On 11/25/2013 11:42 AM, Gene Ruff wrote:
I am looking for information on using folding solar panels with my KX3 . success stories or sad ones. Thanks G. R.
The best response to this is to simply read up on how solar panels are used to charge batteries. There's plenty of good stuff on the internet about it.
The key thing is to get current into the battery without overcharging it. There are boxes that do this -- they are called "charge controllers" and they vary in cost from a little to a lot. The most efficient ones regulate the charging current by generating square waves and modifying their width. The problem with that approach is that unless the designer is VERY careful, the square waves generate lots of RF trash. Another approach is to simply use your brain and a simple volt-ammeter, monitor charging current and voltage, and disconnect the charger when the battery is fully charged. I use a real cute little inline volt-ammeter called Watts Up. About $50 with power pole connectors.
One simple charge regulator that does not make square waves is the 7A Sun Force unit. About $15. It's designed to work with 12V batteries and panels that put out up to about 20V open circuit. It simply senses battery voltage, and functions as a simple on/off switch to allow charging if the battery voltage is below 14.2 volts, and cuts off above that.
Someone turned me on to a really nice and more efficient MPPT charger made by Genasun. Kansas Wind and Power is selling one for $125. I bought one, and it's RF quiet.
Hookup is quite simple. Solar panel feeds the battery, either through a controller or directly, and the battery feeds the radio.
Our FD group runs QRP battery, using a 50W solar panel and a big battery for each radio. We don't use charge regulators, because we're not charging the batteries hard enough or long enough.
73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
