Solar Panels

[Urandom]

Where is the best place to get panels now for a DIY 12v system.
I heard the guy by J Hara is no longer doing business.
Someone told me that Home Depot now has some called "Grape" and even kits that come with a controller and wireing with the panels.

I just need to put me together something to run a mini fridge and water pump. Hell, if it works out well enough I might get real internet.

[terracore]

Home Depot sells different brands that they will ship here periodically as part of their "deal of the day", but I haven't found most of their deals are any better than amazon.

Here's a "complete" 400 watt kit: https://www.amazon.com/s?k=solar+panels&linkCode=ll2&tag=pw016-20&linkId=85409f6a7c36165eb1c4e0525e0517da&language=en_US&ref_=as_li_ss_tl

"complete" meaning, not really complete because it doesn't include inverter or batteries. You can select different sized systems.

I don't know what panels are going for these days. I have a mix of 100 and 150 watt panels. I generally paid about 70-80 cents per watt (includes shipping) buying them over time.

I don't know that you want a mini fridge, they don't use significantly less energy than a full sized fridge. They are usually horribly insulated. Any "frostless" appliance is going to consume more electricity being frostless than used for actual refrigeration. Your best bet is to use a manual defrost freezer that can be turned up high enough to be used as a refrigerator, or get one of those gizmos that controls the power to the unit based on a temp probe so any freezer can be converted to a refrigerator. Uses a fraction of the electricity as a typical household refrigerator.

You didn't say where you live but you'll probably need a small generator to keep the batteries topped off when there has been no sun.

[Urandom]

Thanks terracore. I live in Kau now, used to live in Leilani.... seems like so long ago now.

Are you sure that Amazon will ship solar panels to the island? I haven't ordered from Amazon in years but just assumed that something of that bulk they would not do it.
And I had forgotten about the chest freezer conversion. Do you happen to have some real life numbers on power usage for those?

I was honestly hoping to get a 400-600 watt system and maybe 2x12v or 4x6v Costco golf cart batteries and run a 12v system for this. I don't have a lot in power needs... seriously just a fridge, lamp, and charge my phone/tablet.... and I can't lie, I'd like to get real internet (even if it is just Aloha Broadband).

[tada]

I bought some panels from Interisland 4 years ago.


http://www.solarsupply.com/products/APPLIANCES.aspx

My understanding is it a wholesale biz on Oahu but can walk up on Neighbor islands. Good thing I bought a Whynter a.c. dc freezer from HD last year before the China tariffs hit. I keep checking for a break on overpriced a.c. dc fridge but those material shortage is killer.

[MarkP]

Most of the panels I have now were bought off of Craigslist. They were brand new from an installer going out of business. I would definitely try Craigslist. Had to pass once on a whole containerload that as on Oahu that would have worked out to $0.50/watt if it had been on the Big Island and if I had wanted a whole container full.

I advocate skipping the small 12 volt system and going right to a 48 volt system large enough to get a standard modern 120VAC fridge. That would be so much more flexible and user friendly.

For example:

https://honolulu.craigslist.org/big/for/...66135.html

[kalakoa]

There is a smaller size of panel that can be trivially shipped, usually ~100W. A "full-size" 300W+ is about 3x5.5 feet, see Mattos or Alpha electric (or Gexpro, if can, not sure they deal with individuals anymore).

Proper mounting hardware is worth the cost, and it's better for the panels (they like to breathe).

A 4CF mini-fridge uses about the same power as the 10CF Magic Chef fridge-freezer combo from Home Depot. Best cheat is a timer to turn it off at night while you're sleeping. Ballast the fridge with some bottled water or soda or beer or something.

MPPT controller for the win. I like the blue one from Amazon. It will run at 12-24-48V with wet or gel batteries so you can change your mind later.

Pure-sine inverter will run the fridge more efficiently.

Sealed gel AGM-VRLA batteries are worth it. No maintenance (including no equalize cycle).

