Testing A New Panel

[SolarPrepper]

I bought an ACOPower 100W panel and a 12V 150W heating element from Amazon. For the purpose of heating a 3-gallon jug of water. Hooked it straight up, good sun on the entire panel and the rig didn't heat water. To the touch, the element was just warm, not hot like expected. Open circuit panel voltage: 20V, and short circuit current: basically zero!. Placed amp meter in series with the heating element and the panel. Reading: .2A. Element resistance .9ohm.

Bad panel?

 

[timselectric]

I wouldn't expect much heating from a 100w panel.
And don't expect 100 watts. Probably 85w at best.
It will take a long time to heat water.

 

[MisterSandals]

Open circuit panel voltage: 20V, and short circuit current: basically zero!.

Isc = 0 sounds bad. Tested with nothing connected to panel, right?

good sun on the entire panel

Can you elaborate on "good sun"? How low in the sky is the sun?
To get anywhere near panel rated Isc (secret specs?), you need great sun.

 

[SolarPrepper]

I'm in Virginia, so the sun an hour ago was somewhere between 30 and 36 degrees. I used the shadow method to get the angle correct. Specs on the back-panel: Voc is 21.9V, Isc is 5.79A, made by ACOPower (Vietnam). BTW, I have some 250 watt panels putting out 36V and 9A. I can get 9A from them by simply placing my amp meter across the +/- leads. Doing the same thing with this 100W panel gets zero current. I've made 4 calls to the company's California location and left messages. No return calls. I hate to give this back to Amazon without making sure it's defective. Kohl's is no longer doing returns for Amazon. The UPS store is.

 

[octal_ip]

Defective solar panel aside, it takes *a lot* of energy to heat and boil water. Given 100 watts and no thermal losses (there would be plenty in reality), it'd take over 10 hours to boil 3 gallons.
The more likely outcome is that the water would rise to a temperature where thermal losses to the surrounding environment would equal the energy being put in, and would stay at that temperature.

Directly connecting a resistive heating element to a solar panel will also give poor results, as it'll pull the panel down to a very low voltage, at which point it'll be running a long way below it's maximum power point. A 150W element connected to a feeble 100W panel will behave almost like a short circuit.

You'd be much better off with a solar thermal heater (i.e. black panel or pipes) for warming water.

 

[SolarPrepper]

I really appreciate the comments regarding heating water this way! It's not working at all; I can hold the heating element in my hand while connected to the panel. I'd expect it to be very hot. Nope! Just lukewarm. Don't need it to boil. 110-120F would be great. So, is this panel defective because I can't get ANY short-circuit current from it?

 

[octal_ip]

So, is this panel defective because I can't get ANY short-circuit current from it?

If you're placing your multimeter in current mode directly across the positive and negative leads while the panel is in full sun and you're not seeing any current, then yes, the panel is defective.

 

[timselectric]

Unless you have managed to blow the internal fuse in the meter.

 

[SolarPrepper]

No. I didn't get fooled by that. I just posted my b/u solar system in show and tell. Title: Emergency Power in an HOA community. Something like that.