Xtra power for Garmin 800

[fossil]

Hi ,
 I have a Garmin 800 and this weekend i took part in the "St Crispin’s Day Night Ride", a 100 mile ride at night in the freezing cold , which was not a problem for me But poor Garmin gave out after 50 miles I'm sure due to the cold as I've done a 100 mile ride with it before in the summer and had power to spare at the end .
So it never occurred to me about the cold being a problem   .
does anyone know of a bigger power source that could have held out for 14 hours in the cold of winter ?

Regards
Ade

[Feanor]

Expiring after 50 miles even in silly cold sounds wrong to me.
( Unless you took 14 hours to do the 50 miles! )

A fully-charged edge 800 is good for about 14 hours in cool-ish conditions.
I rode a silly 200k in nearly 14 hours a month or so back, and it was bleating by the end. ( And so was I! )
I did not have it on the map display page, though; that may use more battery.
Also, it depends how much back-light you use.
14 hours is for using it as a track-recorder only, with no back-light use or map display or routing in use.

I've also used mine on a silly-cold commute, but only for 40 miles, where it then got a warm-up and then a further 40 miles in silly-cold.   It's capacity was not noticably reduced compared to normal temperature on that route.

I have a TeckNet iEP390 11000mAh external battery pack which I use on longer rides, and it was not even off the 'full' mark after a 40-hour ride.

[fossil]

Ahh  yes ,well , It was running a map constantly showing the track that I downloaded but I did have the screen brightness low .
 But as I saied in the op I did run it like that in the summer , but with a brighter screen as it was daylight .


 Ade

[morbihan]

In a previos life many years ago, I was in the Royal Marines.  On Winter training exercises we used to use lithium batteries in the extreme cold there.