Range Decreases soon after Tony Test

[mihalakj]

Hello,

I've seen that my battery range only shows about 73 miles these days after a full charge. I looked at this forum and saw the "Tony Test". I performed this test and this caused my range to go back up to 147 miles. It lasted maybe about 1 week, and then the range drops rapidly each full charge. Its recentely gotten pretty low, 73 miles these days which seems like alot of charge to be missing. Am I doing something wrong or do I need to do the tony test more often?

I do not charge on extended charge mode either.

 

[smkettner]

How cold is it there? How many miles on the odometer? Are you using the heater?

Test only resets the meter. Same charge is in the battery. Meter adjusts over time for temperature, general conditions, and driving habits.

 

[mihalakj]

I'm in washington DC. I did the tony test on 2/23. The batter stayed high for about a week. Then suddenly dropped to like 90 after a charge. stayed around there for a week or two, dropped to the 80 range... another week or two, now in the 70 range. We had 3 days last week where temperatures were bitterly cold in the 20's. Other than that its been a warm winter. average 50 degree's I'd say.

about 20K miles. I do use the heater sometimes, the seat warmer often. I guess I could see these things adjusting it downward, but into the 70's? Thats like 1/2 the range.... seems like a lot.

Also When I reset the battery, I drove it about 110 miles till it was down to 30 miles left so I know the batter is capable of going pretty far. Its annoying though because if I have to go on a long trip I need to do the reset procedure.

 

[davewill]

The "Tony test" just resets the meter allowing us to get a handle on the actual battery capacity, it doesn't really change your range! Once the system gets a handle on your efficiency, the range shown will go back to what it was. The actual distance you can drive is completely unaffected by any of this.

Resetting before a trip will accomplish nothing.

 

[n3ckf]

Yes you're seeing the car adjusting to what it "thinks" the right range is. By clearing the memory you get the maximum possible range. (which indicates what the car thinks the battery is capable of, which is why its a good battery test).

However the car will self-adjust to what it thinks the range is.

When i drive in the mountains for more than a few days, i end up around low 80s for a "standard" charge, but if i drive on the flat (and not really fast) i'll get mid 90s. The range you see is just what it thinks for the last 1-2 weeks you've driven the car.

 

[michael]

I would like to ask the basis for the "Tony Test". I have to say I'm a little skeptical.

My best understanding is that this test is equivalent to Tesla's "rated range", which is the standard that all the Tesla fans use to claim very little degradation. Tesla rated range, as best I understand it, applies some reference Mile/kWh to the car's estimate of the remaining battery capacity. This is effectively the same as the Tony test, except that it is easier to do.

My question is: How accurate is the car's estimate of the battery's capacity? How does it know? Do we trust this estimate?

Anyone know?

As far as I can tell, the only true way is to run the car down to zero and measure the available energy. Surely the car doesn't do this...so what does it do instead?

 

[miimura]

I would like to ask the basis for the "Tony Test". I have to say I'm a little skeptical.

My best understanding is that this test is equivalent to Tesla's "rated range", which is the standard that all the Tesla fans use to claim very little degradation. Tesla rated range, as best I understand it, applies some reference Mile/kWh to the car's estimate of the remaining battery capacity. This is effectively the same as the Tony test, except that it is easier to do.

My question is: How accurate is the car's estimate of the battery's capacity? How does it know? Do we trust this estimate?

Anyone know?

As far as I can tell, the only true way is to run the car down to zero and measure the available energy. Surely the car doesn't do this...so what does it do instead?

The purpose of the Tony Test is to expose the "rated range". While I am not an expert on the specific BMS used in the RAV4 EV, generally, Battery Management Systems have to use what is called Coulomb Counting to make accurate estimates of the SOC at any given time. Basically what it's doing is monitoring the energy going in and out of the battery all the time. When it sees an excursion to very high or low SOC it can calibrate the extremes and correct its SOC estimate. In the course of doing this over time, it knows the total capacity of the battery.

 

[TonyWilliams]

As far as I can tell, the only true way is to run the car down to zero and measure the available energy. Surely the car doesn't do this...so what does it do instead?

As stated above, the Tesla BMS capacity is only as accurate as the coulomb counting and the cell temperature / OCV voltage. I don't know if they have a way to measure cell impedance. The BMS will adjust for things at known intervals (for instance, an OCV of 4.16v means that the count should reflect 100%, and if not, there needs to be an adjustment). The same is true on the bottom... all the cells at 2.5-3.0v (whatever they actually consider the bottom), that's getting close to 0%. The coulomb count between those two extremes and the known total usable capacity is the degradation.

I'm not convinced that Tesla isn't playing games with the "Rated Range" on Model S and X, since the Roadster (and RAV4 EV) all lose capacity at a fairly predicable rate. The Tony Test is not really rated range... it's default range.

So, do the Tony Test, then do a range test. I think you'll find them to be quite close. One suggestion is to run the car all the way to near empty (as close as you can safely get) and then fully charge, then do the Tony Test.

