I was just thinking that a good way to charge when it is hot out is to plug the car in and use the precool feature to cool down the inside of the car then use value charging to start the charge after the car has been cooled?
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Hot Battery using Precool?
Posted 08 August 2018 - 05:57 PM
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Posted 08 August 2018 - 06:29 PM
Posted 08 August 2018 - 06:57 PM
I mean using the AC to precool before charging, my car takes about 7 hours to charge on 120V
Posted 08 August 2018 - 07:42 PM
7 hours no way. Should be more like 5 hours 45 minutes or less on average. Did you time it? It says 7 hours on the screen but it always finishes earlier. Look at your charge log in MFM. Even a brand new Cmax takes under 6 hours, I don't think I've ever seen it go over.
As for the AC precondition, it won't do anything. The only thing to make it matter is to turn the AC on and leave it on and set it to 60 degrees. Then in that case when the temp finally drops to around 68 (internal temp) then the HVB temp will start to drop. Also depends on how high the HVB temp is, or what is the differential between the battery, outside temp, and inside temp of the car. Remember that the HVB cooling air comes from the cabin, and outside air is pumped in while charging which gets heated additionally by the charging circuit. So if you shut off the AC the charging air will warm the car up pretty quickly and negate any benefit.
I think the only way is to leave the AC running all the time. In that case the battery temp will drop (I tried this once) but it will take forever and a day to charge it up.
Edited by rbort, 08 August 2018 - 07:42 PM.
- muchkneaded likes this
Posted 08 August 2018 - 08:04 PM
Sorry i was going by my cell phone notification 3 1/2 hours
Posted 08 August 2018 - 08:09 PM
3 1/2 hours is too short also, unless the battery is not completely empty or its been degraded alot. I just looked at my buddy's 2013 Cmax driving log and found an entry on August 3rd for a full charge and it shows 5 hours 10 minutes.
Posted 09 August 2018 - 05:59 AM
Sometimes I have a few miles left on the charge but I have done a lot of highway driving the last 3 years and even though I put in in EV Later when the traffic slows it will go back to EV mode and if I don't notice I am doing 50 -60 MPH mostly on battery I have 65K miles about 1/2 EV.
Plan is to sell it when the 2019 models come out I want to see what the latest PHEV offerings are at that time. If i buy something in December I can take advantage of the tax credits and get the use right away when I file.
Posted 09 August 2018 - 06:58 AM
The only way it should go back to EV mode is if you park it or power cycle it then it defaults back to AUTO from EV Later. I have not had mine default back to AUTO by itself. Sometimes in the old 2013 model if you're constantly switching modes between AUTO and EV later it will X X out EV now and EV later and stay in AUTO only not allowing you to switch. The only solution I found for that not to drain my battery on the highway was to pull over and power cycle the car.
We bought a Mini Cooper plug in hybrid for my wife, she loves the look and style of it. Its 1/2 as good as the Cmax in regards to range, but she doesn't care, its all about the looks for her. She's getting about 20-22 miles range with the battery and about 38mph when she uses gas also. I just came back from a trip in Indiana, I net 58.2 mpg for the whole thing with the Cmax. She told her friend I net 20mpg more than hers but she doesn't care because her car is "cooler".
Edited by rbort, 09 August 2018 - 06:59 AM.
- muchkneaded likes this
Posted 09 August 2018 - 12:13 PM
No, it wouldn't do much. The battery is such a large, dense heatsink that it takes hours to drop several degrees. Plus, once charging starts the fans pull in outside air (uggh) and heat up the interior again.
Posted 10 August 2018 - 12:08 PM
I have found the best way to charge is with the windows open and at night when its cooler. I typically have the front windows down a couple of inches and the rear ones down 4-5 inches. This seens to keep the interior of the car close to the outside air temp. I don't have a garage, so I have to keep an eye on the weather. The other important factor is try to park in the shade if possible, when charging during the day. This keeps both the inside car temp cooler and the outside air temp cooler. Its good to park in the shade on a sunny day and keep the windows open some even if not charging, otherwise the interior temp rises and the battery temp goes up along with it, with some thermal lag delay. If the temp gets to 113F, it will damage the battery just sitting there. Acutally, from the reasearch I did, the battery can start to be affected over 87F, but that is when charging or operating with a full charge.