[tada]

I recall used to walk up at Velcro


https://www.gexpro.com

[terracore]

"I advocate skipping the small 12 volt system and going right to a 48 volt system large enough to get a standard modern 120VAC fridge. That would be so much more flexible and user friendly."

Agreed but that scales up the startup costs and makes finding emergency replacement components harder to source. Staying in the 12v realm doesn't require leaving the safety net of being able to use anything in the automotive world.

A 12v system can handle a full sized fridge no problem. Mine is running a full sized fridge and two freezers, among other things, and can even start and run a 1.6 kw 1 HP well pump that makes the lights dim when it kicks on running on grid (serious startup draw). I would definitely recommend gear that accommodates upgrading later.

Amazon ships solar panels to the island now. My favorite were a 150 watt model that were square. Their dimensions lined up perfectly with Z brackets to mount on corrugated roofing. They were about as large as I wanted to deal with going up and down a rickety old ladder in a 1 man DIY situation.

Definitely go MPPT controller, otherwise you're leaving a lot of power behind. Most units allow for an array 3x the capacity of the controller. Panels are cheap enough you can oversize the system to generate more power under cloudy skies without frying anything when there is full sun.

---

"Do you happen to have some real life numbers on power usage for those?"

I read an article by an off grid Aussie who gave a lot of data and over time determined a converted chest freezer used 10% the electricity of a similarly sized regular kitchen frostless unit. But also he was comparing a standup refrigerator to a chest freezer.

In my own personal use the freezer uses under 90 watts when it is running. The refrigerator uses more than that, and it runs almost all the time. The refrigerator uses over 700 watts when it's in defrost mode, as measured by my kill-a-watt. I've only ran a freezer as a refrigerator myself temporarily when our fridge was kaput. We have access to the grid and don't need a permanent low wattage solution, so I don't have any long term data on my own.

In addition to saving the power normally 'wasted' in defrost mode, manual defrost freezers tend to have better insulation, and chest freezers in particular lose less cold air when they are opened. On the other hand, it's a pain if what you need is at the bottom of a chest freezer.

While we're on the topic of electricity consumption, a lot of new off-gridders are disappointed to find out their gas ovens use a LOT of electricity. Due to nanny state safety laws, when the oven is being used an electric "glow bar" has to be used to ensure the gas is always ignited. They use between 400-700 watts. You can circumvent by using a non-residential gas oven that doesn't have the requirement (like a camping, RV, or marine oven).

[Urandom]

[...]

Thanks mate. Been reading up on this since I last posted. I like the idea of the conversion, but not sure if I want to be reaching into a 'bag of holding' every time I want a cold beer... something to think about.

I see that Renogy has a 400 Watt "kit" with a MPPT charger on Amazon for $600. I'm sure a few bucks can be saved by piecemealing the thing together (and likely get a better CC) but there's something to be said for getting a "kit" and having a company to call if I hit a snag with any of it.
I could grab a Samlex 1000W PST inverter... and one of their battery chargers (I like Samlex, used them in the past for various things). I already have a good quiet Honda generator.
4 of the 6v golf cart batteries from Costco should give me plenty of Ah @12v - can always top it off with the gennie at night.

This sounds like it would get me started, allow me to leave the cabin during the day knowing that the batteries/solar should keep the fridge going - maybe add an additional "kit" later should I get tired of using the generator so often.
Just thinking out loud here.

[terracore]

I have some Renogy equipment including their inverter and can speak first hand that as of about 2 years ago their tech support was virtually non-existent. Nightmare might be a better description. Their equipment on the other hand, when you don't get a factory dud, is excellent.

My first PSW inverter was a Samlex. So was my second, third, and fourth. That was one purchase and 3 warranty replacements. #4 is still in the box because I gave up on them. Moving their production to China has ruined their quality, at least on their lower priced equipment. Fortunately their customer service is top notch. They paid for shipping all those inverters back and forth to Canada to keep me happy. Unfortunately one of the failed inverters failed by deciding 80 volts was as much as it was going to give and it fried my solar hot water controller. Not covered under their warranty. Fortunately everything else I had hooked up to it had a UPS between it and the inverter. Lesson learned.