[jakedata]

I have been building, rebuilding, optimizing several small-scale solar installations off-grid for nearly 30 years. These systems need to "just work" for guests and family, not be so finicky and fragile that people are afraid to use them.

The number one innovation that has made off-grid life more than just tolerable is low-voltage LED lighting. It's wonderful to be able to work in a well-lit space without worrying so much about battery life. All lighting is on mechanical timer switches, walking out of a room and leaving the lights on is a bad habit that's hard to break.

The next innovation to increase utility and practicality will likely be LFE (LiFePO4) batteries. In 30 years I have worn out or accidentally destroyed dozens of lead-acid batteries in various forms. They are fragile and heavy. Moving them by boat is brutal. I have high hopes that my current set of replacements will be the last ones for many years.

Electrical loads keep increasing. First lights, then radios and phones. Now laptops and a long-range WiFI link for remote work, and overnight power for CPAP machines. Next up will be DC solar powered refrigeration to displace propane. That will require more panels, more batteries but will have an immediate and long lasting benefit.

It has been a long and mostly satisfying project which has benefitted everyone around me.

[eternityforest]

Solar is such an amazing tech. It's not perfect, but what else lasts 30 years, but doesn't involve compromising and giving up features? Even people who hate green energy all seem to like solar for some things, they just don't believe it's the answer to everything.

The batteries are the weakest link, but now we have LTO batteries (20k cycles), and Sodium ion starting to be available.

[happytiger]

Ever use the EG4 18KPV? I’ve been looking to build a grid tied off grid-style system because it’s very difficult to unplug where I live legally (thanks PG&E!) and they look fantastic. Just curious if you’ve ever used them?

[jakedata]

No grid to tie into, so no need for that level of interoperability. I'm more likely to centralize my battery storage and solar collection once I understand the tax credit ramifications of a non grid-tied system.

[happytiger]

Gotcha. They make a product called the eg4 6000xp for fully off grid applications that looks kinda awesome.

I just want to unplug. I think that you can claim the full 30 percent if you’re in the US.

I looked it up for you and here’s what I found…

https://www.energy.gov/eere/solar/homeowners-guide-federal-t...

[Borg3]

likely be LFP? I think those batts are already available. The problem is they arent that great. Power density is low, they are advertised for 2000 cycles so I guess reallife is sth like 1500, so around 5 years only. We really need great bettery innovation with decent lifetime (minimum 10 years, 20 years preffered) and decent energy density. Once that will kick in, we could really start smart grid revolution.

[jakedata]

I am watching performance of the new LFP battery. Weight is not an issue in a stationary installation like mine, longevity and ruggedness are everything. The space is unheated throughout the winter and cold has done terrible things to previous batteries.

So far the one LFP battery I have deployed has been operating properly but there were some initial compatibility issues - my solar regulator did not interact well with the BMS despite alleged compatibility. That cost me several hundred dollars in downstream equipment damage due to voltage surge.

I am watching the new solid-state lithium batteries with great interest.

[thebruce87m]

What about sodium batteries?

> Even under frigid conditions, sodium-ion batteries can maintain a high degree of ion mobility within their electrolyte. This increased mobility ensures that the battery can continue to deliver reliable performance when temperatures drop.

https://nadionenergy.com/why-sodium-ion-batteries-perform-we....

Or is it temperature cycling that causes your problems?

[jakedata]

Sodium batteries aren't exactly commodified yet, LFE is readily available and not terribly expensive.

For the most part I don't actually need batteries that work in the freezing cold, so much as survive it unmaintained for months at a time. I had solar panel damage last winter that allowed one battery to discharge enough to freeze. That is fatal to a standard flooded lead-acid battery.

If my test battery survives this winter then I will consider using the same type to replace lead-acid ones as they age out.

[Borg3]

Oh I read the wiki article about them. Looks interesting indeed. Decent density, they claim 10000 cycles so if its real world 5000 cycles to start with thats solid 10 years!

[eternityforest]

Lithium Titanate will probably last 20 years. It's just expensive. AliExpress sodium ion batteries are claimed 4k to 6k cycles, no idea if that's real but it's cool to see stuff happening there.