txt notifications tell me that the charge usually takes about 3 hours.

 

[MajorAward]

After a long, hot (90+F) drive and parked in a 100+F garage, the wall energy required to completely recharge was 20.168 kWh. Normal full recharge is 14.1-14.5 kWh. Yes, you could hear the AC running at least 50% duty cycle, cooling the battery for 5 hours. Nearly 6 kWh of cooling!

Moral of the story: after a long, hot discharge, if your schedule allows, you can save significant energy letting the battery cool until late at night to start charging. Time to learn to use the delayed charge feature.

Good to know. That would raise even my off-peak cost to recharge from $1.20 to $1.68., and as high as $2.52 peak.

 

[Bender]

I wonder if this is the same concern with 110V charger

 

[MrFixit]

the wall energy required to completely recharge was 20.168 kWh

Wow - I have never seen any hint of increased wall energy with higher temperatures.
Are you sure this is not an anomalyous reading? Have you seen it more than once, and/or did you see it trending up as temperatures trended up?

 

[M.M.]

That's really interesting, although perhaps not a surprise. An unconditioned garage will make it particularly bad, since all the waste heat from cooling the battery (and the energy used for the cooling itself) will all be dumped into the already-hot garage, and the cooling gets proportionately less efficient the hotter the garage gets.

A small vent fan in your garage might save a lot of energy...

Of note, if your utility offers time-of-use EV rates, nighttime charging will probably be drastically cheaper than daytime (for PG&E's EV2-A plan the summer off-peak is 3 times cheaper than the full-peak).

If your utility offers EV rates, unless you use a lot of energy at home in the middle of the day and don't want to put in a separate meter for your EV, it's kind of nuts not to switch to an EV rate schedule and schedule your charge in off peak. If I had a regular residential rate gas and electricity would probably be roughly comparable in cost-per-mile; with an EV rate electricity costs half what gas does, and I probably ended up saving money on my home as well since very little use was during peak times.

A tip for those who might be interested in trying the charge scheduler in the Clarity: It is the dumbest scheduler I've ever seen, and Honda should have been embarrassed to ship it. You can set a start time, an end time, or both. But if you set both, then plug in at any time after the start time (say you got home late), it won't charge until the day after unless you manually start the charge by holding down the button on the remote. Even one of those '80s era rotary light switch timers is smarter.

Contrast with the Volt, in which you could set full, part, and off peak windows, tell it when you usually leave in the morning, and have it optimize charge timing for hard price, soft price, and/or combined with ready-to-go time.

 

[ken wells]

Wow - I have never seen any hint of increased wall energy with higher temperatures.
Are you sure this is not an anomalyous reading? Have you seen it more than once, and/or did you see it trending up as temperatures trended up?

Pretty sure it's normal and only due to the heavy use of the AC to cool the battery during charging. You could hear the AC cycling continuously thru the whole charge. In cooler temperatures, the AC never comes on.

I didn't mention before, but I am charging at 3.6 kW

 

[2002]

That's really interesting, although perhaps not a surprise. An unconditioned garage will make it particularly bad, since all the waste heat from cooling the battery (and the energy used for the cooling itself) will all be dumped into the already-hot garage, and the cooling gets proportionately less efficient the hotter the garage gets.

A small vent fan in your garage might save a lot of energy...

Of note, if your utility offers time-of-use EV rates, nighttime charging will probably be drastically cheaper than daytime (for PG&E's EV2-A plan the summer off-peak is 3 times cheaper than the full-peak).

If your utility offers EV rates, unless you use a lot of energy at home in the middle of the day and don't want to put in a separate meter for your EV, it's kind of nuts not to switch to an EV rate schedule and schedule your charge in off peak. If I had a regular residential rate gas and electricity would probably be roughly comparable in cost-per-mile; with an EV rate electricity costs half what gas does, and I probably ended up saving money on my home as well since very little use was during peak times.

A tip for those who might be interested in trying the charge scheduler in the Clarity: It is the dumbest scheduler I've ever seen, and Honda should have been embarrassed to ship it. You can set a start time, an end time, or both. But if you set both, then plug in at any time after the start time (say you got home late), it won't charge until the day after unless you manually start the charge by holding down the button on the remote. Even one of those '80s era rotary light switch timers is smarter.

