how to connect different pv with different WP and mppt point to my solar set?

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ropski asked Oct 17, '20

how to connect different pv with different WP and mppt point to my solar set?

Hi all, I'm new here and looking for some answers....

I'm currently using 2 solar sets for my house truck.

The first set is my household set, currently one pv combination (3x monocristal 210Wp parallel connected) which is connected to mppt 100-50 also with 4 new agm batteries 24v parallel 145Ah each battery. I have victron inverter 24v500W and all guarded by my BMV (with apps for bmv,mppt 2x, and inverter) also I connected directly to the batteries a cheap nonsinus inverter (chinese) of 1500W (i have 230VAC fridge 150W which needed some more peakpower).

My second set is a seperate victron set for my lead - start batteries. 2 panels with 75-15 victron mppt loading start batteries ( they only use drop load, since batteries stays almost full.. its a bit overdone, but want always to be able to drive when needed).

When turned one the generator/AC from the net, I use a victron centaur 30A 24v to charge my household batteries and a 10A 24v mastervolt charger to charge start batteries.

I'm here at this forum because I want to figure out how its possible to use 2 or 3 DIFFERENT sets of pv (perhaps connected to a new easysolar 24v 1600VA, co combine all the seperate parts into one. BUT, the 2nd and 3rd PV set will be another type of panel with different mppt point and Wp..

So my first question is to figure out, how to use max. capacity of solar panels in different sets, connected to a MPPT, or easySolar. My dream solution is to use 3 different pv sets,connected to a Easysolar, which load both household set and (dropload) my startbattery. I want to ask you guys if this would work and if that means that my victron centaur, my existing mppt 100-50 and my mppt 75-15 become obsolete.

What I already found out here is that each input on the easy solar is protected 30A. But what happens between the 30A connections and the mppt? are the cables just connected together in 1 PV connection at the internal mppt from the easysolar and does this give space for different pv sets?

And second question, is it harmfull that i put a second nonsinus inverter directly to my batteries? The batteries are almost new (bought last summer) and i don't want to destroy them. but i realise with almost no sun, the batteries run empty in 2 days.. which is too fast..

i hope my question is a bit clear and hope to find some tips and tricks to tackle this problem!

thanks already! Ropski. :)

EasySolar All-in-One AC PV Coupling mppt charging

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Answer 1 · 2020-10-17T07:43:25Z

Matthias Lange - DE answered · Oct 17, 2020 at 07:43 AM

It is not recommended to connect different PV arrays (different panel sizes, different series/parallel configurations) together to one MPPT that will decrease the performance.
You should use one MPPT for each array.

The MC4 connections at the EasySolay are not protected at 30A they are rated for max. 30A.
The 3 sets of MC4 connectors are connected together on the inside.

You can connect another inverter to the battery but this drain you batteries even more!?

I guess the truck starter battery is 24V?
In that case the easiest solution would be to install a cyrix-ct between the stater battery and the household battery.

https://www.victronenergy.com/battery-isolators-and-combiners/cyrix-battery-combiners

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Answer 2 · 2020-10-17T07:51:14Z

wkirby answered · Oct 17, 2020 at 07:51 AM

The three inputs in the EasySolar are all combined. You should not mix different solar arrays here.
It would be ideal to keep you 100/50 amd 75/15 to separate the different arrays into their own controller. The third controller of course will be the one inside the EasySolar.

The EasySolar can charge at 40A. If that is enough, then maybe the Centaur would be obsolete.

The EasySolar should be able to power your fridge, so then you could eliminate the cheap inverter.

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Answer 3 · 2020-10-17T08:32:36Z

ropski answered · Oct 17, 2020 at 08:32 AM

the cyrix is a really good idea! I'm gonna do that.

I'm still doubting, whether to buy a mppt 100-30/100-50for the new PVset or an easysolar.

the centaur IS functioning, but it would be awesome to sometimes have 16A in the truck (when connected to main net) (which the easysolar provides)

the cheap inverter i need to measure how much watts it consumes first. maybe it's not all that bad.... (24w when standby just like the victron inverter)

Moneywise (which is also important!) there's some BIG differences between the options.. and i want to invest wisely but have not the possibility to go all the way i fear ...

So another question;

can i just add up all the plus cables from different MMPT's/easysolar to the plus connection? Or do i need to make A 'common plus' like i did with the minus on my other pole (i made a common block which goes to the battery)

It starts to look like spaghetti a little bit (do i need a sort of regulator, or something like that, that connects 1 cable to the battery. since i have 4 batteries, 2x24v parrallel, now both plusses from each 24v set is used a bit to 'spread' the load a bit.. but maybe this needs to be done differently??

thanks already for the swift replies :) <3

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Matthias Lange - DE ♦ commented · Oct 17, 2020 at 08:58 AM

Take a look at the "Wiring Unlimited" book:
https://www.victronenergy.com/support-and-downloads/technical-information
(it is also available in some other languages, just change the language of the website)

Chapter 3 and 4 are about wiring batteries.

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