Renogy 550W Panel system.

[AmpD]

It's been almost a year. I'm still wanting to go with the 550W renology panels for my build.

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Specs:

Maximum Power: 550W

Open-Circuit Voltage (Voc): 49.95 V

Optimum Operating Voltage (Vmp): 41.97 V

Optimum Operating Current (Imp): 13.11 A

Short-Circuit Current (Isc): 14.05 A

Maximum Series Fuse Rating: 25 A

Maximum System Voltage: 1500V DC (UL)

Operating Temperature: -40°F to 185°F


We are looking at 4 panels for a 2200w system. I want to use 48v server rack batteries. Minimum of 10kWh likely 15kWh bank.

I was hoping I can get some input on the charge controller. Since I already am going Renogy I was leaning towards a 100a renogy mppt controller.

specs:

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• Nominal Voltage: 12V/24V/36V/48V Auto Recognition (for non-lithium batteries)
• Rated Charge Current: 100A
• Max. PV Input Voltage: 150VDC (77°F), 140VDC (-13°F)
• Operating Temperature: -31°F to 113°C
• Dimensions: 12.00 x 17.44 x 4.35 in
• Weight: 22 lb.
• Max Terminal Size: 4 AWG

Any free advice or suggestions on the build? The one controller should handle all four panels right? It does get down towards -20F a few weeks each year.

 

[Crowz]

You could do 2s2p since all in series would put you over the max voltage of that controller.

 

[AmpD]

You could do 2s2p since all in series would put you over the max voltage of that controller.

Thanks for the reply. That would put me @ 100V 28.1A correct? I was mainly looking for the confirmation on that. Much appreciated.

I noticed the Weize Lifepo4 batteries in your sig. I've not committed to a brand there yet. Mostly looking at the SOK for the durability factor in a mobile setup. I had also considered the CloudEnergy 150AH. Both for its prime availability and I would only need 2 for a 15Kw bank. I just wasn't sure of what is cheap versus quality. I saw a vid Will did comparing a few 48v server racks and that is what had me leaning towards the SOK line.

 

[MisterSandals]

Minimum of 10kw likely 15kw bank.

10kWh kilowatt hours (get the units right and the math just works out)

10,000Wh / 2200W solar = 4.5h to charge from empty
2200W / 56V charging = 39A very reasonable!

With 2S2P, you would need a 115V, 40A+ charger. Victron 150/50 works. 5 year warrant mighty nice. Bluetooth setup and monitoring awesome.

 

[Crowz]

Use the "Click here for Solar Panel Calculator" in my signature. Then fill in the panels and amount of them you have. It will then tell you what they will do series and also parallel. You can use the add panel button to add another spot to put panels in to see more combos via paralleling them. I use that thing all the time when configuring my panels. God send. Especially if your mixing panels.

 

[Crowz]

Thanks for the reply. That would put me @ 100V 28.1A correct? I was mainly looking for the confirmation on that. Much appreciated.

I noticed the Weize Lifepo4 batteries in your sig. I've not committed to a brand there yet. Mostly looking at the SOK for the durability factor in a mobile setup. I had also considered the CloudEnergy 150AH. Both for its prime availability and I would only need 2 for a 15Kw bank. I just wasn't sure of what is cheap versus quality. I saw a vid Will did comparing a few 48v server racks and that is what had me leaning towards the SOK line.

Nooo don't use that for battery choices on what your doing. Those batteries are just for my small dc stuff. I don't have batteries on my tp6048 yet so no batteries picked out yet to run my house.

SOK looks good but I can't find them on amazon. I will probably go with either sungolds server rack ones or lvgoo via this link :

https://www.amazon.com/48V-LiFePO4-Battery-Lithium-Off-Grid/dp/B0BTHQZZP3/ref=sr_1_1?crid=DV9IL7V062QO&keywords=lvgoo%2B48v&qid=1683264903&sprefix=lvgoo%2B48v%2Caps%2C134&sr=8-1&ufe=app_do%3Aamzn1.fos.ac578592-0362-4e0a-958c-0f2dd61d30d4&th=1

I really prefer to stay on amazon for my ordering. My blood pressure prefers it.

