Usable range

[Scc18603]

So I just saw a post about running the mme to 5%. It made me wonder.
On a trip you should only charge to 80% and not go below 20%. So does that mean the MME has a usable range of about 167 to 178 miles?

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[DevSecOps]

Charge to what you need. Unless you are the type to keep a car for 10+ years just drive it.

On long trips sometimes I need to charge to 100%. Do what you have to do, don't worry about it and have fun. What's not recommended is to leave it too high or too low for extended periods of time.

And yes, usable range isn't the same as ICE. The main reason is that there's not a charging station every .05 miles like there's a gas station. So, when you charge, the vehicle charges fastest to 80%. That's the optimal spot to stop if you can, but just for pure time sake, not battery health. Then if there's a charge station 50 miles from empty you have to stop there because you would be out of juice before you get to the next.

Apps like Plugshare are helpful because they tell you what % to charge to so that you aren't spending extra time at a station. For example, if you only need 100 miles to the next charger and the one beyond that is 200 miles, then you need only 100 miles. Lets say you want to have dinner at the current stop, well then let it charge longer and at the 100 mile one you'll need less time to get the 200 miles needed for the next. It's definitely wise to plan accordingly and have backup chargers in case one doesn't work.

Lastly, make sure you take things like wind and temp into consideration. If you have a headwind add 25 miles per 100 otherwise you'll be sorry.

Ultimately, 270 miles (my cars estimated range) is never going to happen for me. My stats show that 235 is all I'll likely see and given stations are only every so often, I'm getting closer to 180 per stop.

There's a ton of posts on this forum about this.

 

[AZBill]

Going below 20% once in a while is fine, the battery has some buffer at the bottom anyway. It is more about the stress of wondering if you will make the next charger. I have run my Bolt down to 3% twice, sometimes things do not go as planned, but in both cases I made it to the charger. Eased up on the speed both times.

I like to charge just enough to get to the next charger, plus 10-15% margin.

 

[RickMachE]

So I just saw a post about running the mme to 5%. It made me wonder.
On a trip you should only charge to 80% and not go below 20%. So does that mean the MME has a usable range of about 167 to 178 miles?

You can both go below 20% and above 80%.

 

[Accord07]

So I just saw a post about running the mme to 5%. It made me wonder.
On a trip you should only charge to 80% and not go below 20%. So does that mean the MME has a usable range of about 167 to 178 miles?

It depends on your driving pattern. That was what I got on the coldest days this past winter - I see that you are in PA as well - even though I used way beyond the 20%-80% range of SOC. The most rosy range I get is in the morning when my car was still inside the garage, it gets worse as the day progressed: after sitting outside for hours the battery gets cold and its capacity to discharge drops considerably (the nominal 88 kWh useable for my 2021 ER battery pack is accurate only when its temperature is in the high 70s), combined with more energy spent on heating the range estimate from when the car leaves the garage in the morning always turn out to be too optimistic. Similarly the range estimates at the end of a DCFC charging session is too optimistic in cold weather. Did a road trip in January that was barely over 300 miles each way but mostly highway driving, had to use Electrify America twice, the charging time plus detours to reach EA added more than an hour.

In current weather conditions we get about 200 miles at ~75mph, discharging from 90% to 10%, which is consistent with the nominal 249-mile EPA highway range; for day to day mixed driving, it extrapolates to a range of ~290 miles (EPA rating is 270 miles).

Before getting my MME, I had expected to have a 1/3 reduction of range in winter; in day to day use it mostly exceeded that modest expectation. As long as you set reasonable expectations for winter days and plan accordingly, you will be happy with the car.

 

[kirkus02]

Charge to what you need. Unless you are the type to keep a car for 10+ years just drive it.

On long trips sometimes I need to charge to 100%. Do what you have to do, don't worry about it and have fun. What's not recommended is to leave it too high or too low for extended periods of time.

