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Battery Life in PowerTap Hub

 I was going to place this in "Gear" and probably should have, BUT since this forum requires a power meter, I thought there would be a good number of folks with some experience here.

Question is simple - How much battery life do you get out of your power meter?  I changed my battery in the G3 at the end of December and had it died on me mid ride today.  Granted, it had been sending low power warnings to my head unit, but I didn't really take it seriously.  I am riding three time a week for probably 1.5-2.5 hours per ride.

Is two months all I should expect from the little watch battery in the hub?

Comments

  • Hey Dino, I just started using a powertap in November and have had the same issue. The owners manual says the hub batteries should last for 300 hours but I've had to replace them twice now. I figured the first time was due to bad/old batteries that came with the hub. But, I had to replace them again this past week and they probably didn't even have 100 hours on them. Kind of annoying.
  • I have a couple of different old Powertap SL+ units. I generally change my batteries about 3-4 times per yr even if it doesn't need it... In the spring when I go outside, before any major A-races and then prolly once in the OS. It's a bit of a pain, but batteries are cheap. I learned a lesson early on by losing my Powertap to a dead battery 10 miles into a 145 mile event.

    With that said, neither of yours (Dino or Doug) seemed to last as long as mine do.
  • My first PowerTap battery change came after about 6 months of steady use. I am now into about 6 months on the second set as I start the OS. "Steady use" means the EN training protocol. I have no road bike, so all my miles are on my TT bike wheel, whether on the trainer or road. 2-3 months does not sound right. Maybe there are some settings to be tweaked to conserve power, like an auto shut down after a certain time? I have mine set @ 5 minutes and 30 minutes.

  • Hi Al,

    Not sure about settings. The thing has no buttons, and no lights. The is a USB port under the cap near the battery. I checked the owners manual and there nothing accept the vague forecast "200 hours of battery life".
  • I have a 2.5yr old PT Pro+, batteries in the hub last about 6mo of solid use.

    I spoke with Sawiris yesterday about the G3 battery thing. He said it's a problem with the firmware, Saris nows about it and will issue a firmware update in March. Dino, suggest you call/stop by WB if you continue to have issues.

  • Not that I am having an issue with this yet-but since I am new to power (Nov) I figure Id rather ask now than freak out on a ride because I don't know whats going on. How do you change the battery on the hub? Is it something I can do, or do I have to take it somewhere? Where do I buy new batteries-and how do I charge the ones in the hub? This is all new, I didn't even know it was a possibility for the hub to die. Thanks!
  • @Lauren - totally easy to change. It takes about 10 minutes and can be a bit dirty dealing with the chain. On the G3, the hub cap nut comes off releasing the hub cover. The battery comes out of the hub cover. It is just a watch battery - 2032 I think. I bought 5 at best buy for $4. It's just a pain to do every two months.
  • Lauren: here's a youtube video on how to change the batteries. I think it was done by en ENer, Greg V. For batteries, try batterybob.com. Cheap batteries via USPS. 

  • Great video!! It is a little different from the G3 model, but basically the same thing.
  • Thanks guys! Ill take notes now and keep in mind for when that battery goes out! I learn more on this site everyday image
  • Well, this thread is really an obituary for my Powertap G3. She died on the road yesterday. I changed the battery and before leaving the driveway I get the low battery error. I think no problem maybe a bad sensor or firmware issue.

    First interval, no problems with power reading. Second interval, one minute I am doing 300 watts out of the saddle and the next minute I am doing 16 watts. WTF!?! I stop and recalibrate, but it didn't work. Unit would only show 20-40 watts if I stood up and hammered. Otherwise, It was blanks, like I was coasting.

    So today, back to Wheel Builder we went. Those guys there are just so cool!!! Rich S. totally hooked me up with a new "brain" for the G3 and was out of there is less than 3 minutes. I have not tested it again, but I am sure I squared away. If you are looking for a meter, work with Coach Rich to get one from Wheeler Builder!
  • Dino - I'm want to buy a G3 powertap through WB, but am worried that there is a bug. Is your problem associated with the Firmware issue or something else? I'm thinking I should wait until they fix the firmware before I pull the plug and buy some new wheels.
  • @Paul - I say why wait? My unit had a little bug (I don't think it was firmware related) and Wheel Builder completely fixed me up. Their service is impeccable. The owner, Rich, handled it himself and was totally accommodating. He is also a really cool guy and has a great relationship with coach Rich.

