solar panels ( 4) 250 watt panels in series/parallel

[sparkyv]

It depends on where the state of charge info is being derived. If it's the % on the charge controller, it is almost certainly incorrect as those are typically voltage based, and they mean nothing.

The battery determines it, not a SoC measurement. The battery NEEDS X amps to hold it at the absorption voltage.



If you understand it, then you're the best judge as to whether 3-4A is what you should be getting or not.

3-4A may be completely normal for the conditions/array facing. Without divulging that extra info to us, we can only guess.

As an example, my 3000W array was only putting out 506W today when it was putting out 2550W yesterday. The difference was:

1) less solar today.
2) Yesterday would have been higher, but it was limited by being in absorption mode.

506W today was normal.

oh, so for example if the 12 v 200ah battery is reading 12.8 it may not be 20% ? I mean in bulk does it not mean that you would put 14.4 volts in and a higher amp? and does not the controller figure out what the battery gets by voltage?

 

[sunshine_eggo]

oh, so for example if the 12 v 200ah battery is reading 12.8 it may not be 20% ?

No. A lead-acid battery resting at 12.8V is likely fully charged.

You're clinging to the idea that voltage and SoC have a reliable correlation. They do not.

I mean in bulk does it not mean that you would put 14.4 volts in and a higher amp? and does not the controller figure out what the battery gets by voltage?

No. You can't "put 14.4 volts in". The charger and the battery are essentially at the same voltage because once you connect two things together, they are at the same voltage. Any voltage difference between them will produce a current. The charger will be a LITTLE higher because it has to be to as a result of the current flow to the battery, but that's a function of the resistance in the circuit for a given current.

Bulk means you're throwing everything you have at the battery current-wise and continue to do so until it hits the absorption voltage. This is also called "constant current" charging.

Once the absorption voltage is hit, current decreases progressively to hold the battery at the absorption voltage. Purely voltage-based, NOT SoC based. This is also called "constant voltage" charging.

 

[Wellbuilt]

My 900 watt string of panel will put out 750+ watts in good sun @ noon for 4 hours or so in June .
In In December I’ll get 400watt in good sun for 2.5 hours @noon .
This is a bad time of year for solar in my area .
I would think you could get 450 watts if your battery in low this tim of year in good sun .
I never really use full sun power , my system starts charging at 900 am if the sun is out .
by 11am I’m entering absorb and the controller is limiting the power so I don’t see more then 2000watts this time of year with4500 watts of solar .

 

[sparkyv]

A 1000W array should be giving you between 0W and 1000W at midday depending on the arrangement (series/parallel), the angle they are mounted, the direction they face, any shading, sky conditions, and temperature. And it also depends on the battery SOC. If the battery is nearly full you'll get very little out the panels no matter what the conditions.


STC is at 25ºC (77ºF), not 25ºF.

The panels will put out the amount they are capable of, not determined by battery. the amount the charge controller outputs to battery is determined by the battery volatge/ Soc . My issue is before controller.

 

[sparkyv]

No. A lead-acid battery resting at 12.8V is likely fully charged.

You're clinging to the idea that voltage and SoC have a reliable correlation. They do not.



No. You can't "put 14.4 volts in". The charger and the battery are essentially at the same voltage because once you connect two things together, they are at the same voltage. Any voltage difference between them will produce a current. The charger will be a LITTLE higher because it has to be to as a result of the current flow to the battery, but that's a function of the resistance in the circuit for a given current.

Bulk means you're throwing everything you have at the battery current-wise and continue to do so until it hits the absorption voltage. This is also called "constant current" charging.

Once the absorption voltage is hit, current decreases progressively to hold the battery at the absorption voltage. Purely voltage-based, NOT SoC based. This is also called "constant voltage" charging.

How is the voltage of a battery not a state of charge? does 12.9v (30%) on a lithium battery dictate a low state of charge?

 

[sunshine_eggo]

The panels will put out the amount they are capable of, not determined by battery. the amount the charge controller outputs to battery is determined by the battery volatge/ Soc . My issue is before controller.

It would help if you don't go two weeks between posts...

No they won't. The charge controller will output what is input if the battery can't accept the output, it will reduce both the input and output.

You can't shove 1000W into a MPPT and have it only output 100W to the battery. If it can only put out 100W to the battery due to battery voltage/SoC, it will only accept 100W from the array.

How is the voltage of a battery not a state of charge? does 12.9v (30%) on a lithium battery dictate a low state of charge?

Voltage and state of charge for lead-acid and LFP do not have a strong correlation. Voltage depends on current. I indicated "resting" when I linked voltage to SoC. That's the only time it's somewhat reliable.

A LFP battery resting at 12.9V with no load and no charge does indicate a low SoC. Saying it's at 20, 25 or 30% SoC is not reliable.

 

[sunshine_eggo]

Going to say it this way:

If your battery is at a high state of charge and can only accept 180W of charge to maintain the absorption voltage, then the array will only output 180W even in the most perfect solar conditions where it can output 1000W.

As I mentioned on the first page, if you want to eliminate the battery's state of charge as a factor in restricting array output, power loads > 1000W at high noon.

 

[acdoctor]

The panels will put out the amount they are capable of, not determined by battery. the amount the charge controller outputs to battery is determined by the battery volatge/ Soc . My issue is before controller.

