Will the "Beginner Friendly All-in-One Solar Power System" trickle charge a Tesla? Help!

[Supervstech]

Ah, I see. Yep-oops. Sorry.

So would a 48v inverter work?

That is up to you, you would need more batteries to use one.

 

[Doggydogworld]

Would the charge controller be for my current inverter so I can use my panels in series?

Yes. You'd use the new standalone MPPT controller to charge your battery but still use the inverter in your 2724 all-in-one.

Let's say I go with a different inverter. I'm assuming this would be a 48v all-in-one, correct?

You can move to 48V if you want to spend more money on a new all-in-one and two more 12V batteries. It's not necessary. But little in life is, haha.

You could also sell your 240s and buy a couple of 300-400s with a Vmp closer to 40V. You might even come out a few bucks ahead.

Did you do the single panel experiment?

 

[houts]

Yes. You'd use the new standalone MPPT controller to charge your battery but still use the inverter in your 2724 all-in-one.


You can move to 48V if you want to spend more money on a new all-in-one and two more 12V batteries. It's not necessary. But little in life is, haha.

You could also sell your 240s and buy a couple of 300-400s with a Vmp closer to 40V. You might even come out a few bucks ahead.

Did you do the single panel experiment?

I did the single panel experiment, pulling in nearly 200 watts from each.

My thought with getting a 48v inverter, say a Growatt, is that it would be able to handle more voltage than my current inverter can't.

 

[houts]

You could also sell your 240s and buy a couple of 300-400s with a Vmp closer to 40V. You might even come out a few bucks ahead.

Is the issue with my panels in parallel are not pulling over 30v? Why is 40v the magic number here?

 

[Supervstech]

Is the issue with my panels in parallel are not pulling over 30v? Why is 40v the magic number here?

When voltage is low, amperage maxes out before energy can be transformed to watts...

 

[12VoltInstalls]

Is the issue with my panels in parallel are not pulling over 30v? Why is 40v the magic number here?

the issue with my panels in parallel is they are not pulling making over 30v? 40v is the minimum number here because I have to make at least 20% higher voltage than my 24V batteries need to charge

 

[Doggydogworld]

Is the issue with my panels in parallel are not pulling over 30v? Why is 40v the magic number here?

30V is the magic number. That's the minimum spec for the MPPT controller in your AIO box. Your panels are rated at 30.4 Vmp in the idealized STC lab test. Voc and Vmp vary in real world conditions, especially with temperature. Look at this IV chart for a 60 cell CSUN panel that's similar to yours:


The red line is STC, i.e. 25 deg C and full 1000 W/m2 solar flux. Voc is ~37V, like yours, and Vmp looks to be about 31V. But look at that 75 deg C blue line -- Vmp is down to 25V!!! More importantly, the power output at 75 deg C and 30V (the minimum your MPPT will allow) is a meager 50W or so.

Also note how steep the right side of the IV curve is. Operating just a few Volts over Vmp completely destroys your power output. This is a key point.

Your panels probably aren't heating up to 75 deg C in October, of course. But you also have voltage drop across wires and connectors. And in a parallel array one low voltage panel will pull the voltage down for the whole array.

My guess is this. A single panel directly connected via a short wire has almost no voltage drop. So 30V at the MPPT is 30.2V or something at the panel. That's pretty close to Vmp, even if your panel temp is running a little hot (e.g. 30-35 deg C). So you get ~200W. But the Y connectors you use to connect four panels in parallel cause enough voltage drop that 30V at the MPPT becomes more like 32V at the panels. That's far enough above Vmp to move you 100W or so down that steep IV power curve. Especially if your panels are running a little hot.

In theory you could get better output with perfect Y connectors and short, fat wires. But you've still got a temperature problem. On windless summer days when your panels heat way up you'll again ride down the steep slope of that power curve. 40Vmp, or something close to it, gives you margin for error. 30.4V doesn't.

 

[houts]

Thanks to everyone who responded. This has been extremely eye-opening and educational without feeling bad for being ignorant.

There seem to be two options here.

Option #1
Buy different solar panels for my current inverter.
- Is it better to buy (used) 200-300 watt 12v solar panels and put them in a series or buy (used) 200-300 watt 40v solar panels and put them in parallel?

Option #2
Sell my inverter and buy a Growatt SPF 3000TL LVM and put my current panels into series.
-Am I correct that putting 4 x 240 watt - 37.2 panels in a series would (should) work to get to 120v needed for the Growatt?

 

[Doggydogworld]

From what I've seen 12V panels tend to cost more. They work directly with cheap PWM controllers and Bluetti / Jackery boxes, and people pay for convenience.

This Growatt? It says max Voc is 145V. Four 37.2 Voc panels in series is 4 * 37.4 = 149.6 Voc. Too high. You could use 2S2P with the 3000 TL LVM-24. The 74.8 Voc is fine and the 60-ish Vmp is smack in the middle of the 30-115VDC MPPT operating voltage. 2S2P would not work with the 3000 TL LVM-48 because its MPPT range is 60-115V. Your 2S2P would be 60.8 Vmp, so you're right back in the same boat with no margin for error.

