Fast charging more than 80% degrades battery?

[chandwawar]

I'm on a trip towing 5,000lbs today and need as much range as possible, but I noticed that the Fordpass app recommends only fast charging to 80% or else battery life could be degraded. Is it hype or a recommendation we should all try to obey?

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[Mandalorian]

I swear I saw on the official ford page or video for the Lightning that they recommend charging to 90%. I’ll see if I can find the link and post.

 

[Mandalorian]

Yep. On the FAQ for the Lightning it says for everyday driving to charge to 90%.

https://www.ford.com/support/how-to...ightning-charging-frequently-asked-questions/

 

[petemill]

I'm on a trip towing 5,000lbs today and need as much range as possible, but I noticed that the Fordpass app recommends only fast charging to 80% or else battery life could be degraded. Is it hype or a recommendation we should all try to obey?

That recommendation is only for daily charging - the battery shouldn't sit like that. If it's for same-day use then it's completely fine, especially if only occassional.

 

[RickLightning]

I'm on a trip towing 5,000lbs today and need as much range as possible, but I noticed that the Fordpass app recommends only fast charging to 80% or else battery life could be degraded. Is it hype or a recommendation we should all try to obey?

The reason why you see references to 80% for DC fast charging is SPEED, and COST.

SPEED

At 80%, charging will drop dramatically in speed of charge, to protect the battery. I've only charged over 80% once in my Lighting, and as I recall saw the low 50s. On the Mach-E it's around 44kW.

So, to go from 80 to 90%, which is 13kW, it will take say 15 - 20 more minutes. In other words, you're wasting a lot of time. If you need the range to get somewhere or to the next charger, you can go to 100% if necessary, but it will take a long time. I charged from 14% to 90% and it took me one hour exactly, 108.5kW or 1.8 per minute. I've hit 2.5kW per minute at lower percentages, but only DC fast charged 2 other times.

The other reason is COST. In some states (about a dozen), charging is per minute, not per kWh. So, when it slows down at 80%, you're paying much more per unit of energy.

Ideally, you go from 80% down to 20%, and then back up to 80%. But, if you need more, then it's fine.

Edit - some people who use DC fast charging are rude. They don't need more than 80%, but they don't care about others that may be waiting. This is especially true of those that get years of charging for free. And locals.

 

[chandwawar]

Thanks for the replies. I saw the "80%" notice in the Fordpass app, but now I cant find it again. In the digital owners manual it shows this.

I still havent figured out how to limit the daily charge limit. All i see is the one-time max charge limit. Do you need to set that everytime you plug in at home?

 

[Jim Lewis]

As discussed on other threads in this forum, the real battery capacity is 143 kWh, not 131. https://www.f150lightningforum.com/...43-4kwh-and-standard-range-sr-107-6kwh.11928/ That's probably deliberately, in part, to protect the battery lifespan by preventing charging to the true 100% capacity of the battery (131/143 = 91.6%). So, when Ford says it's OK to charge to 90% every day, you're really only charging to ( (131 x 0.9) / 143 ) = 82.4%.

It's the old conflict between having maximum charge available to use and prolonging the lifespan of your Li-ion battery. I mainly only go on short trips in the city, so staying in the 40% to 60% SOC range works for me and will probably give the longest battery lifespan possible. I have no reason to charge to an 80% or 90% SOC, especially during hot, hot summer temperatures in the Southwest, esp. found in asphalt parking lots, etc. Being at 90% SOC in that sort of environment will probably help shorten the battery lifespan. For long trips, I will fast charge as much as possible in the 15% to 80% SOC range because, as Tom Moloughney and others have pointed out, going above 80% results in prolonged charging times that aren't worth it unless necessary to reach your next charging destination (and harder on the battery lifespan, too). I have quite a few Li-ion devices that I've used heavily and are still above 90% battery capacity after 7 to 13 years of use by staying in the 40% to 60% SOC range and not overheating the device batteries in use or while charging. The Lightning manual recommends letting your vehicle battery cool for 2 to 3 hours before charging. If you've got money to burn, burn up your battery, and don't worry about SOC. But if you'd rather spend your dough on other things, not doing 90% SOC every day if you don't need it will probably help in the spare change department.

 

[Maquis]

Thanks for the replies. I saw the "80%" notice in the Fordpass app, but now I cant find it again. In the digital owners manual it shows this.

I still havent figured out how to limit the daily charge limit. All i see is the one-time max charge limit. Do you need to set that everytime you plug in at home?

You should see charging locations (places you’ve previously charged). Find the one that corresponds to your home and assign a limit to it.
Do not choose “Charge when plugged in.” Doing so will cause the truck to ignore other settings.

 

[Lightning Rod]

Yep. On the FAQ for the Lightning it says for everyday driving to charge to 90%.

https://www.ford.com/support/how-to...ightning-charging-frequently-asked-questions/

I see here that with regular AC charging and everyday driving, it is recommended to charge to 90 percent. I've been charging to 80 percent while using my 80A FCSP charger. I usually wait until I get down to about 55 to 60 percent before I plug back in. Should I just set charger to 90 percent? There are so many supposed proper ways of charging, I get a little confused.

 

[Maquis]

I see here that with regular AC charging and everyday driving, it is recommended to charge to 90 percent. I've been charging to 80 percent while using my 80A FCSP charger. I usually wait until I get down to about 55 to 60 percent before I plug back in. Should I just set charger to 90 percent? There are so many supposed proper ways of charging, I get a little confused.

