2021 Interstate Fuse Diagrams <> Solar Charging Problem?

[Yak-55]

Originally Posted by VelmaTKB

The batteries are under the chassis beneath the passenger and drive seats. For 2021 Airstream put the terminals to the inside of the vehicle. they are covered by a metal cage to protect them. you can get a glimpse of the battery terminals but it is impossible to tell if they are 'blown' without removing the cage...which is my plan for the weekend.

Thanks.

An additional data point in my situation. After dark this evening the MPPT control/display was blank (no display and no backlight) and unresponsive. Since it (and the solar charge controller) are powered by either the battery or the solar panels, it appears my charge controller is not in electrical contact with my battery. Fits the blown fuse/breaker hypothesis.

So now there are two of us who need to find this circuit protection device and replace or reset it.

Please let me know if you find it. I’m going to search the documentation again.

Edit: p 9-31 of the owners manual calls for a 10 amp inline fuse within 12” of the battery. So apparently it’s under the “cage” below the driver or passenger seat.

Peter

[BeachBrad]

First, you guys are great as a community. So many helpful suggestions, pictures, posts from lots of people here. Thanks for continuing the original thread. So I FINALLY was able to get our 2021 AI GL inspected in Maine at one of the few combo Mercedes/Airstream service areas (good experience). In addition to having them do a multi-point inspection to make sure the vehicle is in good shape to do a 2nd cross country trip (lessons learned from the first one here), I had them inspect the solar panels/charging issue that I originally posted. Just wanted to close the loop for the group in case helpful.

I also had purchased the Victron Energy VE.Direct Bluetooth Dongle prior to getting it serviced so they could just install it (still beats me why the SmartSolar Bluetooth Victron was not part of the OEM). Airstream corporate said that I could use both the dongle and the MPPT circular control panel (originally installed) but that was NOT true on the BlueSolar MPPT 150/35 installed in our 2021 AI as some of you noted.

@WeekendBob 's explanation of "PV output from your panels has to exceed your house battery voltage by +5V for the Victron MPPT solar charger to turn on and charge" was consistent with what the service technician said. It seems like this may be the reason my solar didn't seem to be working. Thanks WeekendBob yet again!

My suspicion is the lithium house batteries were drained enough by leaving the fridge on (and whatever other trickle charges were happening) during the time we kept our AI parked in a driveway with no electrical hookup. Sidenote: maybe I should plugin when parked at relatives homes even if it's a regular 15 amp plug...but not use AC or microwave).

Now that I have the Victron app, I can see some of the history (see pics below) and, while I'm in Kindergarten when it comes to understanding solar power and battery systems, the days that register no solar charging show the yield on the PV systems were within that 5V range mentioned above (maybe too much pollen on the solar panels +/- clouds)?

My theory may be way off, but for those of you more experienced with batteries/solar/boondocking, here's a related question. I *think* the fridge uses about 2amps (is that 2 amps per hour?) so if we have two 100amp hour batteries in the AI, that would be 200 amp hours total of house battery usage right? and if so, that could power the fridge for a little over 4 days (200 amp hours / 2 amps per hour = 100 amp hours of house battery life = about 4 days)? Or, as long as you have sun/solar voltage +5V higher than house battery voltage and your solar panels are clean, you should be able to keep the house battery charged/topped up continuously?

I bet there are other things eating into the house battery even with USB cords removed, propane switch turned off, battery heater off, etc....but just trying to understand how long you can keep the fridge on if you are boondocking.

P.S. as some of you noted, you can "pop off" the central control panel touchscreen with sharp flat knife or maybe your fingernails to get access to the spaghetti of cabling and solar charge controller system (to plug in the Bluetooth Dongle).

tx again everyone.

[uncle_bob]

Originally Posted by BeachBrad

My theory may be way off, but for those of you more experienced with batteries/solar/boondocking, here's a related question. I *think* the fridge uses about 2amps (is that 2 amps per hour?) so if we have two 100amp hour batteries in the AI, that would be 200 amp hours total of house battery usage right? and if so, that could power the fridge for a little over 4 days (200 amp hours / 2 amps per hour = 100 amp hours of house battery life = about 4 days)? Or, as long as you have sun/solar voltage +5V higher than house battery voltage and your solar panels are clean, you should be able to keep the house battery charged/topped up continuously?

