Anyone using the Merlin Solar Panel Bundle? Is it worth it?

[KPHealy]

Hi - I'm new to RV'ing, but so far loving our 2024 I19 w/ E1. I'm debating the value of having solar panels. Except when using the a/c, the batteries hold enough charge for normal use for at least 3 days (so far, that's the longest i've gone not plugged in). As I head towards retirement and venture further West, i'm guessing there will be more and longer stays off the grid (most use so far is music festivals and IndyCar races).

Based on some research, contact with 3rd party panel makers, etc., I'm resigned to not risking use of a 3rd party (I'm not comfortable making modifications and there are enough warnings and cautions that it's not worth the stress of wondering if i got it right or am slowly harming the Volta system, which is already unstable and still working out some kinks). So my question is really just to get some feedback from anyone using the Merlin Solar package from Airstream Supply (seems like the only way it can be purchased, which means an annoying extra mark-up) and is it working and worth it? Thanks.

[Boxster1971]

Are you referring to the Merlin Solar Panel Bundle offered by Airstream Supply Company?

https://airstreamsupplycompany.com/p...ouring-coaches

I also have a 2024 AI19 w/E1. The solar system on these vans is seriously flawed because the designed panel voltage is inadequate to provide much solar charging beyond a couple hours mind day in high sunlight. The other issue is Airstream has put two 100-watt panels in series with a 50-watt panel. That limits the power this array can provide to about 130 watts instead of the 250 watts you might think from the specs.

I'm not sure if adding more panel with same voltage will help much.

Recommend this YouTube video with an excellent discussion about effects of mismatched solar panels

https://www.youtube.com/watch?v=jejro4zkl8I

[JeffKim]

If it is the Merlin package @Mike linked to, this is a pretty outrageous price. I don't see anything in the description to lead me to believe there is anything special about these. I don't know the E1 package, but they plug into the camper - does it have a dedicated solar controller? Any old 300W portable panels will do, they don't have to be Merlin. The electrons are all the same. I have 2x200W portable panels I bought for $200 ea. They work great.

[JeffKim]

Originally Posted by Boxster1971

The other issue is Airstream has put two 100-watt panels in series with a 50-watt panel. That limits the power this array can provide to about 130 watts instead of the 250 watts you might think from the specs.

The other consideration is solar exposure. Parallel does better when some panels are in partial shade. BB has a good description of this.

You could always rewire the panels to the configuration you want. I randomly looked at specs of Renogy panels and they all operate around the same voltage (20V) with the 50W panel at 2.5A. So, you should get 250W in parallel.

[KPHealy]

Mike, yes, to clarify I am referring to the portable solar panels at Airstream Supply, which in theory are designed to support the rooftop panels and are compatible with plugs on either side of the van. I'll review the video link. Thanks.

[KPHealy]

Originally Posted by Boxster1971

Are you referring to the Merlin Solar Panel Bundle offered by Airstream Supply Company?

https://airstreamsupplycompany.com/p...ouring-coaches

I also have a 2024 AI19 w/E1. The solar system on these vans is seriously flawed because the designed panel voltage is inadequate to provide much solar charging beyond a couple hours mind day in high sunlight. The other issue is Airstream has put two 100-watt panels in series with a 50-watt panel. That limits the power this array can provide to about 130 watts instead of the 250 watts you might think from the specs.

I'm not sure if adding more panel with same voltage will help much.

Recommend this YouTube video with an excellent discussion about effects of mismatched solar panels

Mike - thanks for the video, it's really helpful and well presented (though it'll kill my productivity this afternoon as i'll head down the rabbit hole of watching his other videos) - thanks again.

[Boxster1971]

Originally Posted by JeffKim

. . . You could always rewire the panels to the configuration you want. I randomly looked at specs of Renogy panels and they all operate around the same voltage (20V) with the 50W panel at 2.5A. So, you should get 250W in parallel.

That could work with a 12V battery system in the base AI19.

But that won't work with the E1 package Volta battery system. Airstream put the three solar panels in series to get about 67V. That is insufficient to be useful for the Volta battery that runs at 57-58V. They chose a series connection of standard AI19 different sized panels that limits the overall array power.

On the AI19s without E1 with 12V batteries the two 100W panels are connected to the 12V coach batteries. Then the 50W panel is connected separately to the Sprinter 12V chassis battery.

