Christmas Solar Panels!

[HarveyH42]

My brother gave me two used panels, unknown specs. They are about 12" x 36", unloaded, and overcasted, I got 16V to over 20V (scale). Wasn't enough sun to get into further tests. Figuring from the size, they are consistent with my 14w and 18w panels. Was wonder if there is much of a problem just hooking them up in parallel, and using a single charge controller. Up until now, I've been trying to keep everything matched, but want to use a large battery, and need higher current. I've got a 1500 watt inverter, and hope to run a few small appliances.

Just wonder if it'll matter much using different size panels together. My brother has some of the same panels, but cracked and broken. If not to bad, should be able to salvage a few watts from some of these as well.

 

[bryan1]

If you say hookup 14 watt and 18 watt PV panel in series you'll only get the lower wattage. Being smaller panels I would think they are 12 volt ones so by putting them in parallel is the go. For example on my house array I have 14 kaneka thin film panels all hooked up in parallel going into a Flex Max 60 Outback MPPT. I also have 2 off 24 volt 175 watt pv panels hooked up in parallel going in too.

As far as the broken panels go if you can isolate the broken cells then put them in series your batteries will hold them to the voltage. Mind you won't get the full wattage but still some pv power is better than none.

Also Harvey this isn't considered alternate energy so I'll move the thread in the RE forum. If you need a hand with a charge controller soon I'll be putting the one Eric is helping me with for my fridge array in the forum and it will be easy to re-configure it for other needs.

Regards Bryan

 

[HarveyH42]

Thanks. Just wanted to avoid significant losses. I already have several small charge controllers, but think the largest is only 10 amps. Will most likely be buying a larger one, batteries are expensive...

Read the rules, and got the impression RE was for completed projects, mine is still in the works, have to build a bigger frame, install the panels, run wires... Have most everything, except time and weather (cold and wet, lately). Is the Alternate Energy forum for stuff like Stan Meyers or perpetual motion? I sort of hate seeing those threads pop up, sometimes amusing, but not when trying to make some real power.

 

[rossw]

If you say hookup 14 watt and 18 watt PV panel in series you'll only get the lower wattage.

Thats not strictly true, Bryan.

Current in a series circuit is the same throughout, so if you hook a 14W, a 18W and a 20W all in series, the CURRENT will be the same, and will be what the 14W can produce.

The output will then be 14W + 14W + 14W (assuming all 3 panels are the same voltage).

So you'll only get the power *of the lowest panel* from the others in the string, but in series, all will be contributing to the voltage.

Hope that makes it clearer, not more complex!

 

[HarveyH42]

I'll be using them for a 12 volt system, so the will be going in parallel. Pretty sure the voltage will be roughly the same. The two mystery Christmas panels could be the same physical size as the 18w panels, different framing material, less than 1 inch difference in length and width. I've been trying to piece together some sort of mount, from materials on hand. Think I'll put the 6 x 18w panels on one mount, since they are all the same. Will figure something out later for the other three. Going to drop the idea of making them adjustable, with a later option of tracking. I just going for the quick and dirty fixed position. Kind of tempted to check on some pressure treated wood for a mount, be much easy to work with than the metal I've got on hand, and would likely last as long as the panels.