Contrast with the Volt, in which you could set full, part, and off peak windows, tell it when you usually leave in the morning, and have it optimize charge timing for hard price, soft price, and/or combined with ready-to-go time.

I have the type of rate plan you are describing with super cheap rates from 11:00 pm to 7:00 am so that's what I have the schedule set to. Using the app I can work around the limitations and quirkiness without too much trouble. If I come home at say 11:20 pm I plug in then I go into the house, then I launch the app and modify the charge schedule to start at 11:25 pm, but leave the ending time at 7:00 am. Once I see that charging has started I then modify the starting time back to 11:00 pm for the next night and I am done. If the battery is over half full and I know charging will complete before 7:00 am anyway then I just start charging right away either with the fob or the app.

 

[M.M.]

If I come home at say 11:20 pm I plug in then I go into the house, then I launch the app and modify the charge schedule to start at 11:25 pm, but leave the ending time at 7:00 am. Once I see that charging has started I then modify the starting time back to 11:00 pm for the next night and I am done. If the battery is over half full and I know charging will complete before 7:00 am anyway then I just start charging right away either with the fob or the app.

Out of curiosity, if you're not changing the end time why jump through all those hoops when the battery is empty instead of just pressing the button on the fob? It'll still stop at 7am whether you start it with the timer or the fob.

 

[KentuckyKen]

Are we sure the Freon AC compressor is running to cool the battery?
I thought the 3 glycol based cooling loops were separate and independent of the AC. If that is the case then what you are hearing is just the twin radiator fans and pump running. I know that’s a lot of kWhs for 2 fans and a pump but then it’s also spread over 5 hours of 50% duty cycle. Also the AC, for me, seems to use very little power since my range reduction seems to be from mid 60s to low 60s/high 50s. So maybe all that power is going to just the fans and pump.
Anybody know for sure?
@AnthonyW, please come to our rescue!

 

[M.M.]

So maybe all that power is going to just the fans and pump.
Anybody know for sure?

I don't know what the algorithm or design are, but 1.2kW seems ridiculously high for just a couple of fans and a small pump to me, especially if it's not a constant duty-cycle.

And I'm pretty sure I can hear the cooling loop (no fans) running in mine when charging at 7kW in ambient temperatures below 60F (which I'd expect to improve battery life), which would mean that the pump parasitic load is already factored in to a "regular" low-temperature charge.

 

[2002]

Out of curiosity, if you're not changing the end time why jump through all those hoops when the battery is empty instead of just pressing the button on the fob? It'll still stop at 7am whether you start it with the timer or the fob.

It doesn't work that way, at least mine doesn't, maybe yours works differently. If the scheduled start time arrives and the charger is not plugged in then that charge session is cancelled. If you do nothing it won't charge until the start time comes around again. If you press the fob it starts a charge-until-full session.

Easy to test this, schedule a start time in five minutes, with a stop time five minutes later, but don't plug in. When the scheduled start time arrives the car clicks a few times. Wait a couple of minutes then plug in. Nothing happens (other than the green light blinks for a few seconds). Press the fob and charging starts. However when the stop time arrives a few minutes later it doesn't stop charging.

 

[M.M.]

It doesn't work that way, at least mine doesn't, maybe yours works differently. If the scheduled start time arrives and the charger is not plugged in then that charge session is cancelled.

Well, I've learned something today. It indeed does work that way on mine as well, but I'm virtually certain I tested that when I first got the thing. Either I'm remembering completely wrong or they changed the behavior in one of the software updates I had done.

In either case, this confirms that when I thought there was no way to make the charge timer any worse than it already was, I was wrong. It literally does every possible thing wrong it could, and there are only three settings.

 

[MrFixit]

Pretty sure it's normal and only due to the heavy use of the AC to cool the battery during charging. You could hear the AC cycling continuously thru the whole charge. In cooler temperatures, the AC never comes on.

I didn't mention before, but I am charging at 3.6 kW

Ken - I hear noises during charge too, but as @KentuckyKen states, I am assuming it is coolant pumps (should be negligible drain of wall energy). My highest charge ever was 14.6 kWh and that occurred in the cold (December). My full charges seem slightly less when it is hot.

