Working the Bubbles (power indicator bubbles)

I've decided to upgrade my EVSE and that means shipping my only means of charging off to Phil for a few days. I have a 23 mile round trip commute and I work four days per week. I live and work in Fresno, where the land is basically flat and my commute can be either highway or streets. Streets are better for getting the most miles out of a charge. Most of my street commute is comprised of 4-lane streets, 2-lanes in each direction. So, generally, I can go as slow as I want without causing road rage.

I want to be able to go one week without charging (figuring that is the longest time the charging cable will be gone). To prepare for this, I've played around some concentrating on the power bubbles. By barely feathering the go-pedal from a stop, you can keep the car at one bubble. Then, on a flat surface, you can slowly gain speed to about 25 mph keeping on the one bubble. I'm combining this with ECO mode, no accessories or climate control, doing my best to time the lights and coasting/regen at stops.

What's the benefit to this? Well, after charging to 100%, I've driven 46 miles of mostly one-bubble driving. My SOC bars have just erased bar number five -- but I always see the top bar erase after barely driving at all so that's not accurate. And my guess-o-meter is showing 85 miles remaining. If this holds up, that would be 131 miles on this charge!

The downside? My 11.5 mile one way commute is taking 45 minutes so I have to leave earlier. Starting from a complete stop using just one power-bubble is agonizingly slow (feeling like 0-20 mph in 60 seconds). And even though the road has unused lanes going the same direction, some people just ride my tail (they don't look upset, they just don't look like they're putting much thought into driving).

I recommend LEAFers try working the bubbles. If you get your driving habits to show just a few bubbles and no more, I think you'll see your range improve.

Thanks for reading!

If your dealer has a demo car, why don't you ask if you can borrow the portable EVSE from that car for a week?

You can also do an "advance upgrade" from Phil. He sends you an upgraded unit, then you send your unit back to him. There is a deposit and maybe an extra charge but you will always have an EVSE available.

While I don't recommend staring at the nave screen, monitoring the power meter on the energy screen is more accurate than the bubbles as the bubbles have quite a bit of hysteresis.

Super-glad your car is not in front of mine!

turbo2ltr said:

While I don't recommend staring at the nave screen, monitoring the power meter on the energy screen is more accurate than the bubbles as the bubbles have quite a bit of hysteresis.

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turbo2ltr, with all your knowledge, I totally trust what you're saying. I'll try that.

turbo2ltr said:

While I don't recommend staring at the nave screen, monitoring the power meter on the energy screen is more accurate than the bubbles as the bubbles have quite a bit of hysteresis.

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hystereis.
HT to turbo. there's a word to tip your hat to.

Phil's advanced purchase upgrade is $75 + a $600 deposit. I did this and had no troubles. Phil's system works really well.

downeykp said:

Phil's advanced purchase upgrade is $75 + a $600 deposit. I did this and had no troubles. Phil's system works really well.

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I didn't want to spend the extra money on it.

0-20 in 60 secs? That's not slow, it's glacial...and I'm not really sure that it's saving you as much as you seem to think. I find it more likely that your top speed and brake avoidance are the actual kwh savers.

I'm also glad I'm driving nowhere near you.

If you are going to spend more time in commute - you could potentially instead go to a charging place and charge the car for a couple of hours once in 2 days.

Actually, acceleration that slow will buy you virtually nothing in range and may even cost you since you are extending your time at inefficient slow speeds. Anything less than 3 bubbles of acceleration (20Kw or so) is a false economy.

Randy3 said:

The downside? My 11.5 mile one way commute is taking 45 minutes so I have to leave earlier. Starting from a complete stop using just one power-bubble is agonizingly slow (feeling like 0-20 mph in 60 seconds). And even though the road has unused lanes going the same direction, some people just ride my tail (they don't look upset, they just don't look like they're putting much thought into driving).

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mogur said:

Actually, acceleration that slow will buy you virtually nothing in range and may even cost you since you are extending your time at inefficient slow speeds. Anything less than 3 bubbles of acceleration (20Kw or so) is a false economy.

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I've wondered about this.

Anyone done any experiments to figure this out ?

We also really don't know what the ideal speed is (we all think it is 38 mph because Nissan published some scenario that mentioned 38 mph - but that doesn't mean the range is less at some 30 mph).

mogur said:

Actually, acceleration that slow will buy you virtually nothing in range and may even cost you since you are extending your time at inefficient slow speeds. Anything less than 3 bubbles of acceleration (20Kw or so) is a false economy.

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While I agree with the principle you describe, I wonder if you have any data to back up the 3 bubbles idea. I have 5.7 miles per KWh over 1,000 miles of driving (and including over 1,000 feet of elevation gain/loss on my 4 day a week commute). I accelerate between 10 and 20 KW, rarely go over 20 KW. The advantage of the slower acceleration (10 KW) is that you are less likely to get up to a speed that requires the use of regeneration to slow down, thus saving energy. Around town with a lot of stoplights, I imagine this savings might be significant. Just my two cents.

My 11.5 mile one way commute is taking 45 minutes so I have to leave earlier.

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I applaud your willingness to try to make this work, but you could ride this distance in less time on a bicycle! Try it one or two days a week... :lol:

Electric4Me said:

My 11.5 mile one way commute is taking 45 minutes so I have to leave earlier.

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I applaud your willingness to try to make this work, but you could ride this distance in less time on a bicycle! Try it one or two days a week... :lol:

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Uh.....Not in Fresno in July. I used to live there. Much too hot, with lots of smog.

derkraut said:

Electric4Me said:

My 11.5 mile one way commute is taking 45 minutes so I have to leave earlier.

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I applaud your willingness to try to make this work, but you could ride this distance in less time on a bicycle! Try it one or two days a week... :lol:

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Uh.....Not in Fresno in July. I used to live there. Much too hot, with lots of smog.

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I drove through Fresno today and it was very pleasant!

evnow said:

We also really don't know what the ideal speed is (we all think it is 38 mph because Nissan published some scenario that mentioned 38 mph - but that doesn't mean the range is less at some 30 mph).

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I find that I can consistently glide at zero bubble (or very minimal on the energy window) for a long time on flat roads by cruising at around 40 mph. So I think the 38 mph ideal speed makes sense.

The 38MPH appears to be related to motor efficiency but the primary energy loss physics is air resistance followed by rolling resistance. From this chart there is at most a 10% efficiency factor based on motor RPM but air resistance increases by velocity squared which will swamp the other energy loss factors. I would go slow to extend the range. If you were close by, I would be happy to loan you my unused level 1 charger while yours is being modified.

Nekota said:

The 38MPH appears to be related to motor efficiency but the primary energy loss physics is air resistance followed by rolling resistance. From this chart there is at most a 10% efficiency factor based on motor RPM but air resistance increases by velocity squared which will swamp the other energy loss factors. I would go slow to extend the range. If you were close by, I would be happy to loan you my unused level 1 charger while yours is being modified.

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Now...there's an excellent idea. There must be other Leafs in Fresno; and I'm sure someone would be happy to lend you their EVSE.

Volusiano said:

evnow said:

We also really don't know what the ideal speed is (we all think it is 38 mph because Nissan published some scenario that mentioned 38 mph - but that doesn't mean the range is less at some 30 mph).

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I find that I can consistently glide at zero bubble (or very minimal on the energy window) for a long time on flat roads by cruising at around 40 mph. So I think the 38 mph ideal speed makes sense.

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You can also glide at 30 - try it. Would Leaf's best speed be 38mph, where as rodster's is around 20 ?

We are talking about a situation when not using AC.