no power on panel when hooked to controller

[kenbob]

Im trying to hook up a system to use when the power is off ,just want to have power to run some small appliances! I have been given 2 solar panels left over from a solar farm project <vsun445-445 watt/open circuit volts 49 > 3 catepillar batteries /just bought epever tracer 4210 controller,I was testing it with a marine deep cycle battery first before hooking up larger batteries ,my panels show 42 volts until I hook up to controller then they go to 0 volts?? my battery is fully charged ,does the controller somehow turn off panels if the battery is charged,,as you can tell I know very little about this I was trying to use things i have to make a simple system!!! any help would be appreciated

 

[Bob B]

There is most likely a bad connection causing the loss of voltage .... I'm not up to speed on troubleshooting MC4 connections .... Others will chime in who are..

 

[42OhmsPA]

Can you post some photos of your connections?

 

[seneysolar]

For troubleshooting try a single panel at a time to controller. This is also a good way to verify output of each panel as it gives you the most direct connection. As you hook others together you may find your problem connection. Look for an mc4 connector with the pin pushed back, i find that alot.

 

[kenbob]

Thanks,I tried both panels,replaced male connector on 1 panel and no change might replace the other 1 tomorrow ,my understanding the male connector on panel is the positive? and I did try 1 panel at a time ,not sure if I can send pics or not,also i am going to clean panels good and get them in better sunlight tomorrow ,they have been in storage for a couple of years

 

[seneysolar]

Unscrew the backshell on the mc4 connectors and give them a tug

 

[LydMekk]

Buy a multimeter and MEASURE each disconnected panels cables.
You should see the panels VoC value roughly reflected on the MM screen.
NOTE the polarity and mark the cables accordingly.

 

[kenbob]

thanks will test some more today lots of sun this morning

 

[Mattb4]

... my battery is fully charged ,does the controller somehow turn off panels if the battery is charged,,....

Panels when not loaded will show voltage at about Voc. If there is no load on them after battery is charged this would be the voltage you would expect to see at the SCC (some less from SCC self consumption being a small load). When you see that voltage drop to nothing it indicates a bad connection, no sun light on panels or a bad panel.

Panels do not push power. Loads draw power form the panels. As they do the panels attempt to maintain voltage as the current demand rises. Vmp is the voltage that they reach their max ability to produce current. Volts X Amps=Watts.

 

[kenbob]

thanks I'm hearing a lot about bad connections will work on this today and update tonight

 

[kenbob]

Well it is working !! the 20 ft wires i bought to hook panels to the controller were red and black so I assumed when connected to the panel the red was positive switched today and its working good thanks for the help ?? will this panel with 43 voc 445 watts be all I need to keep a 3 battery bank charged,and will the commercial caterpillar batteries work till I can get some deep cycle batteries?

 

[seneysolar]

Why not use both panels? (in series)

Size batteries? 8D? All 3 parallel?

Inverter? Battery loads?

 

[kenbob]

I have not hooked up cat batteries yet,just temporary hooked up 1 marine deep cycle to test, i have a 3000 watt,6000 peak inverter, when i hooked up 2 panels in series it showed about 90 voc my controller is a tracer 4210 and max voc is 100,I thought it might be too much for my controller,I was planning to hook up the batteries in parallel to keep it 12 volts,I will be building some cables next few days

 

[kenbob]

I just purchased a 100 ft roll of # 12 wire how long a distance can i run from pv to controller I was thinking about installing them on the roof of my home which would be about 60 ft