Best way to hook up two solar panels to CT

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robcaz
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Re: Best way to hook up two solar panels to CT

Post by robcaz » Tue Dec 12, 2017 3:16 pm

Hi,

I assume the 40amp solar regulator is the MPPT regulator of a Redarc BCDC1240? This needs unregulated solar input to make it work how it was designed. There would be confusion between two solar panels with their own regulators charging the one battery.

A MPPT or Maximum Power Point Tracking regulator is able to convert excess voltage into amperage by calculating the output from the solar panel to provide the maximum current possible at the required voltage at any given point. During low light level situations the MPPT will compensate for the low light level & find the new point at which the solar cell delivers its maximum power output. For example our 130 watt solar panel puts out 17.5 volts at 7.5 amps however first thing in the morning when I point the panel towards the sun I have seen 13.5 volts at 10 amps going into the battery.

It is not hard to bypass the regulator on the back of your panel. All you have to do is cut the wire between the panel output & the solar regulator & add two Anderson connectors. If you want unregulated output from the panel just disconnect the anderson & plug it into the lead to the Redarc. It is handy to have the regulated option on the panel in case you want to charge your vehicles battery or someone else.

I did the same when I installed a Redarc BCDC1225 http://www.campertrailers.org/bcdc1225_install.htm

The two unregulated panels need to be connected in parallel, that is pos to pos & neg to neg as they head towards the Redarc regulator. This can also be easily achieve by connecting the unregulated output of both panels to an Anderson double adaptor as in this diagram http://www.campertrailers.org/bypass_regulator.jpg

From the double adaptor I have found there is little voltage drop from a 10 metre length of 6mm twin core auto cable & gives enough lead to chase the sun around the shadow of the trees.

Auto Elec have great cable prices https://www.autoelec.com.au/ as does their Ebay store under autoelecau

You can pick up ten grey 50 amp Anderson connectors on Ebay for around $30 delivered. Just make sure they are genuine & not labelled as Anderson style as they are reproductions. The terminals rust & the plastic quickly breaks down in the sun.

I have crimped all my Anderson & you can pick up a crimper on Ebay for about $30 to $40 as in my article above.

Hope this helps.
happy camping
Rob & Carol
Australian CamperTrailers Group co-owner


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We're just two lost souls swimming in a fish bowl, year after year

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robcaz
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Joined: Sat Oct 12, 2013 4:07 pm
Location: Stockton NSW
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Re: Best way to hook up two solar panels to CT

Post by robcaz » Thu Dec 14, 2017 3:34 pm

Hi Greg,

There were diodes already in place, all I did was splice into the wires just before the Plasmatronics PL1210 regulator, so I had another set of positive & negative wires that were unregulated. http://www.campertrailers.org/redarcbcdcinstall16.JPG

I added a 10 amp fuse & ran the wires to a red anderson to say the outlet is unregulated, while the grey anderson is regulated. http://www.campertrailers.org/redarcbcdcinstall17.JPG

Different coloured anderson connectors will not go together, but I doctored the red so it would fit the grey. It is easier just to put red nail polish on the anderson. Funny story, I was adding an unregulated anderson on the back of mates solar panel & went down to the house & asked Carol if she had some red nail polish. My mates wife said, what are you boys doing in the shed? :lol:

If you send me a photo of the back of your panel including a close up of the regulator to owners@campertrailers.org I can do a diagram for you.
happy camping
Rob & Carol
Australian CamperTrailers Group co-owner


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We're just two lost souls swimming in a fish bowl, year after year

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