[JeffKim]

Originally Posted by Boxster1971

That could work with a 12V battery system in the base AI19.

But that won't work with the E1 package Volta battery system. Airstream put the three solar panels in series to get about 67V. That is insufficient to be useful for the Volta battery that runs at 57-58V. They chose a series connection of standard AI19 different sized panels that limits the overall array power.

On the AI19s without E1 with 12V batteries the two 100W panels are connected to the 12V coach batteries. Then the 50W panel is connected separately to the Sprinter 12V chassis battery.

Interesting, I'm wondering about the controllers. The Volta website alludes to custom MPPT controllers, seems like they could be more optimal with the charging? Without the E1 are there two separate controllers?

[Boxster1971]

Originally Posted by JeffKim

Interesting, I'm wondering about the controllers. The Volta website alludes to custom MPPT controllers, seems like they could be more optimal with the charging? Without the E1 are there two separate controllers?

The solar controller in the Volta Power Distribution Hub (PHD) with E1 is a Victron SmartSolar MPPT 100/20-48V. The custom part is the settings for the Volta lithium battery. I connect to mine all the time to monitor the seldom seen solar charging of the Volta battery.

One owner of a 2024 AI19 w/E1 on the Facebook Interstate 19 Group reported that the replacement PDH installed for a repair came with the Victron SmartSolar Bluetooth feature turned off. Not surprised that Volta would do this so owners can't change the settings.

When my PDH was replaced in January it came with a SmartSolar I could still connect to with Bluetooth.

The AI19s without E1 do have two solar controllers attached to two separate solar panel arrays.

The problem with the AI19s with E1 is a poor design by using the same three solar panels used on the standard AI19s connected in series. That does not work well with the high voltage of the Volta battery.

[KPHealy]

Mike and Jeff, really appreciate your insight. Just a quick update. I received a letter yesterday from Airstream advising of a “Product Enhancement” for the AI w/ E1, for all owners of coaches with the Volta E1 model years 2023, 2024 and early 2025. “The enhancements have been developed in a an effort to improve the overall performance of the Volta battery pack and reduce the potential for the battery pack to completely discharge.” This seems like a voluntary recall - I’d already scheduled, but had to wait almost a month to get in - hopefully this will address the core issue and Volta has a solution or software update. Thanks again.

[Boxster1971]

Originally Posted by KPHealy

Mike and Jeff, really appreciate your insight. Just a quick update. I received a letter yesterday from Airstream advising of a “Product Enhancement” for the AI w/ E1, for all owners of coaches with the Volta E1 model years 2023, 2024 and early 2025. “The enhancements have been developed in a an effort to improve the overall performance of the Volta battery pack and reduce the potential for the battery pack to completely discharge.” This seems like a voluntary recall - I’d already scheduled, but had to wait almost a month to get in - hopefully this will address the core issue and Volta has a solution or software update. Thanks again.

I got the same letter, but it has no details on what is involved for this "enhancement". I'm not eager to go back to a dealer for this if it is just a software/firmware update.

[Graceric]

Not sure if additional info is needed here but we own one Merlin Solar "95W" solar panel (P/N BXD95). I refer to it as "95W" because it typically puts out over 100 Watts. We purchased it from rhinoadventuregear.com for $380. One reason it's more expensive than some others is because it only weighs 7.7 pounds, and it is very thin. It is not made with glass or bus bars so it is supposed to be very reliable. We have had it for 2 years with no issues. So, three of these panels should cost $1,140. For our use, one panel is fine. We have a 19' Airstream trailer (2002 model), we never watch tv or use the stereo. So we only use the battery to power LED lights, water pump, water heater, etc. Our fridge runs on propane. We find that our battery is usually charged back up in about 2 hours or so. We use the Merlin Solar P/N MST-TS15 MPPT controller ($150). Hope this was useful.



Grace

[Boxster1971]

Thanks Grace - that is good info.

The solar problem with the Interstate 19 w/E1 Volta Flex-Pack battery is the poorly design solar panel array. Airstream placed a 50-watt solar panel in series with the two 100-watt panels. A smaller, lower current panel in series, limits the entire string to the current capacity of the smallest panel. So, instead of getting 4.5 amps at 27 volts from the 100-watt panels, you will get 2.25, the current rating of the smaller panel. Then the maximum solar power will be about 58 volts at 2.25 amps or 130 watts.

