Solar and Electronics question

[guitar99]

I've been having a bit of fun with Solar and Electronics.

I have a small Solar Panel that's supposed to charge a 12V Battery.

I have a small outdoor camping type 12volt rechargable battery.

I have a 100w inverted (Black and Decker).

Now if I plug in my AC/DC Converter and hook up the 100W Inverter, the green light goes on
and I can plug in a light bulb and it works.

If I hook my Solar Panel to the Battery, and the Battery to the Inverter, the green light on
the Inverter won't light (It stay's red) and of course I can't run anything off the Inverter.

Can you explain to me in simple terms why it won't work and what I can do to get the Inverter
to run off the Solar Panel?

Thank You
David

[dacflyer]

ist of all, do you have a charge controller between the solar panel and the battery ?
if not, then your battery is backing up into the solar panel, taking away your battery power.
whats the rating of your panel anyway ?
either way, you should have a charge controller, this prevents power backing up into your panel, and it also prevents it from overcharging your battery as well..

also its impossible to run inverter off of solar panel alone..

not sure i understand this part of the question... "Now if I plug in my AC/DC Converter and hook up the 100W Inverter, the green light goes on and I can plug in a light bulb and it works."

could also be that your creating some kind of fault having the solar panel directly to the battery and inverter.. thats another reason you need a charge controller..

[haklesup]

without knowing the specs of the solar panel (fully lit V and I) and the capacity of the battery its hard to say what exactly will happen.

In general, while fully lit, the solar panel will charge the battery but at night or while poorly lit, it's possible that the battery is just dumping its charge back into the solar panel which will act like a diode at that point. Most commercial panels will have an additional blocking diode to prevent that though.

A 100W inverter (I'll assume you really mean DC to AC Inverter) will discharge that battery some even with no load. If you're trying to light a 75W bulb for example, it will deplete the battery quickly. If that battery does not have a full charge and decent capacity, it will be dead in moments.

My gut feeling is that the panel is underpowered for the battery or load you are using. To gain a full understanding of what you are doing, you need a voltmeter and ammeter to look at what's happening over time between the panel and battery and between the battery and inverter.

Maybe you want to simplify things and eliminate the inverter for a DC load. An LED lamp might be a better application to learn with.

[jwax]

Like dacflyer says, you need a solar charge controller.
Your inverter runs off the battery. The battery gets charged from the solar panel. The device that moves the current to the load and manages control of the state-of=charge of the battery is the charge controller. A 20 Amp device may cost all of $30.
A more specific answer requires more specifics of your panel and battery.

[sofaspud]

Is the AC/DC converter you mentioned your "indoor battery charger"?
It sounds to me like you need a blocking diode in series with the solar panel + lead (with the cathode on the battery side, the
anode on the solar panel side).
As others have stated, the specs of the equipment you're using are essential for a proper hook-up.
Whether or not you need a charge controller also depends on those specs, namely the amp/hour
capacity of your battery and the output voltage and current of your solar panel.

[guitar99]

These are helpful responses.

Let me provide more details so I can better understand what's going on:

The Solar Panel is a: gm 684n-sp70-12v or sp-12/bi
I think the brand is Hunter and/or made for when you out hunting.
It's got about 4 silicon pannels and a wire.

I have a SunForce 7amp battery charge controller
7A max
14.2v cut-out
13V cut-in

I have a Black and Decker 100Watt DC/AC Converter.
I have a smalll Night light I plug into the DC/AC Converter.

When I hook the Panel wires to a Volt Meter, it reads about the
same as when I hook it to the batter. So it's cranking out some
juice. With the Charge Controller plugged inline and the out
wires hooked to the Battery terminals, and a wire from the battery
to the DC/AC converter, the Light on the DC/AC stay's red.
If I plug this same DC/AC into the Cigerett lighter in a car the
light goes green and it can run a light bulb.

So is it correct for me to hook the panel to the Charge Controller,
the Charge controller has red/black wire to solar pannel (Labeled)
and red/black to Battery(Labeled).

The hook Red/Black on what battery terminals that goes
out to the Cigerette lighter type socket (Simulate plugging
into a car cig lighter) and wire out from that Cigerette lighter
type male plug and DC/AC 100watt converter.