Hi

I believe you will find that the fridge has two compressors in it. Depending on which one you got, they either pull 3.5A each or 4.1A each. The Nova Kool spec sheets changed over the last year.

At turn on, both compressors will be going full bore. You will have 7 to 8A out of the battery until things get cold. The spec you most commonly see claims an average drain of 3 to 3.5 A. That would be 72 to 84 AH per day. There are other things in the MH that also draw power all the time ....

One thing that is *very* useful in these sort of situations is a shunt based battery monitor. A Victron BMV-712 is one, there are a bunch of others .....

If you have the 300W solar package on the roof, the fuse between the MPPT and the battery should be closer to 30A (or 40A ) than 10A. The Victron is rated to put out 35A. Does it ever get there with 300W on the roof? Probably not ....

Bob

[BeachBrad]

Thanks Bob! I'll look into the Victron BMV-712. is that easy self-install or let the pros do it?

[uncle_bob]

Originally Posted by BeachBrad

Thanks Bob! I'll look into the Victron BMV-712. is that easy self-install or let the pros do it?

Hi

The install it's self isn't to complicated. Getting to this and that can be a major PIA though.

Here's the short version:

1) Pull all the cables off the negative terminals of the battery. (yes those batteries in that tray way under the chassis ...)

2) Put the cable that goes between the two batteries back on (or don't pull that one off ...)

3) Add a nice new beefy cable from the negative terminal on the battery (either one) over to the shunt.

4) Run all those other cables you pulled off over to the *other* side of the shunt.

5) Mount the shunt somewhere out of the dirt and rain ( so either inside the cab or in a water tight enclosure)

6) Run the control cable from the shunt over to the round display gizmo.

7) Run a 12V wire from the display gizmo to the battery via an inline fuse.

8) Drill a hole in something and mount the display gizmo.

Since you *can* talk to the device with your phone, you don't *have* to mount the display where it can be seen. My preference would be to put it up with the other displays above the driver's seat and have it visible.

My GT is still "incoming" so I have not put one in it (yet) I do have two of them in my Classic. I installed both of them myself. Without them, there was no way to rationally manage power in the Classic. The GT looks like it is even more power challenged ....

Bob

[Yak-55]

Originally Posted by Yak-55

Thanks.

An additional data point in my situation. After dark this evening the MPPT control/display was blank (no display and no backlight) and unresponsive. Since it (and the solar charge controller) are powered by either the battery or the solar panels, it appears my charge controller is not in electrical contact with my battery. Fits the blown fuse/breaker hypothesis.

So now there are two of us who need to find this circuit protection device and replace or reset it.

Please let me know if you find it. I’m going to search the documentation again.

Edit: p 9-31 of the owners manual calls for a 10 amp inline fuse within 12” of the battery. So apparently it’s under the “cage” below the driver or passenger seat.

Peter

Further update on my lack of solar charging.

With help from a patient tech at Airstream a Jackson Center (long wait on hold, but ultimately worthwile) I learned:
1). There is NO FUSE inline at the battery- despite the diagram on p 9-31 showing one. There is no need (or point) in looking for it under the front seats.
2). The charging circuit IS protected by a 40A (auto resetting) circuit breaker under the road side ottoman, directly behind the access panel there.
3). You can easily verify the CB is closed (conducting) by measuring voltage across its terminals (easily accessed). There should be essentially zero voltage across the terminals (less than 50 mV). Mine was fine. Be careful, there are significant voltages accessible behind the access panel.
4). The Victron Solar charge controller is accessible directly behind the LCD display in the cabinet behind the drivers head. The LCD panel will pop out of its frame with finger pressure behind the edges. Furthermore, the wooden panel that the LCD is mounted on will also snap free with hand pressure (it is held in place with the same laches used to hold the drawers shut).
5). There is a very small rotary switch on the bottom of the Victron solar charge controller near where the cable to the MPPT display plugs in. The switch has positions 1-8 corresponding to different battery types. For those with the Lithium package (12V Battleborn batteries) the proper switch position is 7. MANY (including mine) have been shipped from the factory with the switch in position 2. This is appropriate for an AGM battery, but WRONG for the Lithium (LFP) batteries. If you have the lithium batteries, change this switch to position 7.
6). Finally, check that the 4 connections to the Victron controller are tight. There are simple screw terminals for battery plus and minus and solar panel plus and minus. Mine were snug, but not tight. The poor connection resulting caused my solar charging to fail. Tightening them fixed my problem. The Airsteam tech has seen this problem more than once, so definitely worth checking. No need to remove the wires, just tighten up the screw terminals.

