Bellyaching about the GuessOmeter (GOM)

[wayzin]

I just installed my 240V/40A charger last week in my garage and after ~3 charges the mile range has gone from 105 to 90 miles. Before using the 240V charger, I was using the 110V charger that came with my Rav4 and it always charged to 105 mile max charge. Has anyone seen a drop in charging capacity like this and is it due to the difference in Level 1 and Level 2 charging? I hope it doesn't drop anymore. I haven't tried charging with the 110V yet to see if there is a difference.

 

[Jscifres]

The range displayed in the GOM is based on your recent driving habits.

If you go onto your entune app, you'll likely find that your recent driving efficiency is around 2.6 mi/kwh.

Standard charge battery capacity is approximately 35 kwh. So, 35 kwh x 2.6 mi/kwh = 91 miles of "Range" if you continue to drive it under the same conditions.

 

[Dsinned]

There is NO FREE LUNCH! If you are not driving efficiently, battery range WILL BE REDUCED. That's a fact! The EPA rating is only 102 miles based on the average range obtain between a standard charge (92 miles) vs. extended (113 miles). 102 is somewhat reflective of how most ppl drive, perhaps a bit more conservatively with respect to acceleration and braking and maximum speed, but while still using heating, ventillation and air conditioning. However, some ppl are rather oblivious as to how long their battery capacity will last no matter how they drive.

As just stated by Jscifres, the key indicator of projected range is the running average for "miles per kWh". A fairly "doable" overall average for many would be ~3.0 mi/kWh, which corresponds to the range rating of 105 on a standard charge. The higher this average, the longer your projected range may be. Conversely, when this average is lower, the less your range will be in general.

A fellow member (Tony Williams) created a "range chart" elsewhere here on this forum, that can give you an estimate of your projected battery range based on this same miles/kWh measurement of your RAV4 EV's driving efficiency. However, range predictions are SIGNIFICANTLY controlled by the driver(s) of the car, by HOW, WHEN and WHERE they drive the car. The affect, whether positive or negative, from "how" you drive should be quite obvious. However, when and where you drive the car are less apparent, but each of these factors into the range you'll get from any given charge vs. the depletion rate of your battery capacity.

 

[TonyWilliams]

A fellow member (Tony Williams) created a "range chart" elsewhere here on this forum, that can give you an estimate of your projected battery range based on this same miles/kWh...

It's always in my signature line:

Range Chart

 

[Jscifres]

Ah, where are my manners...? I just realized this was your first post. Welcome to the club and I hope you enjoy your Rav4 EV.

I'm guessing that this is your first EV? If yes, then I was in your shoes back in December... And I also wondered if my battery was bad as I noticed my range drop as low as 79!!!! Yeah... I was driving it like I stole it!

Then I reset the 12V battery (which resets the GOM to 3.5 mi/kWh) and hypermiled for two months, averaging close to 4.0 mi/kWh during that stretch. I'm now driving normally and getting 3.3... But my two month test was a nice way to learn what it takes to squeeze maximum range outa this baby!

 

[Dsinned]

Welcome to the forum, and because you may be new to the EV world, the term "hypermiling" may be unfamiliar. It is way of driving your car to MAXIMIZE range. Generally, it means you are very, very gentle on the accelerator, and use the (mechanical) brakes sparingly. You will likely be driving in "B" a lot to slow down, but hardly ever in "sport" mode to speed up. You will dress appropriately to avoid using the heater in the Winter or the A/C in the Summer. You might even be inclined to turn off the Daytime Running Lights and disable all the interior lights from turning on when a door opens. You will drive slower on the freeways; maybe appreciably under the speed limit. You will probably try to avoid driving in inclement weather, keep your tires pumped up to maximum, and never drive (over 45 mph) with your windows down. You will avoid storing a lot of things in the the car that contribute to unnecessary cargo weigh. All these things and a few other such things generally constitute "hypermiling" and help to maximize range.

Btw, we have one or two member's here that claim to have hypermiled their way to over 175 miles on a single battery charge! AMAZING!!! :mrgreen:

 

[wayzin]

Thanks for all the good info. I owned a Honda Civic Hybrid and know how it helps to drive conservatively. I have to admit that I was enjoying that sport button too much but what a rocket when I first tried it. It's hard to resist the feel from such a fine automobile or I should say EV-mobile. I have been averaging 3.3 mi/kWh now that I have taken the advice from all the feed back and it's been fun.

 

[Vach]

Hey everyone, after having the car myself for a few days, I am pretty sure I know how this works, but I wanted to ask around on here to see experiences from drivers who have had it for much longer.

Anyway, when I took delivery at maximum charge with no AC the gauge displayed 76 miles. After fully charging twice, it now reads 88. This car had over 1000 "taxi" miles on it from test drives and dealer use. I'm okay with those, as I got a gigantic discount. However, I am pretty sure the meter is basing the range off of the previous driving which obviously wasn't efficient. Is that all that is? Or is this premature battery degradation?

