chemo brained begginer needs someone to look this over and tell me if im close!

[sozo13]

I recently traded around and got a "starter system" for next to nothing ...im new to solar setups and due to some harsh chemo recently ..feel like I have the focus of a 9 year old with ADD and a bag of candy...so my eyes glaze over on some of the calculation for running x and y for z hours on this and that ...so sorry if this comes off a bit scattered .but heres what I have and heres what I want to do. how far off am I with what I have ..

4 120 watt matching Kyocera panels on a single axis sun tracking mount/pole
1 2210 tracer mppt controller
4 220 ah gc2 6v batteries
2 300 watt pure sine inverters
1 2000 watt mod sine inverter

my current plan is to get the 4 panels going as 2 24v sets going into the 2210 cc
connected to the 4 batteries set up as a 12v bank
the 300 watt inverter will be used to run a 30watt water pump for a fish pond 24/7 ...if that's doable or timed a bit at night if needed
the 2000 watt inverter would be there hooked up ...just incase I needed to run something bigger in a pinch for a few minutes during the day

I live in middle Tennessee have great clear shot of the sky for 90% of the day before it gets a bit of shadeing late afternoon ..the tracking seems to do a great job

is this doable ..am I close ..will I have ah to spare? from the best figuring I could do I was under the impression this would handle the load pretty well with some to spare..

and thanks to those who helped a bit with my wire size and fuse questions on an earlier post

[sozo13]

no comments? any suggestions, warnings, confirmation, laughter even brutal mocking would be appreciated..

[Sunking]

4 120 watt matching Kyocera panels on a single axis sun tracking mount/pole
1 2210 tracer mppt controller
4 220 ah gc2 6v batteries
2 300 watt pure sine inverters
1 2000 watt mod sine inverter

I will help you out here. I know all about the Chemo thing. Unfortunately with solar you have to be able to crunch numbers so you understand what is going on. I will make it as easy as I can.

To start you are going about this all wrong. You want to make one single system. You can use as many inverters as you want providing the batteries and panel wattage can handle it. Easy enough?

First you have more Inverters than your Controller, Batteries and Panel wattage can handle. Sorry but that is just a fact. You have a 20 amp MPPT controller for 12 or 24 volt battery. That means the maximum panel wattage input at:

260 watts @ 12 volts
520 Watts @ 24 volts

So you have a total panel wattage of 480 watts which is just about perfect for a 24 volt system. There will be no room for growth with that charge controller OK?

Batteries need a minimum charge current to prevent them from Straifying, water floating on top of the heavier acid. It takes a minimum of a C/12 charge current. In you case you have about 19 amps of charge current from the panels which means the maximum size battery they can support is 19 amps x 12 = 228 AH. So you have a good match up of panel wattage, controller, and battery capacity. Wire all the batteries up in series and you will have 24 volts @ 220 AH. Perfect match.

Batteries also have a maximum current they can deliver without excessive voltage sag. For Golf Cart batteries being hybrid you can go realistically got to C/6 to C/5. On a 220 AH battery that is 220 AH / 5 Hours = 44 amps maximum before you start loosing voltage to quickly. At 24 volts means the largest Inverter you can realistically run at full power is 44 amps x 24 volts = 1056 watts, let's just say a 1000 watt Inverter is about all they got in her Scotty.

So loose the 2000 watt inverter and use the two 300 watt inverters. Just remember to turn the inverts off when not being used. Or trade all of them for a 1000 watt inverter.

[sozo13]

thanks for the info just to clarify I really have no intention on actually loading up all the inverters.

my total plan ..if possible is setting up a aquaponics setup in my shop. I have AC out there but id like to get the waterpump completely on solar ..its going to be in the 30-35 watt range and would most likely need to go 24/7 on the 300 watt 12v inverter

The other inverter..the 2000 I was just going to hook up on the off chance I needed to fire up a light or a tool in the shop dureing a power outage for a short time that might spike too high for the 300watt ..figured since I have it id put it in on stand by ..this setup wasn't something I went out and shopped for its a hand me down/ trade the inverters are 12v and the only real thing im buying is some heavier wire here and there and fuses ..the other owner had some scary small stuff in the mix and no fuses/breakers.

so am I understanding right that if I wire these batteries up as 12v to use a 12v 300watt inverter im gonna shorten the life of the batteries if there series/paralleled for 12v bank? so getting a 24v inverter is a must?

