Garmin Colorado External Power

My old travel companion Garmin Colorado.... He use two AA battery as a power source. According data this shall be enough for 15 hours, but.... ny 2500 mAh NimH battery usually is exhausted in 8 hours work. Its happened to me that at end of day I found Garmin out and I have not get data for last miles or last hours or so. Conclusion - each day new set battery which may or may not hold all day tracking. On he WEB I didn't found any useful info how to solve this problem..... so I make my own external power source

I take drill an made a small hole 3 mm diameter through cover. Inside cover I make a grouv to accomodate wire when putting cover back im place,

Assemble external pack of 4 D size alkaline bateries 1,5 V in parallel, to get 3V by fresh batteries and cca 20000 mAh.capacity. Garmin Colorado spend usually 250 mAh at normal work. Pack of external baterries can be assembled from any set of two NimH....Alcaline or Lithium batteries.
At end I made two woodstick equal dimensions, which acting as two AA batteries and made same connections inside Garmin.

Waterproofing is not an issue. It can be made gluing wire which pass through. If is neccessary.
I do not need this feathure....

So I have now power source for 8 to 10 days hiking/tenting.....

Sincerelly

Krešimir