2008 23'CCD Pre-wired solar

[RosiesGuy1]

Having problems understanding pre-wired. I got the info on where (cable by Fantastic fan and controller under R/S dinette set). When i got to the dinette all there was is a RJ11 which said inverter. Most if not all controllers i've seen have a RJ45 connector. What am i missing here? I need help (more ways than one).

I understand that wire from solar panel go to controller, wires from batteries go to controller. I assumed I'd have to buy a controller. But an RJ11?

[wulfraat]

RJ11 is not the solar pre-wire.

Check out the fridge compartment via the exterior vented access door - coming from the floor likely in the corner of this compartment you should find a capped yellow 10ga wire and a capped green 10ga wire with white label that says “solar” (I think those are the right colors from memory). This is your solar pre-wire.

These run straight to your hot bus and neg bus (no fuses) bypassing your “use/store” battery disconnect. Note that the are hot.

Wire these wires to the output side of your solar controller then run a second set of wires from the input side of the controller up through the fridge vent to the roof then onwards to your panel(s).

At least that is how my 2008 25’ was wired.....

[wulfraat]

BTW - yes you will need to purchase a solar charge controller that is sized correctly for the combined wattage output of your solar panels.

[RosiesGuy1]

Let's say I need a 30amp controller but plan to place more panels at a later date. Any problem with just starting with a 40 amp controller? thinking bout placing it under the dinette seat, remote viewer and maybe with a small fan.
What brand and where best to buy?

Inverter ? 1000, 2000, 3000?

Also, found my prewires up by fan.

[alano]

Go with a 40 A! The RJ45 includes 4 twisted pairs. This is fortunate if you intend to install a battery monitor since the Blue Sky series of controllers requires one twisted pair for connection to the shunt resistor and uses an RJ-11 for the remote control. You can repurpose the RJ45 to perform this task and have an extra twisted pair as a backup.

[wulfraat]

Originally Posted by RosiesGuy1

Let's say I need a 30amp controller but plan to place more panels at a later date. Any problem with just starting with a 40 amp controller? thinking bout placing it under the dinette seat, remote viewer and maybe with a small fan.
What brand and where best to buy?

Inverter ? 1000, 2000, 3000?

Also, found my prewires up by fan.

So:

1. Spend some time searching through the forum there is already a ton of great information out there on this topic

2. Forget you ever saw the RJ45 connector. I it will not be used for your install. Modern solar controllers have bluetooth and you use an APP on your mobile phone to monitor what they are doing. so no need for an external monitor.

3. Charge controller size. Yes you can buy big in the event you add more solar down the road. no downside except.... see next item #4....

4. Number of solar panels. Here is the thing - the standard solar pre-wire is a small 10ga wire. It is at least 20 feet long as it snakes through the trailer. For a 12v system the most you can throw at a 10ga wire that is 20 feet long is like 12 amps of current before voltage drops. So 12 amps at the battery @ 14.4 bulk charging is like 2 x 100w panels worth of output after you account for the fact that panels never kick out their actual rated wattage. 60-70% at best for a flat panel install. If you want to have more than 2 panels, well then.... don't even bother with the solar pre-wire you are going to need to run new heavy gauge wire from scratch..

5. Inverter size: completely depends on what you want to power and how far down the slipper slope of off grid power you want to go. To run basic things in the trailer like computers, TV, DVD, etc... 1000w is fine. When you get into microwave territory now you are talking 2000w. Air conditioner powered by $8k of Lithium batteries now you are talking about a 3000w hybrid inverter that costs close to $2k. etc. etc.


6. Solar controller recommendationr. Recommend Victron MPPT Smart Charge Controller. It is more efficient than a PCM charger and you can control / monitor from your mobile phone with a powerful viltron app. The 75/15 model would do you fine for 2 panels and 10ga wire. No need for the external monitor and no need for a fan.

https://www.victronenergy.com/upload...-100-15-EN.pdf

If you want good guidance / consultation, support and a "complete" system (solar panels, wires, controller, etc..) from a one-stop shop then go to www.amsolar.com / give them a call.

...but in any case, your next homework assignment is to start reading through the Solar sub-forum

[wulfraat]

BTW - here is a 12v wire gauge chart that plots out what gauge wire is necessary to carry X amps over Y distance with < 3% drop in voltage.

[alano]

1. Wulfaat's plot is valid for 12 V but your panels likely operate at about 18 V, so the losses in the plot are overstated by 50%. You also have the option of stacking panels in series if you use a MPPT controller, so it's possible to keep the losses < 3% while adding up to 400 W on your roof!

2. Although the Victron series do offer Bluetooth capabilities, the Blue Sky series is excellent and the RJ45 cable can also be repurposed when using the Trimetric monitors since a twisted pair is required from the shunt to the monitor.

[DreamStreamr]

OTOH, if you can run your panels in series and have a charge controller that will accept nominal 24vdc input (some are 48/24/12, some 24/12, some just one or the other) then you can halve the current in that pre-wire. That allows same amount of power through smaller wire on a given length.

I wired my panels in series to make 24vdc, connected to the pre-wire in the bottom corner of the outdoor fridge cabinet. The other end of the solar pre-wire wasn't terminated at the bus at the front road-side corner of the trailer. I connected it with a 2" length 12gauge wire to the 12gauge terminals on the solar charge controller.

The solar pre-wire in the fridge cabinet was a bear to dig out - it'd been buried in a wad of Vulkem caulk. A utility knife and 1/2 hour of careful digging freed it without cutting the insulation. A heat gun to soften the caulk might have been easier and less risk of cutting important wire jackets.

I'm running two 125watt Sharp panels to a BZ Products MPPT2550 (25amp) charge controller, all purchased and installed November 2007.

[wulfraat]

True that you can re-purpose the RJ45 to support a display ... just feel that is an antiquated approach given the state of current tech blue sky is a good controller for sure and will do a great job.

RE wiring in series - I agree that approach would work... been there ... the issue is that a bit of shade on any panel and you are toast as total output from the entire array gets impacted.

After having over 500 Watts of panels in series I quickly went back to parallel and performance definitely improved.

Just something to consider. Lots of options....

[alano]

I've had very good success with four 100 W panels in a series/parallel configuration. I'm somewhat skeptical of the improvement claimed by the series/parallel comparisons I've seen because bypass diodes should theoretically lessen the impact of shading in a series approach and often the response time of the MPPT controller is ignored.

That being said I'll suggest folks stay with a parallel configuration unless their losses accumulate above 3%. If folks want more power but are unwilling to run heavier gauge wire, I will always recommend a series or series/parallel configuration.