Critique this plan?

[wrybread]

I'm helping a friend install a solar system on his mobile bar, and I'm wondering if people have any tips.

Here's his rig, The Sandbar:



He's bringing it down to Baja California (Mexico) in a few months and wants to run off solar with as little fuss as possible. His needs are pretty simple:

- a stereo that pulls at most 75 watts when on full, more like 20 watts usual use though

- a 70 pound ice maker that pulls about 190 watts (it's this one). Won't run all day. I'm interested in alternative ice makers if anyone happens to have a suggestion. And I haven't run it off a inverter yet, I'm hoping it doesn't have a startup surge when the compressor kicks on.

- a bunch of lights that pull a max of 30 watts

So that's about 300 watts max draw. I'm thinking he'll probably eventually want a chest freezer fridge at some point, and maybe want to run a projector, so I'm trying to give the system room to grow. But there's budget constraints, he's trying to keep it cheap-ish.

At the moment the system I'm planning consists of:

- four 280 amp hour Eve cells (or similar) wired for 12 volt. Not purchased yet, if anyone knows of a good source or something else we should consider, very very interested. Would love for that to be under $800 with BMS shipped, but I know that's a long shot.

- three 260 watt solar panels (purchased for $75 each! So awesome how cheap this stuff is getting. Planning to wire in parallel so he has freedom to shade one or two panels with cargo, and the charge controller is only 100v)

- I have a Tracer 40 amp charge controller that I'm donating to the cause (this one), but that's less than the theoretical max capacity of the solar panels, which is 65 amps. The panels will be flat mounted, which means I think about 15% less capacity (so we're down to 55.25 amps). I'm a big fan of over panelling, but since he'll be in the tropics (just south of the Tropic of Cancer) I'm worried we'll be squandering a lot of amps. Any thoughts on whether we should bite the bullet and buy either a bigger charger controller, or maybe a second controller that we connect one of the panels to? Or is this array unlikely to make much more than 40a given this setup?

- And any thoughts on how well the Tracer charge controllers work with LFP batteries?

- a Peak brand 800 watt inverter that he had, probably purchased from Home Despot (link). I'm a bit worried about that dying on him. Any recommendation for a good and relatively cheap inverter? I always use Xantrex inverters, but they're a bit outside his price range.

Planning to buy:

- this 10 gauge wire
- these branch connectors
- these fuses (one for each panel)
- this fuse for the battery

Anyway thanks for any help. Trying to avoid the inevitable stupid mistake or three.

 

[gnoeld]

I'm helping a friend install a solar system on his mobile bar, and I'm wondering if people have any tips.

Here's his rig, The Sandbar:

View attachment 96850

He's bringing it down to Baja California (Mexico) in a few months and wants to run off solar with as little fuss as possible. His needs are pretty simple:

- a stereo that pulls at most 75 watts when on full, more like 20 watts usual use though

- a 70 pound ice maker that pulls about 190 watts (it's this one). Won't run all day. I'm interested in alternative ice makers if anyone happens to have a suggestion.

- a bunch of lights that pull a max of 30 watts

So that's about 300 watts max draw. I'm thinking he'll probably eventually want a chest freezer fridge at some point, and maybe want to run a projector, so I'm trying to give the system room to grow. But there's budget constraints, he's trying to keep it cheap-ish.

At the moment the system I'm planning consists of:

- four 280 amp hour Eve cells (or similar) wired for 12 volt. Not purchased yet, if anyone knows of a good source or something else we should consider, very very interested. Would love for that to be under $800 with BMS shipped, but I know that's a long shot.

- three 260 watt solar panels (purchased for $75 each! So awesome how cheap this stuff is getting. Planning to wire in parallel so he has freedom to shade one or two panels with cargo, and the charge controller is only 100v)

- I have a Tracer 40 amp charge controller that I'm donating to the cause (this one), but that's less than the theoretical max capacity of the solar panels, which is 65 amps. The panels will be flat mounted, which means I think about 15% less capacity (so we're down to 55.25 amps). I'm a big fan of over panelling, but since he'll be in the tropics (just south of the Tropic of Cancer) I'm worried we'll be squandering a lot of amps. Any thoughts on whether we should bite the bullet and buy either a bigger charger controller, or maybe a second controller that we connect one of the panels to? And any thoughts on how well the Tracer charge controllers work with LFP batteries?

