Garmin Cadence / Speed Sensor

[Steve H]

Last time I had the bike on the turbo trainer, the speed and cadence was a bit sporadic and cut out every now and then. I went on again today and got nothing from them at all. The main GPS unit is fine - as is the heart rate monitor.

I've had it about 6 months.

How long do the batteries normally last in these things? Not sure why, but I thought it would have lasted longer than this. I want to make sure it is the battery and not a fault with the unit. I've only this one for a couple of months and about 300 miles. The one I have on my mountain bike seems to have lasted a lot longer. Is it the battery? Could it be the cold weather? Could it be a fault?

 

[Garz]

Most of the time it's down to being knocked or off alignment. It does also happen when it requires new batteries so check them in that order.

 

[yello]

I've had decidedly variable life from the sensor batteries but they don't last that long, maybe 12 months max ime, and 6 months would not surprise me.

I always make sure I leave the crank magnet away from the sensor when I park the bike up. The sensor is supposed to shut down but I'm not convinced and so take no chances.

Those button type batteries (CR2032s aren't they?) are not cheap either. I stock up every year when Aldi/Lidl get them in.

 

[snomaes]

Those button type batteries (CR2032s aren't they?) are not cheap either. I stock up every year when Aldi/Lidl get them in.

You can actually purchase them at very low cost on EBay; for instance 10 x GP brand for £3.99 delivered click here

I use these all the time and they last a reasonable time and have a long 'use by' date. You cannot say these are 'not cheap'.

 

[yello]

However, bought from the shelf of your local newsagent you pay significantly more than that. As I suspect you know, having taken to ebay to find cheaper!

They must be amongst the more expensive 'standard' batteries going, for some weird and wonderful reason! I suspect retailers know they can charge that, and get it, knowing people will buy (albeit begrudgingly) because such purchases are often of the 'need it there and then' type... i.e. simple supply and demand.

 

[zacklaws]

My first GSC10 sensor is just over two years old and I have just changed the battery last week, not because it had failed to work, but as a precaution in case it does whilst out riding.

My second sensor, I've had problems with and presumed the battery had failed but I have found out that it is the speed sensor part that has broken in the end, but what I did find out and it may relate to your problem, I first noticed problems when I set it up on the turbo as I had no speed readings, only cadence, so I swapped it with my other one, got it working for both speed and cadence, then soon as I lowered it on to the flywheel of the turbo it stopped working, remove it from the flywheel and it works again, it seems that when you lower it onto the flywheel, somehow it must alter the alignment of the magnet and the sensor as eventually I repositioned the sensor and it works perfectly now, on or off the flywheel.

As a test, remove the magnet from the wheel or find another small magnet, and wave it about close to where the cadence sensor is and then the speed sensor part. If it is working, you should see the reset button flash orange every time the magnet passes the cadence part, and green every time the magnet passes the speed part, and if you also have your garmin switched on, then you should also get a reading there. If this is the case you just need to reposition the sensor as they can be a bit finicky.

I have just tested mine again this minute, and if you try to test it out, you must press the reset button first to get the lights flashing as they only do it within 30 seconds of the reset button being pressed. If you find that one light does not work, the related part may be US, if both don't work then it could be your battery flat.

Also I do presume you have switched the "GPS" off so that it does take the speed reading from the sensor? otherwise you do get odd readings on the Garmin.

Also Boyes do cheap batteries for the sensor, I found this out my self two weeks after I had just bought some from Wilkos and then went into Boyes. I think they where about £1 each

 

[HLaB]

Those button type batteries (CR2032s aren't they?) are not cheap either. I stock up every year when Aldi/Lidl get them in.

The last time I got them was from the 7 days shop £3 for 10 Panasonic is fine by me; they've got other makes for cheaper (1.09 for 10) but I don't know how long they'll last.