[paulcheung]

If you want to stick with the 12 volts inverter, you need to get the 40 amps charge controller, the 20 amp won't work.

[Sunking]

Hold the bus.

Your Controller has limits with respect to battery voltage. At 12 volts you can only use 2 of your panels and 2 of your batteries. With your Controller being 20 amp on a 12 volt battery means your maximum panel wattage input is limited to 260 watts. Your panels are 120 watts which means you can only use two of them with a 12 volt battery. That also lowers the maximum Inverter wattage to 500 watts.

Take my advice loose all your 12 volt Inverters and get yourself a 1000 watt 24 volt Inverter. Then you can use all your panels and batteries. 12 volts is for toys and RV's.

[sozo13]

If you want to stick with the 12 volts inverter, you need to get the 40 amps charge controller, the 20 amp won't work.

hmm ok maybe I missed something ..very possible with me but to double check my panels are like 7.1 max amps if I set them up as series/parallel 2 pair of 24v wouldn't I end up with a max amps of 15? or am I misunderstanding the way that would work or is there another reason other than amps in that would cause an issue?

[Sunking]

hmm ok maybe I missed something ..very possible with me but to double check my panels are like 7.1 max amps if I set them up as series/parallel 2 pair of 24v wouldn't I end up with a max amps of 15? or am I misunderstanding the way that would work or is there another reason other than amps in that would cause an issue?

MPPT Output Current = Panel Wattage / Battery Voltage

PWM Output Current = Input Current

So for MPPT controller you have with 2 panels wired in either series or parallel 240 watts / 12 volts = 20 amps.

If you had a PWM Controller running 12 volts you are forced to wire the panels in parallel so 14.1 amps or 170 watts out of 240 watts of panels.

You want 12 volts then you need a $300 40 Amp MPPT Controller to use all 4 panels in either series or parallel. 480 watts / 12 volts = 40 amps

Loose your inverters and get a 1000 watt 24 volt inverter. Lot cheaper than a 40 amp mppt controller.

[sozo13]

ok probably will go with a 24v inverter ..but frustrated I thought I understood this better I was under the impression ..120v 7.1 amp panel in series with another would give me 240w 7.1 amp @ 24 volts do that with both pair and put them in parallel I would have 480w 14.2 max amps @ 24v and I was under the impression while not the most optimal set up my mppt 20 amp control could send that into the 12v 440 ah bank of 4 6v batteries ..and could use the 12 v 300w inverter with that was I mis understanding the panel/mppt side of this?

sorry im so dense lol

[Sunking]

What you are not understanding is how charge controller work and the MATH behind them. There are two types being PWM and MPPT

A PWM controller is really nothing more than a switch that connects your panels directly to the batteries. PWM Output Current = Input Current. So if you take just one of your 120 Watt panels that has an Imp of 7 amps and 17 volt on the input of a PWM Controler you get 12 volts x 7 amps out or 84 Watts output. If you connect two of your panels in series on the input you now have 34 volts @ 7 amps, you get 12 volts X 7 amps out or the same 84 watts. Put 100 of you panels in series and you still get 7 amps @ 12 volts out.

Sticking with PWM if you take two of your panels in parallel you have 17 volts @ 14 in, and 12 volts @ 14 amps or 168 watts. With 3 panels in parallel 21 amps out @ 12 volts is 252 watts. All 4 panels in parallel 28 amps out or 336 watts out of your 480 watt panels.