- a Peak brand 800 watt inverter that he had, probably purchased from Home Despot (link). I'm a bit worried about that dying on him. Any recommendation for a good and relatively cheap inverter? I always use Xantrex inverters, but they're a bit outside his price range.

Planning to buy:

- this 10 gauge wire
- these branch connectors
- these fuses (one for each panel)
- this fuse for the battery

Anyway thanks for any help. Trying to avoid the inevitable stupid mistake or three.

View attachment 96866

Where in Baja? I need a beer!!!!
I'm in Puerto Penasco, Sonora

 

[wrybread]

Where in Baja? I need a beer!!!!
I'm in Puerto Penasco, Sonora

Ha! Beers will be served! And cocktails with solar ice!

 

[timselectric]

Sounds well thought out. You might want to think about DC to DC charging from the tow vehicle, for cloudy days.

 

[gnoeld]

Ha! Beers will be served! And cocktails with solar ice!

But Where> Adonde?

 

[Don B. Cilly]

The controller is programmable, so you can set the charge parameters you want. You need a USB cable.
If you're worried about the over-panelling, just put an ammeter between controller and battery. If you see it getting to 40A often enough, get another controller and put a panel (or two) on it... but I'd say it's unlikely.

If it moves around a lot, the DC converter for charging is a good idea. If it's mainly stationary, maybe a small generator is better.
-

 

[wrybread]

If it's mainly stationary, maybe a small generator is better.
-

I respectfully strongly disagree. Which I bother to mention because I hate generators with a passion and hate to see them promoted on a forum like this, especially for a use case that's so easily accommodated with solar.

There's no way in which a noisy and stinky generator and hauling around gas cans beats solar in this case. In my opinion of course.

 

[wrybread]

But Where> Adonde?

Surf spots between la paz and Cabo. I don't think he knows exactly yet.

 

[Don B. Cilly]

There's no way in which a noisy and stinky generator beats solar in this case.

Well, one way would be to charge on rainy days. Some small inverter generators are neither particularly noisy nor stinky, but if you don't like them... you can run the truck's clean and silent engine instead. It just uses a lot more fuel, but then ;·)

Also, saying "maybe it's better" is not exactly "promoting" is it?
-

 

[wrybread]

Well, one way would be to charge on rainy days. Some small inverter generators are neither particularly noisy nor stinky, but if you don't like them... you can run the truck's clean and silent engine instead. It just uses a lot more fuel, but then ;·)

Even a Honda eu1000 is horribly stinky and noisy and requires hauling gas. This is a solar forum, right?

Anyway all good, but I very very strongly disagree with your advice here. This is easy peezy for solar.

-

 

[HRTKD]

This is a solar forum, right?

Sure it is. But we're also realists here so we're likely to recommend a sure thing instead of a "maybe".

You need to perform a power audit so you know exactly how much power is needed by all these devices. The surge of the ice maker is important.

I have 640 watts mounted flat on the top of my RV. One a good day they'll produce 550 watts if they're clean. I've seen over 600 watts but I think that was due to edge of cloud effect. I don't push my 50 amp controller to the limit on a daily basis.

 

[gnoeld]

Surf spots between la paz and Cabo. I don't think he knows exactly yet.

On the East Cape

 

[Shimmy]

On the generator... it really comes down to daily energy consumption vs the worst-day PV production, and balancing your PV and solar to accommodate it. It is usually cost-effective to size a PV system for about 95% availability, and about twice the cost for year-round 99% availability. Beyond that you need to either be able to load shed (close?) or have an alternate energy source.

Look at PVWatts and the hourly data. Using La Paz, your worst day would have about 400Wh of production, and your worst two-days would have about 1,000Wh of production average per day.

What is the average daily consumption, and what are the hours they will be on location?

You need to think in terms of both *power* and *energy*.

