Charging batteries with Solar energy
Posted by Matthew
Depending on the application, charging batteries can be complex process. Charging methods range from constant voltage to pulsed and random charging. Once power is being delivered back into the battery, you have to know when to stop charging!
Once a battery is fully charged, the charging current has to be dissipated somehow. The result is the generation of heat and gasses both of which are bad for batteries. The essence of good charging is to be able to detect when the reconstitution of the active chemicals is complete and to stop the charging process before any damage is done.
Typically, common household batteries are charged with a current that is kept constant and relieved when the batteries reach a predetermined potential. However, solar cells typically generate a constant voltage of 0.5V and a varying current that depends on the amount of collected light. As such, a consant voltage charging model is easier to implement. I found two respectable tutorials on building your own charger:
- AA Battery Solar Charger
- Clean Power’s Solar battery project charger

The first solution uses a diode to stop the batteries from discharging when there is no sunlight. I highly reccomend including this protection. Unfortunately, neither project implements a charge limit. You have to remove the batteries and test their charge with a multimeter. A shunt regulator is the simplest way to regulate the upper limit.


Hi, Interesting article! Do you think this method would be suitable for lead-acid batteries?
Lead-acid batteries are generally charged using the constant voltage method. In a car, the current delivered by the alternator varies much like the current of the solar cells. A regulator makes sure the voltage output by the alternator stays relatively flat around 12volts.
Therefore, you could use this method to charge lead-acid batteries. Generally lead-acid batteries are very high capacity, though. You will need a large solar array or a lot of patience.
Matthew, thanks for the reply!
I’ll tell you about the idea…
I have a long back garden and I don’t want to lay a cable all the way down there for a garden light. The idea was to get a high capacity battery that can slowly charge it up and by the weekend then there would be enough charge to power the light on Saturday nights when I’ve got friends round. I might use it for a radio too. I’m also considering wind power for a more reliable charge year round. Same voltage variation problem.
The voltage delivery for both these sources would be lower (I imagine) than the 12v battery, so I’d need a way of stepping the voltage up or a lot of solar cells!
Thanks for highlighting our solar battery charger, the url has changed we dropped the cleanpower subdomain in favor of a more stream line site. the new url is http://www.thesietch.org/projects/solarcharger/index.htm
Thanks. Great site by the way full of great stuff.
Thanks for your sharing
I found lots of interesting information here. The post was professionally written and I feel like the author has extensive knowledge in the subject. Keep it that way.
thanks admin. nice good article.
Thanks for your nice comments. I am glad that this information has been of use to you.
This is a really good read for me, Must admit that you are one of the best bloggers I ever saw.Thanks for posting this informative article.
The beauty of these blogging engines and CMS platforms is the lack of limitations and ease of manipulation that allows developers to implement rich content and ‘skin’ the site in such a way that with very little effort one would never notice what it is making the site tick all without limiting content and effectiveness.
This is a really good read for me, Must admit that you are one of the best bloggers I ever saw.Thanks for posting this informative article.
Gift Ideas UK is a UK store bringing you a huge range of gift ideas. Gift ideas for men, gift ideas for women, gift ideas for children, and gift ideas for any occasion.
What if an insurance company and sands you notice?
I recently came across your blog and have been reading along. I thought I would leave my first comment.
This brand, introduced in 2000, features the blend used in the Fuente Fuente Opus X brand and a Connecticut broad leaf maduro wrapper aged in Cognac barrels.The Anejo offers a full-bodied and full-flavored smoke. One of the rarest cigars in the world, the Anejo is a dark, oily cigar with a woody, slightly spicy flavor and a lush draw. Production of this blend is extremely limited and these cigars are typically only available twice a year.
In 1986, Hyundai entered the United States market with the introduction of the Excel, but now the automaker is expanding from base economy cars to offer more spirited and more luxurious vehicles. Even as Hyundai is preparing to launch its 2011 Hyundai Equus flagship, which is expected to cost around $60,000, it is still focused on delivering stylish and affordable vehicles. For 2010, Hyundai offers a total of 10 nameplates ranging from the sub-$10,000 Hyundai Accent hatchback to the luxurious Genesis Sedan. New for 2010, Hyundai offers the Genesis Coupe and is preparing to launch the all-new Hyundai Tucson crossover.
superposition. Superposition can refer to: The superposition principle in physics, mathematics, and engineering, describes the overlapping
ny dentists : Dentists in New York, NY, See Reviews and Book Online Instantly. All appointment times are guaranteed by our dentists and doctors.
Sells replacement factory car radios. Don’t accept aftermarket radios, get a factory OEM car radio back in your vehicle. Easy to use online car radio catalog. Free Shipping.
Offers auto air conditioning parts including ac compressor, ac condenser and more. Toll free phone support and full warranty on all ac parts. Free Shipping and 30 day return policy.
Nice! To charge the batteries by using the help of solar energy. It can be possible and thanks for this great information. I came to know the message only after viewing your post. Thanks a lot.
How long have you been in this field? You seem to know a lot more than I do, I’d love to know your sources!
Cool Blog… Its very good new for the vehicle users…. now it cut the cost of my fuel expense….. also the way you made this article is really superb keep it up.
Thanks