Solar Panel Voltage

[kp12345]

I'm making a solar powered speaker system and am wondering about something. I'm using solar cells which are rated at .5 volts each: http://www.ebay.com/itm/40-WHOLE-3x6...V8aMVRgm9hu2-Q
I can fit 10 on the top of the box which would create 5 volts in series (I have tested some panels in sunlight, they produced about .54 to .58 volts each). I have seen some voltage upverters, but they seem to require a certain input voltage. I am charging a 12 volt sla battery connected to a charge controller designed for a solar system. Any help would be appreciated
Thanks!

[SunEagle]

You will need to build a solar panel using about 36 of those cells because you need about 17 volts to charge a 12volt battery. You also need a solar charge controller between the solar panel and the battery to make sure the battery gets charge the correct amount without over charging it.

You may want to read some of the sticky posts in the DIY section of the forum.

[kp12345]

I would do that if it were an option, I cannot practically move around a speaker box with 36 solar cells on it. 10 allows for dimensions that produce the correct box volume and layout for the speakers and electronics. I purchased one of these, http://www.ebay.com/itm/381518809191...%3AMEBIDX%3AIT
hopefully it will work, but if anyone has any other ideas or has dealt with a situation like this, it would be helpful to know what you did.

[bcroe]

I'm making a solar powered speaker system and am wondering about something. I'm using solar cells which are rated at .5 volts each:
I can fit 10 on the top of the box which would create 5 volts in series (I have tested some panels in sunlight, they produced about .54 to .58 volts each). I have seen some voltage upverters, but they seem to require a certain input voltage. I am charging a 12 volt sla battery connected to a charge controller designed for a solar system.

If you have an adequate 12V battery, and a solar charge controller properly matched to the battery, their input requirements will dictate
the solar panel to be used. The switching up converter you mentioned will not work from a solar panel, and the controller you have
most likely is not compatible with a switched supply. And your cells may be entirely inadequate for the job. My suggestion: start with
your speaker power requirements, work back to battery and charge controller compatibility, then continue by buying a solar panel (or
several) dictated by the requirements.

Outdoor speakers may get banged around a lot, and DIY solar panels tend to be quite fragile and heavy, as well as short lived. My
experience is that building your own is going to be a major problem. good luck, Bruce Roe

[SunEagle]

I would do that if it were an option, I cannot practically move around a speaker box with 36 solar cells on it. 10 allows for dimensions that produce the correct box volume and layout for the speakers and electronics. I purchased one of these, http://www.ebay.com/itm/381518809191...%3AMEBIDX%3AIT
hopefully it will work, but if anyone has any other ideas or has dealt with a situation like this, it would be helpful to know what you did.

You can do whatever you feel will work but the basic physics say that to charge a 12volt battery requires about 15 or more volts. To get 15volts out of those cells requires at least 30 of them. 10 of them only gets you ~ 5 volts which is no where near enough to charge a 12v battery or even a 5v battery. Using an electronic booster may raise the voltage but increase the loads and reduce efficiency which reduces the total panel wattage.

You would be better of building a solar panel with 36 of those cells and move that around to you can point it at the sun and be able to charge a 12volt battery with a solar Charge controller.

[Wy_White_Wolf]

...(I have tested some panels in sunlight, they produced about .54 to .58 volts each). I have seen some voltage upverters,...

Your testing is measuring VOC (voltage open circuit) and not VMP (voltage maximum power). A cell with a VOC of .54 to .58 will have a VMP of .47 to .50. A 12V nominal panel should have a VMP of 17 to 18V and a VOC of 20 to 21V. 36 cells per panel puts you right in those ranges.

WWW

[kp12345]

Thanks for the advice guys, I bought some bus wire and tabbing wire on ebay and they came with 40 smaller solar cells (I'll use 36), each rated at a half a volt each. They will only produce 10 watts, but this is probably better than producing slightly more and then losing 10-20% with a voltage booster. Some of the stuff is coming from China, will be about a month before I can finish the project, but I'll post pics when I get it done

[SunEagle]

Thanks for the advice guys, I bought some bus wire and tabbing wire on ebay and they came with 40 smaller solar cells (I'll use 36), each rated at a half a volt each. They will only produce 10 watts, but this is probably better than producing slightly more and then losing 10-20% with a voltage booster. Some of the stuff is coming from China, will be about a month before I can finish the project, but I'll post pics when I get it done

Be sure to go read some of the sticky posts in the DIY section of this forum. There is a lot of good info concerning the building and using your own solar panel.