www.rambler-info.org.uk - Economy Mode of eTrex Summit (and Gecko)
These models offer an "Economy Mode", switched on/off within the System Menu. For me, this is one of the very best features of the models.
Normally I keep my Summit switched permanently to Economy Mode. On a pleasant day out, we walk about 16km and I leave the GPS switched on all the time (stops included). At the end I save the track and find I have a file of 250-350 points and that will print me a super accurate map at 1:25000 scale. (The Active Log will have a size more than four times larger)
If I do a similar walk with Economy Mode switched off, I find that I have an Active Log of 2999 points, the start of the track has been overwritten and the track cannot be saved at all: the GPS freezes if I attempt it.
Similar advantages apply to the Gecko, although it does have more memory.
With a difference like that are you surprised that I never use anything but Economy Mode!
For a Geko you will need...
NiMH rechargeables, charged that morning, for days of up to 7hrs
Alkaline Manganese disposable batteries , for days of up to 10hrs.