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-   -   Trek FX+ rapid battery discharge normal? (https://www.bikeforums.net/electric-bikes/863162-trek-fx-rapid-battery-discharge-normal.html)

J.Montuori 12-17-12 11:01 PM

Trek FX+ rapid battery discharge normal?
 
I test rode a "new" 2010 Trek FX+ from my LBS as a potential commuter for my 18 mile hilly ride to work. The LBS put a new battery on it just months before. I fully charged it before my test ride. The ride to work is mostly downhill; I used the assist for perhaps 3-5 miles total, pedaling unassisted the rest of the way. I'm just 140 lbs, 5'6" and in excellent shape for a mid-fifties guy.

On both occasions, with only moderate use of the assist, the battery charge display went from full-except-one-bar to 0 bars at mile 16 and 18 respectively.

My questions: Is it normal for a Bionix battery to cut out like that from nearly full to nearly dead in 3 minutes? Am I unrealistic to make an 18 mile hilly commute on a Bionix-powered Trek FX+ bike? Any suggestions for my LBS to fix this if it is indeed "broken"? Really disappointed as I don't have the time or interest in building my own. Thanks for any answers, suggestions, and advice you might offer.

Yumadons 12-18-12 09:24 AM

We're Trek FX+ owners, my husband rode his coast to coast. What you describe is not normal, our battery lasts for 20+ hilly miles or 10+ of uphill mountain pass using it the whole way @ level 1. Using electric @ level 3 or 4 WILL eat up the battery that fast. Unfortunately, I'm not techie enough to hazard a guess about what's wrong with yours. The one time when Don's battery didn't work at all, it needed an "update" from a shop that had the update software. Those shops are few & far between, not even Eugene OR had one. Trek's FX+ guru who figured this out by phone is David Studner (800) 313-8735 ext 1204 or 12104, david_studner@trekbikes.com

One other thought. Keep riding and see if your assist is truly gone or it's just the battery display crapping out. A couple times when Don's display seemed to crap out early, the assist lasted for many miles more.

350htrr 12-18-12 10:05 AM

You should easily make 18 miles on 1 charge even using the assist all the way, since you only used it for 5 miles of assist out of the 18 there is something not right with the set up.... (now it does depend on how big those hills are)

J.Montuori 12-18-12 09:32 PM

Thanks, Yumadons! I don't own the FX+, but if my LBS is willing, I'll ask them to call D. Studner at Trek to figure it out.

BTW, I had read your travel posts previously. Very impressive "Trekking" you've done! Many thanks.

J.Montuori 12-18-12 09:41 PM


Originally Posted by 350htrr (Post 15063013)
You should easily make 18 miles on 1 charge even using the assist all the way, since you only used it for 5 miles of assist out of the 18 there is something not right with the set up.... (now it does depend on how big those hills are)

The total climb is about 600' to work; maximum grade is 15%. The ride home is about 1,100', but the battery gave out just getting to work. Thanks for the info!


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