It is my understanding that here are 3 cooling loops: cabin, batteries, and inverter/charger. Whether or not the coolant flow can be switched to warm the batteries from ICE heat or from the cabin resistance heater when not plugged in is the question. Here are some diagrams and articles that have been shared on other threads that may help. Sorry, but I could only download the other SAE article by way of 5 files, one for each page. I also included the file from The first article that @victor_2019 linked to. Now maybe the Clarity Brain Trust can tell us what’s going on with the Canadian battery heaters.
Here is a blow-up of the message in the manual to make it easier to read: Cabin heating is done through the normal "heater hose" loop from the engine like regular cars. In addition there is a branch off from the heater hose loop that passes through the resistance heater which is located in the engine compartment (towards the back and on the left side if facing the engine with the hood up). During resistance heating a valve closes off this loop from the rest of the engine cooling system so that the resistance heater only has to heat the coolant in the cabin heating loop. A separate smaller water pump is used during resistance heating to pump the coolant into the cabin since the main engine electric water pump will not be operating. At least this is how I infer that it works from looking at the various parts involved. The battery meanwhile is on a completely separate cooling system that includes only the battery, the charger and the DC-DC converter. This system has its own radiator at the front of the engine compartment. During cold weather the battery is thus being warmed by the charger and DC-DC converter waste heat. In addition to being warmed by charger and converter waste heat Canada has a battery heater that can be used when plugged in. However I have not seen details anywhere of how this works, the only clue that I know of is found is in the manual which states (page 466): "If the vehicle is plugged in when outside temperatures are low, the battery warming system will use the power from the charging equipment to maintain the temperature of the battery until the next time the vehicle is driven." Presumably the "charging equipment" has some method to create heat even when not charging. Whether this heats the battery directly or heats the coolant in the battery coolant loop is unknown. Also based on the "Please wait while the vehicle is warmed" message it appears that the battery heater can also operate if the engine is running, presumably powered by electricity from the generator.
As an aside for northern U.S. owners / prospective owners, I forgot about the -22F (-30c) limit for the U.S. Clarity. A year or two ago, I added an electric heater in the ceiling of my closed, but unheated garage. At first I set the temperature to 0F (~-18c), but it was eating too many of my saved solar credits (I prefer to "burn" them in a toasty living room or office), so I finally set it as low as possible, to somewhere between about -15F and -20F. The car always started, no problems.
“Please wait while the vehicle is warmed “ sounds to me that if I wait long enough, the battery will be warm enough and I will be able to drive. Am I correct? Sent from my iPhone using Tapatalk
Yes, you wait until the engine warms up the car. I am still assuming that they will use the power from the generator to heat the batteries with the battery heater, because doing it just with the radiator in the engine compartment scavenging heat at -30c will take a ****ing long time. I can't believe they would design the car in a way that strands you somewhere if you don't have a L2 charger nearby
Interesting articles, goes into quite a bit of detail about battery cooling. Although nothing that I could find about a battery heater, presumably the articles were written only about the U.S. version. And even then there is nothing stated about battery heating in general, other than it does mention that in the ES cooling loop (battery, charger, DC-DC converter) the battery can be bypassed. It said this occurs when the battery is hot and the coolant temperature is even hotter, or if the battery is cold and the coolant temperature is even colder. But also in one of the charts which shows various situations where the battery is bypassed or not bypassed, one of the scenarios shown is when the car is charging and the ambient temperature is very cold, the chart says in this case the battery is not bypassed and it refers to this as "Battery warming". Implying that heat generated from the charger flows through the coolant loop to warm the battery. Maybe there are some other documents that go into more detail about battery warming and maybe even the elusive Canada battery heater.
If I was somewhere with my Clarity PHEV in temperatures below -22F (-30C) I would probably start the engine before it cold soaked too long. In the OP scenario I would start it during lunchtime and run it until warm. Is anybody aware of any actual case where a Clarity PHEV ever did not start due to cold?
