ALL POSTS about Charge Timer Failure

[waidy]

............... I don't like my EVs sitting at 100% because it allows the battery to discharge itself.

I have not had that experience with other Lithium batteries. Could you explain what you mean by "discharge itself"?

http://en.wikipedia.org/wiki/Self-discharge

 

[Ampster]

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.

 

[waidy]

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 actual capacity in Ahrs.

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 45kAhrs 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.

This is what I learn from a long time Roadster driver (also advisory board member of PlugInAmerica) about Tesla's BMS:

• 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]

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.

 

[Dsinned]

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.

Actually, the maximum USEABLE capacity is "41.8kWh", which has been published by many different sources including Toyota.

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]

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.

 

[elia72]

Are you sure you are in the right mode?

Yes, thank you but I've tried all the modes. when in the timer mode it will go onto standby, when I plug it in, then unplug it and plug it back in a second time (twice out of 12 in recent couple day survey it went to standby mode first thing). It does charge when in the timer mode, just after the ready time has passed, or a few minutes before the ready time, with no identified pattern yet.

I have an appointment Tuesday to bring the car in. I talked to Toyota again and they explained a service rep won't have any info on any problem until it is fully diagnosed, and procedure released. They said I need to bring the car in to start and official review.

My wife corrected me, one time the climate control worked for her on timer setting. (yesterday) The only way I've gotten it to work while car is plugged in is to unplug the car, turn car on, turn heater on, then plug back in and then the heater will run and car charge at the same time. even if car is on, heater will not turn on while plugged in without doing the description in previous sentence. it might be a heater thing and not timer?

I have not tried mine on a levitron charger yet. Clipper Creek said they have worked with toyota engineers and Tesla, and have not heard of this problem yet.

 

[TonyWilliams]

Actually, the maximum USEABLE capacity is "41.8kWh", which has been published by many different sources including Toyota.....

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?

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.

 

[elia72]

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

 

[Brandy]

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

 

[TeCKis300]

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.

 

[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.

See my previous post.

Try adding a pre-climate after the charge. Clear the day's setting first add new charge time with pre-climate.

=D~~ Brandy

 

[TeCKis300]

See my previous post.

Try adding a pre-climate after the charge. Clear the day's setting first add new charge time with pre-climate.

=D~~ Brandy

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]

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?

 

[Brandy]

See my previous post.

Try adding a pre-climate after the charge. Clear the day's setting first add new charge time with pre-climate.

=D~~ Brandy

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.

Interesting, looks like there are several failure modes. Any one keeping a chart?

=D~~ Brandy

 

[TeCKis300]

TeCKis300, I think your car is unusual if it only fail that 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 "on time"?

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]

Toyota sent two techs to my dealer today and they installed the monitoring device. It connects to the diagnostic ports in the front and back. Unfortunately I won't get photos because they installed it in the side panels and packed foam around it to prevent rattling. They unmounted the connectors in both locations so that their equipment could be connected without sticking out. So basically I can see nothing without undoing panels and I don't want to disturb anything. But it is recording info from both the Toyota and Tesla halves of the car.

They want me to wait for a charge failure and then keep recording for 7 days after that. Then they'll remove it and search through the records.

More news as I get it.

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...

 

[jspearman]

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.

 

[Dsinned]

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.

 

[jspearman]

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.

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.