Some noob/curious questions

[Jman]

What is typical array voltage? I keep reading how series in the proper way to set panels up, If you have 4KW of panels (12-14 individual of 30V+) that means the whole array must be 400+V while CC can only handle around 200 volts max. Do they split the array up into two groups paralleled or something?

If battery bank is far larger than array but array voltage is alot higher than Batt bank, like array 60Vmp vs 24V bank. will the battery still pull down the array voltage so it won't charge?

Can equalization be done with CC and solar over a period of a few days provided you are not using the bank with any loads?

thanks

[SunEagle]

I would say you are confused.

With a 4000 watt pv system you can only charge a 48Volt battery system using an 80 amp MPPT charge controller.

Quality charge controllers will reduce the voltage from the panels down to what is required to charge the battery system. That allows you to wire the panels so you can deliver a higher voltage to the CC and reduces your wire sizes.

If you are wiring 4kw of panels to a 24volt bank you probably will cook the CC or at least clip the amount of charging amps provided by the panels so that half of your pv wattage is wasted.

[SooFilthy]

I believe That is the current issue i am having. I have 8X 255w pannels on a 12v system. My CC/Panels are maxing out at around 1.1kw and they are connected to a 12v outback inverter/charger. I am currently shopping for a new inverter/charger and am having trouble deciding to go with a 24v or 48v system. Am i right in thinking that i will produce more power from my panels with a 24v or 48v system?

[SunEagle]

I believe That is the current issue i am having. I have 8X 255w pannels on a 12v system. My CC/Panels are maxing out at around 1.1kw and they are connected to a 12v outback inverter/charger. I am currently shopping for a new inverter/charger and am having trouble deciding to go with a 24v or 48v system. Am i right in thinking that i will produce more power from my panels with a 24v or 48v system?

Some basic math for solar / battery systems using an 80amp MPPT type chargers

12v x 80a = 960w which is about 1000 watts
24v x 80a = 1920w which is about 2000 watts
48v x 80a = 3840w which is about 4000 watts

So 8 x 255w = 2040watt which is too much for a 12volt battery system using the largest MPPT type charger rated 80 amps.

To use that 2000 watts of panels going to a 24v or 48v battery system would work depending on the type MPPT CC you use.

[SooFilthy]

thanks! I have a Midnite classic 200 so i think my max is right around 80 amps. The inverter is my neighbors on loan until I decide which inverter I want. I am still having trouble in that department deciding on a 24v vs a 48v system.

[SunEagle]

thanks! I have a Midnite classic 200 so i think my max is right around 80 amps. The inverter is my neighbors on loan until I decide which inverter I want. I am still having trouble in that department deciding on a 24v vs a 48v system.

With 2000 watts you need to go to at least 24v but a bigger (and better for larger loads) system should be at 48volts.

[SooFilthy]

Ok so a 48v is better on the PV side but is it also better on the battery storage side?. I currently have 16 6v 230 amp hr batteries (lead acid). So 12v is 8 strings, 24v = 4 strings and 48v is only two strings. My concern is only having 2 strings in a 48v configuration, how likely is I am going to lose a whole string?

[SunEagle]

Ok so a 48v is better on the PV side but is it also better on the battery storage side?. I currently have 16 6v 230 amp hr batteries (lead acid). So 12v is 8 strings, 24v = 4 strings and 48v is only two strings. My concern is only having 2 strings in a 48v configuration, how likely is I am going to lose a whole string?

4 strings of parallel wired batteries have a higher chance of failing then 2 strings. If your fear is system failure and loss then use a generator to supplement if your battery system is reduced.

Besides anyone with a battery system needs to have a generator on hand to properly take care of them because a solar pv system will not be able to perform a high energy charge that they require every so often.

[SooFilthy]

I did not know that a 48v was more reliable on the battery side! Reliability and backups are my big concerns due to how remote I live. I do have a 5700w generator and had to use it a couple times a week all winter but less than expected. I was looking at getting a Schneider inverter/ charger because of the ability to run a smalller ( cheaper) inverter generator. My understanding it the generator support with Schneider will run smaller generators at 80%. The cost saving of a 2800w compared to a 5000w inverter generator is huge. I

[SunEagle]

I did not know that a 48v was more reliable on the battery side! Reliability and backups are my big concerns due to how remote I live. I do have a 5700w generator and had to use it a couple times a week all winter but less than expected. I was looking at getting a Schneider inverter/ charger because of the ability to run a smalller ( cheaper) inverter generator. My understanding it the generator support with Schneider will run smaller generators at 80%. The cost saving of a 2800w compared to a 5000w inverter generator is huge. I

A battery system that is only wired in series has a higher reliability then any that are paralleled wired.

A 48volt system allows you to generate a lot of watt hours yet it keeps the size of the wiring smaller due to lower amps going through them.

[Jman]

I would say you are confused.

With a 4000 watt pv system you can only charge a 48Volt battery system using an 80 amp MPPT charge controller.

Quality charge controllers will reduce the voltage from the panels down to what is required to charge the battery system. That allows you to wire the panels so you can deliver a higher voltage to the CC and reduces your wire sizes.

If you are wiring 4kw of panels to a 24volt bank you probably will cook the CC or at least clip the amount of charging amps provided by the panels so that half of your pv wattage is wasted.

Well 4000 was just a number without considering the CC limits, but by the looks you can easily go well beyond the CC OCV limit with even 2000-3000watts. So I assumed the only option with one CC would be to setup two groups (each group of panels in series) & parallel those two groups.