mpc avatar image
mpc asked

Optimal setup (parralel- in series???) and expert advice wanted!

Hi members,

I've got a question which may be simple for the most of you, but i want to be sure to hook my system up right before switching it on.

Components: Easysolar 48/5000/70-100 MPPT150/100
Panels: LG Neon2 N1K-V5 320Wp X 4
BYD Bbox 7.5 KWh

Question no.1 : do i need to wire the panels in series or parallel?
2: do i need to put any fuses between panels and inverter or inverter and batteries?

Any other indispensable tips to take into account?



wiringfusesbattery system voltage
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2 Answers
JohnC avatar image
JohnC answered ·

Hi Marcel. Firstly, "Expert: A man who makes three correct guesses consecutively" (Laurence J Peter).

My guesses:

Q1. Cool looking panels. The 150/ designation of your mppt determines the max length of your pv strings by using the Voc rating of your panel. Google tells me 40.8Voc, so 4x is too many, 3x ideal, but for you it's 2x per string. So 2S2P for your pv wiring. 2x the panel 33.3Vmp for 48V batts is fine.

Q2. Pv to Easy needs an isolator & fuse, or a dc breaker. I'd go a double-pole Noark type, maybe 30A. Google it.

The 150/100 I think has an internal 200A fuse for it's output in the Easy, but that's just to the big wire terminals that head off to the batts. Not sure what the BYD has onboard, but it's always nice to have an isolator, & fuse in between to protect those big (70mm2?) wires.

For 'indispensable tips', download Margreet's new book here:

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mpc avatar image
mpc answered ·

Hi John,

Thanks for clearing that up. I looked a little more into the methods and voltage/ampere/wattage stuff.
So according to the attached diagram i will have the following input in my MPPT: 81.6 Volts and about 16 Ampere. So about 1.300 Watts. Right?

About the circuit breaker, have to look for another, NOARK is not easy to get here online in Spain. So a 30A ABB or Eaton will do as well i guess.

Thanks again for all the tips, and if i'm stuck i know where to find you ;)


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JohnC avatar image JohnC ♦ commented ·

"Right?". Not exactly. Use Vmp and Imp for production conditions. My google says 33.3V and 9.62A. Multiplied together gives 320W, your panel rating.

2S string gives 66.6V, same A. 2S2P gives same V, double A, so 19.2A. I picked a 30A dc breaker for some 'headroom', and your Victron supplier may have suitable kit off-the-shelf, or could suggest a local supplier of such.

30A is nothing to sneeze at though, so don't undersize your wires.

And, oh. I use an Easy 5000 myself. Love it.. :)

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mpc avatar image mpc commented ·

Hi John, thanks for your answer. So the 2S2P scheme is the right connection method though?

I already ordered 6mm cable with the panels. Panels are 30 metres from the inverter.

I got the following CB:

Using the 5000 yourself, OK then i'm talking to an expert ;)

Thanks again,


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JohnC avatar image JohnC ♦ mpc commented ·

2S2P is correct, just like your diagram.

30m is quite a distance, but the 6mm2 wire is the max MC4 connectors are designed for, and typical of what domestic installers would supply (if it's proper solar wire).

Your ZJ Beny is a high end isolator, but it's not a breaker as such. In Australia, they are mandatory on domestic panels, designed for firefighters to jump up there on the roof and isolate the pv, ha! Weatherproof, but a little 'sunshade' is usually installed for them.

Note the high V-rating for the longer strings of ac-coupled-grid-tied inverters. Added fuses would be nice, but I don't think even the certified domestic stuff install them anyway.

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mpc avatar image mpc JohnC ♦ commented ·

Thanks again John, i'm gonna wait for my panels and batteries to arrive and hopefully next week i can install them.

I'll Keep you updated!


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