Hope this helps,
Peter

[Yak-55]

Originally Posted by uncle_bob

Hi

I believe you will find that the fridge has two compressors in it. Depending on which one you got, they either pull 3.5A each or 4.1A each. The Nova Kool spec sheets changed over the last year.

At turn on, both compressors will be going full bore. You will have 7 to 8A out of the battery until things get cold. The spec you most commonly see claims an average drain of 3 to 3.5 A. That would be 72 to 84 AH per day. There are other things in the MH that also draw power all the time ....

One thing that is *very* useful in these sort of situations is a shunt based battery monitor. A Victron BMV-712 is one, there are a bunch of others .....

If you have the 300W solar package on the roof, the fuse between the MPPT and the battery should be closer to 30A (or 40A ) than 10A. The Victron is rated to put out 35A. Does it ever get there with 300W on the roof? Probably not ....

Bob

My NovaCool documentation claims the unit draws 88W (presumably this is the instantaneous max while operating since it’s used for sizing/electrical design). At 12 V this suggests about 7A of draw. I haven’t measured it (and it would depend on use pattern) but I would *guess* my fridge duty cycle is around 60%. If so, 24 hrs of operation would consume 1267Wh of energy (105 Ah at 12V).

The Battleborn LFP batteries are rated at 200Ah, and we can probably practically (safely) get 180Ah out of them from a full charge - so that’s about 43hrs of fridge operation - IF there are no other loads. My experience suggests planning for 24hrs when solar and shore power are not available.

My solar experience (so far) in the southern US suggests I can often collect 500-1100 Wh of solar per day. Just enough (on a good day) to keep the fridge going without drawing down the battery very much.

Peter

[BeachBrad]

Tx bob & Peter for the new posts. I believe the fridge in the 2021 Interstate is the Nova Kool 3100 DC that seems to use 2.2 amps while it's running if I read this right.

[Hawk-ination]

We have a smaller refrigerator than you but they take around the same amounts of power to run in general. With an older solar setup that is virtually useless, we can go around a couple days unplugged with the fridge running, along with the other parasitic draws. Haven’t quite found the exact time frame yet, but I’d say around 40-48 hours would be what we are seeing. We also have 200 amps of Battle Born batteries.

Glad you found the solution to your problem. Sometimes having issues forces you to learn about those things you didn’t know before. I found wiring daunting but learned quite a bit in installing the Battle Born batteries. Glad you shared your information because there will probably be others having issues with the factory installed setups unfortunately.

[uncle_bob]

Hi

The 2021 GT gets a different fridge than the GL. The GT fridge appears to be a Nova Kool 7300D. It's got a separate fridge and freezer ( door on the fridge and drawer for the freezer if that matters).

Each section has its own compressor. The compressors are each either rated at 3.5 or 4.1 A (depending on what spec sheet you look at). Max drain is 7.0 to 8.2A as a result. Power drain depends a *lot* on which model Interstate you have.

Bob

[BeachBrad]

Tx for the comments Hawk-ination & Bob...yeah, kinda wish I had the larger GT fridge. the GL one is SUPER small. We've been driving around with a YETI 45 cooler that we load up with ice and put a lot of extra food/frozen items and just keep refilling the ice. takes up the center aisle but since we're on the road for a few months, we wanted to extra "fridge/freezer". maybe I should take out one of the captain's chairs and put in a better fridge.

The ~2 day duration of powering the fridge (without sun/boondocking) FEELS about right but I'll keep evaluating it and report back. fwiw, very cloudy day here in Maine and saw about 20 Wh solar yield, p max of 12W, V max 21.81V (vs. 530 Watt Hours ; p max of 195W, V Max 22.29V a few days ago when it was sunny) in case anyone wanted to geek out on the #s

[uncle_bob]

Originally Posted by Yak-55

Further update on my lack of solar charging.