From what people are saying, the CMax draws its cooling air from under the car when charging. During operation, the cooling air comes from inside the car. Both charging and operation cooling fans exit inside the car as I understand it. Someone correct me if I am wrong.
I have decided to not charge and operate in EV later (hybrid mode) if the air temp gets over 90. This is too prolong my battery life and prevent degrading. Luckily I live on the coast North of Boston and we have only had 2-3 days in the 90's. Lots of days in the 80's in though, but I feel that is safe if below 87F.
Edited by ScottB, 10 August 2018 - 12:10 PM.
Posted 10 August 2018 - 08:23 PM
Good ideas Scott. however, don't feel "safe" if its 87 outside, the battery will still get into the 90's. Generally speaking even if you take it easy on it, I find that it can get several degrees warmer than ambient when you're driving around. Even hybrid mode does warm it up. You need to be cognisant of what is going on with the battery and try to avoid charge/discharge all the time if you're in hybrid mode and can avoid that by keeping the ICE running. You can not worry about anything, or get deep into it and try to think of anything and everything to keep the battery cooler. Also rolling down the windows at night while driving will drop the battery temperature but keeping them up will not. Just something to think about. All depends on the OAT, the battery temp, and car's internal temp. The wider the gaps, the easier it is to cool down the battery.
Goes without saying always park in the shade no matter what, unless its winter time. This summer has been hot and I've tried to keep the battery temp down. Not always possible to my liking, but I never went over 100 degrees which is good I suppose. I prefer the 80's but sometimes it gets into the low to mid 90's. Its hard to keep it down when its hot outside, best course of action is to not drive the car when its hot, if you can manage that. I have other options so I use them when I can.
Posted 11 August 2018 - 07:29 AM
Generally speaking even if you take it easy on it, I find that it can get several degrees warmer than ambient when you're driving around. Even hybrid mode does warm it up. You need to be cognisant of what is going on with the battery and try to avoid charge/discharge all the time if you're in hybrid mode and can avoid that by keeping the ICE running.
I was wondering how much hotter the battery gets compared to outside air temp (OAT). I am glad to hear you say it is 2-3 degrees if taking it easy. If hot, I always drive with the windows open, no AC, unless I go to EV Later and have the engine come on. If the battery gets into the very low 90's I am OK with that. From the research I did, that should be OK unless the battery sits at that temp with a full charge, which it will not while driving. Once the charge level drops, the battery can handle a little more temp, up to a point.
One thing you mention about keeping the ICE on in hybrid mode. As far as I know the car does that and controls it, how can we influence that while driving along on back roads??? I put the car in EV Later mode and it does its thing. On the highway it tends to keep the ICE on due to the power required to keep it at speed. I am not aware of anything we can do?
Posted 11 August 2018 - 08:04 AM
From what I've found its generally not 2 to 3 degrees it can be as high as 8 degrees higher. I can recall the battery reaching 95F when the outside temp is say 87. It all depends on the situation and how you're using it.
You're correct lower charge level is better, always, no only when driving. So don't charge it at home and let it sit charged if you don't need it. Mine has been sitting <40% even when not in use on hot days. The battery can get to 86F just sitting around as its hot outside. I just charge it before I need to go out, and sometimes not to full if I don't need all of it, enough to go and come back and just leave the battery is the lower quadrant of the charge level instead of in a higher one, or in other words hanging around between 10 and 50% instead of between 100 and 60% for short trips. This morning it was at 40% and I'm thinking to go out to Boston later so I'm charging it now.
As for the hybrid thing, on country roads generally speaking yes it tends to do its own thing, but you can also avoid that in some situations be tapping the gas to restart the engine so it doesn't drain the battery all the way down and charge it all the way back up in hybrid. I did some videos about this for highway driving which is more important for good gas mileage. Used to work very well with the 2013 models (improving MPG) but in the 2017 they have adjusted the charge rate so its not as aggressive as it used to be and its not as "necessary" any more.
