Factory Installed Solar Charging System

[jjabkowski]

I am a new Airstream owner and do have solar panels. I know there are many variables but I was wondering if you are just using say general lighting and the radio, how long would you expect your fully charged brand new batteries to last on a full charge?

[PaulG_4307]

We learned to manage our electric use by watching Youtube (Pippi Peterson) so Solar adds more power than we use daily and AGM Batteries never go below 12.3v.

[ljaecks]

There’s a small square ‘solar’ panel on the roof of our ‘99 Safari. I can’t see where the wire goes after it enters the refrigerator vent.
Can anyone tell me more about this? What is it for? It doesn’t seem to be charging the batteries. Although the PO moved the batteries from the compartment under the couch to the tongue so maybe it was disconnected??? Do these panels wear out?
Thanks for any input. My apologies if this question has already been answered elsewhere. Just point me in the right direction, please.
Cheers!
Laura

[azflycaster]

Originally Posted by ljaecks

There’s a small square ‘solar’ panel on the roof of our ‘99 Safari. I can’t see where the wire goes after it enters the refrigerator vent.
Can anyone tell me more about this? What is it for? It doesn’t seem to be charging the batteries. Although the PO moved the batteries from the compartment under the couch to the tongue so maybe it was disconnected??? Do these panels wear out?
Thanks for any input. My apologies if this question has already been answered elsewhere. Just point me in the right direction, please.
Cheers!
Laura

Typically, small panels like that would be used to keep the battery charged when yhe trailer was not in use. If you open the back of the fridge, you should see the wire coming down the chimney and possibly trace it destination.

[turk123]

I have not seen any posts on the 2019's yet. Well, here's one!

My wife and I just purchased a Classic 2019 30'. It was ordered with factory solar. I already have a controller and portable 300 Watt system for the ground, but thought that the factory system was worth the effort. So what will I get?

AS is now including 3-80W panels on the roof. I am not sure what controller and I have no idea if the new Czone electronic panel will incorporate the solar info in its programming (replacing firefly). The dealer does not know and AS could not tell me (that is a little scary!). I've PM'd the Lewster (pick up the phone Lewster!) and await what his advise on what can be improved or left alone on the system. I will be a few miles away from Naples for our dealer delivery location (Ft. Myers), so Lewster, pick up the PM!

We have a mid-September delivery time and will be staying 3/4 of a mile from the dealership for at least 1 to 2 weeks or until everything is working. I will report here as we find out what we have ordered for solar.

[uncle_bob]

Originally Posted by turk123

I have not seen any posts on the 2019's yet. Well, here's one!

My wife and I just purchased a Classic 2019 30'. It was ordered with factory solar. I already have a controller and portable 300 Watt system for the ground, but thought that the factory system was worth the effort. So what will I get?

AS is now including 3-80W panels on the roof. I am not sure what controller and I have no idea if the new Czone electronic panel will incorporate the solar info in its programming (replacing firefly). The dealer does not know and AS could not tell me (that is a little scary!). I've PM'd the Lewster (pick up the phone Lewster!) and await what his advise on what can be improved or left alone on the system. I will be a few miles away from Naples for our dealer delivery location (Ft. Myers), so Lewster, pick up the PM!

We have a mid-September delivery time and will be staying 3/4 of a mile from the dealership for at least 1 to 2 weeks or until everything is working. I will report here as we find out what we have ordered for solar.

Hi

I've seen a couple of posts / flyers that indicate AS went to a Victron controller on the 2019 Classic models. It's pretty likely to be a Smart Solar rather than the Blue Solar model. Is it a 75/15 or a 100/20? Who knows.... I'd hope it's the 100/20 ...

Bob

[turk123]

Hi Bob

It has to be the 100/20 as the 2019 classic now has 240 watts in three panels. The 100/20 goes up to 290. The lower two models are 220 watts.

[uncle_bob]

Originally Posted by turk123

Hi Bob

It has to be the 100/20 as the 2019 classic now has 240 watts in three panels. The 100/20 goes up to 290. The lower two models are 220 watts.

Hi

Never say "has to be" when it's an AS

The lower power unit simply would not put out as much current. Nothing dramatic would happen other than 15A max instead of 20A. That said, 280W at 13.6V is right at 20A so it *should* be the 100/20.

Bob

[Rocinante]

You’re forgetting that AS persists in using skinny 10 gauge wire for solar. With the losses inherent in that approach, the smaller controller is probably plenty. [emoji6]

[uncle_bob]

Originally Posted by Rocinante

You’re forgetting that AS persists in using skinny 10 gauge wire for solar. With the losses inherent in that approach, the smaller controller is probably plenty. [emoji6]

Hi

Ok, let's go through the math yet again.

10 gauge wire is one mili-ohms per foot. Typical run from roof to controller is < 40' round trip. That's <0.04 ohms for the round trip. At 17V out of the panels, 280W is 16.5 A. You get a 0.65V drop in the wires. That's a 3.8% loss. Go to a superconductor with zero loss and you can get it all back.