    As he explained to me, the brains of the unit are outboard of the axel and easily swapped without the need to take the spokes apart, remove the hub, etc. If you want to train with power, I would do it now. I really have enjoyed it since December and feel it has measurably improved my training. Connect with coach Rich and he can hook you up.
  • Posted By Paul Hough on 22 Feb 2012 05:22 PM

    Dino - I'm want to buy a G3 powertap through WB, but am worried that there is a bug. Is your problem associated with the Firmware issue or something else? I'm thinking I should wait until they fix the firmware before I pull the plug and buy some new wheels.

     

    Ok, I just called Rich. He said that Dino's issue was hardware (the hub) not software related. He said he's sold over 250 G3 hubs and has had to warranty repair (this fix he did for Dino) 2 = <1% failure rate. </p>

    It's electronics getting bounced around in a wheel on a bicycle...so stuff happens but <1% is pretty damn good!</p>

  • It's great product! I love mine. The best part id swap wheel sets between my Tri and Road bike all the time....
  • OK...I've written the check. I've been resisting for a long time but the kool-aid is starting to have an effect.
  • Not sure how to start a new thread...newbie here. I just got a power tap pro from wheelbuilder.com and I can't get it to communicate with my garmin edge 500. I've googled and youtube'd but still can't figure it out. Can anyone help? Thank you much.

  • @greg - I don't have a Garmin 500, but I do use the power tap on my Garmin 705 and 910xt. The set up on both is very similar. You need to pair them by going to settings and finding the button for ANT+ Accessories. There should be a selection for ANT+ Powermeter and then selection for "start scan" or "restart scan". It should then pop-up a message saying "power meter detected". Before you do the scan make sure you spin the crank a few times to wake the meter up. Do that before you event turn the Garmin on. Also have the 500 close to the hub. ANT+ has a pretty limited range. if it don't pop-up right away, spin the crank again.

    You should only need to do all this once.

    Hope that helps....
  • Thanks Dino, I did try that but it just doesn't recognize it. I will call wheelbuilder tomorrow.
  • Wheel builder will get fixed up. Those guys are awesome!
  • Posted this in the dashboard but just figured this might be a better place: I am having trouble finding (in my home town in Brazil) SR44 betteries to replace those in my Powertap. I can only find SL44 which are "basically" the same though not silver oxide but lythium.
    Is it ok (or not) to go for those above??
    Tks
    Juan
  • I use lithium in my (wired) PT LYC because thats what I happen to have on hand. So I know that you can get by. However, I have been finding that my battery life is shorter than I'd expect - and I base that on the fact that the lights on the LYC dim during data xfer, or when it is clearing it's memory of data. Just general past experience has taught me that when the numbers on a digital display dim, the battery is wearing out.
    Lithium batteries supposedly have a longer shelf life than silver, but silver maintains its voltage output longer. The trade off is that when it goes... it goes suddenly.

    So if you can't find silver oxide, either order online, or get the locally sourced lithium and be mentally prepared for the possibility that you'd have to replace the batteries more often.
    Unfortunately, I don't have much input as to whether the voltage drop over time of the lithium batteries would affect the PT's hub ability to transmit data reliably.
  • To answer the original question, I got 6 months out of the batteries in my G3 powertap. Very easy to replace with this model...so easy a caveman (me) could do it.
  • Since IMFL, I have gotten a "Hub Batt" message on my Joule so it is time to change 'er up. (My freakin' 7.5hr bike split wore it out) I was going to have the bike shop do it when they change my tires but after watching the video, I'll do it myself. Exciting stuff! First battery change since getting PM last Oct. Lasted about 1 year, through OS, and training for IMFL so not bad!
  • That is awesome, Kim. Way better than I ever got. Plus, my Garmin reads low all the time for no appearent reason. I just change it before all races now. Batteries are cheap and easier than racing without power. image
  • I found the battery lifetime very much depends on the actual battery brand. The original battery lasted about 6 months, then after replacing it I had to change it about every 3 months or less. Was using batteries from RadioShack that turned out to be pretty poor. Now using Energizer, which seems to last much longer.
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