How to / DIY > Everything else

Solar - 24vdc Panel with 12vdc Charge Controller

(1/3) > >>

veggie:
Hi All,

I came across this video where a fellow uses a small buck converter to match a 24 volt (28 -34 vdc) solar panel
to a 12 volt charge controller to charge a small gel cell battery.
https://www.youtube.com/watch?v=AD7g5BNy5fM

This interested me because I have a few 50 watt (24 volt) panels and I would like to use them on some protects involving 12 volt gel cell batteries and a microprocessor. I also have a few cheap Ebay buck converters kicking around.
Now granted, this may not be the best accepted practice, but if one has the components sitting around collecting dust, maybe it's ok.
So my question is...
Does anyone see a problem with this setup when used for small batteries and low amperage?
I'm not really concerned with efficiency. I just want to use a surplus 24 volt panel to charge a small 12 volt battery using a 12 volt charge controller.
The microcontroller would run 24/7 so it will draw from the battery constantly.
Battery charges in the day and draws down at night.
I am aware of the necessary depth of discharge limitation that I must consider with the microcontroller draw.
I have multiple 50 watt, 24 volt panels if needed.

BruceM:
As long as the solar charge controller can manage with the high EMI and ripple of the buck converter, I see no problem.  A PWM type charge controller will be likely to do fine since it was already coping it's own rather substantial EMI. 

veggie:

Thanks for the guidance fellas. I'll give it a try.  :)

BruceM:
Glort's got it right and I missed the obvious. No need for two stages of pulse regulation when one will do.  Set the buck regulator output voltage depending on the type of battery and typical daily depth of discharge and time to charge. 

 You might be able to find a 24/12V PWM controller that can do directly what you want, and is smart enough to go to float charge voltage when charge current tapers off.  That will increase battery life somewhat, perhaps adding a year.  You can either do a seasonal average temperature adjustment on the charge voltage yourself or better select the charge controller for one that does it automatically for you.   That will add a year or two to battery life.  Few (lead acid) batteries die, most are murdered before their time.

mike90045:
Watch out for the simple Buck converter not being able to start or be stable with the variable output from the PV panel. if it hangs up, you won't get charge

Navigation

[0] Message Index

[#] Next page