 

[AmpD]

10kWh kilowatt hours (get the units right and the math just works out)

10,000Wh / 2200W solar = 4.5h to charge from empty
2200W / 56V charging = 39A very reasonable!

With 2S2P, you would need a 115V, 40A+ charger. Victron 150/50 works. 5 year warrant mighty nice. Bluetooth setup and monitoring awesome.

Thanks for the correction.

It sounds like that controller I was looking at while doable is not my best option then eh? If I get brand uniformity out of my head and look for quality and efficiency what are some good options? For example the Victron 250V/60A tr mppt

• Battery Voltage: 12/24/48V Auto Select (software tool needed to select 36V) –– Rated Charge Current: 60A –– Nominal PV Power: 12V-860W, 24V-1720W, 36V-2580W, 48V-3440W –– Max PV short circuit current: 35A –– Max PV open circuit voltage: 250V absolute maximum coldest conditions, 245V start-up and operating at maximum –– Peak Efficiency: 99%

Would that one let me run them all in series for a 200V string and leave room for the temp correction. While even leaving room for an entire second string put in parallel?

Aside from panels I'm open to switching up components. For budget on controller lets stay under $1k please.

@Crowz

Thanks for that link and advice on the batts. I was using VoC and lsc. As for buying I was hoping to get something on that same site. That was another reason I was looking at the cloudenergy 150ah batts. I noticed Weize had some server rack 48v style also. Prime deals are nice when you can find them. So that is the clickbait for not getting the SoK's. If I happen to see something built well on discount there instead.

I was thinking $5K or less on batteries.

 

[MisterSandals]

For example the Victron 250V/60A tr mppt

This is way overkill and spendy.

Is there a reason not to connect 2S2P? It’s quite popular and an easy setup. Just need a pair of Y connectors.

BougeRV Solar Connectors Y Branch Parallel Adapter Cable Wire Plug Tool Kit for Solar Panel https://www.amazon.com/dp/B0753X68PS

 

[AmpD]

This is way overkill and spendy.

Is there a reason not to connect 2S2P? It’s quite popular and an easy setup. Just need a pair of Y connectors.

BougeRV Solar Connectors Y Branch Parallel Adapter Cable Wire Plug Tool Kit for Solar Panel https://www.amazon.com/dp/B0753X68PS

To lower the overall amps and allow room for future expansion. I was also under the impression Parallel involved a combiner box.

Edit: I think I see it now It would limit me to 6x550W panels put into 3s2p wouldn't it. 3300W@48v max cap.

K forgive my ignorance as we educate thru this some more. Was just looking at Max V/A ratings.

Moving forward. Victron 150/45 vs 150/60 I didn't see a 150/50 on the 'zon store. If in the future I wanted to add 2 more panels for a 3300W/hr system I would need the 150/60 correct? I don't see us ever requiring more than that.

Also if price is the same would there be any disadvantage in getting the 250/60? It would allow me to wire all 4 in a series correct? Is there something bad about that instead of going with 2s2p?

 

[MisterSandals]

I think I see it now It would limit me to 6x550W panels put into 3s2p wouldn't it.

You cannot do 3S with a 150V SCC. 3x ~49.95 Voc will be well over 150V just a couple degrees below 25C (77F).

 

[AmpD]

I think I'm getting confused here. The calculator said VmP and lsc. Am I supposed to be adding those or Voc and Imp?

So the 250/60 would handle 3s2p at full wattage 3300W and would handle 4s2p but not allow me to use the extra 1100W based upon it's 48v watt rating at 3440W. The 150/60 could handle 2s3P as well but that would run my cables at a higher amp rating if I follow things.

So if the 2 controllers are same price wouldn't I be better off with the higher V rating or is that somehow going to put inefficiency into the system?

 

[pollenface]

I'm still wanting to go with the 550W renology panels for my build.

Do you mean Renogy?

 

[MisterSandals]

The calculator said VmP and lsc. Am I supposed to be adding those or Voc and Imp?

The panel Vmp, Imp, are the working voltage and current. The Voc and Isc are the maximum volts without a load (like revving you car in neutral) and max current should a short circuit occur.

