Solar Panels charging 9V Battery

Thread Starter

iamaslayerinside

Joined Dec 22, 2008
3
I am trying to get a set up going for my Bread Board.

I purchased 2 Solar Panels (6 Volts 50mA) from Radio Shack. I think this is the max. I read on the back that if I do a Series Hookup I can get Double the Voltage. So that would make a Max of 12 Volts.

Would that be sufficent enough to Charge the 9 Volt Battery?


If so How would I set it up so I can Have my Solar Panels Charging the 9V battery and then have my Negative and Positive going to my Bread board?

I am in Northern California and read somewhere that I wont get max output.

Im also worrying about overcharging the Battery. I need some type of converter for that right?
 

SgtWookie

Joined Jul 17, 2007
22,221
You cannot charge a primary battery, if that's what you have in mind. It must be a rechargeable type.

Re-charging even rechargeable batteries must be done at proper current levels for the type of battery, or severe damage (including explosion of the battery and bodily harm) can result.

Who manufactured your battery, what type is it, and what is it's model number?
 

Audioguru

Joined Dec 20, 2007
11,249
RadioCrap doesn't sell the 23-448A battery on the internet. They have the older 23-448 that is 8.4V.
It charges at 12mA for 14 hours if it was dead then the charger should be turned off.
The charger should have a voltage of about 10V or more but the current must be limited to 12mA.

Your solar panels will have an output of maybe 20mA at noon on a sunny winter day. In summer the current will be close to 50mA at noon. The current is much less at other hours and obviously is zero at night. The battery will probably discharge into the solar panels at night unless a series diode blocks it.
 

floomdoggle

Joined Sep 1, 2008
217
Hey Bal,
Are those diodes going the right way? Also, what size wire is your transformer, and what core? As always, I'm jusy the handyman.
Dan
 

leftyretro

Joined Nov 25, 2008
395
Hey Bal,
Are those diodes going the right way? Also, what size wire is your transformer, and what core? As always, I'm jusy the handyman.
Dan
Yes, diodes are going the right way, charging is pushing current through the battery backwards from normal flow, correct?

Lefty
 

nameshiva

Joined Jan 25, 2012
4
RadioCrap doesn't sell the 23-448A battery on the internet. They have the older 23-448 that is 8.4V.
It charges at 12mA for 14 hours if it was dead then the charger should be turned off.
The charger should have a voltage of about 10V or more but the current must be limited to 12mA.

Your solar panels will have an output of maybe 20mA at noon on a sunny winter day. In summer the current will be close to 50mA at noon. The current is much less at other hours and obviously is zero at night. The battery will probably discharge into the solar panels at night unless a series diode blocks it.
can v use a positive buck boost converter here
 

wayneh

Joined Sep 9, 2010
17,020
My 2¢

Two of those panels in series, along with the required blocking diode, are not enough to seriously risk damaging the battery except after prolonged full sun without any load on the battery. I doubt much risk even then, since the current flowing against a charged battery is going to be FAR less than the rated (short circuit) current. The ni-cad battery can absorb that small current. I believe 0.1C can be tolerated for long periods. I'm not saying there is NO risk, just that the risk is very small. So the setup the OP needs is simply a blocking diode between the panels in series, and the battery. Battery wired to breadboard directly.
 
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