Charging to 80% ? 100% from ?

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Tim94549

Tim94549

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Last night I had this discussion with a TESLA owner. He says that he charges his TESLA every night to 80%, regardless of how low the batteries are. When we took possessions of our KONA EV, we were told to allow the batteries to go down to like 10-20% to plug in and charge to 100%.

Anyone know the real technical details on this issue? Or able to point me to a specific recommendation? We really don't use the vehicle that often, so I've been reluctant to just leave it plugged in every night and rather allow the batteries to drain over a week or so. What do YOU all do for charging?

Thanks in advance.
 
I set the charge limit to either 60 or 70% and plug in (using the 230V 8A trickle charger) at night gaining 2% per hour. The most I use in a normal day is about 10%.
If I need 100% for a trip I can either charge at home for a full 24 hours or visit a nearby public DC charger to fill in the gap.
That saves me about $3,000 for a 16 or 32A outdoor EVSE install.
 
I follow SkookumPete referenced takeaways. I generally anticipate driving 50-100 km day so I keep my max SOC 70% and charge every evening, with a charge range typically between 50-70%. Ultimately charge to what your needs are. If you really need a 100% of the battery its less than ideal on a continued basis but the battery has safeguard buffers in place to protect itself so don't stress over it too much.

https://batteryuniversity.com/learn/article/bu_1003a_battery_aging_in_an_electric_vehicle_ev


Simple Guidelines to prolonging the EV battery
  • Limit ultra-fast charging, especially when the battery is cold. Use Level 2 when possible.
  • Only charge the battery to the level needed for the daily routine. Full charge hastens capacity fade.
  • Do not discharge the battery too low as this increases the internal resistance. Charge more often.
  • Charge and use the battery at room temperature. Operating when cold reduces capacity.
  • Store the battery in a cool place at partial charge. Usage and storage have different requirements.
  • Moderate the battery to room temperature in winter before charging and driving. The BMS may do this automatically.
  • Charge the EV after a sabbatical. Resting at low charge reverses capacity fade.
  • It is best to let the battery rest at low SoC and only charge before use. Dwelling at low charge reduces calendar aging and may also reverse capacity fade.
Lab Observations
  • At 40°C (104°F), battery efficiency is above 95%, but stress levels are high. At 25°C (77°F), the efficiency is between 93–95%, and at 10°C (50°F), the efficiency is only 89–92%.
  • SoC above 80% hastens cathode degradation, discharging below 20% increases internal resistance.
  • Capacity recovery is only possible at a SoC at 50% and lower over time.
  • The EV fuel gauge is not absolute. The accuracy can be improved by an occasional full charge and deep discharge toe reset the flags. This exercise is similar to calibrating a smart battery. (See BU-603: How to Calibrate a “Smart” Battery.)
 
On Lithium Ion batteries, you will get better life if you charge to 80% and to 100% only when you need the range. It's best to charge every day and don't let the SoC drop too low except when you have no choice on road trips. I usually use 20 to 30% of charge each day, so I charge every night from somewhere between 50 to 60% back to 80%. Whenever I go on a road trip or expect over 150 mile of driving in one day, I charge to 100%.
 
Thanks everyone for your words of wisdom. Very good information here for a newbie. We installed a LEVEL 2 charge a week ago.
 
Thanks for this thread! I’ve learned a lot. So now I have set up my Kona for 80% charge in both AC and DC, set a charge schedule so the battery has time to rest between use and charge in time to leave in the morning, and will once a week not charge and bring the charge level down an extra 20-25% between charges (I commute 100k per day)

Does that sound about right?
 
Kathryne said:
Thanks for this thread! I’ve learned a lot. So now I have set up my Kona for 80% charge in both AC and DC, set a charge schedule so the battery has time to rest between use and charge in time to leave in the morning, and will once a week not charge and bring the charge level down an extra 20-25% between charges (I commute 100k per day)

Does that sound about right?
Click to expand...
That sounds perfect
 
So I set a schedule to prioritize charging between 8pm and 8 am with a departure time of 7 am. My battery charge pattern is significantly different than when I just plug in without schedule. See below graphs for the last 3 days.

I don’t understand why it’s not charging based on departure time. Instead it gradually ramps and at 8pm starts pulling full charge rate.

