Instructables

How to charge a 12 volt battery using Solar Power

video How to charge a 12 volt battery using Solar Power
Learn how to charge any 12 volt battery using the power from the sun!
SougataB24 days ago

Hi,

I have gone through your blog "How to charge a 12 volt battery using Solar Power" this is such a good topic. I really enjoyed a lot and the blog is really very interesting.

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N2NXZ1 year ago
I use four of these panels in series.Direct sunlight they produce 85 volts into a pair of
6v / 4.5 ah batteries in series.The transmitter uses 6v off one of them.
http://i430.photobucket.com/albums/qq22/N2NXZ/Solar%20beacon/IMG_8320_zps560f4e4a.jpg
The single lone panel keeps charge to a single 12v / 4ah battery.
http://i430.photobucket.com/albums/qq22/N2NXZ/Solar%20beacon/IMG_8318_zps023c0e6b.jpg
hisamks1 year ago
can you send detail product to my email hisamks@yahoo.com.my. i would like to buy.
The title should be changed it's confusing and going by the comments I'm not alone, this tutorial is about trickle charging a 12V battery.

The title, to me anyway, appears to indicate this is a tutorial on how to charge a 12V battery using a solar panel.
Johenix1 year ago
The point is any storage battery (accumulator if you are English) slowly goes dead. With a 12V (okay 13.8V+) solar pannel attached across the terminals even 25 mA for 8 hours a day cancels out the slow discharge and maybe even adds a little charge.

Ask your local VW dealer if he has a few small pannels that he would sell you.
Thanks for the video.... it is really nice
Here you to use a 3-6 volt solar panel if you want to charge a 12 volt battery
you can make it own
here is a DIY Solar Panels Blog where you can know everything how to make it own. 
normie19372 years ago
Using a 1.5 watt solar panel does one have to worry about over charging a 12 v motorcycle battery without a charger controller? Any info would be most welcome.
chichimus2 years ago
I've used these (or similar) on several Ford 550s which were parked for several months at a time. We usually had to buy at least one battery but these ended that problem. For $9 on sale I certainly can't complain.

one thing to note. They come with a cigarette plug but use the alligator clips. Found out that some vehicles disconnect the cig outlet from the battery when the engine is shut off.
67spyder3 years ago
I have an old lawn tractor that doesn't get used on a regular basis, the battery would always be dead when we went to use it. This is hard on the battery and we would have to replace it twice a year. Permanently mounted a solar panel on the hood (about double the size of this one) and we always park it in a sunny spot, now the battery is always fully charged and ready to go and the batteries last for years!
wogga5 years ago

seconding what the other commenter said:  this is a fine tutorial showig how a 12v battery can be boosted, but that or any tiny solar panel is only going to generate 250 ma or so in full sunlight .  If you're charging a smallish 12v battery that is 25 ah (=25000ma).  Even assuming all of the charge was retained by the battery (usually you need to put an extra 10 -20% in) you're talking 100 hours in the sun.  Yes it could trickle/keep topped up, which is a great use for it - but not a normal charge from 'used last week' to 'I want to use it next week'.

It is simply not meant for that, thats why they invented a thing called a "line powered battery charger" to charge your batteries fast but this is meant to stop sulfation happening which can avoid a costly battery replace...
thebair4 years ago
can you start an engine that has spark plugs ran by a magneto and a 12volt starter with a 12volt solar charger.
bmerritt5 (author)  thebair4 years ago
No - this solar charger is solely used as trickle-charge device to try and keep the battery maintained. As the other posters have stated, this is not the solution to use for a completely Dead Battery, and this power source also does not have the proper amperage to Start a cold engine. You need the cranking amps from a battery to turn over an engine. Solar power is good for maintaining and keeping batteries charged. I now use them in my home as well, and you still need an AC converter to convert he DC power into the proper amperage for a lot of other motors.
um... 5 watts for an hour isn't quite enough to charge a battery... especially a fairly large one like that I have a 6 volt flashlight battery that I charge with my solar panel and it takes ... oh, I don't know... like 2-3 days for full charge... an hour is not enough... Not to mention that the amp meter has to be connected in SERIES in order to even read... There are many flaws in this video. Fail.
bmerritt5 (author)  TheWelfareWarrior6 years ago
First of all, I appreciate your comments - however, I would appreciate it if you actually went out and purchased the product I showed, then try it. It takes literally an hour to charge up the battery enough to use it - additionally, I am showing a battery maintainer and showing how to charge a battery that has been used - not dead. You are correct about the amp meter - that is on my tractor - when I turn the key, it reads - so you are correct on one item. I also use this item on my car and boat and it works great! Thanks for your comment, and be my guest to try the item I showed you - you will be surprised how well they charge batteries. If trying to charge a dead battery, it takes a lot longer.
I think the key here is that a full charge is NOT needed to be enough to get one start out of a battery.  After that, the alternator of the vehicle (or in this case, lawn tractor) should start recharging the battery.

Although IMO, a proper line-powered charger is the best bet in the "dead battery" situation, but a low-wattage solar panel is GREAT for keeping a rarely used lead-acid "float charged" so you're never in that situation in the first place.  Otherwise self-discharge -> sulfation -> severely reduced battery life.

I use a 5W panel in my convertible which is pretty rarely driven, esp. in winter - I haven't had a single problem starting it in the 2 years since I started using the panel.
Yeah, right. You are just trying to sell a product that isn't even that great. And just so you know I have a 10 Watt solar panel running batteries in my house. I know what I'm talking about. Now, I'm not saying your product DOESN'T work, I'm simpily stating that you used FALSE information to try and sell it.
bmerritt5 (author)  TheWelfareWarrior6 years ago
Thanks again for your comments. Solar power is a great resource, and I am glad to see that you are also using it. I have a 250 watt system on my home, and it is great. Thanks again for the comments, and I enjoyed your write up on the solat altoid tin.
lilykoart5 years ago
Thanks for the video--i really need visuals to understand things as i'm kinda new to the solar power. :)