But with that aside, if you're on a country road and you see an incline even if you're driving EV mode start the engine so as to not put so much load on the battery to climb the hill. If you go down a hill and it switches to battery mode and then you have a long stretch of slightly uphill road the car can choose to stay on battery until flat and then start the engine. You can tap the gas to re-ignite the ICE and prevent the drain and recharge of the battery once the engine is running. More drain/recharge cycles on the battery help to increase the temperature more than steady state situations. You have to evaluate each situation by itself and decide what is best to do.
Edited by rbort, 11 August 2018 - 08:06 AM.
Posted 11 August 2018 - 08:30 AM
By the way Scott,
Once you roll down the windows at night, if its cooler the car's internal temp will drop, and then that cooler air from inside the car will help cool the battery better. If you leave the windows up, then the battery its hot and its like a little mini furnace keeping the car's inside warm and the battery temp does not drop. I found that having the windows down on a long drive back home from Boston to Franklin can drop the battery temp 4 degrees, maybe 6.
Also if its hot inside the car and the battery temp is hot, the cooling fan will not run. That doesn't start up until the temp between the car's internal sensor and the battery differ by at least 6 degrees. And if it did run nothing much happens anyway if the car is almost as warm as the battery. The bigger the temp difference, the better to cool the battery.
So just as an FYI, this morning my battery temp was 78F. I've been charging it for a little bit, the charge level went from 40% to 65% so far and the temp of the battery went from 78 to 80F now. If you put your hand behind the folded rear seat you can feel hot air coming out of the charging circuit cooling fan. Its like a hair dryer warming up the car's inside. I had the windows down 2 inches each but I just rolled them all the way down. The hot air festering inside doesn't help the HVB and warms it up as well. I'm not sure why Ford didn't exhaust that hot air to the outside. Its good in the winter to take the edge off the cold, but in summer it doesn't help matters at all. Anyway, summer is almost over this whole thing will be a mute point by the time October rolls around.
Edited by rbort, 11 August 2018 - 08:40 AM.
Posted 11 August 2018 - 10:18 PM
FYI for all (Scott you might be interested in this).
I drove today for several hours in Boston. When I charged up my car this morning the temp went from 78F to 82F. I left the house at 82F and in a short period of time the temp went up to 86F then the battery cooling fan started. Outside temp was pretty consistent at 70F +/- 1 degree. The temp almost always stayed on 86F, it did peak at 87, went down to 82 at some point, but then I had to roll up the windows and use the vent instead (on the highway too noisy) and the temp went back up to 86F when I did that.
Just thought you might find that of interest. The last leg home I opened the windows back up and now is back down to 82F. I recharged it to 3% from 38% hybrid and just set it to value charge now it will continue at 4am I don't need it before noontime tomorrow.
So my memory was incorrect, the battery can be much hotter even if the OAT is cooler. Today 15 degree differential most of the day and night.
Posted 12 August 2018 - 08:01 AM
That is very interesting information. I do think it shows that when you charge the battery it heats up. The battery is a big thermal mass that is kind of buried under the rear deck. It will take time (like hours) for the battery to cool down or heat up due OAT changes. If it sits overnigt it will eventually reach the same temp as the interior of the car. When you charge it or drive it, the battery temp increases from its starting temp and the cooling buit into the car is not powerful enough to drive it back down to interior car temp. in a short period of time. If you are driving and generating heat the cooling has an effect, but as you have said Raj, it depends on the temp differences involved.
Was 78F the OAT in your garage and that is why the battery started at 78F instead of the 70F OAT you mention while driving?
From other posts, I think it is a good idea to charge around midnight and give the battery some time to cool down before driving. This should allow for the lowest battery temp while driving. If you drive very shorty after a charge, the battery does not cool back down to OAT. If you consider temp rise or delta T, the battery went from 78 to 82 (and peak of 87) which is the delta T range you mentioned before. I think this time you started the drive with a hotter battery and it only goes up from there. If you waited some number of hours after charging and the OTA of the car was 70F, I bet the battery would have stayed in the 70's. My speculation.
Edited by ScottB, 12 August 2018 - 08:03 AM.
Posted 12 August 2018 - 08:14 AM
Well i'm going out again today. Last night it charged starting at 4am as I like to let it cool some before going out and the temp is still 84F on the battery not. The garage is about 78F I just looked. Most likely it was the same yesterday. I'll let you know how it pans out today.
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