Beach cabana's solar set up

[PalawanWolfe]

Great points about the inverter, I had not thought about the wire size needed for to make that work before. AC and DC LED lighting is similar, installed DC USB vs. customer supplied USB is a wash too, the problem I was trying to solve with the DC system is fans. A normal fan will blow my system requirements through the roof and I can not find a source for efficient AC fans on Palawan. Shipping is not really an option as it is expensive, it will take months to get through customs, and it will almost certainly get slapped with a 60% tariff. I can however put quite a few 'Sunlar 28" inch 12v DC Ceiling fans' and 'Hopkins SP570804 Go Gear 12 Volt Oscillating Fan's into my checked baggage.

Do you have any suggestions for my fan conundrum? Or should I just stock the cabanas with DC hairdryers and tiny inverters.

The timers are a great idea!

[littleharbor]

use timers on all the stuff, guests will abuse power.

When I saw 2 fans for 10 hours I was thinking more like 2 fans for 24 hours.

[Mike90250]

Once you get loads like hair dryers , overall it will be simpler to have a central inverter @ 48V to run it all. Let guests bring their own USB warts, put in the efficient ceiling fans and lights, use timers on all the stuff, guests will abuse power.

[PalawanWolfe]

Not going to work the way you think.


Fan and lights you can get by with on 12V. But that inverter is going to suck a bunch of amps at 12V [ 1200w /12v = >100a ] That's going to take a really fat cable to each cabana.
Could do it with a central inverter and run 120VAC to each cabana.

In my original post
'In order to keep the size of the charge controller, and wire down I would like to run a 24v system and then use one 20amp, 240w 24v to 12v converter in each cabana.'

The cabanas are about 30 feet from each other, with a 24v system do you still feel that running one central inverter is better?. Also, are you suggesting I scrap the DC idea altogether or that I run DC for most items and a parallel AC system?

[Mike90250]

Not going to work the way you think.

I want to run almost everything off of DC. I have test purchased a couple 12v DC fans, they pull 15w and move enough air to be sufficient. 12v DC LED lighting seems very efficient. I will also install combination 12v usb charging socket/cigarette lighter sockets. That should cover most of the power needs, I will however install an as needed roughly 1500w inverter in each cabana that can be turned on if someone wants to run a small hair dryer or something.

Fan and lights you can get by with on 12V. But that inverter is going to suck a bunch of amps at 12V [ 1200w /12v = >100a ] That's going to take a really fat cable to each cabana.
Could do it with a central inverter and run 120VAC to each cabana.

[PalawanWolfe]

I have a remote 13ha beach property in the Philippines that I am building some vacation cabana's on. Two are almost finished with plans for another soon. I would like to install a solar system for them. I have done a lot of research but would love someone to pick my plan apart and tell me where I've erred. I'll start with an overview and then get into load and proposed equipment.

I plan on a single solar array on one of the cabana's that will also serve as the main solar hub. I want to run almost everything off of DC. I have test purchased a couple 12v DC fans, they pull 15w and move enough air to be sufficient. 12v DC LED lighting seems very efficient. I will also install combination 12v usb charging socket/cigarette lighter sockets. That should cover most of the power needs, I will however install an as needed roughly 1500w inverter in each cabana that can be turned on if someone wants to run a small hair dryer or something. Depending on the availability of a small DC fridge/freezer I may have to put in a bigger inverter in the main cabana.
In order to keep the size of the charge controller, and wire down I would like to run a 24v system and then use one 20amp, 240w 24v to 12v converter in each cabana.

I Figure that the worst case scenario load per cabana will be as follows

2 fans running for 10 hours at 15w each 300w x3 900w
3 lights running for 5 hours at 10w each 150w x3 450w
device charging per day, total guestimate. 200w x3 600w

The main cabana
1 mini fridge/ freezer 750w
1 45psi 12v DC RV pump running 2 hours a day 75w



Total 2775w



I do not know what specific panels will be available but plan to run a 900-1kw array. They have a year round 5 hour solar power window. That should be plenty to power everything and some power tools during the day.

I have been looking an MPPT charge controller from ROXSAT MPPT-24V80D. I am not tied to it, it is cheap so i suspect it's not great. My main question about it is that it has a slot for 2 different battery banks. Can it really manage two different banks. If so, would it allow me to buy half the batteries I will eventually need and then buy the rest later without the usual new/old battery problems? Short of that will it manage parallel strings better than normal?


For batteries I will also be limited to what I can get down there but I plan on using 4-6v, 200ah batteries in series, with another string running in parallel. I will need either sealed AGM or gel batteries because the property will spend most of the year unattended. That gives me less than a day extra on the batteries, hopefully my over estimation of the load and the reduced load from fans on rainy days helps to mitigate that. I will probably start with one string and then later replace buy the full sized bank and relegate the older batteries to a different system for a bar/grill area.

For inverters, I plan on using whatever is available locally. I don't see why i would even need a pure sine wave inverter.


Do I need a low battery voltage disconnect since the system will only be attended by our local caretaker for most of the year?

I can bring the charge controller, some inverters, low voltage disconnect if needed, and the DC fans-lights-usb socket with me on the flight.


Comments?