And yes, usable range isn't the same as ICE. The main reason is that there's not a charging station every .05 miles like there's a gas station. So, when you charge, the vehicle charges fastest to 80%. That's the optimal spot to stop if you can, but just for pure time sake, not battery health. Then if there's a charge station 50 miles from empty you have to stop there because you would be out of juice before you get to the next.

Apps like Plugshare are helpful because they tell you what % to charge to so that you aren't spending extra time at a station. For example, if you only need 100 miles to the next charger and the one beyond that is 200 miles, then you need only 100 miles. Lets say you want to have dinner at the current stop, well then let it charge longer and at the 100 mile one you'll need less time to get the 200 miles needed for the next. It's definitely wise to plan accordingly and have backup chargers in case one doesn't work.

Lastly, make sure you take things like wind and temp into consideration. If you have a headwind add 25 miles per 100 otherwise you'll be sorry.

Ultimately, 270 miles (my cars estimated range) is never going to happen for me. My stats show that 235 is all I'll likely see and given stations are only every so often, I'm getting closer to 180 per stop.

There's a ton of posts on this forum about this.

What app is that screen shot from?

 

[DevSecOps]

What app is that screen shot from?

Recurrent Auto
https://www.recurrentauto.com/for-owners

 

[Nklem]

Yes you are correct. And when in Winter and cold, take up to 40% off from that usable range and figure slower charging too.

 

[dmastro]

I think part of the point of OP's question is that when road tripping, the sweet spot for charging is generally up to 80%, with a significant dropoff in charging speed above that threshold. So yes unless there's a reason to wait an exorbitantly long time to squeeze in the last few electrons, the "usable" (I'd call it "efficiently usable" range) can be measured to about 80% on the high side with a low side of what you're comfortable running down to (from experience getting under 10% starts to worry me).

For a car that will be used a lot for road tripping, I think it would be interesting to do the math to figure out when a faster charging car with less range makes sense over a slower charging car with longer range.

 

[Nklem]

I think part of the point of OP's question is that when road tripping, the sweet spot for charging is generally up to 80%, with a significant dropoff in charging speed above that threshold. So yes unless there's a reason to wait an exorbitantly long time to squeeze in the last few electrons, the "usable" (I'd call it "efficiently usable" range) can be measured to about 80% on the high side with a low side of what you're comfortable running down to (from experience getting under 10% starts to worry me).

For a car that will be used a lot for road tripping, I think it would be interesting to do the math to figure out when a faster charging car with less range makes sense over a slower charging car with longer range.

It’s kind of proven. The Hyundai I5 with less range but much faster charging is the road trip king. Recently beating Tesla and Mach E came in last on a trip from Fort Collins to Las Vegas. On a 12 hour road trip the difference was nearly 2 hours…..Out of spec has the review. Mach E Vlog as well. I still love my Mach E though as I do not road trip much and Range is what I need. Ford will come out with some Charge speed improvements I am sure. Just remember the faster the charge the lower the battery overall life.

 

[RickMachE]

It’s kind of proven. The Hyundai I5 with less range but much faster charging is the road trip king. Recently beating Tesla and Mach E came in last on a trip from Fort Collins to Las Vegas. On a 12 hour road trip the difference was nearly 2 hours…..Out of spec has the review. Mach E Vlog as well. I still love my Mach E though as I do not road trip much and Range is what I need. Ford will come out with some Charge speed improvements I am sure. Just remember the faster the charge the lower the battery overall life.

It really comes down to how often you take a trip, and more importantly how many miles you drive in a day. Plus - is there overnight charging when you stop for the day?

My rule of thumb after driving over 10,000 miles is add 20% in time to the trip. We're planning a trip to someone outside Indianapolis. The drive is 304 miles, 4.75 hours per GoogleMaps, or 287 miles but 8 more minutes on an alternate route.

If I plan the trip on ABRP, the shortest option has me driving more miles (299), and charging once for 30 minutes, arriving with 10% charge. 5.75 hours total, i.e. 21% more time. I can take an alternate route, drive another 13 miles, charge less, and the total time is the same within 3 minutes.

