2s2p expansion configuration for epever

[frankz66]

Hello everyone, at the moment I have 4 180watt 12v panels in 2s2p configuration. My epever 4210an supports a maximum voc of 100 volts , which is currently not reached by my configuration which is around 43 volts and 18 amps . Think, if I buy 2 more panels and add them to the existing four or they will be 3s2p if I'm not mistaken, increasing a voc of another 23.2 (those reported in the panel), for a total of 43volts + 23 to get to 70 volts and a little more but with 27 amps. Can it be done with my Epever 4210AN getting even more power or is it stupid what I wrote? Thank you

 

[Rednecktek]

Yup, you've got the basic idea and your 3s2p at 70ish volts is just fine.

 

[frankz66]

Yup, you've got the basic idea and your 3s2p at 70ish volts is just fine.

Hello and thank you for answering . I'm just asking you, currently my epever with the current 2s2p configuration so 43 volts and 18 nominal amps, has managed to give me 620 watts in some conditions and 42 amps towards the batteries at 14.40 charge. The reason why I would like to expand, aware that the SCC will always give the charge at 540 watts 12v (reported in the controller table), is to have in the morning and in the afternoon more power to give to the batteries. Do you think it's money spent well? Will I benefit from it? Thanks a lot

 

[Rednecktek]

It might buy you a little more power under cloudy or lower light conditions, but you're already over-paneling that 40a SCC as it is by 20% or so, you'd probably be better off to get another SCC and add panels to it. Fortunately the SCC's won't care if there are 2 or 10 strapped to the batteries, they'll work independently of each other.

The rule of thumb I like to use is 10a of SCC per 100w of panel @ 12v nominal, so if you were to try to use 6 of those 180w panels you'd need 6*180=1080w or a 100a SCC. More exact numbers would be 1080w / 14.4v = 75a of SCC to really utilize those 6 panels.

Optimum would be either an 80a SCC for 6 panels or get another 40a SCC and 2 panels and do a 3s on each controller. You could face one string SE for morning sun and the other SW for afternoon sun if you wanted that wider production time.

In short, adding more panels to an already maxed out SCC is a waste of money.

 

[pollenface]

I have a 4210AN with 750w attached @ 66-70voc, it works a treat.

 

[Rednecktek]

He'll be fine.

I have a 4210AN with 750w attached @ 66-70voc, it works a treat.

Oh, it'll work, but he's already over-paneled and getting clipping so adding more panels that will just be clipped just doesn't make sense.

Not saying it won't work, just that it won't gain him anything.

 

[pollenface]

Unless it's a rainy day

 

[frankz66]

It might buy you a little more power under cloudy or lower light conditions, but you're already over-paneling that 40a SCC as it is by 20% or so, you'd probably be better off to get another SCC and add panels to it. Fortunately the SCC's won't care if there are 2 or 10 strapped to the batteries, they'll work independently of each other.

The rule of thumb I like to use is 10a of SCC per 100w of panel @ 12v nominal, so if you were to try to use 6 of those 180w panels you'd need 6*180=1080w or a 100a SCC. More exact numbers would be 1080w / 14.4v = 75a of SCC to really utilize those 6 panels.

Optimum would be either an 80a SCC for 6 panels or get another 40a SCC and 2 panels and do a 3s on each controller. You could face one string SE for morning sun and the other SW for afternoon sun if you wanted that wider production time.

In short, adding more panels to an already maxed out SCC is a waste of money.

Yes, I understand, would I certainly have better and better performance in adverse weather conditions or not? Clearly what he writes is correct but I could at the moment give an extra boost in the morning and in the late afternoon and later think about selling my epever for a more powerful model. What do you think if I invest like this at the moment?

 

[frankz66]

ust that it won't gain him anything.

Sorry but in the morning in the early hours shouldn't I push harder or not?

 

[pollenface]

Clearly what he writes is correct but I could at the moment give an extra boost in the morning and in the late afternoon

Thumbs up from me ?

That's the benefit of over panelling.

 

[frankz66]

Thumbs up from me ?

That's the benefit of over panelling.

Yes poll, in fact as Red writes it is technically correct. It would be like having a fast car but with limits on the road! In fact at the moment I would think this is a start to optimize in the morning and afternoon. Then I'll think about selling my 4210 and buying at least the 60 A . Always beginner's mistakes I made !!!

 

[Rednecktek]

Not really. Let's do a little napkin math...

Right now you have 4x 180w panels which could produce 720w of power. Your SCC is a 40a unit at 14.4v which maxes out at 576w of power. 720w - 576w = 144w of power your system could produce but you can't use. In an average of 4 hours of good sunlight that's 144*4=576Wh of power sitting on the table, almost half of a 100Ah battery. If you spent the money on 2 more 180w panels you might see another 40w or so until that 40a limit started becoming a factor which for a couple hours of low light means maybe 120wh of extra power from those 2 180w panels.

Now, unless you're getting those panels super cheap, you can spend $240 on a 60a EPEver unit which would cap out at 60a * 14.4v = 864w of power from the panels you already have. That's your full 720w of panel, and over a 4 hour "Good Sun" period gets you 720w * 4hr = 2880Wh per day to your batteries, or almost 300Ah of battery. That right there is almost like getting a whole free panel.

In the future, and finances permitting, you could add in another pair of panels and get 180w * 6 = 1080w / 14.4v = 75a of charging which would max out your new SCC but also pick up that earlier morning and later day sun because of the higher operating voltages of the 3s strings.

Given the choice, and it does matter how much the panels cost, I'd spend the money on a bigger SCC for 2880Wh of production than another pair of panels that are only going to get you very few watts and then be useless most of the day.

But that's just me. Early morning and late evening I've seen panels that just barely reach working voltage still not have enough to create any meaningful amperage.

Always beginner's mistakes I made !!!

At least you can come here and ask and learn, I started before this forum existed and have spent a LOT of money and headache trying to figure this stuff all out. ?

 

[littleharbor2]

Generally speaking, by going 3S to the SE and 3S SW The over paneling is somewhat mitigated as you will never get full current from all the panels at any time. The larger, 60 - 80 amp controller would clearly harvest more power. Time to adjust battery bank size.