Rotor Power - using with Garmin spd/cadence sensors

edten
edten Posts: 228
I thought I would share some findings of the above and see if anyone else has experienced similar.

I've been using Rotor Power for a couple of months and had noticed there were power drops on both an Edge 500 and 800. The 800 has the latest firmware, the firmware for the 500 is one version out of date (I think the new firmware means the unit always asks for pm calibration on start up now, which I don't want and I'm hearing there's a bug preventing deletion of files). The power drops were lasting for about 10-20 seconds...frustrating when in the middle of an interval or doing a FTP test.

The bike does have a Garmin spd/cadence sensor. My previous Quarq Elsa also had similar drops and Quarq do recommend disconnecting secondary cadence sensors. I thought maybe this could be a similar issue for the Rotor. However disconnecting the sensor when I had the Quarq did not get rid of the drops. With the Rotor I disconnected the Garmin sensor but again it had no effect on preventing the power drops.

Then recently something dawned on me. If the the sensor is still on the bike with a wheel magnet it will no doubt be waking and sending signals. Considering the proximity - it is very close to both cranks I thought it could be this interfering with the ANT+ signal from the Rotor. I have now removed the sensor of one bike and having done a handful of rides it seems to have solved the power drops. Early days but fingers crossed! It wouldn't surprise me if it was the same issue with the Quarq. A downside is when on the rollers my milage wont be logged but not so fussed about that as I train using time. If this is what was causing the drops then hopefully when racing, any surrounding bikes with sensors will not be close enough to create interference - the proximity certainly isn't as close. I should add that I do use a Garmin HR monitor but this doesn't seem to causing any issues.

Anyone else had similar findings with either the Quarq or the Rotor (or any power meter for that matter) when using a Garmin spd/cadence sensor? I don't have the Quarq anymore so cannot check if the drops would be solved.

I have also noticed that when using the Rotor training software if the wi-fi is connected on the laptop the Suunto ant+ adaptor has serious problems staying connected with the Rotor cranks. If I turn the Wi-fi of it works flawlessly.
Rotor states that when updating the PM firmware any wi-fi on the laptop must be turned off.

Any suggestions for a fork mounted speed sensor that will work with a Garmin? After a few more rides to be sure the power drop issue is solved I might give a fork sensor a try to get my distance / speed back when training on the rollers.Hopefully it would not interfere due to proximity - as per the HR monitor.

A bit of an essay and I'm bored of typing now!

Comments

  • The power drops you have experienced on the Rotor Power are a known issue which have been largely corrected in the latest firmware (SW8) for the Rotor Power meter. Whether or not these are due to the speed/cadence sensor is debatable. You should ensure your Rotor Power meter has the latest firmware - SW8 - available from their website:

    http://power.rotorbike.com/downloads

    Upgrading the firmware sorted this issue for me and I use the speed/cadence sensor.
  • Please take caution in deciding whether to follow the recommendation to update to the latest firmware. I had similar problems with the Edge 500 - especially in high RPM situations the cadence would drop and so would the power measurement.

    So I was excited to hear that the SW8 update would solve some of these problems. I had everything set up, the USB dongle was within 30cm of the meter, and the battery had a good charge. However, the update stalled at 13% and the software reported an "abnormal timeout" - since then the meter is unresponsive and does not boot even if the battery is removed and reinstalled.

    I contacted the vendor regarding this issue but have not heard anything back from them yet.

    So, in summary, installing the update may become a $2000 mistake!
  • An update to this: if you do install an update it will not be a complete loss after all, send it back to your supplier and they will fix it by running a manual update. Sure, some time lost but it's good to know that your crankset will be working again.

    Regarding the issues, we will see in time if SW8 fixes anything. The supplier did some tests on my crankset after running the update and found no problems with it.

    Regarding the botched update, since ANT+ runs on the same frequency set as WiFi, many cordless phones, and bluetooth, I suspect that it is prone to interference, it may have switched channels during the update and/or lost communication. So, if doing an update, perhaps disable WiFi and Bluetooth on the computer running the update, and move far away from any cordless phones or WiFi devices. Or perhaps run the update in a tin shed, or run the ANT dongle on an extension cable, tape it under the bottom bracket and then wrap the whole area around the cranks/bb in aluminium foil...