Also... on a side note, anyone getting less than indicated charge times? I'm currently charging with 110 until my new panel installation is finished, and I'm charging faster than indicated. For example, a mentioned 23 hour charge only took 18. This makes me paranoid, but it's probably nothing.

 

[TonyWilliams]

It bases its "guess" on your previous driving. I was driving very aggressively and got well below 100 miles on a full 100% "extended" charge, and I have also gotten over 200 miles after they updated the firmware.

Naturally, none of that has anything to do with the drive I might make today. Tesla has a "rated range" display, which means that when you fill it up with electrons, the GOM shows 265 EPA miles (plus or minus). The great part about that is consistency. I have encouraged folks developing products for monitoring the LEAF battery to used rated range for the LEAF, so that every fill up shows 84 miles. As the battery degrades, that will show lower miles.

It won't change the "guess" because I went up a hill.

 

[dark]

What you guys explain make sense, but at the same time I disagree since the charge behaves differently.

For instance, I used to be getting 116 to 122 range at a normal charge. It has been pretty consistence until one day, there was this S2000 trying to cut me off, so I put on sports mode and I make him go behind me. Haha, that felts good though.

The next morning, I got 97 range at a normal charge. If what you guys explain is true, I can drive gently meaning 3 ~3.5mile/kw, I should be able to get 116 to 122 range right? regardless of what the car shows, in my case 97 range.

So I drove about 82 miles (3 ~3.5mile/kw) with 15 miles left and my low charge warming light came on. Well, this doesn't make sense, I should be getting 116 to 122 range right? What happened if I drive another 15 miles, will the car starts to shut down? Or I should be able to drive another 10 to 15 miles that is hidden?

Anyone can explain this would be great.

thanks,

 

[Vach]

Yea, that's what I figured. my assumption was correct, the previous drivers at the dealership basically drove it like it was a regular car... or had fun or whatever.

Thanks Tony, do you know anything about the charge time thing I mentioned?

 

[cwerdna]

^^^
It's a GOM.

Tony's posted his famous pic at http://www.mynissanleaf.com/viewtopic.php?p=271853#p271853 and elsewhere before.

 

[Vach]

So I drove about 82 miles (3 ~3.5mile/kw) with 15 miles left and my low charge warming light came on. Well, this doesn't make sense, I should be getting 116 to 122 range right? What happened if I drive another 15 miles, will the car starts to shut down? Or I should be able to drive another 10 to 15 miles that is hidden?

This is interesting, because I am curious to see what would happen in this exact circumstance as well. It seems the system is really harsh on single moments of 'bad driving.'

I noticed in the past couple days that the system is trying to gradually adjust to my better driving compared to the bad driving economy of dealer people. I will reset a trip meter and watch it as a drive, I tend to get 2-3 miles of real range from a single mile of "range" in the charge display. I believe this is what would happen for your last 15 miles.

 

[TonyWilliams]

Thanks Tony, do you know anything about the charge time thing I mentioned?

Yes, it's just like a GOM. Unless the vehicle samples what charge voltage and amperage it is plugged in to, the charge time is just dumb. Literally dumb.

But, if it knew, for instance, that it had 240 volts at 60 amps available from the EVSE, it should have no difficulty getting a reasonably accurate time.

 

[TonyWilliams]

I've renamed the thread because it has absolutely NOTHING to do with battery capacity.

You guys will get the GOM figured soon, I'm sure; just follow your tail:

 

[dark]

So, can anyone tell me this? Regardless of what the GOM says, 85, 90, 100 or 110 at normal fully charge. What would be my realistic range? if my efficiency is 3mi/kwh, then 32kwh x 3mi/kwh? = 96 miles without any a/c?

 

[TonyWilliams]

So, can anyone tell me this? Regardless of what the GOM says, 85, 90, 100 or 110 at normal fully charge. What would be my realistic range? if my efficiency is 3mi/kwh, then 32kwh x 3mi/kwh? = 96 miles without any a/c?

http://www.myrav4ev.com/forum/viewtopic.php?p=251#p251

 

[dark]

where is the final draft? some of the figures are covered.

 

[TonyWilliams]

where is the final draft? some of the figures are covered.

If the Nissan LEAF version that I've done is any indication, there never is a "final".

http://www.mynissanleaf.com/viewtopic.php?p=101293#p101293

 

[doug401]

The crappy Leaf GOM makes the Rav's GOM seem like a genius. I can "past predict" the weather by looking at my Rav GOM. If it reads 95 miles, it was raining and in the 50's yesterday. If it reads 110 miles, it was dry and in the 60's or 70's. Another comparison is where I live, on top of a 400 ft hill. The Leaf would gain ten miles going down the hill. The Rav GOM is rock steady going down the same hill. Unlike the Leaf, the Rav knows that you can't go down hill forever, and will eventually level out and go back up. Nissan must have a bunch of 7th graders doing their algorithms.

Tonys range chart is useful for the Rav, but mandatory equipment in the Leaf.