Factory Solar Questions - 2016 Classic

[66Overlander]

Hi, I am looking for anyone that knows how the factory 100W solar is supposed to work on a 2016 Airstream, so that I can determine if the system on my 2016 Classic is working properly. It does not appear that the factory solar system on our 2016 Classic can charge the batteries beyond about 80% state of charge and doubt this is normal.

During our last trip (just got home yesterday), we have the Converter/Charger on our 2016 Classic fail (no output voltage and the internal fan would never turn off, so I had to turn the breaker off to the Converter/Charger and bedroom 120V outlets) and we had to rely on the factory Solar Panel system to keep the batteries charged for a week. This was the first time we have really used the solar system. We were in Canada, so the sun was never directly overhead. I saw a maximum reported charge current of 3.8 amps on a bright sunny day with between 2 and 3 amps more common, which given the sun angle relative to the solar panels on the roof may be OK. The highest reported charging voltage I saw was about 13.1V on the monitor panel, with about 12.9V to 13.0V being more common when charging (12.7V when not charging).

What I am questioning is how much the factory solar system is supposed to charge the batteries? The manual says it will stop charging when it senses the batteries are fully charged so as not to damage them. I can hear the relay clicking from time to time so I know it is checking the voltage level. The solar obviously previously turned itself off when the Converter/Charger was working and putting out about 13.7V. Could the failure of the Converter/Charger have somehow damaged the solar system?

The potential solar system trouble is that when the sun goes down after a full day solar charging, the battery state of charge immediately reads reads about 80% +/-5% and the battery voltage about 12.5 with little to no 12V loads on other than the fridge controller board and maybe one interior light. If I turn on a larger load like the furnace blower motor or water pump, the reported voltage immediately drops to somewhere in the 11.9V to 12.1 V range and the state of charge may read about 65%, and the interior LED lights noticably dim. When the furnace blower or water pump turns off everything returns back to about 12.5V/80%.

The next morning, when the sun returns, the solar will report 100% state of charge within a couple of hours, typically at a 2.0A or less charging current and will then shut off and will only turn back on periodically if it senses a drop in voltage/state of charge. I know there is no way that 4 Amp-Hours (2 hours times 2 Amps) will charge two gel cell batteries from 80% to 100%.

In contrast, after several hours towing the trailer on our way home with the truck charging the trailer batteries, when it got dark, the solar system reported the batteries at 95% to 100% (forget the exact voltage, but think it was in the 12.7 to 12.9V range) when the sun went down, and the voltage did not drop so drastically, nor did the interior lights noticeably dim when the furnace or water pump was turned on. We then watched a movie on the big 32" TV using the factory 1000W inverter (with fan the never shuts off) to power the TV and DVD player for almost 2 hours also with one interior light on, after which the state was still about 80%/12.5V. This seems OK to me.

I think all of this means that the factory solar system on our 2016 Classic is not capable of charging the batteries beyond about 80%. Is this normal, or is our system defective? Or, could there instead be some issue with our batteries?

We have a warranty appointment at the factory next month to repair/replace the Converter/Charger (and other items) and need to know if we should also have them repair/replace the solar system and/or the batteries while we are there. No use having them work on the solar and batteries if what I observed is just normal, though disappointing, operation.

All advice is appreciated. I assume that the factory solar system on other 2016 Airstreams besides the Classic (and maybe recent years as well) is the same, so I would appreciate input from anyone with experience on how the factory solar system works on their recent Airstream. Thanks in advance.

[lsbrodsky]

Joe,
First, be advised that battery voltage is a reliable indicator of state of charge ONLY under no charging and no load. That means dark outside and no load. It will always read high when charging(panel output voltage) or low with a load connected. If under no load, you read 12.5 or so, your battery is fully charged. Your system will fully charge the batteries if the batteries have not been degraded. The controller provided by Airstream is a cheap On-OFF controller, you can search here or on the internet and find out what the voltage settings are for that. But, before I replaced mine with a multistage controller I did note that it would fully charge.

Larry

[66Overlander]

Originally Posted by lsbrodsky

Joe,
First, be advised that battery voltage is a reliable indicator of state of charge ONLY under no charging and no load. That means dark outside and no load. It will always read high when charging(panel output voltage) or low with a load connected. If under no load, you read 12.5 or so, your battery is fully charged. Your system will fully charge the batteries if the batteries have not been degraded. The controller provided by Airstream is a cheap On-OFF controller, you can search here or on the internet and find out what the voltage settings are for that. But, before I replaced mine with a multistage controller I did note that it would fully charge.

Larry

Thanks Larry, As a retired electrical engineer I do understand that accurate voltage measurements can only be made under "no load" conditions, although I have no previous experience with solar charging systems, and had no reason to research them before our experience this last trip. When I worked in the auto industry, we considered 12.8V fully charged. 12.5V would have been partially discharged to maybe 75% or 80% depending upon battery type, if I am remembering it correctly. I can attest that my factory solar system panel interprets 12.5V as 80% and 100% is closer to 12.7V or 12.8V (which is what I saw after dark under the same conditions after driving for a day with the truck charging).