MNSteve as been asking this for several weeks now if anyone has experienced car not starting below -22F. From post #11 yesterday:
according to a reply on the quebec forums, the battery warmer only works when plugged in, either 110V or 220VAC. the heater draws a small amount of power as needed. but it will take a long time to cool down the battery to an ambient of -30C so it's unlikely that the car won't start after just a few hours, for example while parked at work.
Is there any reason that we should give any credence to whoever said that on the Quebec forum? Did they give any supporting evidence for why they believe that? When the battery has become too cold to drive the car, the Canada (not U.S.) model gives a message telling the driver to let the car run to warm up the battery. This presumably is from the battery heater because if it was from heat just migrating somehow from the engine to the battery in spite of the fact that they are on completely separate cooling systems, you would think this would work for U.S. also.
I love the message "Please wait while the vehicle is warmed".... Reminds me of the old diesel engines with glow plugs...
Not saying I am disagreeing with them, just wondering if they have some way to know when the battery warmer is operating. For some reason the manual says that in Canada at least in some situations where the battery is too cold to drive the car, the battery can be warmed up by running the engine, something that is not possible in the U.S. However looking at the manual closer, this apparently only works down to certain temperatures even in Canada, below which the engine cannot be started, due to not only the battery but "other system control temperatures" being too low. Interestingly for Canada the manual also indicates that once the battery is cold enough even plugging in won't help. Apparently the "Battery Warmer" as it is referred to in the manual is only capable of maintaining battery temperature not raising it. Similar to what anyone who has ever used a space heater in their home has probably experienced, it takes a lot more energy to raise temperature than to maintain it. HIGH VOLTAGE BATTERY (page 466) U.S. Models Store the vehicle in a garage to insure that the temperature of the High Voltage battery does not drop too low. Canadian Models ■ Battery Warming System Designed to prevent the temperature of the battery from dropping when outside temperatures drop, thereby maintaining starting and running efficiency. If the vehicle is plugged in when outside temperatures are low, the battery warming system will use the power from the charging equipment to maintain the temperature of the battery until the next time the vehicle is driven. (bullet point) Battery Warming System If the vehicle is left unplugged in cold temperatures, the temperature of the battery will drop, possibly resulting in a loss of running efficiency. If left for an extended period of time in extremely cold temperatures, the vehicle may not start. We recommend that you plug in your vehicle when you are parking or storing your vehicle in cold temperatures CHARGING (page 458) If the ambient air is cold enough to lower the High Voltage battery temperature below -22F° (-30°C), charging may not start. Note - there is no mention about Canada being able to plug in to warm up a cold battery. TURNING ON THE POWER (page 376) U.S. Models If the temperature of the High Voltage battery drops below approximately –22°F (–30°C), the power system will not start, the High Voltage battery will not operate and, as a result, the vehicle will not start. Store the vehicle in a garage or take another measure to insure that temperature of the High Voltage battery does not fall below this temperature. If necessary, consult an authorized Honda Clarity PlugIn Hybrid dealer. Canadian Models If the temperature of the High Voltage battery drops to approximately –22°F (–30°C) or below, the power system will not start. Wait for the High Voltage battery to warm up or move the vehicle to a warmer location. Note plugging the vehicle in will not help in this case. MESSAGES Condition ● Appears when the outside temperature is low. Explanation ● In extremely cold climates, keep the vehicle stored in a garage or connect the charging connector Condition ● Appears when the power system temperature is low Explanation ● Your vehicle has less ability to accelerate and may be harder to start on an incline. U.S. ● In extremely cold climates, keep the vehicle stored in a garage. Canada ● In extremely cold climates, keep the vehicle stored in a garage and connect the charging connector Condition ● Appears when the high voltage battery temperature is too low to operate (approx. −22°F [−30°C]). Explanation ● You can start the engine and use the climate control system to warm up the interior. ● You must wait for an increase in the high voltage battery temperature to drive. Condition ● Appears when the high voltage battery and other system control temperatures are too low to operate (approx. –22°F [–30°C] or below) Explanation ● You must wait for an increase in the ambient temperature or move the vehicle to a warmer location. ● Consult an authorized Honda Clarity Plug-In Hybrid dealer. U.S. ● In extremely cold climates, keep the vehicle stored in a garage. Canada ● In extremely cold climates, keep the vehicle stored in a garage and connect the charging connector.
