Solar Installation Details

[DavidM]

I finally got to see my friend John's solar installation which I helped him with by long distance. It is a two flexible panel installation: two 175 watt 12V nominal panels wired in series and connected to a Blue Sky controller with 50' of MC4 cables.

The first pic shows the panels laying in the gravel about 10' in front of his coach. That is a spot that gets sun most of the day.

The MC4 cables are connected to the coach with an MC4 to "Zamp" plug adapter and socket shown in the second pic. I put Zamp in quotes because the connector meets an ASTM standard and lots of people sell them much cheaper than Zamp, but Zamp is the name most are familiar with.

The third pic shows the incoming cable connected to the Blue Sky controller (with its cover off) and then to the house batteries.

The fourth pic is at another campsite that is shady over the coach but sunny about 30' away. That is the main reason to install portable panels- you can put them in sunny spots and move them as the day progresses.

This system cost about $700 for panels, cable, connectors and controller. The flexible panels are thin and light. I was somewhat disappointed with their output though. The 350 watts of panels were producing 150 watts actual with the sun at 11:00AM at maybe a 30 degree from vertical angle. That should have resulted in at about 250 watts. Such is the problem with flexible panels they don't meet their output specs.

But John is quite happy with the overall performance. He should get at least 50 AH if the sun holds out all day which will easily keep his batteries charged.

David

[Merlin]

Thanks for the pics and info. That does seem really low for output.....less than half of the rating. Were the batteries already charged? Is the controller rated for at least 30A? Was it hazy or full sun? Were both panels working? Are those Renogy panels?

[DavidM]

See answers in original text:

Thanks for the pics and info. That does seem really low for output.....less than half of the rating. Were the batteries already charged?

The batteries were pretty well charged, but the controller was in bulk mode. I measured 11.5 A at 13.2 V. The batteries are 300 AH total.

Is the controller rated for at least 30A? The controller is rated for 45A.

Was it hazy or full sun? The sun was a bit hazy.

Were both panels working? These were two nominal 12v panels wired in series and the controller was seeing 33v. Didn't measure their individual current output. Will do in a few days.

Are those Renogy panels? Not Renogy, not sure whose. Will check.

David

[Merlin]

Well, it sounds like you covered the bases. An MPPT 45A controller seeing 33.2V and 11.5A from 2 12V panels in series with hazy sun and batteries charging in bulk mode probably means the panel manufacturers were way optimistic about output.

[DavidM]

Yes it looks that way.

These panels were purchased through Amazon and supplied by "Beloved Kai" whoever the heck that is. And these are no longer available through Amazon. But they were a good price a few months ago and even if the real output is closer to 100 watts each, that is ok.

David