I guess I assumed that with the fridge and propane detector and maybe a single interior low power LED light on (it was at night), I was getting "close enough" to no load for a reasonably accurate measurement. I certainly understand that turning on a big load will result in the more significant reduction in measured/displayed battery voltage, but having a single larger load cause the lights to dim from what the solar system said were 100% charged batteries just before it went dark does not seem right. The contrast to after a days driving with the truck charging the trailer batteries was stark and the fact that the solar seemed to stop charging for most of the daylight hours did not seem right. It just seems to me that the solar charger is just not attempting to realistically charge the batteries beyond about 80%. (whereas the factory Converter/Charger will attempt to overcharge the batteries if left plugged in continuously).

Was the multi-stage controller you changed to a "mostly" drop in replacement for the factory controller (i.e. using the same control cable and hopefully same display mounting hole in the inner aluminum skin) and still designed to work with just the two factory gel cell batteries (i.e. not for a much larger solar/battery installation)?

[lsbrodsky]

No, I could not find a good controller that uses that control cable. I left the old one in place but not connected to the panels so that it still reads voltage at the display, which I really did not need since I have installed a Trimetric and that shunt is more precise. I bought a BlueSky MPPT controller that I mounted near the old one, but easier for me to see the LED's on it. It is sized to be fine with my factory panels or even bigger.
I do not think the propane detector is enough of a load to matter but I would be sure everything else is off. We can quibble about the exact voltage for fully charged but without something like a Trimetric you will never know how many AH you have put in or taken out, which is the only way to really know. All I can say is that it never seemed to me that my factory system did not fully charge the battery, but I did not like an On-OFF controller, it would never do the job of a multi-stage.
Larry

[SilverGate]

Originally Posted by lsbrodsky

Joe,
First, be advised that battery voltage is a reliable indicator of state of charge ONLY under no charging and no load. That means dark outside and no load. It will always read high when charging(panel output voltage) or low with a load connected. If under no load, you read 12.5 or so, your battery is fully charged. Your system will fully charge the batteries if the batteries have not been degraded. The controller provided by Airstream is a cheap On-OFF controller, you can search here or on the internet and find out what the voltage settings are for that. But, before I replaced mine with a multistage controller I did note that it would fully charge.

Larry

Hi Joe,
As noted above, "Your system will fully charge the batteries if the batteries have not been degraded." I suspect that when your converter died during your week long trip and you continued to turn on the furnace, 32" TV run with a 1000W inverter, water pump (all big energy consumers), and possibly other energy users such as fans, your 100W factory installed solar panel could not keep up with keeping your batteries fully charged and at a certain point they became critically low and degraded.

We have two 53W factory installed solar panels that came with our custom ordered 2007 23' Airstream Safari. For the past 9 years this system has kept our AGM batteries recharged during 5-day non-hookup camping trips (except for one time when the OEM converter died). But when we do this style of camping, we are very frugal in the use of electrical energy. We definitely do not turn on the furnace (we use Mr. Heater Buddy portable propane heater). We don't use the inverter. We listen to the radio and enjoy votive candlelight in the evenings. (See my solar log in my "Airstream Safari trip notes".)

When our OEM converter died the first time, the symptom was the battery at 45% even though connected to shore power. When the second OEM converter died, I replaced it with a Xantrex converter, details shown here.

For additional information on upgrading your battery monitor and converter (which converter is optimal for charging AGMs): "How my Airstream lost its mojo in the carport," (Man in the Maze post.)

More info on installing new converter in original space: "Fridge and charger upgrades."

And finally, there is a wealth of detailed information on the factory-installed solar recharging system here:

Factory Installed Solar Charging System

Along with exciting improvements in the new 2017 model Airstream trailers that make it easy to supplement the permanent solar system with the Zamp Solar Portable Charging System.

I think you'll be fine once you replace and upgrade your converter, get new AGM batteries (if current ones are significantly degraded), become frugal with electrical use when off shore power, and possibly get a supplemental solar charging system!

Bill

[66Overlander]

Originally Posted by SilverGate

Hi Joe,
As noted above, "Your system will fully charge the batteries if the batteries have not been degraded." I suspect that when your converter died during your week long trip and you continued to turn on the furnace, 32" TV run with a 1000W inverter, water pump (all big energy consumers), and possibly other energy users such as fans, your 100W factory installed solar panel could not keep up with keeping your batteries fully charged and at a certain point they became critically low and degraded.

. . .

I think you'll be fine once you replace and upgrade your converter, get new AGM batteries (if current ones are significantly degraded), become frugal with electrical use when off shore power, and possibly get a supplemental solar charging system!

