A reader recently requested I elaborate on the comms equipment battery charging system I carry in my Ruck.
First let me say that the setup I use is not what I would prefer but it works. I would prefer an ultra light weight system that I could attach directly to my Elecraft KX3 and charge the batteries using its built-in battery charger. The radios built in charger requires 13.8 volts dc but I haven’t found a pack-able panel that supplies that voltage. Most backpack/camping panels supply 5 vdc. That would require 3 sets of panels connected in series to get the necessary voltage. So, what I’ve had to resort to is removing the batteries from whatever radio I’m using, and charging the batteries in a charger that’s connected to the solar panels.
My current setup consists of the XTAR VC4 Charger and the Renogy Solar 14 watt E-Flex Solar Power Panel with dual USB ports.
I chose the XTAR based on its light weight and size, its ability to recognize and charge 4 different batteries at once and charge a wide range of Li-ion, Ni-MH and Ni-Cd batteries, plus pretty good Amazon reviews. So far its performance has been good. On the downside, it’s not waterproof, but then I haven’t found one in its class that is. And while it’s not fragile, it’s not private-proof and should be packed in your ruck accordingly. Last but not least, you have to use the XTAR provided USB to charger cable. Why they didn’t design it to accept a common double sided USB cable or micro to USB cable is beyond me. So until I can find a spare or make my own, I have 1 cable and no spare. That makes it a critical failure point. The old “2 is 1 and 1 is none….”.
I chose the Renogy 14 watt E-Flex solar panel due to the fact that the solar panels I installed with my home system were also purchased from Renogy and I have been pleased with them. They offered the E-Flex as a camping solar system and I thought for the low price, I’d give it a try.
The E-Flex weighs in at 1.3 lbs, folds up small, has dual USB charging ports and a pretty nifty charge indicator that glows brighter as the suns intensity increases. One downside is the flimsy attaching loops arranged around the perimeter of the assembly. Other manufactures offer heavy duty grommets that can be used for attaching points. Another is the small storage pocket does not seal completely, so be cautious what you store in it.
Charging time for 4 – Panasonic 2500 mAh Eneloop Pros runs about 6 hours depending on the available sunlight and angle. Charging time for 4 – 2000 mAh Eneloop standards is about 4 hours.
Now you have to ask yourself, which is lighter and takes up less room in the ruck? Lots of spare batteries or a few spares and the recharging system? I would say that’s METT-TC dependent.
What is the Mission? Is it short enough that I can just take some extra batteries? Or is it a long term affair where the weight of the recharge gear will be less than the weight of the batteries. Will we be using vehicles instead of walking? Then we just use our cigarette lighter plug-in inverter and charger.
Terrain: If it is a long term affair, what will the weather be like? Cloudy weather would preclude using the solar panel. Will I have the opportunity to lay out a panel for a few hours during the day or will we be constantly on the move? Is the terrain heavily forested?
Troops: Am I or someone on my team in good enough physical shape to hump the extra weight over rough terrain? Do I have the space in my ruck?
Civilians: Are they on our side? Will we be operating in a non-permissive environment where laying out a panel might draw the interest of a civilian who then compromise our location?
I know, I left out Enemy and Time. You get the gist.