Yet Another Cycling Forum

General Category => The Knowledge => GPS => Topic started by: Ian gaggiaport on 28 July, 2015, 04:37:12 pm

Title: lithium batteries with etrex20 on pbp
Post by: Ian gaggiaport on 28 July, 2015, 04:37:12 pm
How long will my lithium AAs last on pbp?
Not used lithiums before, normally I use no back light, and at night just flick the cursor switch for 30seconds of backlight.
Just working out how many to take.
Thanks in advance
Title: Re: lithium batteries with etrex20 on pbp
Post by: frankly frankie on 28 July, 2015, 11:54:22 pm
Longer than anything else except the best available NiMHs (Sanyo blacks) which have the disadvantage (in PBP context) of being rechargeables.

I would take 4 pairs of lithiums (including the pair you start with), and expect/hope to get back with 1 pair unused.  Nb 4 pairs of lithiums weighs a mere 120g, which is not very significant compared with say 1 bidon of water.  And I would change them at controls - don't mess about with waiting for them to run out mid-leg in the middle of the night.

On a previous PBP, Sheila ran an Etrex Legend Cx for 50 hours on one pair of lithiums.  All the way out, and back to Fougeres. The newer Etrexes are a bit more power-hungry though.
Title: Re: lithium batteries with etrex20 on pbp
Post by: Kim on 29 July, 2015, 12:00:30 am
Quote from: frankly frankie on 28 July, 2015, 11:54:22 pm
The newer Etrexes are a bit more power-hungry though.

And it mostly isn't the backlight that eats the power.

(I should do some measurements, shouldn't I?)
Title: Re: lithium batteries with etrex20 on pbp
Post by: Pingu on 29 July, 2015, 09:23:53 am
Quote from: Kim on 29 July, 2015, 12:00:30 am
(I should do some measurements, shouldn't I?)

 :thumbsup:
Title: Re: lithium batteries with etrex20 on pbp
Post by: Ian gaggiaport on 29 July, 2015, 10:18:11 am
Thank you, 4 pairs ordered
 :thumbsup:
Title: Re: lithium batteries with etrex20 on pbp
Post by: T42 on 10 August, 2015, 01:39:26 pm
Mine'll run most of the time off the dyno but I'll stick a pair of liths in it and keep it running at controls. Putting liths in backup headlight too.