With help from a patient tech at Airstream a Jackson Center (long wait on hold, but ultimately worthwile) I learned:
1). There is NO FUSE inline at the battery- despite the diagram on p 9-31 showing one. There is no need (or point) in looking for it under the front seats.
2). The charging circuit IS protected by a 40A (auto resetting) circuit breaker under the road side ottoman, directly behind the access panel there.
3). You can easily verify the CB is closed (conducting) by measuring voltage across its terminals (easily accessed). There should be essentially zero voltage across the terminals (less than 50 mV). Mine was fine. Be careful, there are significant voltages accessible behind the access panel.
4). The Victron Solar charge controller is accessible directly behind the LCD display in the cabinet behind the drivers head. The LCD panel will pop out of its frame with finger pressure behind the edges. Furthermore, the wooden panel that the LCD is mounted on will also snap free with hand pressure (it is held in place with the same laches used to hold the drawers shut).
5). There is a very small rotary switch on the bottom of the Victron solar charge controller near where the cable to the MPPT display plugs in. The switch has positions 1-8 corresponding to different battery types. For those with the Lithium package (12V Battleborn batteries) the proper switch position is 7. MANY (including mine) have been shipped from the factory with the switch in position 2. This is appropriate for an AGM battery, but WRONG for the Lithium (LFP) batteries. If you have the lithium batteries, change this switch to position 7.
6). Finally, check that the 4 connections to the Victron controller are tight. There are simple screw terminals for battery plus and minus and solar panel plus and minus. Mine were snug, but not tight. The poor connection resulting caused my solar charging to fail. Tightening them fixed my problem. The Airsteam tech has seen this problem more than once, so definitely worth checking. No need to remove the wires, just tighten up the screw terminals.

Hope this helps,
Peter

Hi

One of the benefits of the Bluetooth enabled version of the Victron charger is the ability to program it with your phone. You can turn the "Blue" version into the "Smart" version by adding a dongle.

I believe this is the current manual:

https://www.victronenergy.com/upload..._manual-en.pdf

It pretty much assumes you are running Bluetooth. If it describes the rotary switch settings, it was well enough hidden that I could not find it.

In the past, the pre-programed settings for Litnium's have not been ideal. It looks like they have gotten better in the last couple years. You still probably can do better with the dongle and manual setup. There are lots of features you can program and data you can get at. Highly recommended ....

Bob

[Yak-55]

Originally Posted by BeachBrad

Tx bob & Peter for the new posts. I believe the fridge in the 2021 Interstate is the Nova Kool 3100 DC that seems to use 2.2 amps while it's running if I read this right.

I have the GT with the larger 2 door fridge/freezer (and like it a lot!). I’d have to go look at it to be sure of the exact model, but Bob’s figures above match what I have experienced.

Peter

[Yak-55]

Originally Posted by uncle_bob

Hi

One of the benefits of the Bluetooth enabled version of the Victron charger is the ability to program it with your phone. You can turn the "Blue" version into the "Smart" version by adding a dongle.

I believe this is the current manual:

https://www.victronenergy.com/upload..._manual-en.pdf

It pretty much assumes you are running Bluetooth. If it describes the rotary switch settings, it was well enough hidden that I could not find it.

In the past, the pre-programed settings for Litnium's have not been ideal. It looks like they have gotten better in the last couple years. You still probably can do better with the dongle and manual setup. There are lots of features you can program and data you can get at. Highly recommended ....

Bob

The Bluetooth dongle is certainly a worthwhile upgrade. I may yet do it when I get over my frustration that I am again paying to purchase what Airstream should have installed in the first place.

The LFP settings for (switch position setting 7) are fully appropriate for the Battleborns installed. They are documented in the manual for the Victron charge controller on their website. And anecdotally I have observed better charging performance since resetting the controller.

Also, for those as cheap as me, almost all (but not all) of what can be done with the Victron App and the Bluetooth dongle can be done (laboriously) using the Airstream installed MPPT Control display. Lots of arcane button pushing, but it does work. See this manual for details:

https://www.victronenergy.com/suppor...s-mppt-control

One thing you cannot do this way (that the Bluetooth and phone app allow) is to update the controller firmware. Any improvements Victron continues to make will almost certainly require firmware updates. This will likely be the impetus for me to eventually install the Bluetooth dongle.