HOWEVER, the person we're visiting has no charging (except 110), so if I want to arrive with any usable range, I need to charge again, or park 1/2 mile away and charge at a 7kW charger for many hours. Charging to 75% before I get there will add 40 more minutes, so now my trip is 6.4 hours. 6.4/4.75 = 35% charging overhead.

An ideal trip for me would be leaving my house with 100%, charging at 10% to 80%, and arriving with 10% and charging for free overnight. That's roughly a 400 mile trip at 2.7 miles per kWh. And it's just under 6 hours of driving, and charging overhead is 13%, i.e. one 45 minute charge.

Note - I was thinking of all the trips we've done with two charging stops, and messed up the above numbers, now corrected.

 

[Murse-In-Airy]

If you’re going for distance, there is no reason at all that your usable range can’t be from 100-0%. For most days staying between 80 and 20 will help with longevity (ie 10 years or more). But your usable range is still from 100% all the way to 0% when you need/want it.

 

[RickMachE]

If you’re going for distance, there is no reason at all that your usable range can’t be from 100-0%. For most days staying between 80 and 20 will help with longevity (ie 10 years or more). But your usable range is still from 100% all the way to 0% when you need/want it.

Sure, if you just drive one leg. But if you're DC charging, then the lower speed (44kW) from 80% to 90%, then the 34kW speed from 90% to 95%(?) is a time killer. Realistically, charging to 80% is the best way to minimize time spent charging for most cases.

 

[Nklem]

It really comes down to how often you take a trip, and more importantly how many miles you drive in a day. Plus - is there overnight charging when you stop for the day?

My rule of thumb after driving over 10,000 miles is add 20% in time to the trip. We're planning a trip to someone outside Indianapolis. The drive is 304 miles, 4.75 hours per GoogleMaps, or 287 miles but 8 more minutes on an alternate route.

If I plan the trip on ABRP, the shortest option has me driving more miles (299), and charging once for 30 minutes, arriving with 10% charge. 5.75 hours total, i.e. 21% more time. I can take an alternate route, drive another 13 miles, charge less, and the total time is the same within 3 minutes.

HOWEVER, the person we're visiting has no charging (except 110), so if I want to arrive with any usable range, I need to charge again, or park 1/2 mile away and charge at a 7kW charger for many hours. Charging to 75% before I get there will add 40 more minutes, so now my trip is 6.4 hours. 6.4/4.75 = 35% charging overhead.

An ideal trip for me would be leaving my house with 100%, charging at 10% to 80%, and arriving with 10% and charging for free overnight. That's roughly a 550 mile trip at 2.7 miles per kWh. And it's just under 9 hours of driving, and charging overhead is 5%, i.e. one 45 minute charge.

Exactly right. I add 20% and it works well. It’s not useless time either, it can be shopping, chatting or eating. A Red Robin burger meal and 2 walks around the mall is 1 hour….in case anyone needs to know.

 

[AZBill]

I based my charging strictly on where I am going to stop and charge. Yes I always start from home with 100% and go as far as I can for a first charge. After that is is all about miles, no concern with 80%. Electrify America has a goal to install chargers every 70 to 120 miles apart on the interstates. They have pretty much achieved this in the southwest where I live and take road trips. For me, the sweet spot for charging is usually to 50-60%. I have a CR1 and can get 300 miles at highway speeds. So 50-60% gives me 150-180 miles. If the next charger is 120 miles away, charge to 50% and that leaves 30 miles of buffer. If the next charger is only 70 miles away, followed by another at 140-150 miles, then I will charge to 60% and skip one charger. If there is a mountain or rain, then I just make adjustments to my planning. I have only once charged to more than 80% on a road trip, and that is because we were eating lunch.

The fastest part of the charging curve on the MME is 40% and below, so why not take advantage of that.

On a trip I took earlier this month I stopped on the way home and did a quick 23% to 30% charge and arrived at home with 12%. No real worry about running out of juice.

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