IMG_1157.webpIMG_1158.webpIMG_1159.webp




Sent from my iPhone using Inside EVs
 
Y'know... this makes me think that if *phones* had the ability to set
maximum charge limits instead of going to 100% all the time without
intervention, that people wouldn't complain so often about having
to get a new phone because the old one would no longer get them
through a day. For "devices" I've gotten more into the habit of
keeping an eye on the SOC and pulling the plug around 90% ...
I don't always catch it right, but it probably helps.

_H*
 
hobbit said:
ge limits instead of going to 100% all the time without
intervention, that people wouldn't complain so often about having
to get a new phone because the old one would no longer get them
through a day. For "devices" I've gotten more into the habit of
keeping an eye on the SOC and pulling the plug around 90% ...
I don't always catch it right, but it probably helps.
Click to expand...
when it comes to phones, technology is moving very fast.. Most phones are outdated after 2 years, so most people don't even keep them long enough to have significant loss of battery capacity.. I usually change phones every 2 years which gets kind of expensive as prices have come up.. You can barely get a good phone for under US$ 1000...
 
BlueKonaEV said:
when it comes to phones, technology is moving very fast.. Most phones are outdated after 2 years, so most people don't even keep them long enough to have significant loss of battery capacity.. I usually change phones every 2 years which gets kind of expensive as prices have come up.. You can barely get a good phone for under US$ 1000...
Click to expand...

Well you *used* to be able to easily replace the battery in a phone, and it was a lot cheaper than buying a new one. But in the mindless search for thinner phones, all that went away, and now you need to take it in and have someone do it for you.
 
BlueKonaEV said:
when it comes to phones, technology is moving very fast.. Most phones are outdated after 2 years, so most people don't even keep them long enough to have significant loss of battery capacity.. I usually change phones every 2 years which gets kind of expensive as prices have come up.. You can barely get a good phone for under US$ 1000...
Click to expand...
I suspect this may become an issue for EVs. Lets say we keep our EVs for 10 years will the current battery tech even exist to be supported if a replacement is required? I suspect we are starting to see cars following the disposable technology obsolescence trend that now exist in phones.
 
apu said:
I suspect this may become an issue for EVs. Lets say we keep our EVs for 10 years will the current battery tech even exist to be supported if a replacement is required? I suspect we are starting to see cars following the disposable technology obsolescence trend that now exist in phones.
Click to expand...

The difference is that replacing an EV's batteries is going to be hugely expensive. Although as time goes on, those costs go down as batteries get cheaper. But once the car gets to be a certain age, you have to decide whether to replace the battery or get a new car. No different from an ICE car when the engine blows up.

I gather that there are people scarfing up used EV batteries for other purposes (battery backup for solar, and other such things).
 
ericy said:
Well you *used* to be able to easily replace the battery in a phone, and it was a lot cheaper than buying a new one. But in the mindless search for thinner phones, all that went away, and now you need to take it in and have someone do it for you.
Click to expand...
I was a big fan of removable batteries.. Until the Note 4, Samsung batteries could be replaced easily in a few seconds.. I actually always got the aftermarket extended size battery which would last 3 x as long as the original battery.. Sad that they stopped offering that feature.
 
ericy said:
The difference is that replacing an EV's batteries is going to be hugely expensive. Although as time goes on, those costs go down as batteries get cheaper. But once the car gets to be a certain age, you have to decide whether to replace the battery or get a new car. No different from an ICE car when the engine blows up.

I gather that there are people scarfing up used EV batteries for other purposes (battery backup for solar, and other such things).
Click to expand...
Luckily, not something that US buyers of 2019 Konas have to worry about :-D
 
hobbit said:
Y'know... this makes me think that if *phones* had the ability to set
maximum charge limits instead of going to 100% all the time without
intervention, that people wouldn't complain so often about having
to get a new phone because the old one would no longer get them
through a day. For "devices" I've gotten more into the habit of
keeping an eye on the SOC and pulling the plug around 90% ...
I don't always catch it right, but it probably helps.

_H*
Click to expand...
Check out the app AccuBattery. It can't stop the charging, but it does have an alarm to alert of the charge level you select, health stats, etc.

Sent from my P027 using Tapatalk
 
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