Frequency of Charging

I follow a pattern much like yours. I've always been concerned about this too. However I've concluded that for me this is the only option.

If I had an EV which could get me through several days without charging I would change my charging pattern.

 

I've always assumed Honda expected Clarity owners to keep their batteries topped up to minimize the need to tap into the minimal 7-gallon gas tank.

 

Beware of charging during on-peak periods when electricity rates are high. Depending on your utility district, it might be cheaper to run on gasoline. I have the timer set to charge only at night when rates are lowest and that is usually all I need.

 

Maybe a change in your driving patterns would reduce your need for charging? That would have been one wish for the PHEV Clarity... a larger battery pack.

 

As pertains to the battery, any charging will be between ~10-90% SOC. The cells can’t be charged to 4.2V which represents a 100% SOC for a 3.7V nominal cell. Lithium batteries will not be harmed by fully charging, partially charging, partially discharging, etc. In other words, just charge it and use it as you please.

 

you never really fully discharge it and charging to 100% after 90% use low voltage, so don`t worry and use as it is, you can't do anything to battery

 

I had the same question before buying my EV and was told that that’s ok, and it won’t damage or reduce battery capacity. And I was advised, as y’all know, just not to let it drop under 20% and to avoid charging over 80% unless for long trip.

 

My Clarity is 4 years and 1 month old. I drive it about every other day for around 10 miles. Other than that, it is always full-time plugged into my level 1 charger in my garage, which can vary from about 50-110F. A few times I have run the battery down to 0 indicated (due to forgetting to switch to HV charge on a long trip.) On cold days when I leave, it might say as low as 45 miles on the guess-ometer. Some warm days it will be in the high 50 mile range. I do realize that I must replace the 12V battery soon, due to age. Overall, the Clarity has been one of the most reliable things I own.

 

I charge mine every time I am near an outlet. 240 volt charger at home and 120 outlet at work. 2018 Touring with 45,000 miles. Still get an EV range of 47 - 50 during temperate weather.

 

I agree about the supposedly maintenance free12 volt. I added a lot of water to mine by unscrewing the caps below the sticker but it never revived. So the charging system was being taxed trying to keep a failed battery working. If the indicator on top of the battery shows needs charging, then definitely get it tested

 

Thanks Dominick. That explains why the Honda battery has such a low energy density. Nonetheless, Lithium batteries are not harmed by frequent, low percentage charges. In fact, studies indicate that one can maximize battery life by keeping the SOC near 50% and doing frequent, shallow charges. For the OP, if he's able to do frequent shallow charges, that's great but to maximize battery life, he should keep the SOC hovering around 50% (e.g., charge to 70-80% and charge no lower than 30%). If he does that, he should also charge to 100% about once a month for cell balancing.

 

Do you actually pamper the battery as you recommend?

 

I think it's possible that this would help, the question is how much. In my opinion doing partial charging for the chance of some possible increased battery life makes sense only if the following criteria are met:

1. There is no sacrifice of EV miles, i.e. having to use some gas because of not charging to full, or using gas to avoid running EV miles down to 0.
2. It is convenient to partially charge, i.e. it doesn't take much effort.
3. The owner enjoys doing this, i.e. they find it interesting and sort of fun.

I think for most people #2 is the problem for the Clarity. It's not very convenient because it requires doing scheduled charging and some mental math. Even if someone is already using scheduled charging because they are on a time of use rate plan, they can no longer just leave it on autopilot with a fixed daily schedule, but instead have to modify the ending time each day to get the desired level of charging. Although in some cases partial charging can be done by simply not plugging in when you know that you have enough charge to get through the next day.

If it's not convenient then #3 is probably unlikely also. Which means they are diminishing the enjoyment of their car now just for some possible slight gain later on.

But if someone likes doing all of this, go for it. But I agree they should still charge to full every once in a while. In fact I wonder if cell balancing only occurs when charging from 0 to full in one session? That's how the battery capacity measurement seems to work, the value displayed doesn't seem to change unless charging from 0 to full in one session. Maybe the battery capacity value only updates after cell balancing has occurred, which would indicate that cell balancing only occurs after charging from 0 to full. This could explain why the owners manual says, "To help extend the lifespan of the battery, it is recommended that you fully charge the battery each time prior to driving".

 

I’m jealous. In winter My 2018 averages 37 miles eV range at full charge. Parked in garage that doesn’t get below 50 F. It’ll rise to 45 or so in summer. Seattle area.

 

I own a NIRO PHEV and treat it exactly as you do, if it isn't being driven it is plugged in. My is a 2019 and it has been treated this way every day since April of 2019. While not a Clarity, I have never experienced any issues or decrease in battery range. I agree with Domenick that Engineers expect PHEV owners to do this and the battery management system handles the system to optimize and protect the batteries.

 

Actually, I do, just because of the way I use the car. I make several short drives a day and I charge after each to about 70% and discharge to 50%. After 4 years and about 40K mostly EV miles, I still get 70 miles or more if I charge to 100% (less in the winter of course). I haven't had the battery tested though. I realize most people can't do this but my lifestyle allows it so why not?

 

It would be a really interesting data point for the rest of us to see what your battery Ah rating yields. I would guess your location (ambient temperature) would also impact the degradation of the battery as well. If you are near one of us with an AP200 or a Vgate device, I'm sure someone would volunteer to read it for you.