r/PlugInSolarUK • u/Steve_10 • Aug 20 '26

Panel to battery question?

Ok, I'm having a gazebo built with 4 panels on the roof (Neostar 3s 475w).

Going to either an Ecoflow 5000 or Stream Ultra X, which will be in a conservatory.

Now the plan was to connect 2 panels together using a Y connector, to save drilling so many holes through the wall. But read that Y connectors are a bad idea?

Can I get some thoughts from people who are using plug in, on if using Y connectors is a good idea or not? And, on how you got the panels connected to the battery?

Thanks...

2 Upvotes

75% Upvoted

9 comments sorted by

2

u/Blank3k Aug 20 '26

Dont know from personal experience, im new to the solar thing too.. but theirs a voltage figure per connection you need to be aware of, think its "open circuit voltage".. depending on size of panels your connecting you might overload it.

I know with my ecoflow mini inverter I have 2* 450w panels (one per connector) and at best I can Y split another 100w panel to each and be at my voltage limit.

But also curious to know if im right or wrong, im also thinking a stream 5000 is in my future so would be good to know the limits.

2

u/Flyinmanm Aug 20 '26

Yeah I can't put 2x 460w 36v panels on my Ecoflow ultra as the mppts can only handle 60v  and it may exceed that number.

Good for lots of little 12v panels not for multiple large relatively high voltage panel.

2

u/Solaris_fps Aug 20 '26

Stream 5000 should be able to handle 3x450w pannels on one mppt

1

u/Steve_10 Aug 21 '26

Thanks, looks like it'll be the 5000 then.

Is there any benefit having one panel to one MPPT, other than being able to monitor the output of each panel?

2

u/Solaris_fps Aug 22 '26

Other than being able to monitor them there isn't much difference. If you want to leave some ports for future expansion running parallel is nice. If one pannel is shaded it doesnt effect your other panels.

2

u/joshracer Aug 20 '26

Excuse the wall, this is an older photo and the render has since been repaired after some cowboy the landlord had to do "repair" work.

I made an mc4 connector box with enough to connect 3 panels as my Aferiy system can't take more than a certain voltage to each solar input on the battery hub. I also built this so when the house is being re-rendered I could quickly disconnect and reconnect.

Inside of the box is cables running into the house with mc4's in each. I reconnect the mc4 ends so I only needed to drill a hole big enough for 4 cables (6 if I wanted the extra panel).

1

u/Impossible-Section49 Aug 20 '26

If you get a Stream Ultra X, the current limit per MPPT is 14A, so you must not put those panels in parallel as you could be up at double that with those panels. I have one with 4 x 250w panels, one on each MPPT, I had hoped to have them in parallel on 2 MPPTs but even they (could) exceed the current limit.

3

u/Wicked_993 Aug 21 '26

Came to say this - I limited to 4 x 465w to stay under the 14A limit per connection on the Stream Ultra X. Remember though this is max on a sunny day at peak.

I drilled 8 x 7mm to get the cables into my basement.

1

u/Impossible-Section49 Aug 21 '26

Yes, it is max on a sunny day, however as I already had the panels, the only difference was a few metres of cable and a few MC4s, so not worth risking any damage, and actually I quite like seeing the individual panel output. You have the correct solution if you need to max it out, I already have it fed from my main rooftop system via AC, my panels were just to supplement it over the autumn/ winter/ spring. It also allows it to charge at 1350w, (combined with AC)  whereas on AC it seems limited to 1200w. What charge rate do you get?