What to do with low voltage panels?

[DualFuel]

I was hoping to find a way to charge a higher voltage battery then the panels. I remember about five years ago there was some talk here about capacitor discharge pulse charging.

 I have panels, I have box full of ballast capacitors, I could get some mosfets. I'm wondering if I use the panels to charge the caps, and make some kind of coil to take the capacitor discharge and raise its voltage to 15volts. What I don't know is how to trigger the capacitor discharge.

 Any suggestions here?

Dualfuel

[dnix71]

http://www.powerstream.com/sony-car-adapter.htm

This is a Sony laptop adapter. If you have at least 10v in, it will put out 19v.

Ready to go and less than $30.

[stevend]

You didn't say what the voltages are. If you connect the panels in series (positive to negative) then the voltages add. Then the output of your panels is from the negative of the first panel and the positive of the last panel. Does that give you a high enough voltage?

-Steve

http://rimstar.org/renewnrg

[poco dinero]

Check the kansas wind power website.  They have boost controllers that allow you to charge a 48 volt battery from a 12 or 24 volt solar panel.  Many models available.

poco

[ghurd]

Do they have Imp and Vmp rating stickers?

Match up the Imp as close as possible.

Or measure Isc under the same conditions, with good sun, outdoors, at the same angles.

Then series similar amperage PVs to get a total combined (added together) voltage about 20~22V open, or 16.5Vmp to 17.5Vmp.

Seriesing a 1/2A panel with a 10A panel will only make about 1/2A output.

The fancy converters are not so good for direct solar input, may not work at all, will be fairly inefficient, and may release their magic smoke.

G-

[DualFuel]

Hi,

I am presently using the panels in series. Steve, I forgot what their voltages are, which is why I didn't mention it.

They were panels that were mounted on army trucks to power desulfators. I think they were 3 or 4 volts.

 I have some is series but they don't add well. So I have others just sitting around. The ones in series will provide about 5 watts or something ridiculus. I was digging back in the archives from 2003, reading Charged's posts about capacitor discharge battery charging. I wasn't real sure if he ever arrived at a workable solution.

 Then I dragged out this huge box of caps and wondered if I could put two and two together.

 Anyhow,

Thanks for considering this.

DF

[DualFuel]

Hi,

I measured 21.5 open circuit voltage, with 40milliamps while hooked to the battery.

I don't know for sure how many are in series, as they are on the roof.

DF

[Psycogeek]

i know kludgey ways.

you charge the capacitors with a "vibrator" that switches from cap to cap, charging each cap, then the caps are just connected to the battery, no need to specifically discharge them.  your just using more than one cap to temporarily hold the low voltage charge, then having them in seires to get to higher voltages.

+[ ]- +[ ]-

another way would be with a DC-DC curcuit of which there are many, and they all have a lot of losses also.

[Sr WiNdTeCh]

I have 1 12v 60w panel, and am wanting to keep my 24v battery bank on a nice float charge, until I make my other panel, how can I make that switching capacitor bank?

[Bruce S]

Hello;

Try this setup. I know it was based on being used for a 3-phase mill of Ed's

BUT it'll work.

http://www.fieldlines.com/story/2005/12/23/33930/420

For my money doublers work in a pinch and will get you where you want to go until the other panels arrives.

Hope this helps

Bruce S

[Ekij]

Three ways to deal with this spring to mind.

1: Use a switched coil voltage doubler (like a switched mode PSU)
2: Use the "charge individual capacitors in series" approach
3: Charge individual batteries in your chain approach.

1: Is probably the most efficient, will give you the least voltage issues but is complicated to home brew.

2: Runs the risk of voltage dip as you switch between capacitors, switch too fast and you waste time connected to nothing or run the risk of shorting out a capacitor

3: Simplest but runs the risk of not changing each battery in your chain evenly (this would be reduce the life expectancy of the batteries)

I just drew a drawing of the curcit you need to do 3 but "insert image" turns out not be insert image at all but "insert link to image hosted somewhere else" 

[DamonHD]

Ekij: you can "attach" the image if it meets the size limits.

Rgds

Damon

[wpowokal]

Try one of these.
http://cgi.ebay.com.au/12V-to-24V-3A-DC-DC-Power-Converter-Module_W0QQitemZ350343392704QQcmdZViewItemQQptZAU_B_I_Electrical_Test_Equipment?hash=item519217edc0
I use one to utilize a 12v 55W  panel to 24V, seller is reliable.

allan

[Sr WiNdTeCh]

That looks pretty easy to make, I' may try to make one.

I bought a RHINO 1amp dc dc converter for 15$,  http://www.automationdirect.com/adc/Overview/Catalog/Power_Products_%28Electrical%29/DC-to-DC_Converters it works pretty well, the voltage is very adjustable aswell, you can even drain other batteries beyond repair if you had some junk batteries laying around you may aswell extract all the power thats left in them and put it in another battery.