Battery technology? Hot day, 7 miles, only 1 bar!

[BenBethel]

Well, another interesting thing here... the weather right now is hot, 107 on my way home today. I left work with a full charge, got to my personal trainer about 2.5 miles away, and plugged the HT in at the gym. I was there for an hour, then glided 4.5 miles home. As long as I was moving, the weather was fantastic, since it's so dry here! Before I got home, I only had one bar on the battery indicator gone. ONE BAR! Then, as I rode the elevator upstairs, the top bar started blinking! ONE HALF OF A BAR was used for a 7 mile commute, with only an hour of charging after the first 2.5 miles.

Does the heat have something to do with this? Perhaps my loud grinding noise means something? I could feel the heat from the platform through my tennis shoes! I couldn't keep my hands on the gearboxes for more than 5 seconds... I lifted the mat and could not place my hand on the power base for more than 2 seconds without yanking it away - it was that hot!

Hmm.... Do batteries push out a lot of juice in hot weather? I wonder!

www.benbethel.com

[pt]

ben-

since you're returning your unit, and it's 107-- i'd stay off the ht until you get a replacement.

cheers,
pt



======================

segway ht journal:
http://www.bookofseg.com

other stuff:
http://www.flashenabled.com

[BenBethel]

I have a job interview tomorrow so it won't be then. I may send it back in the morning, but they wouldn't receive it until Friday afternoon and I have a feeling they'll all be gone for the holiday weekend. I'd prefer to send it Tuesday morning, so I may ride it briefly over the weekend.

www.benbethel.com

[toybuilder]

Ben,
It may be that the elevated temperature made the battery look less depleted than they actually were. I suspect the Segway measures battery voltage only to report the battery status, and the warmer temperature made it read "fuller" than it really was.

See chapter 5 in Duracell's NiMH report (http://www.duracell.com/oem/Pdf/others/TECHBULL.pdf) to see how temperature affects battery voltage.

http://www.pasadenasegway.com

[GlideMaster]

You usually get a longer glide when the outside temperature is warm than when it's cold. It can make a big difference.

<center>From The Lessons Of A GlideMaster</center>

[toybuilder]

quote:Originally posted by GlideMaster

You usually get a longer glide when the outside temperature is warm than when it's cold. It can make a big difference.

<center>From The Lessons Of A GlideMaster</center>
Hmmm, actually, that makes sense -- if the Segway is monitoring higher voltages, then it also thinks it has more charge so it will go farther before invoking the safety shutdown at some cutoff voltage. From a casual glance at the Duracell figure 5.2.1 and 5.2.3, a warm battery depleted by 80% is at about 7.4 volts. The same battery running near freezing only depletes about 20% before it hits the 7.4 volts!

Maybe you cold-weather folks can make a battery parka to gain range! Heh!

http://www.pasadenasegway.com

[mzokc]

quote:Originally posted by toybuilder
...Maybe you cold-weather folks can make a battery parka to gain range!...Considering how cold it gets in the winter, that's a good idea. I'm sure someone will use a heating pad under the HT or a heated enclosure in winter areas to keep the battery warm between uses.

Mark

[Deviant]

Great idea!

The cold season is about done here, but maybe the Southern Hemisphere folk can try one of those microwaveable heat pads. (electric heat would defeat the purpose) You heat the pad up for a minute or so, and it provides heat for hours. If it can keep your battery warm for an hour, you could get a large range increase.

[BenBethel]

Thanks for the link to the pdf on battery technology! No wonder the repair guy said that the batteries don't do well in the heat - they *perform* well, but according to him and according to the duracell documentation I just read - the cycle life is 50% less at 104 degrees. Guess what - there will be a lot of 104 degree to 117 degree days from now until october for me! Looks like I may have to be buying batteries again soon - unless my one-year warranty includes new batteries.

Also - if anyone rides for a long distance, does your segway get so hot that you can barely touch it? Mine does, and I can even feel the heat through the rubber mat and my tennis shoes!

Ben

www.benbethel.com

[pam]

Ben, Segway has been testing the batteries with governmental agencies for a while, rather than using a generic duracell document, I'd check with Segway and see what their on the ground data shows.
Pam

[toybuilder]

I had a fairly fast commute this morning. I hit mostly green lights so I was almost always just under the stick limit on my way to work today.

During the entire 22 minutes, the gearbox never felt hot. Just slightly warm. It might be more a function of hot sun beating down onto the case (just like hot pavement)? It was reasonably cool this morning.



http://www.pasadenasegway.com

[BenBethel]

I don't think it was the sun beating on it - since I ride along a really nicely shaded street - shaded by trees and high rise buildings. Could have been the fact that it was 107 today though!

Ben

www.benbethel.com

[dexter]

I've been getting long glides. Estimate 11-12 miles. I attributed my lengthy rides to better riding style gained with experience.

Today my batteries died pretty quickly. Temperature here was lower than it has been. I think that is a huge factor.

Dave C.
me: www.idexter.com
work: www.idealjacobs.com
play: www.nyline.org