Furstrated- Unable to get rated solar Amperage

[inetdog]

They look like 1 Sqmm to the eye. Today I will see if I can make series connection at panel itself and Combine 2 cables to bring power downstairs. Will that help? If wires are hot means they're wasting half the power, aint it?

1 mm² in area would be the equivalent of US #17 AWG.
1 mm diameter would have and area equivalent to smaller than #18 AWG. Either of those would be too small for 10A on a long term basis.

Now the fact that the wires are getting noticeably warm/hot does not by itself meant that you are losing a lot of power, much less half the power, but in this voltage sensitive environment (single panel in particular) it is not a good thing.

[bhvm]

the tech team is here.
they advised we replace the wires of 1sqmm to 2.5sqmm. I brought 4 rolls of wires.

in the end I have 4 pairs of 2.5 mm wires (joint free ) coming from panels to controller. one pair for EACH. I took a temporary reading and I can already notice 50 percent improvement. each 8a rated panel is delivering 3 amps at 5pm. perhaps they'll ramp up to 7 amps in noon. feasible?

[Sunking]

the tech team is here.
they advised we replace the wires of 1sqmm to 2.5sqmm. I brought 4 rolls of wires.

in the end I have 4 pairs of 2.5 mm wires (joint free ) coming from panels to controller. one pair for EACH. I took a temporary reading and I can already notice 50 percent improvement. each 8a rated panel is delivering 3 amps at 5pm. perhaps they'll ramp up to 7 amps in noon. feasible?

How long are these cable runs? (One-Way distance)

One of the most important factors in a design is limiting voltage loss to 2 or 3 % or less. With a 30 volt panel 2% is only .6 volts. With 8 amps of current and lest's say a One Way Distance of 25 feet (8 meters) would require a minimum of a 6 mm^2 copper cable. I do not know how long of a run you have but at 2.5 mm^2 with 8 amps is only good for 14 feet or roughly 4 meters One-Way.

[bhvm]

the distance is about 30ft. I wanted 4 sqmm but couldn't get any. I have also enquired about mppt controller and they're about 250 dollars. the seller suggested me to straight away go for Solar inverter wish mppt for 350 dollars. I'll pass on the spec here so you can judge. thanks.

[Sunking]

the distance is about 30ft. I wanted 4 sqmm but couldn't get any. I have also enquired about mppt controller and they're about 250 dollars. the seller suggested me to straight away go for Solar inverter wish mppt for 350 dollars. I'll pass on the spec here so you can judge. thanks.

4 mm^2 is safe, but still a bit small for 8 amps, but not bad which puts you at roughly 3% voltage and power on the wiring.

FWIW 1 mm^2 was border line safe and resulted in 38% power loss with 8 amps @ 30 volts.

[bhvm]

The Technician visited me second time, What he did-
1)Replace wire Lugs (Wire connectors going into solar panel end)
2)Added second Controller
Panel 1 & 2 in PARALLEL = Controller 1
Panel 3 & 4 in PARALLEL= Controller 2

The outputs of both controllers are now combined (parallel) and joined to battery.
The results is I'm seeing about 240 watts on each controller, which means close to 500W total or 20A Charging.
However I am still at half of specced wattage (1000W or 8A x 4 panels = 32A)
I'll be happy even at 700W! I enquired about MPPT controllers and he says MPPT is not successful in India? Why?

[mapmaker]

I'll be happy even at 700W! I enquired about MPPT controllers and he says MPPT is not successful in India? Why?

Your technician isn't too smart. You asked us for advice on this forum. You got good advice here, and you got a good explanation why you need an MPPT controller.

If you keep asking why your system doesn't work correctly, you will get the same answer, or maybe you will get no answer because you have already been told the answer.

