PP 2017 battery degradation?

OK, that's 3 JuiceBox L2 charger cases with regularly less than 6kWh for a full charge on PRIME. Have you ever measured your kWh usage in any other way to confirm what is being reported by JuiceBox is accurate? I have never checked my Kill-a-Watt meter accuracy either, but it is possible that either or maybe both are off.

 

ChargePoint (at work) for a full recharge matches what I have observed from the JuiceBox.

I do have a dedicated meter on each JuiceBox (which is how the power company provides billing for time-of-use discount) but haven't ever reconciled the numbers.

 

That's a good indication, but by itself, it does not confirm the accuracy of the JuiceBox, IMO.

I wonder how many of PRIME owners have measured kWh usage for a full charge using more than one device either for the same full charge or different charge time. I guess I could install a pass-through kWh meter on my charger circuit to confirm the accuracy of my "Kill-a-Watt meter" at a wall. I never charge my car outside. So, the question is how much kWh is used for a full charge using OEM L1 EVSE.

 

I used to get 6 1/2ish, but as I mentioned above, it dropped drastically for several months to only around 4.7ish, but has partially recovered to about what the OP is reporting — 5.5ish.

Again, probably the most likely explanation seems to be that the charging algorithm got worried about battery life impacts of having the battery “full” (meaning charged up to the top-margin level) overnight for months, so it increased that top-margin.

Then again, I’ve seen reports from others here who have seen this under somewhat similar charging conditions, but others who haven’t seen this. So, that’s probably part of it, but there are highly likely other considerations too.

Level-2 charging all the time rather than level-1, for example, might affect this. I almost always level-2 charge, and typically 2 or sometimes even 3 times per day, although charging it to “full” usually only once per day.

 

we had these issues with pip as well. i wonder if batteries are just not as homogenous as other car parts

 

Yeah, I like that explanation. The car today is becoming more organic. Maybe the battery "adapt" to each owner and "evolves" as it grows old. That would make all the reporting by all the PRIME owners meaningless.

 

The difference between Level 1 and 2 seem too high(15% to 20% range) to be explained by the efficiency advantage of Level 2; 10% better was the highest I've heard possible.

 

This is the result of an overnight recharge, the full EV capacity...

Notice the temperature of the garage is 39°F and the battery was maintained at 59°F by electricity.

I used my OEM level-1 charger connected to a Kill-A-Watt to measure consumption. The tally was 6.01 kWh.

 

I am not sure there is really a problem here. If John used 6.01 kWH to charge his battery in a cold garage and part of the charging current was used to warm up the battery, isn't it possible that in a warm garage it might take only 5.6 kWH to charge the same battery? That certainly wouldn't mean that his battery had degraded; only that it is easier to charge.

 

Certainly, the battery heater and the battery cooler, as well as climate preconditioning, do affect the kWh usage for a full charge. Those day to day variations do exist on the same car. The main points we have been discussing here are that my PRIME charging with OEM L1 EVSE has always taken over 6kWh for a full charge, never below 6kWh. Those numbers have not changed much in the last two years even seasonally averaging around 6.55kWh/charge for me. Whereas John's Prime has always taken less than 6kWh mostly using JuiceBox L2 EVSE. But even with OEM L1 EVSE, his full charge is only 6.01kWh, which is substantially less than what my PRIME's average.

 

If the garage is 39 and the battery is at 59, it's pretty unlikely that the battery heater ran. It only runs enough to get the battery to a few degrees over 32 (maybe up to 37 at most). If it's at 59, it's probably a combination of leftover heat from the previous day, and heat generated by charging. Charging usually causes less than 10 degrees increase in temperature in my experience. And even if I don't plug in, the battery is usually at least 10 degrees above the overnight low by the morning, if it was warm from the day before.

There is some variation in the battery level within HV mode. For my car it seems to like to stay around 14% SOC as indicated by Hybrid Assistant, but sometimes it will go lower. I usually make an effort to drive in EV as much as I can before I get to my house. Someone who lives at the top of a hill might have to have the engine on all the way to their house which would keep the battery more charged. Or someone at the bottom of a big hill might always get some regen within HV mode that increases the SOC a few percent. I basically live near the bottom of an extremely long gradual hill, and depending on how the traffic lights line up I can stay in EV mode for up to a couple miles and sometimes get down to "1 bar" by the time I get to my house which might be 12-13% SOC. But that might not be enough to explain the difference some people are seeing.

Another data point: Lately Hybrid Assistant has been showing 85% not 84% just after I unplug when it's fully charged. But it's maybe not a "full" 1% since just driving across the parking lot is enough for it to drop to 84%.

 

As I posted on another thread, my EV range has dropped pretty dramatically as well. Just this week, it dropped again. Now, when I go out in the morning after an L1 charge, my guess gauge only reads 22 miles of range. I used to never go below 28 miles, even on frigid nights.

I am very close to running in HV mode for the rest of the winter. It's not worth the money to charge it up for 22 miles of EV range.

FWIW, I recently crossed over 82,000 miles.

 

I was able to confirm behavior. The battery temp was 69°F at midnight when charging completed. I unplugged, then checked 3.5 hours later; the temp had dropped to 62°F. Another 3.5 hours later, I plugged back in; at that point it had dropped to 57°F. An hour later, the temp was now at 55°F and the charger did not report and electricity draw during that time.

btw, I have witnessed 41°F from that battery-heater with the garage at 14°F and charging not having taken place for 3 days. Here's video showing exactly that...

 

After another 3.5 hours and no activity indicated from the charger, battery-temp has dropped to 51°F.

 

what does electricity cost down there?

 

unfortunately, toyota has covered themselves in legal armor. if you don't have a dash light, the burden of cost will be on you, and there's no warranty for 'degraded battery', it's binary.

 

I'd suggest using two or three different measurement devices. They can vary in accuracy. As to the drop in range, that's seasonal, so you'd have to compare to this time last year assuming similar temperatures and driving conditions and factoring in your miles per kWh.

AFAIK, there is no warranty protection from natural wear and tear reduction in range. It would be akin to asking for warranty coverage for lower than EPA gas mileage. If it throws a code or quits working, then you're covered.

The biggest things you can do to protect yourself from battery degradation would be not leaving it fully charged (use the scheduler) and not parking it in hot sunny places.

 

Pasadena CA daily low temperature is ranging in the low to mid 40's, this is the temporary reason your battery performance is slightly less.


Rob43

 

I assume all Li ion batteries have life cycle limits, if you drive prime 20-25 miles a day in EV mode and recharge every night you are running battery from 100% to 20% everyday, this will make batteries degrade faster.

Teslas have option to limit charging to 80% of capacity, if you drive Model 3 SR version and don't run battery below 20%, with 25 miles a day commute you only have to charge once a week!.