Not for variable pricing. I’m same electricity cost any time of day but wondering if less time at “full” charge (as full as the built in buffer allows, I’ve read 83% quoted but unsure if it is a reliable source) has any meaningful impact on battery degradation.
Background for me. My last PHEV was a 2013 CMax Energi, now passed on to my daughter, who has no place to plug in. No matter since its battery range, never huge even new, is now maybe ten miles maximum, less with heat or air. Still a fine hybrid car with good gas mileage. My new car is a Prius Prime. All electric range is about 40 and my daily commute is roughly half that.
No harm in setting up the charging schedule function to begin charging at 4 am so it is at its middle range longer. Better for the grid anyway. But I am unable to get any solid answer as to whether less time sitting as “full” battery makes ANY difference to battery longevity. Is “full” actually middle enough to not have negative impact on longevity?
The same logic applies to full BEVs of course. Does it matter? Do you bother? (Again other than to take advantage of variable pricing on electricity.)
For the record, everything I’ve read mentioned the same built in buffering (on both ends of the battery) for our 2024 Rav4 Prime PHEV.
We have scheduled charging starting at 8pm, which is the beginning of off peak, even though we currently have fixed rates as well. Why push the grid when we don’t have to, although since we’re just using Level 1 Charging (one of the reasons we got the PHEV as installing Level 2 would require a new panel and an extra $8k right now) I doubt there’s too much time near max charge during the weekly commute.
For the record, MOST days, my wife leaves in the morning around 6:30am, and gets home around 5:15pm, plugs it in (so she doesn’t forget) and the Rav4 is programmed to start charging at 8pm.
Another reason to schedule, is due to the aforementioned need for new panel and wiring, is that I like to minimize high draw appliance use. So another reason to schedule for a bit later, after all the cooking is done. I normally program a delay for dishes so they don’t start until 7:00am, and am similarly careful with the washer/dryer to minimize the load on the old wiring.
My understanding is that Lithium batteries like to be at a mid-charge level. Anywhere between 20% and 80% is fine. You don’t want them to sit for an extended period fully charged or fully discharged.
All true. But you also don’t know how much the car’s battery control system says "100% " when it’s really 85 and says “empty” when it’s really 15% to enforce the 20-80 range automatically with no user action. If you fill to 80% indicated is that 80% of theoretical capacity or 80% of the deliberately limited 80% of actual, so only 64% of actual?
Yes. And the hybrid side never lets it get too discharged as the ICE then contributes as it goes into hybrid mode. The question is if that built in buffer 83% “full” for a greater amount of time is harder on the battery than spending more its time closer to the middle.
FWIW my wife plugs in our five year old Nissan Leaf whenever it gets below 50% charge, which averages twice a week. So far there is no notable decrease in what it reports as its range Maybe 2%?. No idea if that charging behavior has helped or the batteries just last.
I’m guessing that the buffer point is sufficient to not induce that degradation cost from being full. But wonder if anyone here actually knows.
Oh hey, i had that car. Mine was a lemon, so we traded it in for a new(er) car. But despite the tiny battery range, when we got rid of it, i estimated how many of the total miles had been on battery, and it was about half. I do a lot of short trips.
We charge our PHEV at 7:00pm every night when it has been driven during the day. If it’s at 20%, the minimum discharge level, it takes two and a half hours to get back to 100%. Then it doesn’t get driven until mid-morning the next day. It never occurred to me that it would affect battery life or performance. I haven’t noticed any changes since we bought it a year and a half ago.
Yes, I limit my charging to 80%, which is the manufacturer recommended level for daily charging.
Sometimes I charge to 100%; usually on ski days. On those days I set the car to be heated and charged by 7am (or whenever). The car will usually hit 100% charge around 6:30, and is depleting the battery (aka “driving”) by 7:15 or so.
My guess is the total time the battery spends over 90% is probably less than 2 hours. I don’t know if that really is making a difference in prolonging battery life, but is easy, is unlikely to cause extra damage, and may be better than letting it sit at 100% for 12 hours.
Yeah it’s interesting: it varies by OEM. Volvo and Lucid, for example, allow 100%, or nearly 100%, charging, and strongly advise that owners rarely do so. That allows them to advertise the longer range that is only possible by accessing capacity that would be buffer in other vehicles. The usable capacity is close to the total capacity with little to no buffer built in. Others have various amounts of buffers, so what is shown as fully charged is actually 83% or a bit more or less. So their “full” charge is the former’s 80% level. And few of them seem to be wonderfully transparent about the size of their buffers.
What brand is your vehicle?
I readily accept that time near true 100% accelerates battery degradation. I’m just not finding anything that verifies the size and edges of the, for lack of a better phrase, sweet spot. I think that probably@Fear_Itself’s approach is as good as timing it to be ready just before the morning commute, if in reality charging to 80%. But I would love to hear that someone else knows it.
@puzzlegal most of my CMax miles were electric also, especially when the battery was fresh. 19 miles covered my daily commute. I got frustrated when it went into “engine maintenance” mode, burning gas because its ICE needed to run a minimal amount.
echoreply didn’t explicitly say so, but Tesla at least supports a start and end time for charging. Typically you would set the start time to be when you get low rates, and the end time when you expect to start your trip (whether commute or otherwise). In that case, the car doesn’t actually start charging until the point where it needs to in order to hit the target.
The end time doesn’t make much difference if you limit the car to 80%. But it’s somewhat important if you’re going on a long trip and are charging to 100%. The less time spent above 80% the better.
