Frequency of Charging

I suppose, if you have the ability and desire to charge from 50-70% several times a day. I’d just use 60% of the capacity and charge it once.

 

I too am worried that I'm causing damage to my battery. I bought the car with approximately 24K and had a reading of 50.4 KW and now it's down to 48.3 KW after 4K miles. I know it doesn't sound like much but it is 6% in 4K miles. I charge at night at 120v at night to 100% and commute 32 miles and get to work with like 3 miles left (all freeway at 75mph). I charge to 100% at work on 120v. My drive home has a lot of stop and go traffic so I usually get home with 14 miles left. So I'm basically charging to 100% 2 times a day.

 

If your going to worry about charging the battery in an electric vehicle, it may be time to consider an ICE vehicle.

The battery can’t be charged to 100% and it takes considerable effort to get it below 10%. There are so many other factors involved beyond these 30-80% or 50-70% SOC operating ranges that people believe will extend the useful life of the battery for the next 50 years. Charge it and use it.

 

Thanks for the input Shark! exactly why people don't want to interact in these forums.

 

You’re welcome. I’ll always be a straight shooter. Sometimes folks tend to overthink things. Don’t worry about your charging regimen. If you worry about the car, sell it and get something you don’t have to worry about. A car shouldn’t bring worry to your life.

 

I saw a pretty big step change between 20k and 30k, so I think you are probably within the norm. Here are my tests:

3/07/2021 19,600 miles 51.9 Ah
11/26/2021 29,000 miles 48.0 Ah

For me, thats a 7.5% reduction. I generally drive about 60% EV and recharge to full at L2 every night if it needs recharging. I'm not sure how often the "algorithm" adjusts the battery capacity Ah value, so that may be why we can see "big" changes across not too many miles or months, or it may be just that the degradation happens in "steps" more than "smoothly". I do tend to not worry too much about it. I bought the car to drive and charge and use and that's what I intend to do. I am a believer that "pampering" the battery with charging technique can't be worth the trouble. But at least you know that someone else has seen a similar drop to what you described in your post.

 

It's interesting that SmartCharge gives an option to set a maximum SOC. The choices are 55, 70, 85 and 100. This could imply that Honda recognizes that some people prefer to charge to less than full in order to (potentially) reduce battery degradation. Although I'm not sure why they limit it to those four choices, maybe to make the interface simpler. But then again SmartCharge lets you set start and end times to the minute, for example 4:38 PM, which seems a bit overkill.

But there are a couple of other reasons that I can think of that someone may want to charge to less than full. Some people have issues with the engine starting shortly after they leave home if they have a downhill or stoplight close to the house, due to the inability of a full battery to store regen. But I would think setting it to 95% SOC would take care of that, setting it to 85% forgoes quite a bit of EV miles just to solve the startup problem. But that's the only choice available.

Another situation would be if someone can charge at work for free, so they want to maximize their charging at work. Let's say someone's workplace is at a distance that can be driven with 60% SOC worth of battery power. If they leave home with a full battery, they will arrive at work with 40% SOC remaining. They then charge for free to get from 40% back up to 100%. When they arrive back home they are down to 40%, so they charge from 40% to 100%. So not counting any other driving, each night they are charging 60% worth of SOC at home on their dime. But if they charge at home to only 60% SOC, then they would arrive at work with 0 EV miles, and they could then charge from 0 to 100% for free. They would still arrive home with 40%, but since they are only charging to 60% they only have to add 20% worth of SOC. That's 40% SOC a day that they don't have to pay for. Whatever the conversion happens to be for them from SOC to kWh to $$$, it's a savings that would add up over time. Although to do this in SmartCharge they can't set 60% as a maximum, they would have to choose between 55% and 85%, reducing their potential savings. Again I'm not sure why SmartCharge limits the maximum to four choices.

So what did Honda have in mind by allowing people to set a maximum SOC when using SmartCharge? Who knows, I guess add it to the mystery list which is already pretty long.

 

The emerging theory is that it requires charging from 0 EV to 100% SOC in one charge session. I also had experienced that my Ah value rarely changed. Then I saw a post where someone said they got it to update by charging from 0 to 100. I thought about it and realized that this is something I rarely do. I get down to 0 EV miles quite often, and I charge to 100% at least once a week. But I am on a time of use plan with extremely cheap rates for eight hours per night, so that's when I do all of my charging. I am using Level 1 so I won't get a full charge during that time, but it's always enough charging for what I need. But this also means that I never charge from 0 to 100 in one session.

After reading that post, the next time I got down to 0 EV miles I charged to full, and sure enough my Ah updated. I have done this twice now with the same result. Costs me a tiny amount since I have to pay a higher rate for part of the charge session, not a big deal though. I figure I'll do this every three months or something.

I think I read though that someone tried this and it didn't work for them, so who knows. But it seems to work for me.

 

I’d use the 70% option for charging at home in your scenario. Arrive at work with ~10%, charge to 100%, arrive at home with ~40%, charge to 70%. That way 75% of the daily charging is done at work/free.

 

Yes in that scenario 70 would be best, at least out of the choices that they give you. And there are other finer points to the strategy that I didn't go into. Obviously one of them being changes in season where someone would have to make adjustments for higher SOC usage during cold weather. Also charging exactly enough so that you would arrive at work with 0 EV miles is part art and part science. Falling even slightly short causes the engine to come on, which rankles some people, so they would probably charge a little bit more than they need just to avoid that. Personally I don't mind when that happens, I just aim for 0 EV miles when I arrive home (different scenario, I'm just talking now about normal driving). Sometimes even with my best attempts I arrive home with an extra mile or two, other times my engine starts when I am less than a mile from home (not great for the catalytic converter I suppose but I think it will survive). Other times I squeak it in at 0 EV miles without the engine coming on.