Boondocking with 90w solar and 2 AGMs

[aep71]

Waiting on a 19CB Caravel and I want to get ahead of problems we may have boondocking.

Understanding the 2021 Caravels power their fridges with ELECTRIC and no propane, I'm wondering how much we can rely on the 90w solar + 2 AGMs.

At most I'll want to get away with our kids for 2-3 days, but a bunch of other forums express concern with the time you can even just run the fridge on 90w solar and 2 AGMs.

Questions:
-Electric draw of the 19CB fridge? I haven't been able to find anything to try to do some math on how long we could run it without being plugged in.

-Lots of comments on Lithium: what kind of length could we gain by upgrading to Lithium? Seems like it's worth the upgrade from everything I've seen.

-Anything else to keep in mind boondocking a 19CB much appreciated!

[Bill M.]

I have been looking at adding lithium batteries. My take is that you get twice the usable power or maybe even a little more and better recharging from the solar. The expense seems to be in the $2500 plus range though.

So far I have bought a $50 clamp on DC ammeter and I plan to find out what my current draws really are before I make the battery decision late this spring.

[Hans627]

You may find this video to be helpful; https://www.airstream.com/ask-an-air...power-systems/

[aep71]

Originally Posted by Hans627

You may find this video to be helpful; https://www.airstream.com/ask-an-air...power-systems/

So helpful, will give it a watch this afternoon. Thank you!

[aep71]

Originally Posted by Bill M.

I have been looking at adding lithium batteries. My take is that you get twice the usable power or maybe even a little more and better recharging from the solar. The expense seems to be in the $2500 plus range though.

So far I have bought a $50 clamp on DC ammeter and I plan to find out what my current draws really are before I make the battery decision late this spring.

That's a great callout; we're not planning on boondocking much (and when we do we'll still be really close to home) so I'd rather test out what our battery life looks like in different scenarios rather than drop several grand for batteries off the bat. Testing with a low-budget tool is a great suggestion. Thank you!

[1StreamDream]

one key thing to keep in mind is that the solar "ratings" you have mentioned (90w) are the max capability of the panel. In actual real world use, they rarely (if ever) hit that number. The sun needs to be directly overhead of the panel, this is why many installations of a more permanent nature allow tilting of the panels, so as the sun moves through the sky through the day, the panels can be adjusted to keep them in maximum absorption territory. The only alternative to that is add more panels to try and make up for the loss of efficiency. Bottom line is do not count on getting 90w of energy from your 90w panel. I have 300w of panel, and most of the time my "peak" energy is less than 200w, and a more typical level is 160w. I will be adding a few more panels to try and increase my production.

[field & stream]

A reasonable rule of thumb is at least 100w of solar per battery. We have done well with this on two trailers and we always camp off grid with trips ranging from a few days to a few weeks.

BUT, there are critical variables that might require you to have much more solar and maybe even more batteries:
1) your use of power (we use very little),
2) solar conditions where you camp, and
3) the all-electric fridge, with which I have no experience, but I read on this site that it is a very significant draw. I suggest you use the Search function on this issue.

[JeffofCT]

Originally Posted by aep71

Waiting on a 19CB Caravel and I want to get ahead of problems we may have boondocking.

Understanding the 2021 Caravels power their fridges with ELECTRIC and no propane, I'm wondering how much we can rely on the 90w solar + 2 AGMs.

At most I'll want to get away with our kids for 2-3 days, but a bunch of other forums express concern with the time you can even just run the fridge on 90w solar and 2 AGMs.

Questions:
-Electric draw of the 19CB fridge? I haven't been able to find anything to try to do some math on how long we could run it without being plugged in.

-Lots of comments on Lithium: what kind of length could we gain by upgrading to Lithium? Seems like it's worth the upgrade from everything I've seen.

-Anything else to keep in mind boondocking a 19CB much appreciated!

While a simple DC volt indicator is pretty easy and inexpensive, to really provide enough information about making a $2,000+ additional investment, I suggest just buying a Victron 712 battery monitor. I provides all the minimum information about battery usage, power in and reserve estimates. If you don't upgrade, this information is still critical as I believe you'll be watching those AGM's like a hawk given your power requirements. If you do upgrade, you'll buy the Victron anyhow.

[JunkYard]

You could get a 180w portable to put out facing the sun. I got a 230w for my 25 ft globetrotter. It’s a propane fridge, it’s a bit big most if the time. Keeps the batteries full.

[Hikingsolo]

A small generator might be the ticket. Since you’re boondocking there shouldn’t be issues with disturbing the neighbors.

We’ve used a generator to keep the AGMs in our SOB coach up. 100 W of solar on the roof doesn’t quite do it even on sunny Arizona days.

[B. Cole]

Originally Posted by Hikingsolo

A small generator might be the ticket. Since you’re boondocking there shouldn’t be issues with disturbing the neighbors.

We’ve used a generator to keep the AGMs in our SOB coach up. 100 W of solar on the roof doesn’t quite do it even on sunny Arizona days.

Agree on a generator, for real Amps of steady power.
Especially at 2am.

[Hermes]

You are rightly concerned with running your fridge, but living in Minnesota I would also factor in any boondocking in the Fall or even Spring when you will need to run your furnace and will not have the same sunshine intensity. Being able to heat the trailer while boondocking during the shoulder seasons (when you may occasionally get a bit of snow) is what determined our solar and battery capacity. Given the available space you have, power storage density becomes a factor and lithium may well be the solution, combined with a quiet inverter generator as a backup.

