Solar Battery Charging

This instructable will show you how to make your own solar battery charger from very simple components. It is taken from my documentation provided with a kit I supply - you should easily be able to source the same components yourself of course.

If you have any comments on how to improve the documentation then please do not hesitate to say :)

http://stores.ebay.co.uk/Electronic-Widgets-Inc

Step 1: The Components Needed

The items shown in the image are contained in your kit. This page explains their uses. Your kit may have a smaller/larger copper stripboard than this and may contain extra wire - I try to beef up the kit as time goes on.

The Copper Stripboard contains rows of copper tracks. Each track is electrically separate from its neighbour. It contains holes for your components. The boards I supply are larger than needed, this will allow you to expand the system at some future date.

The Batter Holder ... errrr holds your batteries.... and comes with two pins, one for the positive and one for the negative ends, they will be soldered into the stripboard.

100 Ohm resister - at one point this was needful in the kit as the LED couldn't cope with some of the voltages in the experiments - however the new LEDs do and the resistor is simply in there because it is advertised as such! Maybe you will have need of it when you expand the system.

LED - this is a high intensity light emitting diode. 3.2-3.6V forward voltage, with 10000mcd at 20ma. A LED must be placed in the circuit the correct way around. The longer leg should receive current from the positive terminal/direction.

1N5817 DIODE - this diode allows current to flow in only one direction - this prevents battery power discharging through the solar panel at night. It drops about 0.2V from the system. This blocking diode also needs placing in the circuit in the correct orientation. The diode has a circular band across its barrel at one end of the diode. This should be closest to the negative/ground.

Wires - Usually I include at least 4 wires - a black and red wire for the solar panel, a brown wire as a jumper and another wire for use in unsoldered testing.

Solar Panel - This image shows the back of the solar panel. On your solar panel in the centre of the left side and the right side you will see a small panel of smooth metal - this is the negative/positive terminals. I have marked the positive side by adding black dots on that side. This solar panel will output a max of 3V at 150ma.

Warning - I suggest you read the whole document before making any experiments - information is contained throughout the document which will improve your understanding of charging batteries using solar power.

HINT - you should probably purchase a multimeter and learn how to use it - this will tell you important information on typical voltages and currents you solar panel will produce in varying weather situations.

Soldering

It is quite possible to use this kit without having to do any soldering at all - however at some point you will need to so I include both soldered and non soldered options.

http://www.kpsec.freeuk.com/solder.htm is a good site explaining soldering.

Comments

[chuckiechan]

I'm using three dollar store yard light panels and I was wondering if a Zener diode would work. I have one in my junk box. 20V, Pd 1W. Will this fly?

I'm building an AA and AAA battery charger.

[KBS Visual Media]

How can i use 4V 100ma Solar panel in the above manner?

[jemor143]

Can the 1N5817 diode be use with a 6v solar panel (130mah) to charge 4 AA?

[Goodhart]

According to this Data Sheet, it appears to be a viable, if not over-kill type use. Is there any specific reason for using a Schottky Barrier Rectifier diode?

[krishnan111]

we can charge all types of battery?? ni-cd ,ni-pb or li-on batterirs??

[Goodhart]

No, if the battery doesn't have "rechargeable" on the outside (excluding the OLD style carbon rod batteries), then they are not rechargeable and will leak or explode of put in a charger for any length of time.

[uberdum05]

An improvement: add a LED with no resistor in series with the positive line on the solar panel to the battery holder. It will serve as a current limiter and a basic display as to how the battery is charging
eg. Brightly lit = charging battery a lot
Not so bright = charging more gently
dim = trickle charge

Also *USE A RED OR YELLOW LED FOR CHARGING SMALL BATTERIES OFF A SMALL PANEL*
Just my ten cents :)
Uber

[Keohohina]

Thanks this has really helped, Im trying tho get a pair of solar panels which are the same size as yours to power a water pump and charge a battery at the same time. Any suggestions

[TechKid67]

Hi, I am new to solar energy and am trying to create an emergency power light kit. In my prototype I want a solar panel to charge somewhere around 10 LEDs. First off: Is this possible if they are aligned in parallel? Second: Is it possible to over charge the batteries and if so (which would probably have a horrific outcome) how can I prevent that? Third: How might I go about getting the solar panel to charge a large re-chargeable battery which then charges the smaller batteries. I want to do this so the suitcase doesn't need to be left in the sun in order to charge the batteries. If you can't help me with any of this its alright but thank you for any information you can provide. If some of this didn't make sense please send me an e-mail and I'll try and make it more understandable
[e-mail]

[kylengineer]

i found this very helpful.thanks but i ddnt gt to see the complete circuit with all the components listed from the start,i only saw piece by piece.i would like to see the whole complete circuit.

[lionheartone]

Hi
I am making solar panel jacket. In order to charge phones and i-phones etc
I need some help with circuit. do not know what cicuit to use.

Please help

[rcisneros]

Question. What happens if the solar cells aren't the same? Or one solar cell goes into shade before the other? So you could end up with a cell pumping out let's say 2v @ 20mA and the other 5v @ 100mA. Would they just add up to a 120mA output ? Wouldn't the flow change direction and head into the 2v 20mA cell?

[rcisneros]

Question. What happens if the solar cells aren't the same? Or one solar cell goes into shade before the other? So you could end up with a cell pumping out let's say 1v @ 20mA and the other 3v @ 100mA. Would they still just add up to a 4v output ? or You could have a cell pumping out let's say 1v @ 100mA and the other 3v @ 20mA. Would they still just add up to a 4v output?

