Solar panel

[DavidEM]

Answers in bold below:

Originally Posted by Fullabunk

Using current 10 G wiring from the roof, what is maximum wattage of panels that can be installed with 12v panels in parallel?

Up to a point pushing too much current through small wire just wastes power in voltage drop and heat. But I prefer to keep the voltage drop to 1 volt or less from the solar panels to the controller. Even then you are wasting about 8% of your power.

Assuming it is about 20 feet from the panels to the controller, you can use about 300 watts of panels in parallel and meet that criteria.

The wire from the controller to the batteries needs to be sized for a smaller voltage drop, 0.25V is my limit. If the distance is 8' then it takes #8 wire to meet that limit with 300 watts of panels. It is usually fairly easy to upgrade that wire as it should be fairly accesible.

If in series, how do you change back to feed the 12 batteries. I will install a Renogy 60A controller with cell app.

The Renogy controller, assuming it is an MPPT type, does this automatically. FWIW a 30A Renogy controller will work fine for 300 watts.

Thanks

If you want to install in series/parallel you can double everything, ie 600 watts of panels will work. You need to double the wire gauge from the controller to the batteries to #4. In that case you will need the 60A Renogy controller.

David

[pmorris92223]

Installing solar to our vegas 24.1 next week. I'm not doing the install. I'm having my RV guys do the work. Couple of other additions, outdoor porch light, warning light for the Jeep breaking system and a fill system for the batteries. We're going to do a little bondocking in Joshua Tree next month and see how that goes.

[Chance]

Originally Posted by Fullabunk

Using current 10 G wiring from the roof, what is maximum wattage of panels that can be installed with 12v panels in parallel?

If in series, how do you change back to feed the 12 batteries. I will install a Renogy 60A controller with cell app.

Thanks

Panels don’t actually operate at 12 Volts so you should start by comparing specifications of the panels under consideration.

Simply using 12 Volts for calculations will yield much higher current than you’ll actually see. Below as an example only are specs for a Renogy 100-Watt panel. As can be seen, its rated maximum power comes in at 5.29 Amps and 18.9 Volts.

If you used 12 Volts in calculations, you would estimate:

100 Watts / 12 Volts = 8.33 Amps

You would be overestimating current by over 50%; and in so doing unnecessarily limiting your system’s design capacity.

If using an MPPT charge controller, you can select panels with higher “max power” voltage so “max power” current is lower (compared to Renogy example), allowing for greater overall system power.

Just saying that even with multiple panels in parallel, a 10 gauge wire can still support a lot more solar than many owners will add.

And also keep in mind that when installed horizontally, panels won’t actually produce their rated power to start with. That 100-Watt Renogy in example won’t reach 5 Amps in normal operation.

How much capacity are you after? Curious what your goals are.

[cbeaud]

Originally Posted by GTM41261

In the process of installing a Renogy system. Finding the wires in the vent tube in the roof was interesting. I went with three 175 watt flexible panels and a 40 amp charge controller with Bluetooth.

Hello we have 2019 four winds. Looking into the Renogy that has the M4 connectors. Is it compatible? Are you saying what see on the roof are vent tubes and the connectors are inside them?

[MountainGaut]

My rig was pre-wired, no wire installation from roof to controller. The minimum wire gauge for my installation requirements is 10 gauge. (Max 30 AMP)

[MountainGaut]

Originally Posted by Chance

Panels don’t actually operate at 12 Volts so you should start by comparing specifications of the panels under consideration.

Simply using 12 Volts for calculations will yield much higher current than you’ll actually see. Below as an example only are specs for a Renogy 100-Watt panel. As can be seen, its rated maximum power comes in at 5.29 Amps and 18.9 Volts.

If you used 12 Volts in calculations, you would estimate:

100 Watts / 12 Volts = 8.33 Amps

You would be overestimating current by over 50%; and in so doing unnecessarily limiting your system’s design capacity.

If using an MPPT charge controller, you can select panels with higher “max power” voltage so “max power” current is lower (compared to Renogy example), allowing for greater overall system power.

Just saying that even with multiple panels in parallel, a 10 gauge wire can still support a lot more solar than many owners will add.

And also keep in mind that when installed horizontally, panels won’t actually produce their rated power to start with. That 100-Watt Renogy in example won’t reach 5 Amps in normal operation.

How much capacity are you after? Curious what your goals are.

I'm looking at a max of 350 to 400 watts to charge my 2 deep cycle batteries faster then the 160w panel I have today. No need for too much Amps and Watts for my LED Lights, water pump & satellite radio requirements. But surely faster charging when Boondocking with good and not so good natural light days.

[Scubawise]

Just had my great local kurts repair install solar !
180 watt. 20 amp temp sensing controller..

[Scubawise]

Finally solar!
And best thing done was 30 amp plug at home

[Mwild]

When you're not using RV and leave in storage, do you turn off batteries or is the 200W enough to keep charged if you left for a week for 2? Obviously turning off most major appliance!

[Scubawise]

l leave mine plugged in house 30 amp with use store on

[pmorris92223]

On our coach (2020 Vegas 24.1) we turn off the coach switch and the solar panel continues to charge the batteries. It's not unusual for it to sit for a couple (or longer) weeks at a time

Originally Posted by Mwild

When you're not using RV and leave in storage, do you turn off batteries or is the 200W enough to keep charged if you left for a week for 2? Obviously turning off most major appliance!

[Pete'sMH]

Me too. I have just a single 80W panel and controller that is connected directly to the batteries. It keeps two house and the chassis battery fully charged even during extended storage. I have a second panel that I could install and just plug in but I’ve found no need to do so and likely won’t.