waidy
Well-known member
http://en.wikipedia.org/wiki/Self-dischargeAmpster said:
ALL POSTS about Charge Timer Failure
- Thread starter TonyWilliams
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Ampster
Well-known member
Waidy,
Thank, I understand what you are saying. That article was pretty generic and it wasn't clear if the article was talking about capacity by measuring voltage or actual capacity in Ahrs. It also doesn't show the discharge curve for LifePO4's.
I think Tesla is very conservative about how much of the total capacity of the pack that they are using and I suspect that even with extended charge mode we are really not charging the pack to 100% of its capacity. Unless we could measure Ahrs in and out of the pack we really don't have any hard data. Initially, I was like you in that I didn't want my pack going to 100% but now that understand how conservative Tesla is I believe that the Battery management system would not let me charge to 100% of pack capacity. I think I have heard on this forum that the total pack capacity is about 45kWhrs and extended charge has a capacity of 41k and regular charge gives a capacity of 35k. I also understand that they don't fully discharge the batteries so the unknown is how many Ahrs they keep in reserve at the bottom and how much is at the top.
EDIT Correction to properly state capacity in kWhrs.
Thank, I understand what you are saying. That article was pretty generic and it wasn't clear if the article was talking about capacity by measuring voltage or actual capacity in Ahrs. It also doesn't show the discharge curve for LifePO4's.
I think Tesla is very conservative about how much of the total capacity of the pack that they are using and I suspect that even with extended charge mode we are really not charging the pack to 100% of its capacity. Unless we could measure Ahrs in and out of the pack we really don't have any hard data. Initially, I was like you in that I didn't want my pack going to 100% but now that understand how conservative Tesla is I believe that the Battery management system would not let me charge to 100% of pack capacity. I think I have heard on this forum that the total pack capacity is about 45kWhrs and extended charge has a capacity of 41k and regular charge gives a capacity of 35k. I also understand that they don't fully discharge the batteries so the unknown is how many Ahrs they keep in reserve at the bottom and how much is at the top.
EDIT Correction to properly state capacity in kWhrs.
waidy
Well-known member
This is what I learn from a long time Roadster driver (also advisory board member of PlugInAmerica) about Tesla's BMS:Ampster said:
- You don't have to worry about cell balancing with a Tesla as long as you leave it plugged in most of the time. The computers and sensors that control battery charging and discharging handle it automatically.
- The only way you would be likely to have a problem is if you only let your car be plugged in for exactly as long as it needs to charge every time.
- After the millions of miles of monitored miles in Tesla Roadsters, Tesla has been able to tweak their charging better than any previous EVs so they have automated it to be much better than any user could do. Toyota gave up on the RAV way too early to learn what could be learned and never upgraded their systems in the field to test any improvements they might have learned.
- In other words, the less you try to second guess the sensors and algorithms in the car, the better. Just let it do what it needs to.
Ampster
Well-known member
Yes, I understand Tesla has a sophisticated Battery Management System and I also heard that they ping our cars daily and use that data to further increase their understanding. I would agree with your source that the best approach is to leave it plugged in and let the BMS do its thing. I have a great deal of confidence in Tesla and their scientists.
My only wish is for some data such as kWhrs used, not so I can tweak the system but so I could understand it in terms of a common denominator. The capacity in terms of miles is a soft number to me because it is a function of the assumption made about miles per kWhrs, and that assumption varies day by day.
Sorry for my thread hijack, but getting back to the original topic about charge timing, it does appear that there are some glitches with the software that controls the delayed charging cycles. It appears that sometimes the top off or balancing phase can be interrupted before it does its thing. I don't think this is a serious problem because the only risk in an unbalanced pack is that the weakest cell goes below a minimum voltage. I think the BMS which presumably monitors individual cell voltages, will go into turtle mode if one cell cells to low. To be clear, I understand that the Tesla pack actually consists of a number of parallel cells that then are connected in series to get the 300+voltage of the pack. When I talk about cell level I mean at the parallel cell voltage level which is around 3 volts.