If this is really happening (and is 'normal'), then it would be good to characterize a threshold (specific conditions that can trigger this) in order to better learn when mitigation is required. It is interesting to note that one way to mitigate this would be to charge at a higher rate (lessens the charge time). At the full rate of 7.2 kW, you may suffer half the loss that you got at 3.6 kW.

I still do not quite believe this is 'normal' - Is there any way that you accidentally were running the climate system during this charge? Could have inadvertently been remotely activated with the FOB or through the App...

A possible experiment - During what you consider hot (but maybe not excessively hot), do a full charge with the climate system intentionally running and see if this reproduces your result. I would like to be able to chalk this one up as an 'operator error' rather than a characteristic of the vehicle !

 

[AnthonyW]

Are we sure the Freon AC compressor is running to cool the battery?
I thought the 3 glycol based cooling loops were separate and independent of the AC. If that is the case then what you are hearing is just the twin radiator fans and pump running. I know that’s a lot of kWhs for 2 fans and a pump but then it’s also spread over 5 hours of 50% duty cycle. Also the AC, for me, seems to use very little power since my range reduction seems to be from mid 60s to low 60s/high 50s. So maybe all that power is going to just the fans and pump.
Anybody know for sure?
@AnthonyW, please come to our rescue!

There is no AC/freon cooling the battery. Kentucky Ken is correct in that it is a radiator based cooling loop. See the attachment "Integrated Cooling System for Underfloor High Voltage Devices in PHEV" on post number 145 of the
Honda Service Express Bulletins for 2018 Clarity PHEV:

https://www.insideevsforum.com/comm...-for-2018-clarity-phev.2183/page-8#post-50910

It should be noted that if it is too hot, the Electric Powertrain Temperature Controlling System will not actively cool the battery-the coolant will bypass it, leaving the battery to its own heat rejection as the only way of moderating temperatures. As shown in the diagrams below, calling it a cooling system is a misnomer-it is moreso what I like to call a "Out of Specification Temperature Avoidance System". The system tries to keep the battery between 25C and 35C (77F to 95F) but if it can't the coolant will bypass the battery. It is primarily designed to work at the top of the temp range although I think a lot more could be done to bring the temp up in the winter (that's an entirely different post).

So I would be careful. The battery probably went over the temp range while you were driving. The DC-DC converter and on board charger can get very hot while driving or charging. In that case the coolant will bypass the battery. The system can only bring the temperature down 12K (lets round that conversion to 22F) versus ambient so if the DC-DC or on board charger were above 117 (the highest I have seen on my Scangauge is 120F) then there is no battery cooling taking place. When you plugged it in, it was most likely not charging the battery but bringing the on board charger and DC-DC converter down to inside the temp target range. Once the coolant got the temps down charging would start but it would cycle on and off as temps got to hot in your 100F garage. Like others have said wait as many hours as you can before charging the battery after a long hot drive.

 

[fotomoto]

The system tries to keep the battery between 25C and 35C (77F to 95F)

if the DC-DC or on board charger were above 117 (the highest I have seen on my Scangauge is 120F)

Very interesting data AnthonyW, thanks!

A couple of little things about battery temps I've picked up from the two previous plug-ins:

My C-Max with its air-cooled battery stops the party at 113F pack temp. This can be reached on a hot day, for example, by discharging the pack and charging it outside with 240v during the heat of the day. It will revert to hybrid-only driving till temps fall back below. Personally even though I'm in hot south Texas, 109f is the highest I've seen on my scangauge but I don't do outside charging.

Second thing was back in the fall of 2010 while the Volt was still in pre-production, GM did a publicity demo tour around the country. When they came to San Antonio, I got to drive one and spoke to one of their battery engineers who said this about LiOn battery temps, "If you're comfy, the battery's comfy". That always stuck with me.

 

[2002]

one of (Volt's) battery engineers who said this about LiOn battery temps, "If you're comfy, the battery's comfy".

