How is the 840 solar charging supposed to work?

jeremym2
1 day ago

I find that I get an amount of solar charge when I am riding. For example I gained 20 minutes in a 3 hour ride last week in rather variable conditions. This is probably useful.

However I get no noticeable charge with the unit powered off and left in the sun. This is odd as when I power off the screen it gives a reading of both the battery level and also the current solar power available together with a message saying to “face the screen into the sun” as it shuts down.

So it implies that the unit should change when powered down - but if I leave it in the sun for a few hours there is no increase in battery level.

Is this expected behaviour?

The solar function would be a lot more useful if it worked with the unit powered down.

  • 0 20 hours ago

    Having done a bit reading around I can probably answer some of this myself...

    DC rainmaker's review concludes the solar option is generally not worth it and you'd better off spending the money on ice cream. He observes (as I have)  that whilst there are small gains whilst riding, charging whilst powered off seems ineffective. The battery life is good so most of the time you're not going to need solar charging even it it worked.

    It's not going to do much for you are on a multiday tour away from a power source. This also appears to be the case for its older and bigger brother the 1040. 

    So the solar option appears to be fairly useless - almost verging on mis-selling. I get the impression that this is a design fault - either hardware or software. From a electronic engineer's point of view this looks resolvable and was intended to be useful. Can it be fixed?

    It would be useful to get a response from Garmin.

    My Instinct 2 solar watch performs rather more convincingly in this respect