[TowerTalk] Solar Power Question

Doug Rehman rehman at surveil.com
Tue Sep 26 21:21:10 EDT 2006


Several others pointed out the error of my ways offline also (convert DC to
AC so you I convert it to DC...). It obviously makes sense to keep it as
simple as possible for minimum current draw.

Until I actually acquire the bridge and cable modem, I can only guess about
the current draw, but I suspect it will be 18 watts or less.

I'll probably give it a shot with the 45 watt panels. If there's not enough
juice to keep the battery charged, I'll add another set of 45 watt panels.
(It'll still be cheaper than having the cable installed back to the house-
with all of the potential RFI problems associated with that.)

TNX
Doug
K4DDR

> On Behalf Of Jim Brown
> Sent: Tuesday, September 26, 2006 8:11 PM
>
> Before you go to the trouble (and cost) of an inverter to get 
> to 120V, check the power requirements of the DSL modem and 
> the wireless gear that you're going to use. A lot of that 
> stuff is 12VDC out of the box, and gets it from a 12VDC wall 
> wart. Designing your installation should be simple. Stick an 
> DC ammeter on the gear, and make sure that the charging 
> current will keep ahead of it through a week of the darkest days. 
> 
> Hint:  Do some reading up on solar. Panels produce a lot more 
> current when the sun hits them at exactly 90 degrees, so the 
> long term avg charging current will be a lot less than the 
> peak value. 
> There's lots of stuff on the net. 
> 
> 73,
> 
> Jim Brown K9YC



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