The whole idea was to let the 12volt solar pannel charge the battery
(Recycle battery) and then let the Battery (Like you would from a
car battery this one is just smaller) plug in the DC/AC Converter (Black and Decker)

[dacflyer]

ok, with the info you provided, and with what i seen on the net, the solar panel you have is not even tickling the battery..you seem to have a good charge controller. but the solar panel is not doing squatt. its way too small. that panel might be ok for charging AA batterys or such as the stelth camera it is designed for..

but the rest you seem to have under control..

so. solar panel to input of charge controller....out of controller to battery....inverter directly to battery...
you did not say how big your battery is or how many watts the light is..if its a 4 - 7 watt night light, then it will not be much of a lod on the battery and you should be able to run many hrs. depending onthe battery..i'd recomend a deep cycle battery..as in a small trolling battery or a good sized gel-cell.. and i'd also suggest at least a 20 watt panel or larger..bigger the panel the faster your battery will recharge .
i hope this helps,,if not let us know and we will help you more..
let us know what size battery your using and for how long at a time etc..

[guitar99]

Yes. This does help.

The Battery is a 12Volt. It's small and made to take hunting or camping.

If I plug the DC/AC black and decker 100w inverter into the cig outlet and attach the
wires to a Battery Charger or my AC/DC device, then the Black and Decker green
light is on and whatever I plug into it (Regular AC type plug) and a USB charger will work.

When I hook those same wires to my Small 12Volt Camping battery (Rechargable) it won't
by itself run the DC/AC. So I'm thinking why if it's a 12Volt does it not have enough AMPS
to run the DC/AC Black and Decker?

So what I hear you saying is that if I had a Deep-Crank AMP battery then I will have enough
AMPS to Drive the DC/AC BlackandDecker and thus any < 100watt plug in appliance
and basically the size of the Battery will affect how long that will run for but it will have
enough amps.

In my case my Solar Panel is too small a charge to even make the Charger Regulator work
to charge up the small battery or is it charging and just still not enough AMPS..

I guess what I don't get is 12Volts is potential energy and each Battery will have
a certain number of AMPS? In what way can a Battery have higher AMPS? I mean if
I put a car battery to my DC/AC it will work right?

See what I'm not understanding? How can 12Volt Batteries with two terminals
have higher AMPS?

ON the Solar Panel I assume I have the same type problem.. Not Enough AMS so I would
have to get a bunch more and hook them in Serial or a bigger pannel?

Tnx much!
David

[jwax]

David- the voltage of a battery is determined by its chemistry and the number of cells. The current capacity (maximum amperage) is determined by the size of the battery.
Calling a 12 volt battery "small" means nothing. There's probably a "small" 12 volt battery in your garage door opener remote control. There's another 12 volt bigger battery in your car. Bigger because it has to supply hundreds of amps to start the car. Your remote control only needs a fraction of an amp to operate.
Connecting cells, or batteries in series (+ to-) adds the cell voltages together. There's six (6) 1.5 volt cells in a 9 volt battery, in series.
Connecting cells or batteries in parallel (+ to +, and - to -) keeps the voltage the same, but each cell (or battery) contributes more current (amps). 10 batteries in parallel provide 10 times the current of one battery.
Hope this helps!
John

[haklesup]

I couldn't find the specs for the panel but I did get a peek at one from an ebay auction. That is a pretty small panel. at approx 12V I doubt there is more than 300mA available to a load. You should use a voltmeter to verify that you are getting aty least 13.5V in the sun or you're wasting your time. You need more V than a battery rated voltage for it to charge and you will loose some voltage across the charge controller.

Assuming you are getting better than 13V out of the charge controller, at 500mA (optimistic) it would take 4-6 hours to charge a smallish 2-3Ah battery and when connected to a inverter powering a 15W load at 110V (136mA at the load) but probably closer to 2A at the 12V input would deplete that battery is less than 2 hours. Thats with guessing at the efficiency of the charge controller and inverter which generally aren't all that good.

For camping, there are few things that operate at 110VAC that you can't find in 12V versions. With these you can skip the losses in the inverter at least.

If you have a good DMM, you can connect that inverter up to your car DC socket (AKA lighter plug) and put the ammeter in series with the Red wire to find out how much current is used at no load and with your night light load with (@13.5V) and without (@12V) the car running (you don't really care about the V and I to the AC load but you can measure it anyway if you want. Calculating the power (V*I) at both sides and dividing will show you the efficiency in %). Likewise, it would be useful to measure the voltage and current at the input and output of your charge controller. Measuring the voltage from the red input to the red output wire (across the charge controller) would show you how much voltage is dropped across that device as well (and the efficiency too)

A battery is like a bucket, generally larger buckets hold more water. A hole in that bucket causes a current to flow (Voltage is like the water pressure). If you don't flow more water into that bucket than you are taking out, it will be empty in no time flat.

