Solar Panel Output, 21 Amp Normal?

Marco Garcia

Marco Garcia

.
Feb 10, 2007
213
Hunter Legend 40.5 Coconut Grove, FL
My house bank is 4 group 29 (Walmart), split in 2 of 2 (100 Amp Fused each), Main battery switch is always kept in Both. I have an Air Breeze generator , and 2 Sopray 120W solar panels with a C40 Xantrex controller. Wind and solar are connected in parallel to the "BOTH" terminal on the Main Battery switch.

Sailing east of Key West at 1:30pm on July 17, with light wind (5-7 kt) and sunny, Refrigerator, Freezer, autopilot, VHF, instruments and charplotter switches on. Engine was Off.

I do not have a Battery monitor yet. Here are the pictures taken then on the indications on the Xantrec remote panel and the Boat V and A meters. Is this 21 Amp expected to be normal?

I have seen them producing 13-14 amps in the Chesapeake bay, but is 21 Amps OK in the south?
 

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Sumner

Sumner

.
Jan 31, 2009
5,254
Macgregor & Endeavour 26S and 37 Utah's Canyon Country
Marco Garcia said:
My house bank is 4 group 29 (Walmart), split in 2 of 2 (100 Amp Fused each), Main battery switch is always kept in Both. I have an Air Breeze generator , and 2 Sopray 120W solar panels with a C40 Xantrex controller. Wind and solar are connected in parallel to the "BOTH" terminal on the Main Battery switch.

Sailing east of Key West at 1:30pm on July 17, with light wind (5-7 kt) and sunny, Refrigerator, Freezer, autopilot, VHF, instruments and charplotter switches on. Engine was Off.

I do not have a Battery monitor yet. Here are the pictures taken then on the indications on the Xantrec remote panel and the Boat V and A meters. Is this 21 Amp expected to be normal?

I have seen them producing 13-14 amps in the Chesapeake bay, but is 21 Amps OK in the south?
Click to expand
I think what you were seeing...



... there was the 'load' amps.



I can't see how the 2 panels that have a maximum current rating of 6.74 at 17 volts (say 14 amps for 2 panels) could have a higher output than their rating with the PWM controller you have. A MPPT controller operating at 90% efficiency could maybe produce about 8.3 amps per panel at 13 volts.

To see the array have the battery down to about 50% and then turn everything off except the panels and you will see what the array is putting into the batteries.

The unknown item above is the Air Breeze generator but with only 5-7 kt of wind I doubt it was putting out much,

Sumner

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Last edited:
Marco Garcia

Marco Garcia

.
Feb 10, 2007
213
Hunter Legend 40.5 Coconut Grove, FL
Thank you Sumner,

I will try that test; however at night the Xantrex panel shows 0.0 load, even with lights and refrigerators on. When windy at night, I can see an increase in Voltage on the boat's VM when the wind generator is working, still 0 on the solar array load indicator.
 
Sumner

Sumner

.
Jan 31, 2009
5,254
Macgregor & Endeavour 26S and 37 Utah's Canyon Country
Marco Garcia said:
Thank you Sumner,

I will try that test; however at night the Xantrex panel shows 0.0 load, even with lights and refrigerators on. When windy at night, I can see an increase in Voltage on the boat's VM when the wind generator is working, still 0 on the solar array load indicator.
Click to expand
I'm not familiar with that controller or display but it sounds like something isn't wired correct. It looks like it should either show load or the array amperage depending if you can turn one or the other off. Does it have a shunt and if so how do you have it wired in? A quick wiring diagram would help.

As an example I'd expect to see something like this. It is dark and you turn on a 5 amp load. The panel should show -5 amps out of the batteries. The sun comes up and the panel starts to produce. The minus 5 amps would go down to 0 when the panels are producing 5 amps. When they are producing 10 amps then the panel should show a +5 amps.

The above example is a simple approximation and in reality depending on battery charge it would vary, but still go from negative amperage to positive if the panels can produce more than the load and current needed to bring the battery back to a full charge,

Sumner
 
Brian D

Brian D

.
Feb 17, 2006
5,274
Lancer 27PS MCB Camp Pendleton KF6BL
Is that controller also possibly collecting data from the wind generator? Since voltage remains the same in parallel circuits, but current adds (y+z) it might also be reading the two. Opps... I missed where you said the wind was detcted but the panels were zero.
 
Marco Garcia

Marco Garcia

.
Feb 10, 2007
213
Hunter Legend 40.5 Coconut Grove, FL
I do not know, but do not think so. I did turned the wind generator in the last couple of days to see, and there is no change when the Wind gen is out of the system. I have also disconnected the solar array, while the wind gen was working good, and in that case it goes to 0, as it does at night when both connected and windy, I see the boat Volt meter indication increase a bit, but the Xantrex panel shows 0.

Perhaps Main Sail has an explanation. perhaps it was at a moment during regulation peak...??? I see 13- 14 AH, some times here. I have not seen 21 again....

I guess a good Battery monitor will tell me the truth.

Thank you Brian.
 
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