Solar Panel Help Needed

[DaCosta]

i need some help with many things concerning my airstream, i am hoping some people will be able to give me some answers to some of my questions.
i have a solar panel on the top of my airstream it doesnt seem to be charging my battery. why. please get back to me thank you. rich

[RognChris]

Could be the battery is no good, solar panels won't charge a worn out battery.

[DaCosta]

hi chris i drove the a/s back from VT. and held a charge for 3 days so thi s think the batteries are ok.

[DaCosta]

Its a new A/S it sat in a Barn for 2 years the batteries seem to hold the charges. the people i bought it from said they never had to use the solar power. is there a switch or fuse i have to put on.

[bryanl]

Find the solar charge controller. This is an electronic device between the batteries and the solar panel. You'll find the power leads from the solar panel go into it and a set of power leads to the battery go out of it.

Check the voltage on the leads from the solar panel. It should run about 15v to 18v is the panel has sun on it.

Check the voltage on the leads to the battery. It should be very close to battery voltage (14v down to 12.5v or so). In sunshine, the charge controller voltage going to the battery will be a tad higher than the voltage at the battery itself depending upon the state of charge of the battery.

These tests will give you an idea of how the system is wired and which direction to look for finding problems.

[RognChris]

Originally Posted by DaCosta

Its a new A/S it sat in a Barn for 2 years the batteries seem to hold the charges. the people i bought it from said they never had to use the solar power. is there a switch or fuse i have to put on.

More than likely the batterys are the problem. If these are the original ones in your 2007 coach that sat for two years in a barn where the solar is useless, it's likely they won't cut it anymore. The solar should be active at all times, not sure about the factory systems but our "Go Power" system is always on, no on/off switch, with a display panel that tells me how much it's charging and how much voltage the batterys are holding.

Just because they held a charge for 3 days means nothing, pretty soon it will be 2 days then 1 day, then replace them. 99 out of 100 time the batterys are always the reason for any solar charging problems. Have them load tested.

[DaCosta]

my batteries where always fully charges while sitting in the barn. the barn was heated and the airstream was plugged in the hole time this airstream seems to have two heavy duty batteries and they seem to hold a charge well but still i will have the batteries checked out thank you

[tfmkevin]

The problem might be your expectations. If you have the Airstream factory solar system - some of them just had one small solar panel (rated at 50W, but delivers much less in practice.) With that panel and the factory controller, you probably won't get more than about 1A of charging current - it's like a very small trickle charger. It would take a LONG time to charge your batteries back if they were low.

If it's a factory system, it probably also has a monitor panel somewhere in the rig. The panel should show the % charge of your batteries, and it likely has a button you can press to get other info - like how much charge is coming from the solar panel(s).

[DaveFL]

Originally Posted by tfmkevin

The problem might be your expectations. If you have the Airstream factory solar system - some of them just had one small solar panel (rated at 50W, but delivers much less in practice.)is coming from the solar panel(s).

My 10X10 inches AS installed would in full sun just about have enough production to replace charge for the co monitor at standby and battery self discharge.

[RognChris]

Originally Posted by DaCosta

my batteries where always fully charges while sitting in the barn. the barn was heated and the airstream was plugged in the hole time this airstream seems to have two heavy duty batteries and they seem to hold a charge well but still i will have the batteries checked out thank you

I'm fairly certain batterys sit dormant when the trailer is plugged in, only when towing or in direct sunlight to the solar will the battery get a charge. When we bought our trailer it was 3 years old and the owner had already changed out the batterys once.

Good luck, let us know what you end up doing...

[lewster]

Originally Posted by RognChris

I'm fairly certain batterys sit dormant when the trailer is plugged in, only when towing or in direct sunlight to the solar will the battery get a charge. When we bought our trailer it was 3 years old and the owner had already changed out the batterys once.

Good luck, let us know what you end up doing...

This situation is true ONLY if you leave the battery disconnect switch in the 'STORE' position. This will disconnect the batteries from the converter, and they will not get any charging voltage when plugged in.

If you want to keep your batteries charged (and you should) you need to keep the disconnect switch in the 'USE' position when plugged in. You set the switch BEFORE plugging in. Once connected, you can not determine which position the switch is in, as the power light is always on.

While you're at it, I would suggest a better converter/charger that the Parallax unit that you have in the unit now. IntelliPower or Iota come to mind, as both have 3-stage automatic charging that are gentle on your batteries.

If you have solar, then you probably have AGM batteries (or you SHOULD!). The IOTA converter is better suited for these type of batteries.

[RognChris]

Originally Posted by lewster

While you're at it, I would suggest a better converter/charger that the Parallax unit that you have in the unit now. IntelliPower or Iota come to mind, as both have 3-stage automatic charging that are gentle on your batteries.

If you have solar, then you probably have AGM batteries (or you SHOULD!). The IOTA converter is better suited for these type of batteries.

Thanks for the info Lew, our coach has a "go power" solar package with 2 panels totaling 130 W and was installed by the airstream dealer in Irvine Ca. I think it charges the batterys even when the switch is in the store position. I don't know what kind of converter/charger or battery type it has but I'll have to check into it after hearing your recommendations.

Thanks again, Cheers.

[lewster]

Unfortunately, the charge controller from Go Power is the old Pulse Width Modulation (PWM) style. It surely has it's limitations, as do their panels. They have a rather low open circuit voltage when compared to many other available panels.

A significant upgrade would be the addition of an AM Solar HPV-22B charge controller. It uses the newer and much preferred Multi Point Power Tracking (MPPT) system and is designed to be a direct replacement for the Go Power controller, offers more versatility (shore/dry camp switch), efficiency, higher boost charging and is better suited to the needs of AGMs.

Check them out at www.amsolar.com

[RognChris]

Originally Posted by lewster

A significant upgrade would be the addition of an AM Solar HPV-22B charge controller.

Check them out at www.amsolar.com

Thanks for the link Lew, I spoke with them regarding our coach last fall. They recommended a guy in New Mexico to install their system, not really convenient at the time and neither was going to Eugene. Our system is certainly a big upgrade from the factory Airstream solar, it's way more than we need it seems, 2 weeks of dry camping and we never came close to low voltage. That controller sounds like something I might do at some point, for the time being I'll follow the age old advise that if it works don't fix it.

It's nice to get advise from someone who obviously knows what their talking about, much appreciated. I'm looking forward to our yearly trip to Oregon for some coho salmon along the Sandy river in Sept !

Cheers, Roger.

[bryanl]

re "Then you probably have AGM batteries (or you SHOULD!)" -- why? They cost 2x, last maybe 1.5x, still need proper battery compartment. I mean, they are nice but I can't see pushing it too far.

re: "the old Pulse Width Modulation (PWM) style. It surely has it's limitations" -- the advantage of MPPT is not that much for small installations (under 500 watts) like you'll find in an RV.

What is important in either a converter or a solar charge controller is good charging smarts coupled with a maintenance mode that will inhibit battery sulfation during periods of minimal use. Examples of these would be the ChargeWizard based converters or the BatteryMINDer charge controller.