pv input

robocop · January 14

Hi
mppt controller input is 150v and have 3 panels of 48v 500w each in parellel total is 144v .(3x48v)
Is it ok or too risky

Bob

JRHill · January 14

robocop said:

Hi
mppt controller input is 150v and have 3 panels of 48v 500w each in parellel total is 144v .(3x48v)
Is it ok or too risky

Bob

Mr. Bob, please put your hardware list in your signature line. there is about no way to answer your question.

BB. · January 15

Bob, it is "close"... The system is installed in the southern Caribbean sea off the coast of Venezuela (as I recall).

Curaçao island, West Indies

Your minimum temperature is around 68F (20C)? The Voc/Isc/Vmp/Imp are based on 25C spec sheet rated panel temperature.

What is the panel rating of 48 volts--Is that Voc or Vmp @ 25C?

If that is 48 volts Vmp--Then 3 panels in series would be >150 Volts (Voc-array-cold) as Vmp is lower voltage than Voc (voltage open circuit.

If that 48 volts is Voc-panel-std -- You might not exceed 150 VDC Voc-array-cold for your area (Voc and Vmp array rise as temperatures drop below 25C).

A 3*48volt Voc series array would reach ~146.4 volts Voc-array-cold using this array calculator:

https://www.midnitesolar.com/sizingTool/index.php

It is close--But could work OK. However, if some weird cold front moves through your place several years down the road--All bets are off.

-Bill

littleharbor2 · January 15

As BB mentioned, the correct term is SERIES, not parallel. In parallel the voltage doesn't add, the current (amps) does.

robocop · January 27

Hi especially for Bill you were right I gave wrong details the voc is 58.95 NOT 48v this is the vmp .
so has to put only 2 panel in series . So if use panel has to combine 2S3P .
now only look for a photo with combination to illustrate how to combine.
again I am thankful for your advice .

littleharbor2 · January 27

Typical Combiner box. Often installed near the PV array. Strings in, one pair of larger wire out

Image: https://us.v-cdn.net/6024911/uploads/editor/hg/dtl61dsf31f3.jpg

BB. · January 27

Think of the combiner box as very similar to a standard power panel (main power in, multiple branch circuits out)... However the combiner box is just multiple solar panels in, and the "main power" out to the input of the MPPT charge controller.

MidniteSolar (supplier to our host Northern Arizona Wind & Sun / NAZ) has quite a few documents & videos on their products... For example:

https://midnitesolar.com/productPhoto.php?product_ID=77&productCat_ID=9&sortOrder=5&act=p

Also--Think about lightning protection (surge suppressors) if that is an issue for you(?). Mostly, you want to keep the lightning energy outside of your home (to the best of your ability/design).

-Bill

robocop · January 27

thanks for your advice of the combiner box BUT I meant how to wiring the 5 solar panels in 2 serial and 3 parallel (2S3P).

best regards
Bob

BB. · January 27

You cannot... Your options are:

2s*2p (4 panels only, one "unused" panel)
2s*3p (6 panels, purchase one more)
1s*5p (5 panels, only if the battery bank is 12 or 24 volts--Not high enough voltage for 48 volt bank)

There are other options such as 2s*1p (2 panels) on your present charge controller, and purchase a 2nd "higher voltage" 3s*1p (other 3 panels).

Or purchase a much higher rated array voltage controller and run a 5s*1p array (5 panels total).

Or am I "not understanding" your question?

-Bill

robocop · January 27

Yes yes Bil thank you understood and thnks for your time.

Bob

pv input

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