The Voc is used to calculate max voltage the array can produce so as to not exceed capabilities of the SCC (aka letting the magic smoke out…bad).
So for a 150/50, an array of 150V, with temp compensation) should never be exceeded. For the 250/50, it’s 250V.

The second number in the Victron naming scheme is the max charging amps. The number of watts the SCC can handle bepends on the charge voltage as well.
For a 250/50, it will only charge 50A. If your top charge voltage is 56V (for a “48V” system), then I the handled watts are:
50A x 56V = 2800W
Any available watts that your array is capable of providing will be clipped (ignored, not pulled in from the SCC).
Similarly, the array production potential is Vmp x Imp.

Helpful?

 

[AmpD]

Yes on both accounts. Renogy Panels and MisterSandals is very helpful.

Voc 49.95
lsc 14.05

These are the numbers that I need to see for the charge controller sizing then.

3s2p Total Voc 149.85V (not counting -20F temps) Total lsc 28.1A
2s3p Total Voc 99.9V (again no temp involved yet) Total lsc 42.15A

To be clear we are working with 4 panels to start and planning for 6.

Charge Controller ratings for available Victron controllers.

150/45 Max PV Open Circuit Voltage 150V, Max PV Short Circuit Current 50A, Charge Current 45A

150/60 Max PV OCV 150V, Max PV SCC 50A, CC 60A
250/60 Max PV OCV 250V, Max PV SCC 35A, CC 60A

150/70 Max PV OCV 150V, Max PV SCC 50A, CC 70A
250/70 Max PV OCV 250V, Max PV SCC 35A, CC 70A



I did not comprehend the term "top charge" in reference to 56V on a 48v charge controller so going with 48v on calculations here.

45A * 48V = 2160W/hr
60A * 48V = 2880W/hr
70A * 48V = 3360W/hr

That leaves options of a 150V or 250v controller at 70A for full potential of 6 panels (3300W/hr).

The 150 is 2s3p running 99.9v out of 150v limit and 42.15A out of 50A limit
the 250 is 3s2p running 149.85V out of 250V and 28.1A of the 35A limit

The price point is about the same to me. What I need to decide is what is a most efficient and or safer in the overall system.

The 250 leaves 100v and 6.9 amps until it is maxed
the 150 leaves 50.1v and 7.85 amps until it is maxed

I feel I am I better off running at lower overall amps with the 250 and giving myself more room for temperature extremes on voltage if all this is correct.

Lower amps should give less loss/heat and better conductivity in the system right?

Edit: Thermal info located.

Operational Range -40C to 85C
NOCT 45C
Temp. Coefficient of Pmax -0.35%/C
Temp. Coefficient of Voc -0.28%/C
Temp. Coefficient of lsc 0.05%/C

 

[MisterSandals]

I did not comprehend the term "top charge" in reference to 56V on a 48v charge controller

48V is mostly a marketing term.
LiFePO4 cells are 3.2v
16 x 3.2V = 51.2V nominal
LiFePO4 can charge to 3.65V per cell. I was using a conservative charge voltage of
56V / 16 cells = 3.5V per cell.

So if you have a 50A SCC, the watts it can process are roughly:

50A x 56V = 2800W

 

[AmpD]

Can someone explain to me what they mean by:

"145V start-up and operating at maximum" on a 150v rated Victron controller?

I saw in the safety section of the pdf it says:
"1a) If more PV power is connected, the controller will limit input power.
1b) The PV voltage must exceed Vbat + 5V for the controller to start. Thereafter the minimum PV voltage is Vbat + 1V"

I would interpret all this to mean that I need at least 145V for the 150/70 to function and that the voltage my array is putting out must be higher than my 48v battery bank. It also seems that the controller would limit anything over 150v to 150v so that the controller isn't damaged.

From what I understand if i wire multiple panels in series with the 250/70 controller then I am more prone to shading losses than if I had multiple sets of parallel panels. I have been considering a 2s2p with a 2s3p future plan. The 150/70 is rated up to 50A for the input current 2s3P would put me around 100v at 42A.

I'm not certain if the "145v start-up" requirement would prevent the controller from functioning or if 42 amps will cause wiring issues. Mr. Sandals already said I should look at the Victron 150 so I'm guessing I missed something here. I just don't know what.

