Wiring for solar panel charger in 2x12v parallel setup?

[Carsonsig]

Does it matter how I hook up the solar trickle maintainer?


I plan to add a 2nd 12v battery to my trailer.. Setting it in Parallel. House lines to battery one... connecting battery 2 pos and neg to battery 1...



I plan to add a https://www.northerntool.com/shop/to...2434_200922434 22w with charge controller... Does it matter where I put the + and - from the solar charger...?


appreciate any tips!

[Carsonsig]

TTT

[Jon_C]

Its best to connect the charger positive to one battery and negative to the other, such as charger positive to battery 1 positive terminal and charger negative to battery 2 negative terminal.

[randyrr]

Originally Posted by Jon_C

Its best to connect the charger positive to one battery and negative to the other, such as charger positive to battery 1 positive terminal and charger negative to battery 2 negative terminal.

Agree with Jon_C but would also suggest your house connection to be connected the same way.

Also note that a 22 watt panel will at best maintain your batteries if they are fully charged, but too small to charge them.

[Persistent]

The link you provided has another link. It is a PDF manual for the panel. Open the PDF it contains instructions for connecting.

It does not matter which of the two positive terminals you connect to. It does not mater which of the two negative terminals you connect to.

I recommend you get a much larger panel. Anything less than 100 watts is not useful for a travel trailer.

[Carsonsig]

Thanks so much!



This set up is at my duck club. I go once a week... use some lights and heater over night... this is purely to see if (at the cost of $50 for cable and the charger) I can avoid lugging home batteries to charge them as much....


so House batteries



P to P B 2
N to N B1


Two Batteries lugged together to their respective P and N
solar charger



Panel P to P B 1
Panel N to N B 2

[Persistent]

Originally Posted by Carsonsig

Thanks so much!

This set up is at my duck club. I go once a week... use some lights and heater over night... this is purely to see if (at the cost of $50 for cable and the charger) I can avoid lugging home batteries to charge them as much....

so House batteries

P to P B 2
N to N B1

Two Batteries lugged together to their respective P and N
solar charger

Panel P to P B 1
Panel N to N B 2

As you describe your situation, 20 watts is not going to help. It is not enough to fully charge the batteries.

A pair of group 24 batteries may be rated for 140 amp hours.
20 watts / 12 volts = 1.7 amps.

It will take 84 hours to recharge the batteries. You may get 6 hours of charging per day. It will take 14 days to recharge if every day is sunny and there is no shade from nearby trees and buildings.

Lead acid batteries need to be stored fully charged for long life. Your batteries will spend many days significantly discharged. Life will be shortened.

Get at least a 100 watt solar panel.
100 watts /12 volts = 8 amps.

It will take 16 hours to fully charge. At 6 hours per day, it will take 3 days to charge the batteries.