Solar panel rating measuring

[azimlxp]

Few days ago, I bought a solar panel. It's rating was 6v and 450 mA. But when I measured with my multimeter, It shows around 5.25v to 5.85v and 18mA to 22mA in full sunlight. My Question is - Is measuring current around 18mA to 22mA for per hour or per second?

 

[James]

Amps (or mA) are a measurement of the flow.
they are an instantaneous measurement.

Ah or mAh are terms used to show the capacity of a battery
e.g. a 500mAh battery will provide 500mA for one hour or 250mA for2 hours
the letters are made up from

m = milli (1000th of a unit)
A = amp (a Measure of electrical current)
h = hour

i expect that the rating of your panel is
voltage rating with open circuit output (no load)
current rating with dead short of output

 

[DPG]

Be aware that the specifications of some of the cheaper panels are often exaggerated!

 

[marconi]

I suspect the voltage and current you mentioned in your post are the on circuit no current and short circuit no output voltage respectively. A solar panel’s purpose is to produce energy/power. Maximum power is when the panel is fully irradiated and is loaded such that the power P = maximum(Vout x I out).

Manufacturers’ normally provide details of when max power is achieved in the form of a graph of. Vout against Iout. Roughly it is normally at half Vopen and half Ishort but do check because it changes with irradiation levels.

Good solar chargers have inside ‘maximum power point tracking’ functionality or MPPT.

 

[marconi]

Look up ‘maximum power transfer’ theorem . What this means is that if say 200 Watts is the electrical power output of a panel 200Watts is also dissipated as heat in the panel itself assuming of course 400 Watts of solar irradiation being converted Photovoltaicaly into electricity.

 

[ElliotM]

Be aware that the specifications of some of the cheaper panels are often exaggerated!

Agree, I knew a couple of people who had met this issue. How could you sort this out? is there a measurement tool that can tell you what is the exact capacity?

 

[Amit Bajayee]

I think Current measurements should be measured in amps, not milliamps. Milliamps are used to measure the power consumption of small electronic devices like flashlights or calculators, and discharge rates of batteries in gadgets shouldn't be taken too seriously since they'll often change significantly from day to day and even hour to hour.

 

[DPG]

I think Current measurements should be measured in amps, not milliamps. Milliamps are used to measure the power consumption of small electronic devices like flashlights or calculators, and discharge rates of batteries in gadgets shouldn't be taken too seriously since they'll often change significantly from day to day and even hour to hour.

Not necessarily. How much current does a 60 watt mains light bulb take? The answer is definitely in mA. (obviously nothing wrong in stating it as 0.25A either though).