 

[StuartV]

I personally would buy a Victron 150/35 or a 100/50 and keep your AIO and batteries. With the Victron, at least you will have bluetooth monitoring on your phone. (I'm probably going to do that next year, get a Victron to add to my exisiting set up)

 

[houts]

Might two of these work better than what I have?

 

[Doggydogworld]

Voc and Vmp are right in the sweet spot. Total rated power for two panels is 770W. That's a little more than your AIO can use, so you're a little "overpaneled". But a lot of people do that intentionally and almost all large solar farms do.

Are you near Savannah? Shipping only two panels often leads to damage, so if you plan on shipping make sure they're well-insured.

 

[houts]

Update:
I've been getting about 4-7 miles of daily charging on my Tesla M3 off my solar panels. Not bad.
Mind you, I don't travel far from work, but ultimately, I would love to reach 15 miles of daily charge at some point. I am looking at purchasing a Growatt 24v SPF 3000TL-LVM.

Question:
Will the Growatt 24V SPF 3000TL LVM – 3kW 120Vac handle my four solar panel array (each one produces 37.2) if put into 2S2P with the 3000 TL LVM-24?




As DoggyDogWorld posted above, putting in 2SP2P should "The 74.8 Voc is fine and the 60-ish Vmp is smack in the middle of the 30-115VDC MPPT operating voltage."

Can others verify that this is correct (not that I'm doubting you DoggyDogWorld)?

 

[gelmjw]

Yes. Your 2S2P array will be 74.4VMP which is inside the 30-115 range.

 

[houts]

Thanks to Gelmjw, CuriousCarbon, DoggyDogWorld, Supervstech, 12VoltInstalls, and StuartV.

I'll be purchasing the Growatts this week, and I plan on following up with how everything is working out.

Last question for anyone willing to answer: I am pulling 415-450 (max) from my 4 x 240 (37.2A) solar panels on my PIP inverter, which has a max charging of 25A.
What might it look once I can pull in 74.v?




Inverter x 1: PIP 2724LV-MR 24V 2.7kW 120V Inverter, 600W Solar
Solar panels x 4 (used): SST-240-60P Brand : Trina Solar Wattage : 240 Watts Voltage : 37.2V ( open current )
Batteries x 4: Weize 12V 100AH Deep Cycle AGM SLA VRLA Battery

 

[Supervstech]

Thanks to Gelmjw, CuriousCarbon, DoggyDogWorld, Supervstech, 12VoltInstalls, and StuartV.

I'll be purchasing the Growatts this week, and I plan on following up with how everything is working out.

Last question for anyone willing to answer: I am pulling 415-450 (max) from my 4 x 240 (37.2A) solar panels on my PIP inverter, which has a max charging of 25A.
What might it look once I can pull in 74.v?




Inverter x 1: PIP 2724LV-MR 24V 2.7kW 120V Inverter, 600W Solar
Solar panels x 4 (used): SST-240-60P Brand : Trina Solar Wattage : 240 Watts Voltage : 37.2V ( open current )
Batteries x 4: Weize 12V 100AH Deep Cycle AGM SLA VRLA Battery

Well, the most you will get out of a 24V controller with a 25A limit is 576W at 24V, 696W at 29V, but at that point, the batteries won't be drawing much... but you might have a large demand from the inverter... so 696 is the max wattage you could ever see.

 

[Doggydogworld]

I'll be purchasing the Growatts this week, and I plan on following up with how everything is working out.

Last question for anyone willing to answer: I am pulling 415-450 (max) from my 4 x 240 (37.2A) solar panels on my PIP inverter, which has a max charging of 25A.
What might it look once I can pull in 74.v?

The Growatt you spec'd out can supply up to 2000 solar charging Watts to the battery (24+V * 80A). Your 4 panels are rated for 240W each, so 960W. Depending on location you may get close to 960W at high noon on very sunny, cool days with short, fat wires and perfect connections. Most of the time production will be lower, of course. You can use PVWatts for your location to estimate average production per month.

 

[houts]

Well, the most you will get out of a 24V controller with a 25A limit is 576W at 24V, 696W at 29V, but at that point, the batteries won't be drawing much... but you might have a large demand from the inverter... so 696 is the max wattage you could ever see.

Never thought about it this way. Thanks! This was extremely helpful!

 

[houts]

The Growatt you spec'd out can supply up to 2000 solar charging Watts to the battery (24+V * 80A). Your 4 panels are rated for 240W each, so 960W. Depending on location you may get close to 960W at high noon on very sunny, cool days with short, fat wires and perfect connections. Most of the time production will be lower, of course. You can use PVWatts for your location to estimate average production per month.

Well, this excites me, then as I am looking toward the future with the change from my MPP solar inverter to the Growatt.
Thanks!

 

[houts]

It's finally here!

24P	Growatt 24V SPF 3000TL LVM - 3kW 120Vac Stackable Inverter 2kW MPPT Charge Controller Split Phas

Question: There are the "AC Input" and "AC Output", and I plan to connect a GE surge protector outlet. Which one (green/white/brown wires) do I connect it to?