What do you think the panel output would be if their was no load on system and full charge battery with float disabled?

 

[sparkyv]

It would help if you don't go two weeks between posts...

No they won't. The charge controller will output what is input if the battery can't accept the output, it will reduce both the input and output.

You can't shove 1000W into a MPPT and have it only output 100W to the battery. If it can only put out 100W to the battery due to battery voltage/SoC, it will only accept 100W from the array.



Voltage and state of charge for lead-acid and LFP do not have a strong correlation. Voltage depends on current. I indicated "resting" when I linked voltage to SoC. That's the only time it's somewhat reliable.

A LFP battery resting at 12.9V with no load and no charge does indicate a low SoC. Saying it's at 20, 25 or 30% SoC is not reliable.

My Victron MPPT controller. allows me to see volts and amps from Panels to controller and how much is going from controller to batteries. what I am seeing is If my batteries are at 12.8 volts at rest in bulk mode, (sunny day, noon) and I am getting 2+-(4 at most) amps, 60+- volts from the panels. the amps out of controller rise to like 8 +-amps to battery. The controller is capable outputting 35amps. That is telling me the controller is taking the higher volts and turning them into amps. If under Bulk mode should the controller be getting the most out of the panels?. I just don't think 120watts from a 1k PV is very good under very good solar conditions if the batteries are low and need charge. I always am getting good volts not good amps.

 

[sunshine_eggo]

My Victron MPPT controller. allows me to see volts and amps from Panels to controller and how much is going from controller to batteries. what I am seeing is If my batteries are at 12.8 volts at rest in bulk mode, (sunny day, noon) and I am getting 2+-(4 at most) amps, 60+- volts from the panels. the amps out of controller rise to like 8 +-amps to battery. The controller is capable outputting 35amps. That is telling me the controller is taking the higher volts and turning them into amps. If under Bulk mode should the controller be getting the most out of the panels?. I just don't think 120watts from a 1k PV is very good under very good solar conditions if the batteries are low and need charge. I always am getting good volts not good amps.

Ah. Now you've provided enough information to help eliminate uncertainty, which leaves only your available solar as the unknown. This now returns us to post #10.

Have you tested your panels per the link I included on page 1?

solar panels ( 4) 250 watt panels in series/parallel

4 250 watt panels, rated at 30voc and 8.5sc Hi all, my panels put out 60 vdc, only 3-4 amps . Is there a problem with diodes?

diysolarforum.com

You need to confirm each portion of your array is working. First step is to conduct this test on each string of the array and then work back to each panel. You may find you have a bad connector somewhere or your panels are underperforming.

 

[sparkyv]

Ah. Now you've provided enough information to help eliminate uncertainty, which leaves only your available solar as the unknown. This now returns us to post #10.

Have you tested your panels per the link I included on page 1?

solar panels ( 4) 250 watt panels in series/parallel

4 250 watt panels, rated at 30voc and 8.5sc Hi all, my panels put out 60 vdc, only 3-4 amps . Is there a problem with diodes?

diysolarforum.com

You need to confirm each portion of your array is working. First step is to conduct this test on each string of the array and then work back to each panel. You may find you have a bad connector somewhere or your panels are underperforming.

yes , I've done the testing . the only weird thing I found was there was no resistance on the diodes., totally open 1 way , continuity the other. Amy said there is resistance through the diode, I found none with 2 different meters, Both meters are trust worthy. I was hoping to find some bad resistance through the connections but no. As per my original post. Why do I get full volts but very little amps??

 

[acdoctor]

I haven’t looked at that diagnostic but you can disconnect each panel and short them and check with amp clamp meter.

 

[Bud Martin]

yes , I've done the testing . the only weird thing I found was there was no resistance on the diodes., totally open 1 way , continuity the other. Amy said there is resistance through the diode, I found none with 2 different meters, Both meters are trust worthy. I was hoping to find some bad resistance through the connections but no. As per my original post. Why do I get full volts but very little amps??

So what is the current reading of each panel when tested according to the link?

 

[sunshine_eggo]

yes , I've done the testing .

So what did each panel's Isc measure?

the only weird thing I found was there was no resistance on the diodes., totally open 1 way , continuity the other.

Sounds like measurement error.

Amy said there is resistance through the diode, I found none with 2 different meters, Both meters are trust worthy. I was hoping to find some bad resistance through the connections but no. As per my original post. Why do I get full volts but very little amps??

Any light gives you voltage. Intensity of light gives you amps.

 

[efficientPV]

Welcome to the real world of solar. Even a tiny amount of shade can kill voltage under load and power.

 

[sparkyv]

Welcome to the real world of solar. Even a tiny amount of shade can kill voltage under load and power.

Do you ever reach 50% of expected output from your P.V. ?

 

[sunshine_eggo]

Do you ever reach 50% of expected output from your P.V. ?

What did the Isc measure on your 4 panels? How did that compare to the rating?

 

[efficientPV]

I have 4,000W of panels and almost never get more than 700W at any one time.

 

[sunshine_eggo]

sparkyv

What is your latitude?
What Is your panel tilt?
What is your panel orientation?
What does the Isc measure compared to spec?

 

[sparkyv]

I have 4,000W of panels and almost never get more than 700W at any one time.

what was the most for 1 day