Which Controller for 1KW-Solarpanel-Array and 800Ah Batteries is the best?

[esu]

I have 6 x 180 Watt Solar-Panels and 4 x 200 Ah 12V Batteries. The Batteries are connected parallel, so that the input/output is 24V. Now I want to buy a "Best-Quality" Controller to charge the Batteries. Which Controller is the best for my requirements?

[Sunking]

I have 6 x 180 Watt Solar-Panels and 4 x 200 Ah 12V Batteries. The Batteries are connected parallel, so that the input/output is 24V.

No Sir if they are in parallel would be 12 volts @ 800 AH. You would be much further ahead of the game to configure the batteries at 24 @ 400 AH or 48 volts @ 200 AH. 12 volts is for toys and RV's.

Next eye opener for you is if wired at 24 volts you only need a 40 amp MPPT controller and much smaller copper wire, take it up to 48 volts and all you need is a 20 amp MPPT controller and even smaller wire. You are talking thousands of dollars in savings and a much more efficient system.

Anyway you are looking for Morningstar and Midnight Solar MPPT controllers. Do not even think about PWM.

[esu]

Thank you for your answer

No Sir if they are in parallel would be 12 volts @ 800 AH. You would be much further ahead of the game to configure the batteries at 24 @ 400 AH or 48 volts @ 200 AH. 12 volts is for toys and RV's.

I meant of course that the 4x 12V/200AH batteries are wired to 24V @ 400 AH.

Next eye opener for you is if wired at 24 volts you only need a 40 amp MPPT controller and much smaller copper wire, take it up to 48 volts and all you need is a 20 amp MPPT controller and even smaller wire. You are talking thousands of dollars in savings and a much more efficient system.Anyway you are looking for Morningstar and Midnight Solar MPPT controllers. Do not even think about PWM.

I have already a running system with 24V configuration, but with a "no name" Controller from China. At the moment I can not change the 24V system. So, I want only to replace the Controller. For example which Morningstar controller you can recommend for my configuration?

[Sunking]

At the moment I can not change the 24V system. So, I want only to replace the Controller. For example which Morningstar controller you can recommend for my configuration?

OK that raises some concern. Is it because the charger is faulty, or you are using more power than the panels can replace?

For Morningstar product line you are looking for a Morningstar TriStar MPPT 45 Amp controller. If you see expansion in your future go with the 60 amp model. With the 40 amp model at 24 volts 1200 is the maximum input you can run. Or you can upgrade to 48 volts which gets you up to 2400 watts input.

I do not know how you have the panels configured or the specs of your panels but you will most likely want them in a 2 x 3 configuration meaning 2 strings in parallel with each string having 3 panels in series. If you have high voltage Grid Tied panels you may need to go with 3 x 2.

• What are the panel specs so I can give you the most optimum config? (Voc Vmp, and Isc)
  
• In addition what is the 1-way cable distance between panels and controller?

[esu]

> OK that raises some concern. Is it because the charger is faulty, or you are using more power than the panels can replace?

I can not change the 24V system because I am not a big expert in electricity and I have already an inverter which works with 24V.

> What are the panel specs so I can give you the most optimum config?

The solar panels are already installed on the roof, so I can not see the exact technical details. But each solar panel have 180W @ 17V
I also do not know how the solar panels are wired, but I checked the voltage of solar panel cable (at my home) - there is about 45V in a peek-time when the cable is not connected to the controller.

> In addition what is the 1-way cable distance between panels and controller?

Between solar panels and the controller is about 40m cable.

> For Morningstar product line you are looking for a Morningstar TriStar MPPT 45 Amp controller.

This Morningstar controller looks really good, thank you for this recommendation. I think that I will buy this controller.

[Sunking]

> OK that raises some concern. Is it because the charger is faulty, or you are using more power than the panels can replace?

I can not change the 24V system because I am not a big expert in electricity and I have already an inverter which works with 24V.

