How do you measure Solar Output to system

[john61ct]

Ideally a one-way AH counting meter located so as to show all charging current from all SCs, that you could set back to zero whenever you like.

Many SCs include similar functionality, or have it optionally available.

A full-fledged BM is more expensive, and focus is on the bank's SoC from all sources, not just solar.

[boatpoker]

Just choose the right controller it will show you everything you need.

[SaltyMetals]

If the OP is trying to do stuff as cheaply as poss then i am sure there are ammeters on the internet that would tell him the instantaneous charge level but that is no good as previous comments in this thread hv already said. A good controller will accumulate the info and give all the detail he needs. I have an MPPT hybrid controller that handles my solar and Rutland 1200 windgen from Marlec Engineering, UK. it came with a readout that tells me what the windgen is doing and what the solar is doing and accumulates the info over as long as i like. I added the Victron BMV monitor which gives me all the battery info i need. Think each cost about USD120-150 but i do not have to mess around measuring stuff and have plenty of time for a beer! And the beer stays cold thanks to the system.
Andrew
"Genial Bee"

[TheThunderbird]

Below 20$ tag for a meter which Also measures Ah.

Easy. So cheap, that l am installing a number of them, on each sensitive power-line, In-Out.

[SaltyMetals]

I already thought that having two meters at my chart table display was a bit OTT since i do not have XS space for lots of meters. At $20 a meter, and you are going to be adding 3? 4? 5? 6?, you might as well get one single intelligent meter instead of plastering so many meters on the panel next to your chart table. Thwewn you need to be adding labels against each meter to remind you what they are measuring. If you have so much space it might be nicer to have a pleasant picture or larger plotter. i guess chacun a son gout.
Andrew

[Emouchet]

You cannot compare panel with an outdoor setup. Too much variance.
There is a standard to measure solar panel output power.
It is called the flash test. This is the only measurement test that can be used to compare solar panel output:
A normalized light is flashed in front of the panel and output current generated by the panel is measured. Any decent panel manufacturer will provide the flash test result. Each panel, because of the variability in production have a different output value. However, for a 100w panel to qualified as 100w, its output must fit within +/- 5%. The best is to look for the panel with the +5% output, as their are identical priced as the 95W, but hey, you get 10% more power than the bottom bracket one...
Just google "PV flash test" for more reference.

[boatpoker]

Originally Posted by Emouchet

You cannot compare panel with an outdoor setup. Too much variance.
There is a standard to measure solar panel output power.
It is called the flash test. This is the only measurement test that can be used to compare solar panel output:
A normalized light is flashed in front of the panel and output current generated by the panel is measured. Any decent panel manufacturer will provide the flash test result. Each panel, because of the variability in production have a different output value. However, for a 100w panel to qualified as 100w, its output must fit within +/- 5%. The best is to look for the panel with the +5% output, as their are identical priced as the 95W, but hey, you get 10% more power than the bottom bracket one...
Just google "PV flash test" for more reference.

Where is the relevance to the OP's question ?

[Emouchet]

Originally Posted by boatpoker

Where is the relevance to the OP's question ?

the question is about efficiency of various solar panels, not OP...

[boatpoker]

Originally Posted by Emouchet

the question is about efficiency of various solar panels, not OP...

Sorry, didn't see that question anywhere in this thread.

[Emouchet]

Originally Posted by boatpoker

Sorry, didn't see that question anywhere in this thread.

Read carefully the very first post...

[Uncle Bob]

Originally Posted by Emouchet

Read carefully the very first post...

I too have carefully read the first post and cannot find any questioning of the efficiency of various solar panels, merely a request for information on how to measure the output!

Originally Posted by Steve O

I keep seeing comparisons of efficiency of various solar panels and claims of so many amp hours for an installation. Can anyone explain to a non-electrician how to simply measure output of solar panels?
Can it be as simple as just putting an ammeter in series with the panels and the battery?

[boatpoker]

Originally Posted by Emouchet

Read carefully the very first post...

Sorry, still don't see how that tells him anything about output or SOC which is the topic under discussion.

[Sailmonkey]

Originally Posted by boatpoker

Sorry, still don't see how that tells him anything about output or SOC which is the topic under discussion.

You’re not the only one!

The question is “how many amp hours am I getting from my panels”?

Not “how are my panels rated”?

[hpeer]

IMHO if you want a simple Go/No go test it is enough to see that the voltage on the input (panel) side is higher than on the battery side. How MUCH the difference should be is another matter I would like to hear opinions on.

Other than that there are so many variables and losses as to make definite evaluative measurements somewhat difficult.

My panels are advertised at 310 watts but have a “typical” (or equivalent weasel word) of about 285 watts
Line (resistive losses)
Connector losses
Dirt on panel
Shadows
Angle of sun
Transmisitivy of atmosphere
Can all conspire to reduce your output.

Then, if like me, you have a wind generator the panel controllers will be tracking somewhat above the wind gen output. Maybe.

It gets a bit complicated.

But if your panel/controller input voltage is somewhat above the output voltage, consistently over a range (say 12.5 to 12.8) then it’s probably working OK.

THOUGHTS?

[Steve O]

My original question was meant to be more about how do I measure what do my solar panels contribute to the battery bank on a daily basis? It would seem that a new more sophisticated controller might be in order. Any suggestions for a reasonably priced one with monitoring of amp hours?

I was not looking to shut the boat down and drain the batteries to see what they could do.