With the size panel you have, you're better off charging some AA or cell phone batteries. The rest of your setup would be good if you had a 4x8 foot panel (though the battery you are using might be smallish)

[sofaspud]

The obvious question not yet asked... Is a small night light your intended load for this setup? If so, the DC/AC inverter
is wholly unnecessary.

[Starguider]

Wow great topic!

I'm in the midst of building my solar panel from
Scratch all I have are recycle polycrystaline cells about
1 1/2 inch by 3 inch specs say .5volts with 1amp( I dout seriously the 1 amp part)

Now sad to say I haven't done nearly enough research ok solar panels mainly because I thought it would be straight forward unfortunetly I'm having trouble figuring how to connect the cells I checked online but they always have cells that are completely diffrent then mine ( seriously delicate work)solarcells101.com anyone used that site ? Any good? Anyways thecells I have are on the site the dark ones all I need is adrawing and a connection of what you would suggest for powering a small 50w guitar (plug and play) amp I think such as the best place to buy the ribbonthat connects the cells on the top and bottom or if there's some type of like ribbon that can be used to attach the tops of the solar panels ( sorry if there's bad spelling or something doesn't make sense on my iPhone walking and writing this at the same time

So thank you and if you realize what in talking about any guidance would be extremely appreciated once I figure put how to build it I'll most likely post an Instructional video on you tube LOLyhanks again

[haklesup]

Try posting a photo of the solar cells you have or a link to a very similar one. THis will help us a lot to determine how to hook it up. YOu can always just probe around with a DMM to find that 0.5V spot.

You can probably get "Ribbon" by using desoldering braid. This is braided copper wire and comes in various widths. Just don't get any with flux already on it.

50W guitar amp. Likely possible with a storage battery but Probably not very stable without one since music power can vary quite a bit from moment to moment. What is the primary operating voltage of your amp or are you designing one of those too. for 12V, stick with automotive products, unfortunately the current can be quite high.

You'll need 24 of those modules wired in series to reach 12V and you're right, you probably won't get the reted 1A unless its a sunny day and you have a reflector of some sort so parallel that 12 segment array 2X to 4X and you will have a full sized panel you still need to build a structure to hold and cover it. Most glass covers will reduce illumination some but you shouldn't avoid that, just get the clearest and thinnest tempered glass you can find. (untempered you are likely to break and get pissed)

With an array as large as I desdcribed, you will be able to charge a car battery in a couple days or less and play for perhaps 6 hours before a recharge is necessary (depending on the actual capacity of the battery and efficiency of the charge controller). (50W at 12V consumes 4.1A)

[Starguider]

Hi thanks for the quick response I tried to respond yesterday but fell asleep at 8 while trying to rest up only for couple hours lol.

Sorry you have to download the img filefront stinks! Ill find a better site to upload images unless you can suggest a better one. So basicaly forget the amp part because I can figure that out mainly its just figuring out how to wire these panels together that matters. The rest will be easy. Oh an when im done hopefully i can upload a tutorial (youtube) so you can just link people to the tutorial and wont have to search.

thanks
Solar panel images

http://files.filefront.com/IMG+0288JPG/ ... einfo.html

http://files.filefront.com/IMG+0287JPG/ ... einfo.html

http://files.filefront.com/IMG+0286JPG/ ... einfo.html

http://files.filefront.com/IMG+0285JPG/ ... einfo.html

http://files.filefront.com/IMG+0284JPG/ ... einfo.html

[jwax]

Starguider- Try http://photobucket.com/ or http://imageshack.us/ for uploading images.
You have standard silicon solar cells there. The two strips on the blue (sunny) side are the negative terminals of the cell. The two tabs on the gray side are the positive contacts.
Trick part is getting your ribbon wire (known in the solar industry as "tabbing") in position over those contacts, apply enough heat and solder to reflow quickly. Too much time or heat at that contact, and you risk delaminating the contact from the cell, and that cell is junk. Best contact is to have the tabbing soldered the whole length of the strip on the cell.
Assuming you want to build a higher voltage string of cells since each is only .55 volts, you need to connect two strips of tabbing between the top contacts of cell A to the two bottom contacts of cell B. Rinse and repeat. When you have as many as you want, the bottom tabs are the positive end, and the top tabs are the negative ends.
Keep in mind there will be less voltage under load than the .55 volt specified. (that 0.55 volt is Open-circuit voltage). If you want to charge a 12 volt battery, you'll need 14 volts, and to get 14 volts you need perhaps 30-32 cells.
How to plan on protecting these cells from the weather?