--mapmaker

[Sunking]

The Technician visited me second time, What he did-
1)Replace wire Lugs (Wire connectors going into solar panel end)
2)Added second Controller
Panel 1 & 2 in PARALLEL = Controller 1
Panel 3 & 4 in PARALLEL= Controller 2

However I am still at half of specced wattage (1000W or 8A x 4 panels = 32A)
I'll be happy even at 700W! I enquired about MPPT controllers and he says MPPT is not successful in India? Why?

I can only guess the technician is referring to sales not being successful. Otherwise I am confident by the advice you have been given by locals in your area have no idea what they are doing. If they did they would have never sold you 30 volt panels for a 24 volt battery using PWM controller. That alone tells us they are ignorant.

As I stated before with any PWM controller Output Current = Input Current. You need to fully understand what that means. Your panels are rated 7.94 amps and with 4 in parallel a total current of 31.76 amps. So the maximum charge wattage on the battery is 31.76 amps x 24 volts = 762 watts. Problem is your panel voltage is too low to push that much current.

With a MPPT controller Output Current = Panel Wattage / Battery Voltage. 1000 watts / 24 volts = 42 amps.

So if you want your system to work, use the right equipment and hardware. As state din my first post there is nothing wrong with the equipment. All of your problems are Operator Error in design and implementation.

[bhvm]

I see.
he was saying that if I buy a 40a mppt controller, it won't even start until panels give it 40a to work with. that's really fishy.

I'm going to push him for. mppt again. problem if I force him into something, I'll be left alone. if it doesn't work out, I'll have a huge dent in pocket and wasted hardware. hence I'm looking for maximum info. some of the members are not well versed wish Indian conditions and psychology I see. thanks for info.

[Sunking]

I see.
he was saying that if I buy a 40a mppt controller, it won't even start until panels give it 40a to work with. that's really fishy.

He is incompetent and you should not deal with that person. I take it you are in India? If so we cannot really help you are you do not have access to quality products.

[russ]

He is incompetent and you should not deal with that person. I take it you are in India? If so we cannot really help you are you do not have access to quality products.

Another problem he has is that in India the "electrical technician" is often the guy that has a screwdriver. If he has actually seen anyone do the job before he may have a vague idea.

[bhvm]

I can only guess the technician is referring to sales not being successful. Otherwise I am confident by the advice you have been given by locals in your area have no idea what they are doing. If they did they would have never sold you 30 volt panels for a 24 volt battery using PWM controller. That alone tells us they are ignorant.

As I stated before with any PWM controller Output Current = Input Current. You need to fully understand what that means. Your panels are rated 7.94 amps and with 4 in parallel a total current of 31.76 amps. So the maximum charge wattage on the battery is 31.76 amps x 24 volts = 762 watts. Problem is your panel voltage is too low to push that much current.

With a MPPT controller Output Current = Panel Wattage / Battery Voltage. 1000 watts / 24 volts = 42 amps.

So if you want your system to work, use the right equipment and hardware. As state din my first post there is nothing wrong with the equipment. All of your problems are Operator Error in design and implementation.

Yes It could be the case as MPPT are Exhorbiantly expensive. And because they don't sell well, People who import them are able to charge exploitative premium on them. Solar stuff is already too expensive in India and there is zero help from Goverment makes it worse.

What shall be a better panel voltage to charge 24v system via PWM? If so I could ask him to change the type of panels. Otherswise,
If you are confident I will coax him into getting a 40A 24v MPPT controller. That'll do?

Thanks for detailed info.

[mapmaker]

What shall be a better panel voltage to charge 24v system via PWM? If so I could ask him to change the type of panels.

Sunking answered that question in the very first reply to this thread. You need Vmp = 36 volts. The Voc of such a panel will be about 44 volts.

--mapmaker

[bhvm]

Thanks for bringing to notice. There are clouds and storms these days. So my project is on hold till skies clear.

[bhvm]

Hello again
I had the tech visit again.
They checked the controllers are found them fine. Now they are thinking to replace the Panels.
Perhaps they'll give me 42v ones like you suggested.

However I have insisted that i'd like to try MPPT before swapping anything. Lets see how it goes.