If 80% covers your needs, I’d stick with it. I limit to 80% unless I know I’ll need more.
I charge my Mach-E to 90% because it’s the daily driver and if something unexpected comes up, that’s what we take.

 

[djwildstar]

I'm on a trip towing 5,000lbs today and need as much range as possible, but I noticed that the Fordpass app recommends only fast charging to 80% or else battery life could be degraded. Is it hype or a recommendation we should all try to obey?

Ford's suggested charging limits are:
- 90% for Level 2 AC charging, and
- 80% for DC Fast Charging.

These are recommended standard procedures, rather than "do not exceed" limits. This means that you can exceed the limits when you have an (occasional) specific need for the extra range. So (for example) charging to 100% before starting on a long road trip, or before towing a heavy trailer, is perfectly fine.

Charging -- particularly at DC fast chargers -- slows down as you get closer to 100%. An ER Lightning can fast charge from 15% to 80% in about 40-45 minutes. As you charge, the truck will protect the battery from damage by slowing down the charging. But that means you have to wait longer as the battery fills up. In tests that State of Charge did last year, it took 20 minutes or so to get from 80% to 90%, and about 60 minutes more to get from 90% to 100%.

 

[chl]

I'm on a trip towing 5,000lbs today and need as much range as possible, but I noticed that the Fordpass app recommends only fast charging to 80% or else battery life could be degraded. Is it hype or a recommendation we should all try to obey?

NO, NOT HYPE. Science: battery chemistry and empirical results (observation). So if you are in it for the long haul, say over 10-15 years use, then stick to L2 and the 80% except on rare occasions when that won't cut it.

I guess the two main reasons to stay below 100%: charging performance and battery longevity.

PERFORMANCE: Charging rates slow down dramatically over the 80% threshold, on some batteries the slow down may be more like at 90% - it is programmed in for battery protection and longevity.

LONGEVITY: "Overcharging" your battery can result in a loss of active material in the anode and cathode, reducing the total surface that can attract and fix electrons. It can also reduce the number of electrolytes available to facilitate electron movements. Furthermore, a phenomenon known as stoichiometric drift can appear, which indicates an imbalance between the two electrodes.

In simple terms, charging an EV battery to 100% will lead to a reduction in the total usable capacity of the battery. It might not be noticeable at first, but your battery will gradually lose its range as it degrades over time.

Some research has found that keeping the state of charge between 40-60% is actually optimal for Li battery longevity, while most manufacturers recommend 20-80% probably for warranty reasons - if your battery loses too much capacity before the warranty expires, they are on the hook.

And some say "sweet spot" for an Li battery is 50 per cent charge. That is where half of its moveable lithium ions are in the lithium layer (cathode) and the other half are in the layer (anode). This equilibrium puts the least amount of strain on the battery, and extends the number of charge cycles it can withstand before degrading.
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How much more longevity one gets from the 80-20% range and/or avoid fast charging is debatable however.

The U.S. Department of Energy predicts today's EV batteries ought to last past their warranty period, between 12 and 15 years if used in moderate climates or a service life of between 8 and 12 years if your EV is regularly used in more extreme conditions.

So you may be trading in your EV before the battery degradation reaches unacceptable levels.

The main causes of Li battery degradation are temperature, number of charging/discharge cycles, and time.

As for temperature, fast charging (DC charging) puts a lot of thermal stress on the battery, as does the ambient climate (whether you live in Phoenix or a more temperate climate). The higher the rate of charging the higher the voltage and current (power) and the hotter things get, so overheating damage is possible if not controlled well.

Thermal management/climate may actually be more important than length of time in service.

Warranties usually offer 8-10 years/100,000 miles.

But in real-life examples, some EV batteries (Teslas) have maintained 90% after 150,000 miles of driving.

So a lot of the early predicitons of EV battery lifespan underestimated it. Most early Nissan Leafs and Teslas are still on the road over a decade later.

Time will tell.

 

[GDN]

Many others have chimed in with good answers, but the bottom line is that if you are on a trip or about to drive the truck and you need 100% battery, fill er up. There will be no long term damage - especially with Ford - because you are still really only hitting just about 90% of the real battery - Ford locks you out of the top several percentages and you can't charge it if you wanted.

The DCFC will throttle back and charge at a slower speed, so It will just take you a little longer sitting at the DCFC, but if you need it, you need it.

 

[chandwawar]

The trip was a success. I started the 140 mile return (loaded) trip with 90% charge and had 40-50 miles to spare when I arrived. There may have been a breeze at my back. I got 1.8kwh/mile with 2600lbs in the bed and towing 2000lbs. External temp about 85 degrees and using low AC in the cab.

 

[RickLightning]

The trip was a success. I started the 140 mile return (loaded) trip with 90% charge and had 40-50 miles to spare when I arrived. There may have been a breeze at my back. I got 1.8kwh/mile with 2600lbs in the bed and towing 2000lbs. External temp about 85 degrees and using low AC in the cab.

You might want to learn more about your truck's capacity limits. You were dangerously overloaded.

Read the payload sticker on your door jamb. Subtract weight of any mods to the truck, and all passengers. Now subtract 300 pounds for your tongue weight. Now 2,600 in the bed. I suspect you were over 1,000 pounds overloaded.

Does your truck have the scales?

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