 

[wrybread]

Sure it is. But we're also realists here so we're likely to recommend a sure thing instead of a "maybe".

You need to perform a power audit so you know exactly how much power is needed by all these devices. The surge of the ice maker is important.

I have 640 watts mounted flat on the top of my RV. One a good day they'll produce 550 watts if they're clean. I've seen over 600 watts but I think that was due to edge of cloud effect. I don't push my 50 amp controller to the limit on a daily basis.

I'm a realist too, and this project is easily doable with solar. Hell, a generator would be *harder* since he'd have to lug around gas even when away from filling stations, and be subject to generator breakdowns. He's way more likely to run out of gas or have an issue with the generator than run out of battery.

If he needed air conditioning it might be a bit different of course. Would still be possible, but would take a much more elaborate setup.

I'm a campground host at a campground without hookups, I live off solar 24/7/365, and I pull much more power than this easily. And of course as mentioned this is a bar, I don't think having to bust out the candles a couple days a year are worth changing the design. But I'd be surprised if he even had to do that.

Anyway I hope you're not steering other people away from solar in cases like this where solar is so easy and such a perfect fit.

I haven't needed a generator in 20+ years of boondock RVing. Which doesn't mean I haven't had to conserve power during sunless periods of course, but it's all easily managed. The first thing I do with every new-to-me RV is rip out that gennie and use the space for batteries and tools. And I put my traditional sticker over the generator door: "NO GENERATOR, NO PROBLEM".

 

[wrybread]

On the East Cape

Definitely. And conejo and pescadero etc.

 

[gnoeld]

Definitely. And conejo and pescadero etc.

Muy bueno

 

[schmism]

I think your thoroughly underestimating the amount of ice/cooler needed. The ice maker listed makes 3 lbs an hr. That's enough for like 6 drinks its basically nothing for the purpose listed. only holds 15lbs of ice.
I see a grill, you going to have a ice cooler or plug in cooler for burgers/dogs/grill food? He expecting to run this for 12 hrs? from noon to midnight? 10 am to midnight?

You're going to need a way to charge the battery not on solar.

your guesstimating 300w total.. 10hrs = 3000whr. 280ah*12v = 3360whr. The napkin math says it works. I doubt your 300w draw.

Id vote 12v 1kw Mpp all in one. gives you plenty of overhead (your going to need it) and the option to charge the bats off grid power while at home.

I'd take a small inverter generator and a 2gal can of gas. My inverter honda clone burns about a quart an hr at 500w so getting 8hrs run time out of like $8-10 in gas is very doable. Won't hear it over the music, won't smell it over the beach. $400 plug and play. Put oil in it run it for 200 hrs and sell it on marketplace for $200. buy a new one next summer. no maintance nothing to worry about.

 

[timselectric]

I only have one question.
How does he currently provide power?
I'm going to assume that it will become the backup plan. If solar production is low, he'll just do what he's done before. Because, it evidently worked.

 

[wrybread]

I only have one question.
How does he currently provide power?
I'm going to assume that it will become the backup plan. If solar production is low, he'll just do what he's done before. Because, it evidently worked.

Good point. I set up a system for him using two 36v lithium ion electric scooter batteries I had from an old project, each about 300 watt hours. They have XT60 connectors, and he uses one at a time (they both connect to the same plug). They're connected to a step down adaptor to make 12v. And as you say they'll still be available as backup power. Kind of like the old VW Bugs and their reserve gas tank., even if he doesn't notice from the battery monitor that his main battery is low, he'll notice when the BMS cuts him off, and can then plug in or switch over to the reserve tank. I'll need to find an A/B switch to keep the batteries separate (the 12v LFP battery and the single connected 36v lion battery).

And he's well aware of the dangers of using lithium ion batteries.

 

[scoharri]

I respectfully strongly disagree. Which I bother to mention because I hate generators with a passion and hate to see them promoted on a forum like this, especially for a use case that's so easily accommodated with solar.

There's no way in which a noisy and stinky generator and hauling around gas cans beats solar in this case. In my opinion of course.

Solar Generator??