The often recommended 6AWG is 0.4 mili-ohms per foot. You will still have a massive 1.5% loss with 6AWG.

You can put the three panels in series and cut the loss to 1.3% with the 10AWG. With a MPPT 100/20 there's not much downside to the series connection.

Safety wise, the 10AWG is rated at 30A. You are still a *long* ways from being into a "no go zone" in terms of fire risk.

Keep in mind that these are all max output numbers. If the sun isn't right overhead, the percentage losses will be less than these numbers.

Bob

[Genericm]

The down side with the series connection is that any partial shade on even one of the panels will significantly drop your voltage and increase the resistance in that small wire.

[Rocinante]

Do what you like, it’s your money. Thats what we did. We dumped that skinny wire for fatter wires, and have been much happier with the output of our solar system.

[gcarter]

Not an AS owner, but do use solar. Huge advantage to series wiring as it extends your charging hours, due to the higher input voltage at the MPPT controller. Early morn and late evening will often still see 17vdc at the controller, so still able to to charge if needed. 17vdc panels are putting out 8.5vdc in early morn, not enough to charge your batteries.

[uncle_bob]

Originally Posted by Genericm

The down side with the series connection is that any partial shade on even one of the panels will significantly drop your voltage and increase the resistance in that small wire.

Hi

Ummm ..... errrr .... the resistance of the wire is determined by the physical properties of the wire. It's the same (at a given temperature) no matter how much sun is getting to the panels. In a "low output" case, the loss percentage from the wire will *always* be less than the max numbers in the calculation.

All solar panels (at least the ones that put out more than a fraction of a volt) have cells in series. That's the only way to get a higher voltage. There is no magic about running things in parallel. We all run things in series all the time.

What *is* a bad thing is to get below the operating voltage of your solar charger. In that case, the gizmo stops working. If we are talking about putting 16 to 21V panels in series, that's not an issue with 12V batteries. When you see the YouTube videos of people "demonstrating" an issue, they are going below the minimum voltage of their (cheap) charger.

Bob

[steverino]

Originally Posted by Rocinante

You’re forgetting that AS persists in using skinny 10 gauge wire for solar. With the losses inherent in that approach, the smaller controller is probably plenty. [emoji6]

While talking to the AMSolar tech prior to our install last month, he seemed to think that Airstream may have moved to 6 gauge prewires recently. Unconfirmed. If my trailer was so wired, he’d use that. Alas, my 2018 Classic has the 10 gauge, so now I have a nice hefty 2/0 solar drop.

[uncle_bob]

Hi

You still are loosing a measurable amount of power with 2/0 why stop at something that small? There's always running 4" bus bar to the roof ...

Never mind that your converter has an unstated efficiency curve. Without that data who knows what's going on ....

Bob

[steverino]

Never mind. It’s duplex 2 gauge.

[AirMiles]

The 10 gauge factory prewire works perfectly for up to 400W of solar panels as documented in my “Solar Show and Tell” thread. Here is my post documenting 30 Amps of charging, at the batteries, from my 400 Watts of panels using the factory prewire and Zamp rooftop box. http://www.airforums.com/forums/f448...ml#post2102103 The 10 gauge wire is not the limiting factor on the factory solar. It’s limited by the controller and 16 gauge wire between the controller and the busbars. To improve the factory solar, if desired, I’d suggest replacing the controller and increasing the controller-to-busbar wire to 6 gauge. You need big cables for high amperage output from the controller, but not from the roof if 400W or less of solar panels are installed.

[uncle_bob]

Hi

A lot depends on just how far your controller is from the busbar setup. Since it's AS, there is no one answer to that question. In my case the stock controller was mounted about 4" away from the busbar. While you most definitely do *not* want to run > 30A (400W at 12V gets you 33A) through number 16 (or even number 10) wire, the lugs and the breaker / fuse on the circuit likely have more resistance than any practical 4" long piece of wire.

Bob

[Rocinante]

We had AM Solar replace everything. Panels, wires, controllers, inverter, and batteries. We're happy now.

Before that we had a dealer-installed 150-watt panel that used the pre-wire and a PWM Zamp controller. It never once provided the amount of power we expected. Not once, no matter how many times we asked them to look it over and make sure everything was performing to spec.

So if y'all want to pay Airstream or an AS dealer top dollars to put in a likely deficient solar system, that's certainly your call, but it's not a mistake we will ever make again.

Originally Posted by AirMiles

The 10 gauge factory prewire works perfectly for up to 400W of solar panels as documented in my “Solar Show and Tell” thread. Here is my post documenting 30 Amps of charging, at the batteries, from my 400 Watts of panels using the factory prewire and Zamp rooftop box. http://www.airforums.com/forums/f448...ml#post2102103 The 10 gauge wire is not the limiting factor on the factory solar. It’s limited by the controller and 16 gauge wire between the controller and the busbars. To improve the factory solar, if desired, I’d suggest replacing the controller and increasing the controller-to-busbar wire to 6 gauge. You need big cables for high amperage output from the controller, but not from the roof if 400W or less of solar panels are installed.