Hill Climb -- the Mt Baldy run

[garygid]

From the posts showing the SOC bar on/off values, it appears that there is about 50% of a bar hysteresis.

Since a bar is about 2 kWh, it takes about 1 to 3 kWh gain to light up a higher bar. If a bar just went off, it would still take about 1 kWh to bring it back.

 

[SanDust]

1800kg is about 4000 pounds, i.e., 600 lbs. of people/gear. While realistic for many families making trips to the mountains, I am assuming Sparky's LEAF was not that heavily loaded on his Baldy climb.

If Sparky's potential energy was 3.5 kWh and we are theorizing that he picked up 1.2 kWh in regen, then that would be a regen "efficiency" of 34% if one desires to more simplistically look at the overall picture.

The minor point would be that you could use 400 pounds of stuff and get 3800 wh. Not really a big difference. The major point would be that you have to subtract the aero, drive train, and rolling resistance losses when coming down the hill. If these more or less equal the energy available from converting PE to KE then you'd be looking to recover 30% of a small number.

AKA freewheeling is way better than regen. Bummer this isn't an option.

 

[abasile]

The major point would be that you have to subtract the aero, drive train, and rolling resistance losses when coming down the hill. If these more or less equal the energy available from converting PE to KE then you'd be looking to recover 30% of a small number.

If one can only recover 30% of the "remaining" PE after aero/friction losses have been subtracted, then Sparky would have only picked up about 30% of 1.3 kWh, or 0.4 kWh, of regen coming down from Mount Baldy Village. I don't believe that at all.
Given the relatively high efficiency of electric motor/generators, and in light of my own Prius experience in the mountains, I am much more inclined to believe EVDRIVER's estimate of 90% regen efficiency relative to the "remaining" PE. Actually, I wouldn't be surprised if it's less than 90% due to battery charging losses (plus discharging losses when it's time to use the regenerated energy), but 30% sounds way too low.
Someone needs to try a mountain climb/descent and retrieve more precise regen kWh numbers out of Carwings. Come late April, perhaps that "someone" will be me.

AKA freewheeling is way better than regen. Bummer this isn't an option.

Here we definitely agree. Hypermilers do as much coasting as possible. The only purpose of regen is to capture energy that would have been lost anyway. LEAF ECO-mode drivers will be wise to avoid completely letting up on the accelerator unless they truly do need to slow down.

 

[tbleakne]

The numbers being thrown out for regen efficiency are too high. Regen efficiency for the Prius is 20%. Regen efficiency for the RAV-4 is maybe 25%. GM says the regen efficiency for the Volt is 30% -35%. That's for a roundtrip of course. Assuming the trip out is more efficient than the trip back, which would seem a given, and you're looking at 30% or 35%.

I am surprised and confused as to why the regen efficiency would be anywhere near this low. No one seems to believe the Leaf battery efficiency over a normal discharge/recharge cycle using wall power at 3.7KW is less than 80%. The net regen that abasile calculated for the Baldy run of 1.3KWh would be generated over a period of about 12-15 min, for an average regen power of about 5 KW. That is not dramatically higher than the normal 3.7KW charging rate. Of course the actual regen was not smooth, but in pulses over the uneven decent. I trust that Sparky was careful to avoid hard braking that would cause mechanical losses.

Can you give us a source for the numbers you quote for Prius, RAV-4, Volt ? Is is possible these are mass-market numbers that assume an average consumer who does not try to limit mechanical (lossy) braking ?

 

[JPVLeaf]

Does anyone have info to report for a trip up Mt. Baldy Road beyond
Mt. Baldy Village? Or best yet, to the ski lift / lot?

Beyond Sparky's info, how much charge, bars and/or Gids were used up
going through the few steeper switchbacks up from the village to the lift lot?

We plan to make a trip up after topping off in Diamond Bar, and
perhaps a little more charge, if avail., while catching lunch in La Verne.

TIA.

 

[abasile]

See http://www.mynissanleaf.com/viewtopic.php?f=31&t=3512&start=100#p212837" onclick="window.open(this.href);return false;

 

[JPVLeaf]

Oh, wonderful. Sorry, that didn't come up in my search.

Thank you!

We hope to make it to the ski lift lot today.

 

[abasile]

We hope to make it to the ski lift lot today.

The snow is quite beautiful right now. Just be prepared for Mt. Baldy Road to turn into a parking lot with all of the holiday traffic. It's been quite busy in our mountain area. You'll want extra charge to support running the climate control, as it's windy and cold. Pick up as much charge as you can in La Verne.

 

[JPVLeaf]

Ok, thanks for the tips. We've got the gloves and the heavier jackets.
Only we made need them in the car as well.
The heavier holiday traffic may/may not work in our favor.
We'll see how far we get.