2018 28RBQ Serenity Factory Solar Pre-wire

[Wconley]

We kept trying to get up the enthusiasm to install solar on our 2009 27FB but in the back of our heads we realized we wanted a new trailer. We now have a new 2018 28RBQ Serenity and the hunt is on again.

The 2018 has a rooftop combiner box on the front of the trailer just ahead of the Fantastic Fan labeled “500 Watts Maximum”. Since we are considering 400 watts to be adequate for our demand, I want to use the factory pre-wires knowing they will have slightly more losses than going to the additional work of putting in heavier wires. (I don’t want to get into that discussion as it is covered in just about every other thread...)

My first question: Does anyone know where the termination of the pre-wires in the trailer is? Since the box is located at the front, I’ve been looking in the electronics bay under the front left of the couch and haven’t found anything obvious. Could they be located at or near the converter?

Second question: Does Airstream include the charging wires from the charge controller to the batteries?

Thanks for your help. I’ve searched this section without luck to this newer trailer and have sent an email to Airstream Support but haven’t heard back yet.

[kb7our]

The 2018 PDF manual shows the wiring in section 8-35 p. 104. Seems there is both a Cat 5 display wire accessible behind the Seelevel monitor and 10G power wires, one green, one yellow, for the battery and controller. Unfortunately, doesn't say where they terminate but guessing at the bus behind the front couch (you can see the bus looking under the couch). I don't think a controller is included and of course neither is the display panel you mount below the Seelevel. Hope this helps some. Wade

[Wconley]

Thanks Wade, that’s the same info I found so far. I’m sure the controller isn’t already installed but it is nice they did include the CAT/5 cable for the monitor. The search continues.

[Wconley]

I received this info from Airstream Customer Support this morning. So to complete this for anyone else with a 28 Serenity looking for the wires I will copy it below. Of particular concern note that although the combiner box is labeled 500 watt max, the wires are limited to 300 watts! My thanks to Airstream for their response.

The prewire is only rated for 300 watts so you will need to keep it at or below a 300 watt setup. The pre wire locations in your Airstream are going to be in the 12v distribution box under your sofa. There will be a green and a yellow for the panels and a blue communication wire for a remote monitor. The wires to go from the charge regulator to the battery bus bar aren’t pre-installed so you will need to add these short wires during install. If you have any additional questions feel free to email me and I will be happy to assist you.

[uncle_bob]

Hi

..... ummm ..... errrr ......

Unless you have a very unusual pre-wire, you have number 10 wire running up to the combiner box. As you have noted, the box it's self is rated for 500 watts.

Wire is limited in terms of the current it can carry. Number 10 is good for 30A in terms of safety. At the 16 to 18V a typical 12V panel will put out 30A is > 480W. Loss wise, at that power level, you are below 5% due to cabling.

A much bigger question is - can you fit more than 500W of panels on the roof? Let's say the answer is yes and you can indeed get 800W of panels up there.

Rather than buying "12V" panels that put out 16 to 18V, buy "24V" panels that put out ~ 36V. The current out of 800W of 24V panels is the same as 400W out of 12V panels. Your wire is just as safe. Your loss percentage is 1/2 what it was at the lower voltage,

Since you don't have a controller yet, there is no reason to focus only on 12V panels. If you are putting 800W up there, you will need a controller that puts out ~70A. Looking at Victron, they will happily sell you a 150/85. That's a 150V controller that puts out 85A. You could wire your higher voltage panels in series and get the losses below 1% with that controller and the stock wiring.

So no, you don't *have* to swap out the wires from the roof. The wires required to get 80A to the batteries .... that you will have to take care of.

Next gotcha is the charge rate to the batteries. Unless you have upgraded what you have on the trailer, they may not be very happy with 70 to 80A of current.

So, you *can* do way more than you likely can fit on the roof. You also can do more (if you start upgrading batteries to 800AH of lithiums ....) that the credit card likely will be happy with.