[mdelzo]

what happens if i get a solar panel of 4V and I have 4 AA batteries in series. would it charge?or go the opposite way? tks :)

[ebendersun]

No, you need a higher voltage panel to charge 4 AA's in series. Here at Sundancesolar.com we recommend at least 6V to charge 4 batteries.

[rtyu]

thank you
pure energy

[popa27272]

i was playing around with my solar powered radio once and noticed that i got less static and the battery charged better when i focused a magnifying lens over it to the point where the solar panel appears at its largest,

just a simple way to increase efficiency of the panel

[kroq-gar78]

what is the voltage & current required for the solar cell?

[carlose]

What if you use both connections, parallel and then in series? would that improve charging times? or charge more batteries? or both? or none in the worst case escenario

[Joenavy85]

yes you can wire 4 cells in a series/parallel layout. wire them in pairs first (in series) then wire the 2 sets in parallel.

[cdltpx]

There are ready made recharges by using those solar lights you see in so many walkways. A lot of folks have them stop working not caring to replace the batteries and they will trash them solar panel and all.
A lot of stores will seek to liquidate their stock since it does contain a battery I bought some from home depot that clipped on to a umbrella I paid $3 each (reg $24) for them they had capacity for 3 AA batteries they worked when I got them. I since replaced the batteries with newer better batteries and they will recharge in the sun I take the batteries out and use them in a flashlight and a radio. Use this setup when the grid goes down or take them camping with plenty batteries so you will have them ready to charge in the am. If you have a gps do you carry additional batteries or a way to recharge if not do you carry backup compass?
Reason you would want to use ready built because they have circuitry that will prevent over charging and leakage when the sun goes down.

[adrian_1]

where would i get the kit ?

[DELETED_madscientist167]

(removed by author or community request)

[Punkguyta]

 No.

[coolieo5232]

this was very helpfull, thanks.

[bears0]

you would think that the solar panel would make the electricity into light if it changes light to electricity

[bowser82]

Sorry, just had to post a smile :-) I love logic

[KAiz0ku]

Hey guys  i myself reviewed this guide http://www.squidoo.com/How-to-make-homemade-solar-panels-fast-and-easy
and i really think its just great. Easy step by step guide to make your own solar panel. just brilliant, it also has everything you need to know on how to operate or use one in the best way possible
Leave a comment if you liked my review

[KAiz0ku]

 Niceee ! i on my own made a small review on GreenDiyenergy's guide to make your own solar panel and found it very usefull. Would be nice if you checked it out and left a comment :D
Think i did a good job !
http://www.squidoo.com/How-to-make-homemade-solar-panels-fast-and-easy

[marc00703]

Nice 'tables. Is it possible to use one of those small solar panel you get on small solar charging calculators? I looked at the voltage and it went up to 2volts.

[rhackenb]

I'm a little confused about what end of the solar panel gets connected to the battery holder. In step 3 you say "Connect the RED POSITIVE terminal of the solar panel to the NEGATIVE leg of the battery holder." Yet in the next step you have that wire going into the positive end of the battery holder. I know that step 4 illustrates the use of blocking diode but I think the flow of current is the same. What am I missing? This is a great tutorial and I want to make it work.

[skaar]

the schematic shows serial, the voltages add, so, you can wire it differently, but you get a different effect. parallel for instance, with a bigger panel you'd be able to charge the battery, and run the led, and the battery would run the led at night. in serial, the panel acts as a solar battery. for years i had a hard time figuring out that the hell was going on with the red wires, the plus and minus, but i was reading the web(glory be to the almighty web:P), and found the answer, a supply device, the +(red) is where power comes from, the +(long leg on the diode) on a powered device is where the power goes into. so, with parallel wired devices, the +'s all together, the panel, the battery, the led, all the plusses together.

[siniyaneba]

Hi, so how do i make it parallel? thank you

[skaar]

buh, well, the schematic in the next section shows what you do to charge the battery, you have to reconfigure the wires when you want to switch from charging to running the led... course a dpdt switch could be used to switch the polarity of the panel, then you only have to flip it to change modes. led's are diodes, so, you get one that's rated for the current, you can use the led as the anti-discharge diode.

[DualPhase]

It doesn't really matter where you put the stuff as long as you put it in there the right direction of polarity. meaning possitive and negative are facing the right way. Think of the electricity like a hose. If you kink the hose before the battery or after the battery water (or current) wont flow so it doesnt' matter where you kink it or where you put the led or where you put the diode. It does, however matter if you put possitive "downstream" or "upstream"

[808create]

Can this be used to charge lithium-ion batteries (3.6v/3.7v)? with or without internal PCB Protection Circuit Module?

[n0ukf]

You can use glue, you just have to make sure it's a conductive glue. A circuit trace pen (for drawing circuits on a substrate) might work, but I don't know how much adhesive strength the "ink" might have. If you tried this, it would be a good idea to also glue the wires down beyond the stripped ends.

[sumgupta89]

we know that solar panel gives maximum power at particular voltage.which is a bit less then the actual rating of the panel. my aim is to get a constant voltage across the battery,okh. but can i do sth by which i can get such const voltage 4 which the power provided by by solar cell is maximum. i can introduce a microcontroller which will continuously check the voltage ......and will get stuck at dt particular voltage...but i am getting puzzled with dat,ne idea plz

[alness]

How to detect the status of batteries of current before charging? Is there any charging indicator?

[NightLord]

So if I have 2 x 6V solar pannels joined in serries (=12V) and 3 x 4.2V batters wired in series, I can charge them right?

(I just want to make shure, because I don't want to damage the batteries since they here quite expensive)

Btw, cells reach their max voltage very fast, mine even exceded it at very strong day light. But it's different with current, in the morning I only got about 15% of max current output. On the other hand, overall power output was actualy 10% bigger in the evening.