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brucesterj avatar image
brucesterj asked

Help please..

My system was working earlier.. 4- 400w panels, Victron 150\85 controller, CERBO w\touch 50, BMV-712 smart, 4- 100Ah BB lithiums.


2 panels are on the roof and other 2 are leaning at same angle against side of the RV. All 4 have 15a fuse connected. So this system has never received much over 800w out of total 1600w. So I unplugged the 2 lower ones.. and used my multimeter to verify they were working. They both tested good. So I plugged them back in.. and verified on my phone they were working too. Climbed up top to test the other ones.. while reaching to unplug one of the panels, I noticed one of the connections shorted out and melted the plug. So I got some tools and cut it off and replaced the MC4. plugged it back in and climbed down. Came down and went inside.. Unplugged CERBO to reset it.. but the screen flicker about every 20 or 30 seconds.. and the controller has some flashing lights. Blue light comes on and then the yellow and green light rotate off and on.. I have disconnected the negative wires on the PV and Battery, waited about a minutes and reconnected them. No change. Then I disconnected the negative cable from the batteries for a minute also.. Hoping to restart the system.. No change.

System was getting about 50w of solar when I first unplugged them..

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Since I posted.. I think it was an over voltage issue.



2022-08-07 180343.jpg 20220807_131129.jpg20220807_131853.jpg20220807_154812.mp4

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klim8skeptic avatar image klim8skeptic ♦ commented ·
The first thing to do would be to unplug the solar panels.


Does the blue led blink? (indicates mppt getting battery power and waiting for solar voltage.) Check settings with Victron Connect, esp battery voltage.

No blue led blink?, check battery voltage, wiring and fuses between batt and mppt.

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snoobler avatar image
snoobler answered ·

Guessing you disconnected under load, when it says to not disconnect under load?


It's not clear if the system is working now. Hope so.


Concerning your output, you do not have sufficient MPPT output to capture your full array:

85A * 14.4V = 1,224W Maximum. Period. Never more.

In warm conditions, an array will output about 75% of rated, so your realistic max is a little over 900W.

Panels that are not perfectly oriented perpendicular to the sun at high noon never output rated power. Two flat panels on the roof and two leaned on the side are likely not optimal.

ANY shading on your roof can severely impact your roof array output. Even shading a single cell may reduce output by 33%.

In short, given your suboptimal array tilt/orientation and insufficient MPPT charge current, 800W on your array doesn't sound bad at all.



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brucesterj avatar image brucesterj commented ·

Yes I did. as I stated the incoming was about 50w.. and there is no disconnect switch installed. I have one but need to extend the PV wires to be able to do that. I've called the few large solar companies for some help.. but it's all about GREED\money and they don't work on RV's or existing systems.

So.. MPPT.. Uggh. I'm not good with all these numbers. I thought with 4 of these panels with 2s2p it would work. It's never seen much over 800w.. There is a tree out front which is why only 2 on the roof. None of the panels are shaded until after 12:30 or so.. 800watt is nice.. but I wanna recharge my batteries faster which is why I have 4 large panels.


Thanx for the reply..

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brucesterj avatar image
brucesterj answered ·

I did.. and rechecked all connections.. Good news.. the sun went down and the controller reset. I NEED to install an disconnect switch so this doesn't happen again.


Thanx for the reply.

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snoobler avatar image snoobler commented ·

You can also turn the charger off in Victron Connect. You should do this anyway before disconnecting PV.

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Juha Tuomala avatar image
Juha Tuomala answered ·

Fix your subject!

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brucesterj avatar image brucesterj commented ·

It's doing better.. but have all 4 panels connected.. 2s and 2p.. But it never sees anything over 800w. I know I need to upgrade my 150\85 controller.. The panels are Trina 400w

20210716_202400.jpg

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