I was not suggesting you change system voltage. 24 volts is fine at your power level. I was trying to determine if you have an equipment problem, or equipment sizing problem. It appears from the rest of your responses you have a sizing and configuration issue.

> What are the panel specs so I can give you the most optimum config?

The solar panels are already installed on the roof, so I can not see the exact technical details. But each solar panel have 180W @ 17V
I also do not know how the solar panels are wired, but I checked the voltage of solar panel cable (at my home) - there is about 45V in a peek-time when the cable is not connected to the controller.

OK that tells me you measured Voc or voltage open circuit and your panels are configured 2 x 3 of 2 panels in series wired in parallel with 3 like strings. This is going to be a problem with the distance involved

> In addition what is the 1-way cable distance between panels and controller?
Between solar panels and the controller is about 40m cable.

OK this is a problem as you have roughly 130 feet 1-way distance. You did not mention the wire size, but I bet it is too small. With your panels wired 2 x 3 means the Vmp is 34 volts, and at 1080 watts means the current is roughly 31 amps. At 140 feet to keep the power losses to 2% or less would require 2/0 AWG copper cable or in metric 50 mm^2. That is a cable with a diameter of roughly 10 millimeters or th esize of a big cigar or golf club grip. Not to mention extremely expensive. Since I do not know th esize of the wire used I cannot tell what your losses really are. All I can say is it is possible you are loosing 20 to 30% of your power on the wiring if improperly sized. YOu can cut the losses by 30% just by reconfiguring your panels to 3 x 2 meaning 3 panels in series in parallel with another 3 panels in series.

Can you tell me what size wire is between the panels and controller?

[Naptown]

Another question
We would need to know the panel specs manufacturer and open circuit voltage and location for coldest recorded temperature.
There may be a possibility of wiring all panels in series reducing your losses even further
You may at that point need to go to a midnight 250v controller which would work in any case.
Don't buy anything yet

[Sunking]

Another question
We would need to know the panel specs manufacturer and open circuit voltage and location for coldest recorded temperature.

Rich it sounds like he has standard battery panels with a Voc of 23 volts. Pretty much can go with NEC 125% rating of 6 panels x 23 volts x 1.25 = 173 volts. Classic 200 would make a good fit, but I suspect price might be an issue for him since he is not in the USA. Us price for a Midnite Solar Classic 200 is around $600 to $700 USD

[Naptown]

That's why I asked for coldest temp and panel specs.
Can't do much on cost

[thastinger]

Get a Midnite Classic 200, wire all the panels in series, get some stranded 10Ga copper wire for the panel to CC run. Then eventually, wire those same batteries into a 48V single series string and switch the inverter out to a 48V one.

someone check me...

[Sunking]

That's why I asked for coldest temp and panel specs.
Can't do much on cost

Well if you take worse case of NEC 125% you eliminate the need for derating as it is already overkill @ 125%. 6 battery panels in series are not going to go over 200 Voc anywhere on earth to my knowledge. I agree about the cost.

[Sunking]

Get a Midnite Classic 200, wire all the panels in series, get some stranded 10Ga copper wire for the panel to CC run. someone check me...

OK if he wires all 6 panels in series his Vmp = roughly 100 volts running 10 amps of current. So to limit voltage drop to 2% is 2 volts / 10 amps = .2 Ohm's total loop resistance. With 280 loop feet of cable requires a minimum of #8 AWG but would be at the maximum limit of 2%. It would be wiser to use at least #6 AWG stranded copper or in his case 16 mm^2 to allow for future expansions.

I suspect he also is in defecit charging which means either cut power usage or upsize everything.

[thastinger]

My bad, I thought the run was 40Ft, still, 6Ga would be alot cheaper wire than 2/0

[Naptown]

I suspect maybe a # 8 wire from panels to CC and he currently has a PWM controller.
This is a recipe for deficient charging.
But let's see what he comes back with.

[Sunking]

I suspect maybe a # 8 wire from panels to CC and he currently has a PWM controller.
This is a recipe for deficient charging.
But let's see what he comes back with.

I agree, all so far is speculation.