Comments and guidance always welcome.

 

[MisterSandals]

I would interpret all this to mean that I need at least 145V for the 150/70 to functio

That doesn’t sound right. Can you cut and paste the paragraph or context?

 

[AmpD]

'zon website

Battery Voltage: 12/24/48V Auto Select (software tool needed to select 36V) –– Rated Charge Current: 70A –– Nominal PV Power: 12V-1000W, 24V-2000W, 36V-3000W, 48V-4000W –– Max PV short circuit current: 50A –– Max PV open circuit voltage: 150V absolute maximum coldest conditions, 145V start-up and operating at maximum –– Peak Efficiency: 98%

in this victron pdf too.

 

[MisterSandals]

145V start-up and operating at maximum

Looks like poor wording. Thats the max voltage for startup and operating.

Burried at the bottom:

 

[AmpD]

I did a strike thru on the text so other noobs won't get the wrong idea like I did.

It didn't make sense to me either so I thought I better ask. Thank you for clarifying it. I had been looking at the multiplus II. One of the vids mentioned it's minimum voltage requirement so I thought I would look into the other two controllers requirements.

I appreciate you putting me on the Victron path. I've always felt spending a little extra on quality pays off in the end and I've always liked blue!

 

[AmpD]

Next question. If I parallel 2 panels I get 28.01 lsc. The MC4 is rated at 30A. This doesn't include temperature corrections.

If I put all the panels individually into a 4 string combiner box will this put them in a parallel output without using branch connectors or will the resulting output be as if they were in series?

So basically I'm asking will a combiner box with 4 panels each plugged in as their own separate string gives me:

199.8 voc at 14.05 lsc

or

49.95 voc at 56.2 lsc

or

Something else?

I saw a thread on it when searching for the answer but the end of it got muddled up so I want to make sure I understood correctly. It multiplies the amps in the combiner box when you run the strings in correct?

If I did understand correctly then if I for example put 2 strings of 2 panels in series then it would look like:

99.9voc 14.05 lsc. for each string going into the box from the PV. Then 99.9 voc and 28.1 lsc coming from the combiner box to the controller.

 

[MisterSandals]

If I put all the panels individually into a 4 string combiner box will this put them in a parallel output without using branch connectors or will the resulting output be as if they were in series?

The whole point of combiner boxes is combining strings in parallel.

49.95 voc at 56.2 lsc

This is 4P from combining 4 in parallel. I think i'd look at 2S2P to keep the amps more reasonable, unless you had shading issues on all 4 panels.

99.9voc 14.05 lsc. for each string going into the box from the PV. Then 99.9 voc and 28.1 lsc coming from the combiner box to the controller.

Yes

 

[AmpD]

Again my thanks Mr. Sandals. As a beginner that was a confusing part of the system. I saw videos explaining the electrical path thru the box and components but not how the amps and volts are translated from input to output at the box. I suspected this was the unicorn I needed to get the 2s2p action going on. I really appreciate your confirmation.

 

[MisterSandals]

I suspected this was the unicorn I needed to get the 2s2p action going on.

To get the 2S part, take 2 panels, connect the (+) of 1 panel to the (-) of the other. That is a 2S string.
Do this with your 2 other panels. That is also 2S (2 in series).
Next you need to connect these strings in parallel.
The easiest is with a simple pair of MC4 Y connectors:

https://www.amazon.com/BougeRV-Connectors-Branch-Parallel-Adapter/dp/B0753X68PS/

This connects each of your 2S strings' (+) together and the (-) together, in parallel for 2P.
Your panels are now 2S2P.

You don't really "need" a combiner box for 28A. The fuses and breakers are nice, especially as a cutoff switch. You will want something as a cutoff switch for convenience.

Good luck!

 

[AmpD]

You don't really "need" a combiner box for 28A. The fuses and breakers are nice, especially as a cutoff switch. You will want something as a cutoff switch for convenience.

Good luck!

Thanks for clarifying that. I was worried about being so close to the wire's amp rating. Breakers and fuses will also be nice to have in place. I was under the impression that some kind of cutoff between panels and controller was a necessity. The maximum series fuse rating is 25A so I thought I would definitely need fuses in place as well.