[Soekris] Sanity check a solar/battery setup

Zac Morris zac at zacwolf.com
Fri Oct 14 18:02:10 UTC 2005

I'm wondering if folks on this list might be willing to sanity check a 
power configuration for me:

I've built a Stompbox, using a 4521.

I'm using a CarNetrix DC/DC power regulator to power the 4521(12v) and a 
GPS module (5v).

The CarNetrix has three power inputs:
12v CONSTANT wired directly to the battery.
12v IGNITION that controls the on/off state (powered=unit-on  
12v "PULSE" (off/on/off) that override the IGNITION state to toggle 
power on/off
When "on" and the power on CONSTANT drops below 11v the unit is turned 
off, and requires a "pulse" to reset.

I've got an 18w Solar Array, that's hooked to the vehicle's battery via 
a Solar Regulator to prevent over charging AND it has a day/night 
switch(hard switching logic, NOT photo-resistive "flicker") that 
output's 12v during the "Night".

I have the Solar Regulator's day/nite output powering a relay.  Thus I 
have two 12v power outlets from the relay.  One for "day"(relay not 
powered) and one for "night" (relay powered).

I have the "day" output wired into the "IGNITION" input of the 
CarNetrix, thus it turns on the CarNetrix during the "Day" and then 
turns it off during the "Night"; this is regardless of the vehicle being 

I work from home so most of the time, the vehicle is parked.  I usually 
only drive it on the weekends.

So the question is:
Is the 18w solar panel (it's mounted on top of the vehicle and sits in a 
full sun area) going to be enough to power the CarNetrix, the GPS 
module, and the 4521-receiving EVDO and pumping WiFi, without dropping 
the main battery below 11V figuring avg 10 hours "on" for five days at a 

Any guesses on how long it can ran in this day/night cycle without 
drawing the main battery down to cutoff point?  I know there's a LOT of 
variables in that question but is it likely to get me through the five days?

THANKS for any info anyone is willing to give
-Zac Morris

Stompbox: http://www.stompboxnetworks.com
WiFi card: http://metrix.net/metrix/products/radios/minipci/NL-2511MP.html
CarNetrix 1290: http://www.carnetix.com/CNX_1290.htm
GPS Module: http://www.allsurplus.net/Axiom/
Solar Panel: http://www.campingworld.com/browse/skus/index.cfm?skunum=28098
Solar Regulator: 

More information about the Soekris-tech mailing list