DayTripping
Well-Known Member
I like this one for Gen1 trucks. Make it like the sport mode but with higher ride heights.
- Enhanced acceleration in All-Purpose mode.
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Manual Preconditioning of the Battery to Improve Cold/Hot Weather Efficiency
Singletracker
Well-Known Member
I donāt know if this has been mentioned, but hereās my new plan for having the battery warm on my departure. It involves adjusting the charger output. This may not work for everybody. What Iām going to try doing is starting a charge cycle and reducing the charger output to roughly finish my chosen charge level around the time I think I might leave. For instance, if I want to get my car charged to X miles or so, I can reduce or increase the amperage the charger is outputting, so that a chosen number of added miles will be input by around the time I leave. For me, it doesnāt have to be exact. Mostly, the goal is to have a somewhat warm battery. If I know about how many miles per hour the car is getting and I know I when I might leave, I can, based on the start time, choose the charger amperage level to use. It doesnāt have to be 48 amps all the time. Right now, Iām charging at 16 amps and gettng about 6 miles per hour into the car. Therefore, it should take around 10 hours to get 60 miles. So, if I want a warm battery and Iām going to start charging around 10PM, and just need 60 additional miles, and Iām leaving around 8:00AM, I know that a 16 amps charge rate should do it. Iāll have those 60 additional miles and a warm battery when I leave. This avoids having the car stop itās charging cycle at 4:00 in the morning, and the battery chilling down.
I havenāt seen where anyone mentioned adjusting the charger output to accomplish this preconditioning timing. Iāve usually tried to do this by adjusting my start time and was usually at 40-48 amps. That was always a little sketchy, especially if one has a TOU rate that stops at 8:00AM and one doesnāt want the warm battery until 10:00AM. Charging between 8:00 AM-10:00 AM at 16 amps will be cheaper then charging at a 48 amps, for those 2 hours. Seems a little simple math (energy desired, when do you want it, and charger output) will get you in the ballpark.
I havenāt seen where anyone mentioned adjusting the charger output to accomplish this preconditioning timing. Iāve usually tried to do this by adjusting my start time and was usually at 40-48 amps. That was always a little sketchy, especially if one has a TOU rate that stops at 8:00AM and one doesnāt want the warm battery until 10:00AM. Charging between 8:00 AM-10:00 AM at 16 amps will be cheaper then charging at a 48 amps, for those 2 hours. Seems a little simple math (energy desired, when do you want it, and charger output) will get you in the ballpark.
SPITmadFIRE
Well-Known Member
Significantly more efficient both in charging speed and in drivetrain efficiency. Motive efficiency gains are probably in the range of 10-20%
Between 72F and 85F for the most part.
DayTripping
Well-Known Member
The more power you can dump into the battery over a shorter period of time, the warmer it will be. There is also energy used to manage the charging process. Given the very large pack in the R1, it may not help as much as you'd hope.
On my Tesla Model 3, with about an 80kWh pack, 16 amps will warm it up a little bit if done long enough. It would also depend on how could the temps you are dealing with too.
I wish I had discounted TOU pricing here but I don't. I just set it to charge up before I leave.
Another option might be to hit it with a higher charge to get the temps up, then manually turn it down when TOU pricing is higher. Sometimes it is easier to maintain a temp than bring it back up to temp. I used to do that on colder TX days. Other times I'd just plug it in and start a slow charge while the battery was already warm of about 5 amps and crank it up later.
Singletracker
Well-Known Member
Well, Iām not guaranteeing this will work the best. However, at first glance, it seems to make some sense. However, as you noted, there may be physical issues that Iām not accounting for. Iām certainly no expert and this Rivian has tricked me more times than I can count.
My T has been charging now, at 16 amps (3.4K.w), for over 4 hours. It still says itās adding about 6 miles/hour. It is 35Āŗ outside. The battery was at 31Āŗ when I started charging and It is now sitting at a comfortable 50Āŗ.
If the goal is to stop charging as close as possible to departure, one can charge at 48 amps and then attempt to figure out when the charging cycle should start. The problem I had with this method seemed to be getting the time right. At 48 amps, Iām getting anywhere from 21-24 kW installed, but it can vary. If I plan to start the clock based on the predicted duration, it almost always terminates sooner than expected. At which point, presumably, the battery will start cooling down. So, along the way, there seems to be a significant variation in charging speed, I guess. I thought, that by charging a much lower rate, the length of the charging session might be more predictable, as the charging speed might be more stable. Of course, the 16 amp speed is just an arbitrary number that I chose. Also, as noted, if one is dealing with TOU plans, there is some wiggle room to go past that restricted time at that lower/cheaper charging speed.
My T has been charging now, at 16 amps (3.4K.w), for over 4 hours. It still says itās adding about 6 miles/hour. It is 35Āŗ outside. The battery was at 31Āŗ when I started charging and It is now sitting at a comfortable 50Āŗ.
If the goal is to stop charging as close as possible to departure, one can charge at 48 amps and then attempt to figure out when the charging cycle should start. The problem I had with this method seemed to be getting the time right. At 48 amps, Iām getting anywhere from 21-24 kW installed, but it can vary. If I plan to start the clock based on the predicted duration, it almost always terminates sooner than expected. At which point, presumably, the battery will start cooling down. So, along the way, there seems to be a significant variation in charging speed, I guess. I thought, that by charging a much lower rate, the length of the charging session might be more predictable, as the charging speed might be more stable. Of course, the 16 amp speed is just an arbitrary number that I chose. Also, as noted, if one is dealing with TOU plans, there is some wiggle room to go past that restricted time at that lower/cheaper charging speed.
DayTripping
Well-Known Member
I think you'll have to play a bit with the amperage and your outside temps and see what works best in your environment. Fortunately I don't have to deal with a lot of sub-freezing temps here. At the same time, my R1T seems to have the worst efficiency of the 10 EV's I've owned when on a battery and motors that aren't up to temp (even when not below freezing).
For reference I get about 1 mi/kWh for my R1T and by comparison, I previously thought my Plaid was horrendous when I was getting just under 2 mi/kWh. My R1T on that same section of road when warmed up will get about 3 mi/kWh and my Plaid at about 3.5 mi/kWh.
As a result, I always try and finish my charge just before I leave the house. Even in the warmer, but not hot, temps it makes a difference. It is also why my current lifetime (they reset everything during the last service) is setting about 1.8 overall for the past 300 miles since it was serviced. Most of my trips are shorter lately.
For reference I get about 1 mi/kWh for my R1T and by comparison, I previously thought my Plaid was horrendous when I was getting just under 2 mi/kWh. My R1T on that same section of road when warmed up will get about 3 mi/kWh and my Plaid at about 3.5 mi/kWh.
As a result, I always try and finish my charge just before I leave the house. Even in the warmer, but not hot, temps it makes a difference. It is also why my current lifetime (they reset everything during the last service) is setting about 1.8 overall for the past 300 miles since it was serviced. Most of my trips are shorter lately.
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