Li-Ion performance in the heat over long distances

[polo_pro]

I've been doing some preliminary planning for my next long distance glide. I'm considering gliding from San Diego to Albuquerque, but this will take me across the Mojave. For the most part, I've found places to stay every 50 to 60 miles, but there are one or two legs of this trip that'd be more like 70 miles!

NOTE: If anyone is planning to attend both the Albuquerque Balloon Festival on Oct 6-8 and also the Segfest in Long Beach on Oct 13-15 AND taking their car/truck/RV from one to the other, than I'd like to talk with you. I'm interested in a ride from Albuquerque back to Long Beach, and you'd be amazed at how compact my gear can be. I've squeezed everything into the trunk of a Camry...check out the pictures at http://www.trailjournals.com/segway . And shipping some of the gear home is always an option.

But back to my question: does anyone have performance data for Li-Ion's range in the heat? How much degradation can I expect at 100F or 120F?

Unfortunately, travelling 70 miles in a day across the desert precludes any midday break to avoid the worst of the heat during the day. At a minimum, the gliding alone is going to take 8 hours, and then you have to add another hour for all the battery changes. Figure another hour for breaks and another hour for lunch, and you're looking at an 11 hour day!

DesertSeg (Steve from Dubai) mentioned that he was planning a long distance glide for charity in September. I'm sure after that he'll be able to tell me alot. Unfortunately, my projected departure date is Sept 16th and I'm not sure exactly when the charity event is.

Maybe some of the folks in Israel can tell me how their Li-Ions perform on their longer glides this summer.

[bystander]

How much degradation can I expect at 100F or 120F?With the recent issue that surfaced with the BSA's temperature sensitivity to extreme heat, chances are your range wouldn't be impacted too much, but the HT could slow to a flat face / crawl while it was experiencing high temperatures.

That wouldn't be too much fun if you got a late start and had to travel at 2 mph all day.

Travel at night in the hottest areas?

Evaporative cooling of the power base with some wet burlap on the platform or wrapped under the batteries? Would need to pack some extra water to keep it damp.

At the very least I would get one of those indoor/outdoor thermometers and put the probe in the gap between the battery pack and the base in order to get some realistic figures of what the batteries and power base are experiencing temperature-wise.

If you don't mind opening your power base, it would be even better to put the temperature probe inside, under the BSA (there's a little room there), and run the wire out to the display.

One reason for adding temp sensors is that you can insulate the power base in order to intentionally make it overheat on a test run. That way you can see for yourself if your particular HT reduces performance at 110 degrees, 120 degrees, or higher. It'd be better to know on a short test trip ahead of time instead of the middle of a 300 mile trip in the middle of the desert.

An alternative to adding insulation to the outside of the power base would be to add a small heating element powered by a 12v UPS battery to heat up the BSA area. One would only do this after the temperature sensors are installed and checked out for reliable operation.

[Desert_Seg]

Steve,

I regularly glide at outside temperatures of greater than 110 and I have given demos for three hours at that temperature. And since I glided (glode?) to the demo site, and then glided (glode?) back, the total glide time in this nice warm weather was more than 7 hours.

When I got home I still have 2 bars...full bars, no blinking, which ain't bad for a nice day of gliding.

BTW, this unit is the same unit I use everyday and which gets demoed various times a day. Only special care it gets is that it has its own little room, with its own little power outlet. Other than that, off curbs, up curbs, through potholes, over dirt, sand, gravel. You name it, I do it.

In short, I have full confidence in the LIons, the Segway, and our combined ability to beat the heat!

Steven

[yosgof]

Steve,

I regularly glide at outside temperatures of greater than 110...

Same here. Absolutely nor probems (I-180 on LiIons).

[polo_pro]

It'd be better to know on a short test trip ahead of time instead of the middle of a 300 mile trip in the middle of the desert.

Excellent advice! Thanks very much for giving me so many ideas!!

But don't be too concerned about "testing" out things before I head out again. If you check out my journal at http://www.trailjournals.com/segway you'll see I did five test glides (actually six since I didn't document an 18 mile glide I did in April with an empty trailer with a couple pairs of NiMHs) to nearby towns before I even attempted PCH from SF to LA in 11 days.

And to be honest, the PCH trip was actually just a big "test" for longer glides. I structured it with many easy days at the beginning, and then progressively longer days at the end with more challenging terrain.

ps - I've been doing all this with an i170 and borrowed/rented Li-Ion batteries.

[bystander]

But don't be too concerned about "testing" out things before I head out again.

Glad you like some of the ideas.

Reading through the journals, I know you spent some time doing test runs on various aspects of your planned trip down the coast beforehand. I just thought, if there was any doubt in your mind that the HT might slow down in extreme heat, running a little test that heat stresses the BSA might be confidence building for a long trip.

I should have said "the BSA's possibility of overheating" rather than just "it" in that sentence you quoted. I know you've already tested just about every other aspect of a solo trip!

Since you aren't using an early model I-167 there's probably little to worry about.

Thanks for taking the time to write about your trip (and planning your trip) and post it on the web.