Bill

Hi Bill,
Thanks for the links. Getting them this way is better than the search function on AirForums. It appears I've got some reading to do (haven't followed the links yet).

We are reasonably frugal energy users. We only watched the movie on the inverter after a full day towing topped off the batteries. All 120VAC appliances except the Converter/Charger worked where we were camped until our return trip home, so it was not an issue then. We don't leave the furnace on, but may run it once cycle before retiring for the evening and/or one cycle when we get up in the morning to take the chill off, if overnight temps dipped into the 40s or 50s. We watch our light usage when operating off the battery only. In our previous camper, we attended the Albuquerque Balloon Fiesta Rally and dry camped for 5 days without either a generator or solar panels and had no issues living off two lead-acid batteries for that duration.

After reading about things on the Lifeline Batteries web site since my last post, I doubt that our batteries have been damaged, but I still believe the solar system was not attempting to fully charging them. According to Lifeline, the AGM batteries are supposed to be charged with voltages well above 14V for the Bulk and Absorbtion modes with Float voltages above 13.2V at the temperatures we experienced during our trip. The Solar never appeared to apply a charging voltage above 13.1V. Of course, this is probably because the solar system is current limited and can't apply a voltage that high, but I still can't believe the solar shut off charging most of the daylight hours thinking the batteries were at 100%.

Also according to Lifeline, the Open Circuit Voltage vs. State of Charge (after a 4 hour no load rest period) are 100% 12.8V or greater, 75% 12.5V, 50% 12.2V, 25% 11.9V, and 0% 11.6V or less. I know we never achieved the 4 hour no load rest, but the 12.5V we would see with minimal electrical load after dark suggests the batteries were never charged near 100% by the solar system. I am sure it would take the solar days to get the batteries to 100%, but the concerning fact to me was that the solar system would quit charging early in the daylight hours, thinking the batteries were already at 100%.

Anyway, now it's time to do some more reading. Thanks again for the links.

[Zybane]

Joe, I have a new 2016 Classic too and the solar charging has failed. I am trying hunt down the cause now.

When I took delivery, everything seemed to be working fine. Battery was always at 90+%, showing solar amps charged. Now I get zero amps on a sunny day. I suspect the charge controller under the couch. This weekend I will be troubleshooting.

[SilverGate]

Originally Posted by 66Overlander

Hi Bill,
... the concerning fact to me was that the solar system would quit charging early in the daylight hours, thinking the batteries were already at 100%.

Anyway, now it's time to do some more reading. Thanks again for the links.

You're welcome, Joe.

I'm not an expert on this electrical stuff. The way I understand it is to think of the battery as an iceberg and the energy goes in at the tip and is measured at the tip, but the larger part below takes time to absorb the energy and "become full". And, as you say, when the controller/monitor senses the battery to be close to 14 volts, it stops the flow of amps into the battery, even though most of the battery may not be fully charged and the sun is still shining!

A review of my log notes shows that we typically arrive at a campsite with batteries at 100%, 12.8v. The next morning they're at 85%, 12.5v. Mid-morning sun produces 4-5 amps and brings the batteries up to 100%, 13.5v; by noon to early afternoon, I'm getting 5-6 amps, and that's when I sometimes see that no amps are flowing into the batteries (because the system "thinks" the batteries are full)! When the controller/monitor sensed the batteries were at 95%, 12.7v, the flow of amps into the batteries resumed. During the evenings, the batteries lingered at 100%, 12.9v, but by morning, they were again at 85%. Total amp/hours recorded at the end of 5 sunny days was 186.

For us, the strategy is to continue to be very frugal with energy use even during a sunny day when the batteries look like they're at 100% because we know that it takes time to fully build up the charge throughout the batteries.

This is why some people feel the need to get more and higher wattage solar panels.

I'm glad you have a warranty service appointment next month at Jackson Center. In the meantime you might want to make your own log notes on how your system is currently performing at various times of the day. And while at the factory/service center, you might consider having them install what they are adding to their 2017 models: a Zamp Solar Port built in next to the battery box, which makes it easy to plug in a Zamp Solar Portable Solar Charging System that will supplement the factory-installed system.

Bill

[alano]

I installed the Blue Sky 3024i controller along with the IPN Pro remote to give me a quality battery monitor and MPPT charger. A good battery monitor will use a shunt resistor in series with the negative battery terminal and directly measure charge in and out of the battery. This way you will know exactly at any point in time how much battery capacity you have without regard to the load.

I installed the Blue Sky and IPN pro remote in my classic by reusing the existing wiring. There's a CAT5 cable between your solar charger and remote panel. To use the Blue Sky you'll need to splice in a 4-pin RJ-11 connector on both ends. You'll use one of the unused pairs for the shunt, and you'll have one pair extra. I was able to mount the shunt resistor inside the battery compartment and the Blue Sky controller just behind the sofa. I did need to bring the sofa forward an inch or two to make sure there was sufficient airflow surrounding the solar controller.