MPPT controllers are completely different animals. They are Bboost Converters or DC to DC Converter. A MPPT controller Output Current = Panel Wattage / Battery Voltage.Wire all four of you panels in parallel and you have 17 volts input @ 28 amps, and on the output you have 12 volts x 40 amps is 480 watts. Wire the same 4 panels in series and at the input you have 68 volts @ 7 amps, and on the output you have 12 volts x 40 amps or 480 watts.

MPPT gives you two huge advantages.

1. It allows you to run high voltages on the input at lower current. That means much smaller less expensive wire. It also allows you to use Grid Tied panels which are 1/3 the cost of battery panels you have.

2. The second huge advantage is MPPT controllers are very efficient unlike PWM. It takes a 300 watt PWM system to equal a 200 watt MPPT system.

You gotta understand the MATH. If you run 24 volts with your controller you only have 1 panel configuration because of the Voc input limitation. Wire the panels in 2 x 2. v 2 in series, in parallel of 2 panels in series.

[SunEagle]

ok probably will go with a 24v inverter ..but frustrated I thought I understood this better I was under the impression ..120v 7.1 amp panel in series with another would give me 240w 7.1 amp @ 24 volts do that with both pair and put them in parallel I would have 480w 14.2 max amps @ 24v and I was under the impression while not the most optimal set up my mppt 20 amp control could send that into the 12v 440 ah bank of 4 6v batteries ..and could use the 12 v 300w inverter with that was I mis understanding the panel/mppt side of this?

sorry im so dense lol

Most people get confused with the amp rating of the Charge Controller. That rating is the "output" or charging amp limit based on the battery voltage. It is not the "input" amp rating of what your pv panels produce although there will be a max input voltage rating and a max solar pv wattage input rating based on the voltage of the battery system.

20A max charging capacity = 240watts for 12volt battery system
20A max charging capacity = 480watts for 24volt battery system

[sozo13]

yes THAT is were I was stumbling at..it took a bit for that part to sink in I wasn't adding wrong as much as I was trying to shove my numbers where they didn't belong..

now one more question ..until I get a 24v inverter would this mppt allow me to just use 2 of these panels in series as a 240w 24v input going into the 12v bank? would this be worse or better than just using 2 in parallel?

[SunEagle]

yes THAT is were I was stumbling at..it took a bit for that part to sink in I wasn't adding wrong as much as I was trying to shove my numbers where they didn't belong..

now one more question ..until I get a 24v inverter would this mppt allow me to just use 2 of these panels in series as a 240w 24v input going into the 12v bank? would this be worse or better than just using 2 in parallel?

Short answer is yes. You can charge a 12volt battery with 2 of those panels wired in series to your charge controller. The only thing that is "worse" with parallel wiring is now your wires have to carry twice the amperage then if you wired those panels in series.

Again you are confusing the panel input voltage with output charging voltage.

Most charge controllers can accepts a range of input voltage giving you options on how to wire your panels (series or parallel).

The only thing you have to be aware of is that most "12volt" panels actually have Vmp ~ 17 to 18 volts. And most "24volt" panels have a Vmp ~ 34volts.

You need at least that 16volts to charge a 12volt battery and 32volts for a 24volt battery.

[sozo13]

ok thanks very much I got a path forward now with what I have that's the main thing.

2 120 panels in series
12 volt bank
12v 300w inverter ..and start saving to go bigger down the road

is there any issues with putting a charger on your batteries while everything is connected and charging or shouid I have a disconnect somewhere on the mppt side of the batteries to do that?

[SunEagle]

ok thanks very much I got a path forward now with what I have that's the main thing.

2 120 panels in series
12 volt bank
12v 300w inverter ..and start saving to go bigger down the road

is there any issues with putting a charger on your batteries while everything is connected and charging or shouid I have a disconnect somewhere on the mppt side of the batteries to do that?

When you own a solar/battery system you will need to keep an eye on those batteries. You will also need to give them a good charge using a grid power charger maybe once a month.

I would only connect that charger to the batteries when I want to charge them and not all the time.