My only wish is for some data such as kWhrs used, not so I can tweak the system but so I could understand it in terms of a common denominator. The capacity in terms of miles is a soft number to me because it is a function of the assumption made about miles per kWhrs, and that assumption varies day by day.
Sorry for my thread hijack, but getting back to the original topic about charge timing, it does appear that there are some glitches with the software that controls the delayed charging cycles. It appears that sometimes the top off or balancing phase can be interrupted before it does its thing. I don't think this is a serious problem because the only risk in an unbalanced pack is that the weakest cell goes below a minimum voltage. I think the BMS which presumably monitors individual cell voltages, will go into turtle mode if one cell cells to low. To be clear, I understand that the Tesla pack actually consists of a number of parallel cells that then are connected in series to get the 300+voltage of the pack. When I talk about cell level I mean at the parallel cell voltage level which is around 3 volts.
Dsinned
Well-known member
Actually, the maximum USEABLE capacity is "41.8kWh", which has been published by many different sources including Toyota.Ampster said:
From a previous, but related topic discussed on the forum a few months ago, I think the somewhat interpolated value for the FULL "as designed" battery capacity was determined to be ~50kWh. I think it was Tony who figured this out after doing an extended charge to a fully depleted battery (turtle mode), while measuring the power consumed from the wall to restore the battery back to a full charge. To make this calculation he had to assume the efficiency of his EVSE, which he probably did very conservatively.
Just out of curiousity, I wish Toyota would disclose this kind of information and other specific details about the battery. It really does not need to be kept as some sort of trade secret does it?
Ampster
Well-known member
That estimate of 50kWh full pack size means that the 41.8kWh is about 80% and that is consistent with what a lot of the DIY electric car conversion guys are using as a measure of usable size. On a normal charge then 35kWh would equate to 70% and that is conservative.
I used 80% to determine the range on my VW conversion. That car is so light that I easily get 4 to 5 miles per kWh just driving around town.
I used 80% to determine the range on my VW conversion. That car is so light that I easily get 4 to 5 miles per kWh just driving around town.
TonyWilliams
Well-known member
Dsinned said:
I just did a run from "Normal" charge to Turtle, and got 104 miles divided by 3.1 miles/kWh equals 33.56kWh.
Not surprisingly, 80% of 41.8kWh usable at 100% "Extended" charge equals 33.44kWh. A future revision to the Range Chart will reflect this.
Yes, Tesla does consider it a trade secret, and so far, there are ZERO pictures or specific data on the actual battery.
Took my car to toyota and the acknowledge they are looking at the software charge timer functions with tesla.
Otherwise everything is working perfect. I think all climate issues i was having may have been my errors and I gave up prematurely thinking pre-climate heater was not a function. But know that appears to work reliably.
Today, on the warmest day (70F) I've owned the car, i even hit a new record doing half city and half 55 mph highway I hit 3.5 miles/kw = potential range over 140 miles. That was while carrying 750 pounds of cargo including driver
Otherwise everything is working perfect. I think all climate issues i was having may have been my errors and I gave up prematurely thinking pre-climate heater was not a function. But know that appears to work reliably.
Today, on the warmest day (70F) I've owned the car, i even hit a new record doing half city and half 55 mph highway I hit 3.5 miles/kw = potential range over 140 miles. That was while carrying 750 pounds of cargo including driver
OK,
I have another data point to add. What I have noticed is I experience charge failures only on Saturday or Sunday, Monday through Friday I have not had any charge failures. May have at first before I learned the system, but in the last three weeks to only drive failures I've had are on weekends.
The difference is I have pre-climate setup for M-F and only charging set for the weekend.
I have the Leviton 40A charger.
=D~~ Brandy
I have another data point to add. What I have noticed is I experience charge failures only on Saturday or Sunday, Monday through Friday I have not had any charge failures. May have at first before I learned the system, but in the last three weeks to only drive failures I've had are on weekends.