I am in Quebec and drove mine all last winter. The range is halved, maybe less. In the summer I can do 2 round trips to my work. In the winter, I can't quite make 1. The round trip is 40km. I park in a garage at home and at work. I can't comment on leaving it outside unplugged in those very cold days. Based on the information in this thread, it seems unwise to leave it for a long time during those few weeks when things are below -20C. As others said above, go run it halfway through your day, or find an indoor parking for the winter months where there isn't an available plugin.
it is the words that I bolded that are very clear. This is a very long thread, with lots of folks throwing in lots of opinions and facts, but those six words are not ambiguous. It's moot whether the heat from the engine can warm the battery if the car's system refuses to engage the starter below some temperature. And since it is the HV battery that is starting the engine, the statement makes sense. Methinks that the battery is fragile at those extreme temperatures and could be permanently harmed by excessive load. I do think that sitting in an unprotected parking lot for eight hours would be plenty of time for the battery to reach ambient air temperature, especially if there was any wind. It would be interesting to know how the decision is reached to refuse to start ... is it a sensor for battery temperature, a sensor for air temperature, a measure of state of charge, or some undisclosed parameter. Depending on how this decision is made, running the car at lunchtime might not help. <broken record mode> I am still waiting for someone to post actual experience where they pushed the power-on button and the car said, "Later."
Unfortunately it is very hard to get any data of the battery pack getting below –22°F (–30°C). Since Montreal and Toronto only get down below that temperature once every 10+ years and likely not long enough for battery pack to reach that temperature. Here is a list of occurrences of that temperature per year: Average number of days in winter when the temperature drops below -30 °C (-22 °F). City Days Winnipeg, Manitoba 12 Regina, Saskatchewan 11 Thunder Bay, Ontario 7 Saskatoon, Saskatchewan 7 Saguenay, Quebec 7 Sherbrooke, Quebec 5 Calgary, Alberta 3 Sudbury, Ontario 3 Edmonton, Alberta 3 Trois-Rivières, Quebec 3 Québec City, Quebec 1
For owners in the U.S. yes it's all moot, call Uber or a tow truck. But in Canada there is a big difference between which of these two messages they get: What we don't know is why that is the case in Canada not U.S. that they can be in a situation where the battery is too cold to drive, but apparently not too cold to start the engine, and then by allowing the engine to run something magic will happen and the battery will warm up enough to drive. Much of the speculation has been on exactly what it does in this scenario. Leading to some interesting in my opinion dives into how the battery cooling system works, with the entire discussion being understood (in my opinion) to be speculation while waiting to either find some official technical documentation about it beyond the vague statements in the owners manual, or else waiting for someone to actually get into this situation, although we hope no one does. And it might be better to avoid doing it intentionally unless there is a way to warm up the car, since the manual states that once the system gets cold enough even plugging in to engage the battery warmer won't help.
Likely at the magic –22°F (–30°C) the battery is too cold to operate (charge or discharge) without potential damage, but with the battery heater, you can start the engine to get the generator to supply the electricity to run the battery heater. You would think you could also plug in a L2 charger to do the same thing, but maybe the charger circuits are shut down to protect the battery.
Much more of the U.S. can get very cold than I realized, e.g. if you google something like record low temperatures in the U.S., for all of us moot folks, there is a surprisingly long list of -40s F to -60s F all the way into the mid west. Illinois saw wide spread -30s F last year. Probably has little to do with the pull back to California, but it sure will be interesting to see how U.S. Clarity owners fair too, if we get any these record cold years during Clarity's peak years. I had no idea record lows that low, were so prevalent, if not common. Some are probably remote places or mountain areas, but, it does look like large portions of the U.S. can see very low temperatures.
FWIW, I read that the upcoming all-electric MINI Cooper SE will have a heat pump that scavenges heat from the car's traction motor and electronics. However, it will also have an "auxiliary heater." I presume that auxiliary is a resistance heater to provide heat when the heat pump can't supply enough heat by itself.
