Economy Solar Systems

[kbfeip]

Hey guys;

Harbor freight has a 45 watt solar charging system on sale at $200.  It comes complete with a charge regulator and mounting frame. 

Now...I fully understand that this is not the upper end quality stuff that you might get from some of the major/known manufacturers, but with my occasional need for solar energy on the rare occasion that we dry camp, I'm thinking of picking this up as a modular/temporary mount for my travel trailer. 

I would likely just set it up on top of the roof, and run the leads to my two twelve volt house batteries, only when needed. 

Any cautions from those more experienced than I am?  Since there are two twelve volt batteries (yes, 2- 12v, not 2- 6v)  would I just connect the positive to one of the batteries, and the negative to the other?  (Isn't this called wiring in series, or is it parallel?  I can never remember)

With this system, and my portable generator, I should be good to go.

Appreciate any suggestions or advice.

Kurt

ps:  The manual for the unit can be found at:  http://www.harborfreight.com/manuals/90000-90999/90599.pdf

 

[Ned]

A 45 watt panel is not more than a trickle charger.  On a good sunny day it may put out 3A.  This is probably just barely enough to keep up with the parasitic loads in the RV.  It's fine for keeping the batteries topped off when in storage, but don't plan on using it for supplying your daily electrical needs.  Put the $200 into more gas for the generator, you'll get a better return

 

[kbfeip]

Glad I asked....I see your point.

After re-reading the manual, I see that there is no rating for amperage output, but the fuse limits the unit to 4 amps max.

 

[kbfeip]

Further question:

Approximately how long would it take to charge to 90% or so two 12V batteries that were down to about 50%, with no minimum load during the charge period, at say 45 watts & 3 amps charge rate?

 

[Phil]

Approximately how long would it take to charge to 90% or so two 12V batteries that were down to about 50%, with no minimum load during the charge period, at say 45 watts & 3 amps charge rate?

If you mean two 100 AH batteries for a total of 200 AH, 1/2 power would use 100 amp hours.  To replace 100 AH with a 3 amp rate would take 33 hours.  BUT, you won't have 100 percent efficiency and you won't get full output from your panels all day long SO, the practical answer is never.  A 3 amp rate for two 100 AH batteries is considered a trickle charge.  My 3 90W panels put out 15 amps with good sun and it take about 6 hours to produce 100 AHs.

Phil

 

[kbfeip]

Wow...

At this rate, gas for my generator really is cheap.