Offgrid Solar Battery Option

[Grant H.]

I found these while browsing the internet in Taiwan, and thought I would share here.

A little more expensive per KWH than lead acid, but a way better product overall, and close enough to be worth exploring if you are looking at large battery banks. For reference, the heavy plate lead acid batteries I usually put with large solar installations are ~$2250 for 2.5kwh. So these at ~$2800 for 3kwh are a steal, and they are way more space efficient.

https://simpliphipower.com/

[clodhopper]

for giggles... roughly how many of these batteries would be needed on a typical residential home in Colorado?

[marineimaging]

for giggles... roughly how many of these batteries would be needed on a typical residential home in Colorado?

When you say typical, do you mean 110/220v appliances and lights or more conservative 12v systems?

[clodhopper]

Both.

Always looking for more options and data input. I have been working out solar systems and when looking at battery costs, it seemed the easiest way to slim the investment by arranging a high panel, minimum battery arrangement. Essentially do all your whatever (laundry, cooking, etc) during the day when the sun is up, then shut it all off and run bare minimum lights at night. However, if I can bulk up the battery storage a bit, I can swing running the heater blower overnight.

[Grant H.]

Sorry guys, my down time has been less internet centric recently... I've been in and out of the country and have been using my down time for house remodeling and other projects...

So, to start off... I fubar'd my math earlier. These are nominally 3x the cost of Lead Acid, but the value proposition is still there as they will easily outlast a L/A bank, probably by more than 3x the life.

How many of these for your house depends on your average electricity usage. The average household in CO is usually around 600-800KWH per 30 day usage period. So, if we take the 800 number, that gives some houses a cushion.

So 800/30 is 26.66KWH per day.

The batteries I linked are rated at 3KWH@80% depth of discharge. This means you actually get the 3KWH while maintaining the batteries health and the 10yr/10,000 cycle warranty. So, to go completely offgrid without much of a buffer you would need 9 of them. In the interest of cloudy days, or snow on the panels, I would probably aim for ~12 to provide a longer buffer.

Understand, that is a 100% off grip usage scenario, which many are unlikely to move to in their current homes. To use these in a more likely scenario for lots of folks, you would only need a few to maintain the items you want to move off the grid and onto either a grid tie system (grid charges the batteries and then batteries discharge during power outage) or a separate set of circuits that are fed by a smaller solar array and battery system. For instance, your deep freeze, your furnace, and maybe just a few lights in key areas. Depending on what you have interest in supporting, you can get away with 1-3 batteries and still make it through power outages without loosing any frozen food, heating in your house, etc...

I have only toyed around with small solar systems on my current house, and I will likely be moving in the coming year, but with a more permanent house, I intend to be mostly off grid, with grid power for the welders, lathe, mill, etc.


If you want me to run through more complete/accurate numbers just find out what your average usage is across a 6-12 month period, and I can run through the numbers and also include panel calculations.

[Grant H.]

Both.

Always looking for more options and data input. I have been working out solar systems and when looking at battery costs, it seemed the easiest way to slim the investment by arranging a high panel, minimum battery arrangement. Essentially do all your whatever (laundry, cooking, etc) during the day when the sun is up, then shut it all off and run bare minimum lights at night. However, if I can bulk up the battery storage a bit, I can swing running the heater blower overnight.

This is certainly a good option. Panels are cheap now days, and batteries are getting better. The ones I linked are claimed to be good for 10,000 cycles, which is 27 years if you cycle them 1x per day. When you consider that lead acid will be, at best 5-7 years reliably, the additional cost for Lithium starts to make more sense. Plus no off gassing, no maintenance, just hook them up and go.

As for the "more efficient" 12V systems, I would not recommend running a house on a 12V solar system. Honestly, 24V doesn't appeal to me all that much. 48V is where you want to be. Using 48V coupled with good quality charge controllers and inverters will get you 110/220V without significant loss or heartache.

[clodhopper]

27years is a much better lifespan for the investment cost. That puts batteries back into consideration. I need to research it more.

So I understand you, panels in series to create the 48v, then inverter to 110 for transmission and use? What brands do you recommend for charge controllers and inverters?

[Tmcw]

Inverters available for both 110 & 220 output. We stack two Outback inverters to achieve both of these voltages. Use sixteen L16 lead acid batteries. This gives us a lifestyle like we are on the grid. 2-3 days of power. Only had to fire up the backup generator twice last year! Would love Lithium or nickel iron battery system but expensive.

[Grant H.]

I'm finally back on the board after ~ 2months being gone.

I'll post some thoughts here in a bit once I get my thoughts organized.