peter2407
Well-Known Member
Picked up a second had solar panel for tuppence not sure that it works. Is there a way to check this without going through a palarver of doing a full installation? Thinking of volt meter approach.
Solar panel question
- Thread starter peter2407
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Skipper_Christoph
Well-Known Member
Sure the voltmeter approach works. Gives at least an indication whether there is any life in it but wont tell you something about generated power.
johnalison
Well-Known Member
You could try wiring it up to a bulb of a suitable wattage and see if it will light.
VicS
Well-Known Member
As sugggested a voltmeter check is the first and simple thing to do....... but in bright sunlight! Expect up to 18 volts or more.
If you know the make and its a reputable one you should be able to find all its specs on line, one of which will be the max open circuit volts to expect.
If you get a reasonable volts reading, the next stage is to rig it up to an appropriate load and measure both volts and current. Look to see how the readings compare with the spec figures or for a similar size panel if you dont know its pedigree.
At least measure the maximum current you can get by simply connecting to an ammeter with a suitable range. It'll be big panel to exceed the 10amp range on most cheap multi meters!
If you know the make and its a reputable one you should be able to find all its specs on line, one of which will be the max open circuit volts to expect.
If you get a reasonable volts reading, the next stage is to rig it up to an appropriate load and measure both volts and current. Look to see how the readings compare with the spec figures or for a similar size panel if you dont know its pedigree.
At least measure the maximum current you can get by simply connecting to an ammeter with a suitable range. It'll be big panel to exceed the 10amp range on most cheap multi meters!
peter2407
Well-Known Member
Given its winter would a bright lamp help?
Skipper_Christoph
Well-Known Member
A bright lamp would help as long as it shine on the whole surface of the panel. But dont expect the panel to produce to much electricity
JumbleDuck
Well-Known Member
Probably not. Bright lamps are a lot dimmer than winter sunlight.
LadyInBed
Well-Known Member
Were you told what wattage the panel is?
That will give you an indication of the size of 12v bulb to hang across it and what quantity of current to expect.
That will give you an indication of the size of 12v bulb to hang across it and what quantity of current to expect.
peter2407
Well-Known Member
Its a SuntechSTP0855. Rated max power is 85w, voltat at Pmax 17.6v current at Pmax 4.83a
William_H
Well-Known Member
Many will be horrified but the best test is to connect (short term) an ampmeter directly across the terminals. This should produce your 4.8 amps in bright sunlight. In winter sun a few amps will mean it is good.
A solar panel has in effect an internal resistance which in the case of this panel appears to be about 3 ohms. The output current can not exceed the rated 4.83 amps so shorting the panel output will not harm it or produce any more than 4.8 amps. Unlike a lead acid battery whose internal resistance is low suchy that a short will cause high current and harm.
good luck olewill
A solar panel has in effect an internal resistance which in the case of this panel appears to be about 3 ohms. The output current can not exceed the rated 4.83 amps so shorting the panel output will not harm it or produce any more than 4.8 amps. Unlike a lead acid battery whose internal resistance is low suchy that a short will cause high current and harm.
good luck olewill