Bob

[Wconley]

Thanks Bob. Truth be told, I am wondering if I need to regroup on solar since the Airstream wiring is limited to 300 watts. Mostly when we need solar is during the winter when solar energy is low so my going in thought is that 400 watts is a good place to start. Secondly, we need battery capacity to get through the night running the furnace and not living like a troll. Our trailer is new so we are still with the “wonderful” Interstates. However, I know they don’t really cut it so AGM, 6V, Lithium all fall into the mix of possibilities. Lithium would be the best choice of course, but we don’t like to give up interior space and last year we were down to 11 degrees in Bryce where charging an external battery could be a problem. 6 volt AGM would be good but they are heavy adding tongue weight to our already maxed out F150... The balancing act continues. I watch here and elsewhere to see what solutions people are coming up with. It’s a steep learning curve.

[Wayne&Sam]

11 degrees at night. You won’t be charging at night. And won’t it warm up quickly in the morning, giving smoke time to recharge?

[Wconley]

No, you are not charging at night but it also wasn’t getting above freezing during the day. Last winter was our first with both of us being retired so we are still evaluating what our needs will be. It gets real old real fast watching battery levels at night and finding them already at or below 50% before you go to bed - and that includes using a Little Buddy heater to augment the furnace, keeping the thermostat at 50 degrees, minimizing LED light usage and no inverter, not to mention running a generator as long as possible to charge at night. This may not be everyone’s MO but it happened to us last winter.

[Adventure.AS]

Originally Posted by Wconley

... I watch here and elsewhere to see what solutions people are coming up with. ...

A bit off topic, but addressing the question of enough battery power to keep the trailer warm at night during the winter.

I haven't added solar yet, but am also concerned about available battery power to run the furnace in the winter. I have two group 27 AGM batteries providing about 110 amp/hours usable power.

We added a Dickinson Fireplace. This unit can run without using battery power and will help heat the trailer, reducing the run time (battery draw) of the furnace allowing you to get through the night before your solar panels can start adding charge to the batteries.









I also added Warn Winch 24' quick connect electrical cable to the rear of my gas powered TV and a matching short quick connect set to my batteries. It is switched to only provide power when the TV is running so I can remote start the TV from inside the trailer an provide between 20-40 amps to the batteries in the early morning if needed. Quieter, less expensive and more efficient than a generator.

[Kyacker]

That fireplace is beautiful! Thanks for the pictures!

[Llittle54]

Originally Posted by Adventure.AS

A bit off topic, but addressing the question of enough battery power to keep the trailer warm at night during the winter.

I haven't added solar yet, but am also concerned about available battery power to run the furnace in the winter. I have two group 27 AGM batteries providing about 110 amp/hours usable power.

We added a Dickinson Fireplace. This unit can run without using battery power and will help heat the trailer, reducing the run time (battery draw) of the furnace allowing you to get through the night before your solar panels can start adding charge to the batteries.

Attachment 319550

Attachment 319551

Attachment 319552

Attachment 319554

I also added Warn Winch 24' quick connect electrical cable to the rear of my gas powered TV and a matching short quick connect set to my batteries. It is switched to only provide power when the TV is running so I can remote start the TV from inside the trailer an provide between 20-40 amps to the batteries in the early morning if needed. Quieter, less expensive and more efficient than a generator.

Attachment 319553

Really, did you have to? Already running down this rabbit hole. I’ve researched the remote start but I need DETAILS on the wiring the Warn Winch kit! (Please)

[Adventure.AS]

Originally Posted by Llittle54

Really, did you have to? Already running down this rabbit hole. I’ve researched the remote start but I need DETAILS on the wiring the Warn Winch kit! (Please)

Sent a PM.

[uncle_bob]

Hi

The Airstream solar pre-wire kit is targeted at 300W. You can put far more than that on the stock wires on a DIY basis. The wires are rated at 30 amps. With 36V panels, that puts you over 1,000 W of solar on those wires ....

Bob