Peter

[Yak-55]

Now that I’ve gotten both the Magnum and Victron Solar chargers configured for my Lithium batteries (despite the errors at the factory) I am curious about the Victron buck-boost charger which charges the house (Battleborn) batteries from tbe Mercedes alternator when driving. By observation I believe it is also (improperly) configured for a AGM battery chemistry. In particular, on extended drives it charges hard to 14.4V (good for AGM, but a little high for LFP), and seems to float above 14V as well (significantly high for LFP).

Does anyone know how to interrogate or adjust the charging configuration for this device? Airstream doesn’t provide any type of display, and I’ve yet to find the correct Victron documentation.

Anyone know more?
Peter

[uncle_bob]

Originally Posted by Yak-55

Now that I’ve gotten both the Magnum and Victron Solar chargers configured for my Lithium batteries (despite the errors at the factory) I am curious about the Victron buck-boost charger which charges the house (Battleborn) batteries from tbe Mercedes alternator when driving. By observation I believe it is also (improperly) configured for a AGM battery chemistry. In particular, on extended drives it charges hard to 14.4V (good for AGM, but a little high for LFP), and seems to float above 14V as well (significantly high for LFP).

Does anyone know how to interrogate or adjust the charging configuration for this device? Airstream doesn’t provide any type of display, and I’ve yet to find the correct Victron documentation.

Anyone know more?
Peter

Hi

If the gizmo is what it's been reported to be, this:

https://www.victronenergy.com/dc-dc-...verter-25a-50a

is the master page.

This:

https://www.victronenergy.com/upload...R-DE-SE-RU.pdf

Should be the manual.

It sends you through a couple loops to get to the software here:

https://www.victronenergy.com/upload...SConfig200.zip

One would *assume* it's a Windows only sort of item. Probably Windows 10 is the target.

All going on what others have reported. My GT is still off in "on order" land. Based on other Victron software I've used, getting things to link up may take more than a few tries ... ( turn this on first ... nope ... turn that on first ... nope ... turn this on and then off and then on again ... yup ... )

Bob

[Yak-55]

Originally Posted by uncle_bob

Hi

If the gizmo is what it's been reported to be, this:

https://www.victronenergy.com/dc-dc-...verter-25a-50a

is the master page.

This:

https://www.victronenergy.com/upload...R-DE-SE-RU.pdf

Should be the manual.

It sends you through a couple loops to get to the software here:

https://www.victronenergy.com/upload...SConfig200.zip

One would *assume* it's a Windows only sort of item. Probably Windows 10 is the target.

All going on what others have reported. My GT is still off in "on order" land. Based on other Victron software I've used, getting things to link up may take more than a few tries ... ( turn this on first ... nope ... turn that on first ... nope ... turn this on and then off and then on again ... yup ... )

Bob

Thanks!

A (very) quick first pass through the manual confirms it’s configured from the factory as a constant 14.4V output device (with max current output of 50A). This would appear to the LFP battery as an “absorption” (constant voltage declining current) charge at 14.4V. Higher than ideal for the Battleborn batteries, and consistent with my observation on high mileage days. The output voltage is probably configurable using the windows “monitoring/configuration” program, but I haven’t read that far yet.

Peter

[uncle_bob]

Originally Posted by Yak-55

Thanks!

A (very) quick first pass through the manual confirms it’s configured from the factory as a constant 14.4V output device (with max current output of 50A). This would appear to the LFP battery as an “absorption” (constant voltage declining current) charge at 14.4V. Higher than ideal for the Battleborn batteries, and consistent with my observation on high mileage days. The output voltage is probably configurable using the windows “monitoring/configuration” program, but I haven’t read that far yet.

Peter

Hi

If it's like the other Victron stuff I have, you should be able to set it for a constant 13.5 ( which lets the solar do the "top off" stuff)

-- or --

A 14.4 v phase for (say) an hour and 13.5 after that.

You can pick your own favorite number in the range of 13.4 to 13.8V for the lower voltage and anything in the 14.2 to 14.5V range for the higher voltage. I avoid the 14.2 to 14.4 V region simply to allow for cable drops. That sort of thing is installation dependent ....

While I'm not one of the "immediately discharge" folks, I would not say keeping the batteries always above 13.8V is a good idea. There is no benefit to it ( you don't get more energy in the battery) and you do potentially wear things out a bit quicker.

Bob