 

[mihalakj]

Maybe I'm referring to the Tony test incorrectly? Its basically where I disconnect the batter for a night, then reconnect it and do a certain sequence of button/brake presses, etc... and then the range displayed is back to a high number that you expect to get with this vehicle (somewhere between 120-150 miles)

Most of the time I'm driving 11 miles to and from work, so it doesn't matter if the miles drops low. But everyonce in a while I need to drive 100 miles and in order to do this and know how far I can go I have to do the tony test reset procedure to get an accurate reading of how far I can go. Its annoying and inconvienient to disconnect the battery for a night prior to making a long trip. Can I just skip the disconnecting of the battery part and press the buttons to reset the range learning?

 

[smkettner]

All you need to do is an extended range charge, turn off the climate control and drive.
You already know it will go 110+ miles regardless of the guess-0-meter.
Battery stores electric power, not miles.

 

[TonyWilliams]

You don't need the GOM. Just use the range chart:

http://www.myrav4ev.com/forum/viewtopic.php?f=2&t=67

 

[mihalakj]

so using that chart is about as annoying as disconnecting the battery for a night. Let me rephrase as I'm not trying to figure out what my range really is. I understand that the miles displayed isn't accurate. Is there an easy way to make the car forget my past driving habits and start from zero without having to disconnect the battery and wait for 4-8 hours?

 

[miimura]

so using that chart is about as annoying as disconnecting the battery for a night. Let me rephrase as I'm not trying to figure out what my range really is. I understand that the miles displayed isn't accurate. Is there an easy way to make the car forget my past driving habits and start from zero without having to disconnect the battery and wait for 4-8 hours?

Sure. Disconnect it for 2 minutes. :lol:

 

[TonyWilliams]

Sure. Disconnect it for 2 minutes. :lol:

I'm glad that I didn't have to say it!

 

[michael]

As far as I can tell, the only true way is to run the car down to zero and measure the available energy. Surely the car doesn't do this...so what does it do instead?

.
I'm not convinced that Tesla isn't playing games with the "Rated Range" on Model S and X, since the Roadster (and RAV4 EV) all lose capacity at a fairly predicable rate. The Tony Test is not really rated range... it's default range.

Yes, that's my impression as well. Tesla fans love to point at the minimal loss in "rated range" as evidence the battery isn't fading. I wouldn't place as much confidence in this as they seem to.

My Focus Electric had an Energy to Empty estimate accessible over OBD. This number gradually decreased over the years, but it became increasingly optimistic (compared to actual run-down tests) as the battery faded.

I haven't don't a "Tony Test" on our RAV but its battery has faded a easily noticed amount, an amount I consider reasonable but far less than the amounts typically reported by Tesla owners who rely on "rated range".

 

[TonyWilliams]

I haven't don't a "Tony Test" on our RAV but its battery has faded a easily noticed amount, an amount I consider reasonable but far less than the amounts typically reported by Tesla owners who rely on "rated range".

You can expect 10% degradation, plus or minus 5%, at 50,000 miles

Perhaps 20%, plus or minus 5% at 100,000 miles.

I'm between 15% and 20% loss at 81,000 miles.

 

[michael]

I haven't don't a "Tony Test" on our RAV but its battery has faded a easily noticed amount, an amount I consider reasonable but far less than the amounts typically reported by Tesla owners who rely on "rated range".

You can expect 10% degradation, plus or minus 5%, at 50,000 miles

Perhaps 20%, plus or minus 5% at 100,000 miles.

I'm between 15% and 20% loss at 81,000 miles.

Yes, I'm in that range. Maybe 15% at 60K miles, lots of extended charges (perhaps half the time).

Most of the Tesla fan reports (based on rated range) suggest well under 10% fade at 100K miles. For example

https://electrek.co/2016/06/06/tesla-model-s-battery-pack-data-degradation/

I'm skeptical.

 

[mihalakj]

Sure. Disconnect it for 2 minutes. :lol:

I'm glad that I didn't have to say it!

Thanks guys, but the annoying part is disconnecting the battery (and waiting the night). Is there a way to reset it without having to get out the old tool chest to loosen the battery nut?

What i'm looking for is convenience to reset the GOM without going through too unusual shenanigans

 

[fooljoe]

Thanks guys, but the annoying part is disconnecting the battery (and waiting the night). Is there a way to reset it without having to get out the old tool chest to loosen the battery nut?

What i'm looking for is convenience to reset the GOM without going through too unusual shenanigans

The annoying part is the GOM itself. Just don't look at it! Reset your efficiency meter (miles per kWh) at the start of a long drive and pay attention to that instead of the GOM.

All you need to know is that regardless of what the GOM says, a full extended charge gets you a little more than 40 kWh. If you need to drive 100 miles, just make sure you're maintaining at least 2.5 miles/kWh. If you need to drive 120 miles, maintain at least 3.0 miles/kWh, and so on.

If you want something better than the GOM that will tell you the actual energy in your pack and do math like the above for you, try RavCharge!

 

[TonyWilliams]

Sure. Disconnect it for 2 minutes. :lol:

I'm glad that I didn't have to say it!

Thanks guys, but the annoying part is disconnecting the battery (and waiting the night). Is there a way to reset it without having to get out the old tool chest to loosen the battery nut?

What i'm looking for is convenience to reset the GOM without going through too unusual shenanigans

We use a simple M8 wing nut and two small brackets on JdeMO installs. No tools required.