Monday, June 30, 2014

More On Solar

One of the great frustrations there for a while on solar power was that if you bought enough of a charge controller to handle a really big array, then you were spending a pile of money for a charge controller.  If you wanted to start small and build up your solar panel array, you could save money by buying a small charge controller, but then you would have to upgrade it.

I am not immediately sure of the output capacity of the Battery Tender that I currently have at work in the telescope garage, but I suspect, based on the current version of it, that is probably 9W or 10W.  That isn't going to work if I want to add a 40W panel.  I know that there are problems if you try to combine two different power output panels to a single charge controller--often you end up with the lower output panel limiting the output of the higher output panel.  But I presume that it is possible to feed the output of two different charge controllers into the same storage battery -- or do you end up with that same problem of the lesser source limiting the greater source?  Or is it necessary to use a diode to prevent power from working its way back from the battery to the other charge controller?

Because of the manner in which I will be using these, it might just be simpler to use the low output system for lighting, and the high output system for running an automatic garage door opener.


StormCchaser said...

A question to ask is: why are these electronics so expensive?

The cost of materials for a charge controller is pretty small. My guess at the answer to my question is the huge amount of subsidy money flowing into solar.

Sorry, I can't answer your specific question. I'd have to see the details on the charge controllers to know.

Jim Dunmyer said...

I've bought a couple of charge controllers for $20.00 or so, and they worked OK. Am now using an MPPT controller to get more output from our 2-panel array on the travel trailer.

Jim Dunmyer said...

I found this page on Amazon with charge controllers starting at less than $20.00:

Just did a Bing search for "solar charge controller".

I thought I had an older controller laying around here and would have gladly given it to you, but I couldn't find it, sorry.