The difference is I have pre-climate setup for M-F and only charging set for the weekend.
I have the Leviton 40A charger.
=D~~ Brandy
Grrr, it failed to charge last night again.
My charging schedule couldn't be more simple. Charge only, by 5 AM, Sat - Sun. On the Toyota approved Leviton 40 amp charger.
There was nothing particular about Saturdays usage. Just one mid-day outing leaving 66 miles range left.
My charging schedule couldn't be more simple. Charge only, by 5 AM, Sat - Sun. On the Toyota approved Leviton 40 amp charger.
There was nothing particular about Saturdays usage. Just one mid-day outing leaving 66 miles range left.
Brandy said:
Not sure it's that. I had pre-climate before, and I had it fail on a week day a couple weeks back. So I simplified everything and did a charge only across the whole week. It's been working fine for 2 weeks, including last weekend, only for it to fail last night. Luckily I didn't need the range today, like I did last time when it failed. Irritating all the same.
Dsinned
Well-known member
TeCKis300, I think your car is unusual if it only fails infrequently. Most others seem to fail more often and with respect to schedule charge completion times, I think the failure rate is 100%! Are you sure yours is completing so-called "successful" charges on schedule?
Dsinned said:
I've signed up for the Entune charge notifications and I usually get a 'Charge Start' and a 'Charge Complete' email every early morning. What's curious about Sunday morning is that I didn't get any emails at all, which reflects that the car did not charge that night.
SeaMonster
Well-known member
The Toyota techs removed the recording device today. I met with them and they asked a lot of questions about what I had experienced while the recorder was in. I had 4 charge failures during that time. I had also kept copious notes with all plugin times, unplug times, charge start/stop times, Entune output, stop screen output, charge levels and more. Hopefully they will find something. They said "hopefully" they'll have something in a week. As always, I'll update here...SeaMonster said:
I called Toyota last week to tell them about the charge timing failure both internally and with the Blink. They escalated my issue immediately and I was contacted yesterday by a higher-level customer service person who was very apologetic about the problem and committed to getting it fixed quickly.
I did not make a stink about it, but just wanted to call and inform them of my particular situation and experience. I would encourage anyone having the issue to call and let them know, since the more info they have, the quicker it will get resolved. The first guy I talked to said they were escalating all RAV4 EV issues, so it was nice to hear we have that kind of priority and that they are taking the RAV seriously.
They confirmed my address when I talked with them, but said nothing about the car being out of state, so that was interesting. Like a lot of folks, I'm curious to see how things go with service.
I did not make a stink about it, but just wanted to call and inform them of my particular situation and experience. I would encourage anyone having the issue to call and let them know, since the more info they have, the quicker it will get resolved. The first guy I talked to said they were escalating all RAV4 EV issues, so it was nice to hear we have that kind of priority and that they are taking the RAV seriously.
They confirmed my address when I talked with them, but said nothing about the car being out of state, so that was interesting. Like a lot of folks, I'm curious to see how things go with service.
Dsinned
Well-known member
jspearman, your experience sounds like a carbon copy of my own with respect to Toyota's involvement. BTW, did you emphasize (as I did) that this problem is not unique to your own vehicle, but seemingly adversely affects ALL RAV4 EVs currently out in the wild. I also emphasized that I own a 2012 Chevy VOLT with exactly the same "delayed departure" scheduled charging feature, which works flawlessly 100% of the time, on exactly the same EVSE L2 Leviton charging station installed in my garage. This proves that this malfunction is in fact within the car itself, and most likely has everything to do with how Toyota (or Tesla) programmed the Battery Management System (or related) computer in the car.
Dsinned said:
I did emphasize that, and they acknowledged knowing about the other problems, so hopefully they'll have a fix soon. I also have a Volt, and the charge timer and Blink unit have worked flawlessly on it and on the Leaf we had for 1 1/2 years.