[uncle_bob]

Hi

It's a pretty good bet that the fridge pulls at least 3A and *might* pull as much at 10A. I'd go with 3A for now.

3A x 24 hours = 84 AH.

Your two AGM's have roughly 100AH of usable capacity to the normal "stop using" point. Simply put, you could run for a bit over a day with *only* the 3A fridge was a load. No lights, no fans, no water pump, no TV, .... just the fridge.

Up around the Great Lakes area, something in the "6 hours full sun equivalent" is not a bad starting point for solar. 90 W x 6 hours = 540 WH from solar. A bit will get lost in the charger, the wires, and the charging process its self.

540 WH at 13V would be 41 amp hours. On a typical day, with no loss, you would make up roughly half of what the fridge pulls. Park in a shady spot and you would make up less. Get lucky with the sun in July and you would do better.

Net result, you would be lucky to make it 48 hours *if* the fridge averages 3A drain.

Bob

[coasttocoast]

Uncle Bob is giving you solid advice. It's a simple math equation. By asking the boon docking question, you have put your name on the sign-up sheet which reads: my batteries are dead, please charge me $1000 for 2 new ones.

Here's a solution- buy a Goal Zero 3000x and 2 portable 200 watt panels. Keep the GZ in a dry location, like your covered tow vehicle. Set up the panels when you park. Plug in your 30amp into the GZ with a 110v adaptor. This will provide you with enough power for 2 or 3 days without compromise.


Given that you are going to spend money on replacement batteries in the short run, you might as well invest that money into something that works. When you are not in the trailer, you can use the GZ for home back-up power.

[Toasterlife]

If you plan to do any kind of boondocking, and that includes National Parks, where many of the most desirable sites may prohibit generators, you might consider replacing the fridge with a model that will run on propane as an alternative fuel from the get go.

We travel with a solar panel that we can move to maximise our sun capture, and in the reasonably sunny areas can boondock for about a week at a time. Even with LED lights, and a propane fridge (some draw for the fan etc), and careful use of the water pump, boondocking is a challenge in power management, for 2 adults, no kids. We often use Luci lights which we charge outside in the daytime, and if we need to use the furnace use it very sparingly.

You will likely want/need a generator for backup, but even the quiet ones are noisy, often with limited hours - unless I planned to ALWAYS camp with shore power, I would be careful to choose a rig with a real propane oven and a fridge that runs on propane if needed.

The theoretical calculations are for Best Case Scenario, with new batteries, and all batteries become less efficient when cold, and when you most need them most...and firing up a generator in the middle of the night is not something you will ever want to do.

Part of the charm of Airstream camping is learning to keep an eye on your batteries, and an overnight oversight can lead to an expensive mistake.

[field & stream]

[QUOTE=Toasterlife;2463778]If you plan to do any kind of boondocking, and that includes National Parks, where many of the most desirable sites may prohibit generators, you might consider replacing the fridge with a model that will run on propane as an alternative fuel from the get go.




I believe that along with the recent change to the electric-only refrigerators, Airstream eliminated from the body the external venting required by propane refrigerators. Therefore changing to a propane refrigerator is quite complex and will cost many thousands of dollars. Also costing thousands is all that is involved in upgrading to lithium batteries and lots of solar.


Rather than spending thousands of dollars, here is a suggestion that will save thousands of dollars: buy a gently used recent vintage Airstream with the propane/electric fridge.

[JTChapmon]

I just watched this video....MOST excellent.

[Garfish]

Get portable solar, 230 watts and a generator, gas if you tow with truck and propane if no truck bed

[aep71]

Originally Posted by Hans627

You may find this video to be helpful; https://www.airstream.com/ask-an-air...power-systems/

This video was so helpful. Any fellow newbies with similar questions on this thread, make sure you take an hour to watch and take notes.

Thank you!

[aep71]

Originally Posted by coasttocoast

Uncle Bob is giving you solid advice. It's a simple math equation. By asking the boon docking question, you have put your name on the sign-up sheet which reads: my batteries are dead, please charge me $1000 for 2 new ones.

Here's a solution- buy a Goal Zero 3000x and 2 portable 200 watt panels. Keep the GZ in a dry location, like your covered tow vehicle. Set up the panels when you park. Plug in your 30amp into the GZ with a 110v adaptor. This will provide you with enough power for 2 or 3 days without compromise.


Given that you are going to spend money on replacement batteries in the short run, you might as well invest that money into something that works. When you are not in the trailer, you can use the GZ for home back-up power.

Thanks for the breakdown, Uncle Bob and Coasttocoast. We definitely don’t plan on exclusively boondocking, but having the option to get away for a few days would be nice. We’re also thankful to have access to some areas where we’re likely to be the only people around when we do boondock, so neighbors will be less of a concern usually. Like a lot of newbs I have slowly come around to the idea that a generator will likely be in our future.

I definitely came into this thinking that the equation was about “how much solar do I need” vs “what’s the energy budget required for what we need.” Having no experience with this we are admittedly shooting in the dark, but all these answers are really helpful in framing my thoughts while we wait for our Caravel. The electric fridge does give me pause, but we will figure it out and make it work once she arrives.

So many helpful comments and answers. Thanks to everyone on here!