4 replies to this topic

[Jollyrogers]

So I have a renogy portable 200w panel w/ 25ft 8ga extension I plug into back SAE that goes to a VE MPPT. Occasionally the MPPT would not start charging due to voltage differences <5vdc. So, I rewired my Renogy suitcase in series, and now get 36vdc to MPPT and have good production.

I just bought 2x100w for the roof, same voltages. I’m planning on wiring them in series, and then parallel with my suitcase input at the MPPT.

Can I expect the same output still from my suitcase if my roof is shaded?

Edited by Jollyrogers, 02 September 2023 - 02:27 PM.

[Vic Harder]

In theory, yes. Can the mppt handle the combined power output, should there be no shade? When I was first starting out with solar, my Victron 75/15 did not like having more than its rated max power coming in… it would shut down requiring a full disconnect from all power sources before it would reboot. Inconvenient.

[Jollyrogers]

In theory, yes. Can the mppt handle the combined power output, should there be no shade? When I was first starting out with solar, my Victron 75/15 did not like having more than its rated max power coming in… it would shut down requiring a full disconnect from all power sources before it would reboot. Inconvenient.

Vic, thanks for the reply. I know it may have sounded newbie. I am to solar, but not parallel/series or DC circuits. I have 37 years as a radar tech. I was hoping for real world experience.

In theory, I agree. In shade my roof should still make the voltage, just no current, and my suitcase in the sun would still produce. If it doesn’t work I can add another disconnect for the roof.

My MPPT is a 100/30, it should handle it if by some reason I actually made 400w, which I never expect. I think with my roof/suitcase combo I’ll probable manage 300-350w at best in the area I live and camp.

Panels are on. Will wire it in AM and test it out as a system. They did out perform my suitcase when tested and tilting towards sun.

[Jon R]

I have two 200 watt Renogy rigid panels wired in parallel feeding my Smart MPPT 100/30. They are fixed flat on my camper roof, and have at times been in full July sun at 45 degrees latitude. I’ve seen charging currents of between 29 and 30 amps at times with around 370 watts showing as the panel output on my BMV-712. At no point has the 100/30 misbehaved with my 400 watts of panels.

Edited by Jon R, 03 September 2023 - 02:24 PM.

[Jollyrogers]

Just finished wiring it up and testing it, shading the roof and then un-shading it, and shading/un-shading the portable panels. It’s working as I would hope, though my roof doesn’t perform as well laying flat with morning sun. What was cool, is I was getting voltage output and a small charge in total shade early this morning.

I do plan to replace the roof pass thru to something better than that SAE connector!

Edited by Jollyrogers, 03 September 2023 - 02:40 PM.