Victron 150/35 mppt parallel string question

Inverters
1

This is my first time hooking up a Victron 150/35 mppt, client has six 315 watt panels, Voc 41.95 and Isc 9.8A.
The inverter/charger is a 12 volt system, connected to 2X200Ah in parallel.
Can the strings be set up as 3S2P or is the mppt limited to one string because the output is 12 volt

2

Use this: MPPT Calculator - Victron Energy

Custom panel, then you can mix and match for a fact.

3

Thanks, looks like I was way off base.

4

I am all for pushing an MPPT to its limits.
In my empirical testing, (with off-orientations, dirty panels and non-ideal slopes) would suggest 150% -200% is the way to go.
That said the voltage limit must always be adhered to.
In this case, you have 6 x 315Wmpp of panels available. (1890wmpp)
The limitation of this system is that it is 12V, call it a charging voltage from the MPPT of 14V.
But the MPPT’s output current maximum is 35A.
So the maximum power the MPPT is limited to is 14V x 35A = 490W.
So even given my liberal take on overpanelling, 3 panels in series would be my best practice. (945Wmpp)
The other 3 panels are surplus and will only contribute a negligible amount due to the bottleneck effect a 12v inverter has on the MPPT output.

2 Likes
5

Client actually bought two 150/35 and one 150/45, he was thinking of using two panels each. Not being used to Victron, thought all six using a 3S2P, however, @Phil.g00 , based on what you suggested, I could use one 45A and one 35A mppt, cutting down on breakers/fuses/wiring,etc.
Hopefully, the client bought the three mppt’s at a give away price, as all the other stuff and labor will add up.

1 Like
6

Or go 48v … I’ve been 12v adamant many many years ago … till I ran into the exact same issue.

Vehicle, always 12v.

House/backup, 48v.

7

Your client could do this.
However, I assume his batteries are LA. which means they won’t last long.
So use what you’ve got, but when it gets around to replacing batteries then take @TheTerribleTriplet 's advice and upgrade to 48V.

8

Attaboy! I like the cut of your jib!
PS: Just mount them in a cool place with adequate ventillation…

9

Mine works so hard I bought a fan for warm summer months to force cool it. It sommer cools the area, the inverter too … :innocent: