Is it a problem using only one side of solar “Y” connector?

[dstefan]

I have a 100 AH Battleborn LFP for my house battery in a National Luna portable power pack. The battery is charged through the packs DC/DC charger from my alternator. I hook a portable 100 W panel to top-off the system in camp when needed. My camper shell has two windoors, so currently I can run the portable panel PV cable through either side to the power pack and plug it in just by reaching inside.

However, I’m making some changes that will make reaching the power pack much harder, and I want to hard wire a Y plug-in to the MPPT controller in the power pack so that I can plug in with a plug mounted at each windoor (inside the door) rather than fumbling around under the cabinet I’m building to connect it.

The wiring to do this is is not a problem. Its a simple Y junction. My question is that since I’m running only one portable panel at a time and one side of the Y connection will be open at any given time the panel is being used is that a problem? It feels like its an open circuit somehow. I can do the wiring and know the basics, but am nowhere near versed enough in solar electronics to know if this will cause any problem in charging, voltage drop, etc. BTW the connectors will be 50amp Anderson plugs since thats how the Powerpack is set up and my portable solar panel cable terminates in an Anderson plug.

Is this OK to do? Thanks for checking me on this!

 

[clydeps]

I'm a bit confused about what you are doing (and I've never heard the term windoor before, though I assume it's some kind of a cross between a window and a door) but if you are suggesting that you install a y-cable with one branch left unconnected most of the time, and then you will plug into that with an extra solar panel when it suits you, that would work just fine.

 

[ripperj]

There would be no electrical issue, I would try and find a cover of some kind to prevent dirt and corrosion for getting in.


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[dstefan]

Windoor = hatch. See avatar thumbnail.

Thanks guys. Thats what I was hoping/thinking when I came up with my scheme.

 

[dfinn]

Assuming your Y plugs use MC4 connectors you could get some of these to cap them:

MC4 Terminator Caps (1 pair) - e Marine Systems

Pair of caps for MC-4 type connectors (1 male, 1 female). Protects from weather and dirt, enables safe winter storage for solar panels. - #EPE54506A MC-4 Terminator Caps (1 Pair)

www.emarineinc.com

Also assuming these are MC4 connectors I don't think it's too risky to just leave them as is, maybe with some electrical tape over them. I don't think you would even be able to accidentally short them since they are male/female type connectors and require plugging in to make contact.

 

[dstefan]

Actually, they will be Anderson SB50 connectors. Thats what the Powerpack uses and my portable solar panel cable to the Powerpack has already has already been converted to match. I do have cover caps for them. They will be mounted inside the camper near the side hatches.

 

[dfinn]

Inside and with caps on, I don't think you have anything to worry about.

 

[Mccaf]

So, a while back I was in the same situation-creating a “Y” junction with SB50s. This was my experience:

I tried putting 2 10ga wires into a 6ga terminals as recommended by a guy at Powerx because thats the next size terminal that would fit 2 wires. (The 10ga wires each ran to a different panel). I used my dedicated crimp tool from Powerx and it worked for a while but they eventually pulled out from reconnections. I ended up going another route as I didn’t trust the cheapo crimper or -my crimping skills- to re try…

I am using 2 panels, a 100w and an 80w. The 80 is roof top tent mounted and is primarily for a trickle charge when the trailer is not being used. So my SB50s sit in my nose box -uncovered, but Powerx makes a couple different covers, and yes that is fine for connection to your solar controller.

Uncovered or unused solar leads will not bother anything that I can think of in this application. As mentioned above, get some covers. I plan on it-like this: Dust cover

Per one of the solar guru’s on this forum:
“Don’t run 2 sizes of panel off the same controller at the same time or you will only generate the lower panels wattage”

 

[vtsoundman]

Per one of the solar guru’s on this forum:
“Don’t run 2 sizes of panel off the same controller at the same time or you will only generate the lower panels wattage”

Not a correct statement - not even close...the actual answer lies in the details.

Panels, with similar/same Voltage characteristics placed in parallel will have no idea there is another 50W or 150w or whatever sized panel on the circuit (or if there is 1500W of panels in parallel)...solar controllers, MPPT or PWM vary voltage to control the overall power, not current.

Panels with similar/same Current characteristics placed in series, have no idea whether there is one more or ten more panels connected...for the same reason.

Placing mismatched panels in parallel or series depends on their voltage and current characteristics - and then if those fundamental items are not optimal, is a weighted average of the two, not just a flat lower operating limit.

The above principles are how 10s to 100s of GW worth of solar systems are built...large and small. Operational differences develop (shading, soiling, etc).

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