The Prius Prime (and I'm guessing Volt also) uses cabin air to cool the battery, thus their comment. In fact Prius Prime in cases of very high temperature runs the cabin AC when plugged in just to cool the battery.

Like others have said wait as many hours as you can before charging the battery after a long hot drive.

I'm sure that is the best advice, but in cases where you can't wait, I wonder if there is anything that can be done to help? Ventilating the garage would be one idea, but I wonder if there is some strategic place that a regular fan could be placed to help carry away heat? If the battery is completely cut-off from air circulation then maybe not directly, but when the cooling pumps are running, to help the battery radiator get rid of heat maybe place a fan in front of the car blowing air into the front grill? Maybe simply popping the hood would help?

 

[RobinBrain]

I have an OBD II reader and the torque app, what temperature are you guys looking at? The engine coolant temp or is there some other temp field I can bring up in the app?

There is no AC/freon cooling the battery. Kentucky Ken is correct in that it is a radiator based cooling loop. See the attachment "Integrated Cooling System for Underfloor High Voltage Devices in PHEV" on post number 145 of the
Honda Service Express Bulletins for 2018 Clarity PHEV:

https://www.insideevsforum.com/comm...-for-2018-clarity-phev.2183/page-8#post-50910

It should be noted that if it is too hot, the Electric Powertrain Temperature Controlling System will not actively cool the battery-the coolant will bypass it, leaving the battery to its own heat rejection as the only way of moderating temperatures. As shown in the diagrams below, calling it a cooling system is a misnomer-it is moreso what I like to call a "Out of Specification Temperature Avoidance System". The system tries to keep the battery between 25C and 35C (77F to 95F) but if it can't the coolant will bypass the battery. It is primarily designed to work at the top of the temp range although I think a lot more could be done to bring the temp up in the winter (that's an entirely different post).

So I would be careful. The battery probably went over the temp range while you were driving. The DC-DC converter and on board charger can get very hot while driving or charging. In that case the coolant will bypass the battery. The system can only bring the temperature down 12K (lets round that conversion to 22F) versus ambient so if the DC-DC or on board charger were above 117 (the highest I have seen on my Scangauge is 120F) then there is no battery cooling taking place. When you plugged it in, it was most likely not charging the battery but bringing the on board charger and DC-DC converter down to inside the temp target range. Once the coolant got the temps down charging would start but it would cycle on and off as temps got to hot in your 100F garage. Like others have said wait as many hours as you can before charging the battery after a long hot drive.

View attachment 5286

View attachment 5287

Very interesting data AnthonyW, thanks!

A couple of little things about battery temps I've picked up from the two previous plug-ins:

My C-Max with its air-cooled battery stops the party at 113F pack temp. This can be reached on a hot day, for example, by discharging the pack and charging it outside with 240v during the heat of the day. It will revert to hybrid-only driving till temps fall back below. Personally even though I'm in hot south Texas, 109f is the highest I've seen on my scangauge but I don't do outside charging.

Second thing was back in the fall of 2010 while the Volt was still in pre-production, GM did a publicity demo tour around the country. When they came to San Antonio, I got to drive one and spoke to one of their battery engineers who said this about LiOn battery temps, "If you're comfy, the battery's comfy". That always stuck with me.

 

[fotomoto]

(and I'm guessing Volt also) uses cabin air to cool the battery

The Volt has a coolant TMS similar to the Clarity.

 

[Pushmi-Pullyu]

The Prius Prime (and I'm guessing Volt also) uses cabin air to cool the battery...

The Volt's battery heating/ cooling system includes a heat exchanger which allows excessive heat to be removed by the car's air conditioner system. As I understand it, that's a direct use of the A/C refrigerant loop, not indirect cooling using cabin air.

Normal cooling for the Volt's battery is liquid cooling using a water/glycol (antifreeze) mix. (Presumably the Clarity PHEV and the Clarity Electric also use that sort of system?) If my understanding is correct, the Volt's A/C heat exchange loop is only activated when the battery temp gets too high for normal cooling.

Note the source specifies "2011 Volt", so this would be Voltec 1.0. I'm not sure the setup for Voltec 2.0 is the same.

Source: "The Chevrolet Volt Cooling/Heating Systems Explained"