[Elecraft] X-Dragon 20W Solar Panel

[Jim Brown]

On Tue,4/21/2015 10:37 AM, David Ahrendts wrote:
> Well, let’s broaden the convo. Who successfully uses solar to operate KX3 QRP? What’s the system?

I've not yet used solar with my KX3, but I've used it extensively with 
my K3/P3/KAT500. The most common way to use solar power is to charge 
batteries of suitable type and rating. For that, you need a charge 
regulator that sits between the panel and the battery.

On Field Day, we set up a couple of panels next to the operating tent or 
trailer and run a twisted pair of #12 to the battery that's next to the 
rig. Long leads on the panel, short leads from battery to equipment.

The best charge regulators are made by GV -- MPPT technology, which 
yields best efficiency, and lowest noise (they are VERY quiet). Charge 
regulator must match the panel voltage, the charge current rating, the 
battery voltage, and the battery type.

One of the best battery types for our use is the LiFePO4 chemistry. Two 
good places to buy them.

http://www.bioennopower.com/collections/12v-series-lifepo4-batteries

http://www.batteryspace.com/128vlifepo4batterypacks.aspx

Both companies provide intelligent technical support by email and by 
land line. Their prices are very good, and about the same for the same 
product. BatterySpace sells the RF-quiet GV charge controllers. Bioenno 
shows a much cheaper one, and I'll bet it's noisy.

If you're going to pack the batteries, pay attention to capacity and 
weight. For example, the Bioenn BLF-1220W and BLF-1220TS are both rated 
20A at 12V, but the 1220W weighs 5.5 # while the 1220TS is 7#, the 1220W 
costs $12 less ($193 vs. $205)! This is only one example -- both 
companies sell a lot of different batteries.

73, Jim K9YC