Originally Posted by Graceric

Not sure if additional info is needed here but we own one Merlin Solar "95W" solar panel (P/N BXD95). I refer to it as "95W" because it typically puts out over 100 Watts. We purchased it from rhinoadventuregear.com for $380. One reason it's more expensive than some others is because it only weighs 7.7 pounds, and it is very thin. It is not made with glass or bus bars so it is supposed to be very reliable. We have had it for 2 years with no issues. So, three of these panels should cost $1,140. For our use, one panel is fine. We have a 19' Airstream trailer (2002 model), we never watch tv or use the stereo. So we only use the battery to power LED lights, water pump, water heater, etc. Our fridge runs on propane. We find that our battery is usually charged back up in about 2 hours or so. We use the Merlin Solar P/N MST-TS15 MPPT controller ($150). Hope this was useful.



Grace

[BikeCamper]

Originally Posted by Boxster1971

Thanks Grace - that is good info.

The solar problem with the Interstate 19 w/E1 Volta Flex-Pack battery is the poorly design solar panel array. Airstream placed a 50-watt solar panel in series with the two 100-watt panels. A smaller, lower current panel in series, limits the entire string to the current capacity of the smallest panel. So, instead of getting 4.5 amps at 27 volts from the 100-watt panels, you will get 2.25, the current rating of the smaller panel. Then the maximum solar power will be about 58 volts at 2.25 amps or 130 watts.

I’m no expert, but it sounds like you effectively have three 50W panels then.

Would it make sense to disconnect the single 50W panel, leaving two 100W panels?

[Graceric]

I was thinking the same thing -- remove the 50 W panel on the roof. If there is room, install a 3rd 100 W panel on the roof in its place. But I am thinking there is probably not room for that.

[Boxster1971]

Originally Posted by BikeCamper

I’m no expert, but it sounds like you effectively have three 50W panels then.

Would it make sense to disconnect the single 50W panel, leaving two 100W panels?

Yes - by putting the 50w in series with two 100W panels you then effectively have three 50 W panels. They did it on the cheap to get the Voltage required to charge the 57-58V Volta battery.

Just having the two 100W panels would not have the voltage, less than 50V, to charge the Volta battery. The best solution for the limited space on roof of Interstate 19 would be two 24V, 120W panels. Using something like those offered by Newpowa would give you reliable 240W at 69V.

https://www.newpowa.com/120w-24v-mon...e-solar-panel/

[JeffKim]

Originally Posted by Boxster1971

Yes - by putting the 50w in series with two 100W panels you then effectively have three 50 W panels. They did it on the cheap to get the Voltage required to charge the 57-58V Volta battery.

Just having the two 100W panels would not have the voltage, less than 50V, to charge the Volta battery. The best solution for the limited space on roof of Interstate 19 would be two 24V, 120W panels. Using something like those offered by Newpowa would give you reliable 240W at 69V.

https://www.newpowa.com/120w-24v-mon...e-solar-panel/

Just wondering, isn't it the solar controller which determines the output voltage to the battery? Or is there something special about the Volta?

[Boxster1971]

Originally Posted by JeffKim

Just wondering, isn't it the solar controller which determines the output voltage to the battery? Or is there something special about the Volta?

No - the battery determines the voltage and the controller sets what is needed to charge. In case of most charge controllers they need about 5 volts above the battery from solar panels to even turn on charging.

[JeffKim]

Originally Posted by Boxster1971

No - the battery determines the voltage and the controller sets what is needed to charge. In case of most charge controllers they need about 5 volts above the battery from solar panels to even turn on charging.

Continuing my ignorance. That seems weird. There are 12/24/48V chargers depending on the system available but the PV input can be most anything as long as it's not over the charger's limit.

[Boxster1971]

Originally Posted by JeffKim

Continuing my ignorance. That seems weird. There are 12/24/48V chargers depending on the system available but the PV input can be most anything as long as it's not over the charger's limit.

No ignorance as I forgot there are solar boost controllers that will boost lower voltage panels to higher voltages to match the battery.

I was focused on the Victron controller used in the Airstream Volta system. They won't boost low voltage panels.

Here is one example of a boost controller.
https://www.bougerv.com/products/20a...ar-controller?

Unfortunately, I can't use one with the Volta system in the Airstream Interstates as the Victron controller is buried in the Volta Power Distribution Hub, that is sealed to prevent owners from opening while the unit is under the three-year warranty.