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https://hackaday.com/2017/08/17/living-on-mars-the-stuff-you-never-thought-about/#:~:text=In%20the%20case%20of%20Mars,build%20up%20different%20charge%20amounts.

Plug in an ethernet cable?

Use the backup feature: https://solar-assistant.io/help/historic-data/backup

I outgrew using my RPi4 for Home Assistant, it just didn't have the grunt, storage or backup capability I felt important as Home Assistant grew and became more important to our home's operation. I migrated to a mini PC using Proxmox to set up virtual machines, one of which is Home Assistant. I...

After runners eat, they fartlek.

The jokes here have taken a step down.

What EV has 200p? Most are 400 V and some 800 V architecture. How can they be 200p? You need 100 cells (or more) in series to get 400 V.

My EV's pack configuration is 104s1p. ~400 V architecture. NMC.

3.2 V/cell is the nominal voltage typically quoted for LiFePO4 chemistry and along with the Ah rating is used for estimating energy capacity. Actual operating voltage will of course vary.

Thanks but science it is not. Just data to be treated with due caution. Real science is far far more rigourous. I have 400 Ah of SLA @ 48 V so 0.1C is ~ 2kW so I think I'm fine on that front. The hybrid bank doesn't charge any faster than ~3.6 kW and that's while the LiFePO4 are taking the vast...

This is what's confusing about your posts. You talk about wanting "UPS" or outage back up: That's a use case where there is bugger all cycling. Hence why suggesting batteries designed specifically for that use case. The batteries sit there at float ready to supply energy when you need it. There...

I'm not convinced large vs small battery is much different from a fire risk POV. A devastating fire can be started with a match, it doesn't need a flame thrower. Most battery fires are caused by small battery failures, usually a charging fault because everything is made cheaply. And yes, the...

When I built a system purely for grid outage backup I went with pre-loved SLA data centre backup batteries (Enersys SBS 190F). Four of those for a 48 V system to begin with, then added another four in parallel later. That gave us about 12 hours of comfortable backup capacity, longer if we were...

Not really, prices are not really all that different here. I looked at DIY but frankly the server rack units I have I could not build DIY for much less, let alone the quality of construction and superior form factor. The small cost difference just wasn't worth it and I could get a battery...

Buy nothing critical / expensive from AliExpress. It's the wild east and chances are you will get screwed. Alibaba yes (if the seller is well known/trusted to you). Your use case is confusing. If a battery is for back up and not going to be cycled, then I'm not sure lithium is the right...

A Tesla Powerwall 2's RTE is 89%. That's about as much as you can expect from an AC coupled battery.

Yes, a faulty pre-made battery. Had pouch cells in 16S4P even though the product was supposed to be prismatic 16S. https://diysolarforum.com/threads/wow-basen-rack-mounts-batteries-destroy-a-home-in-germany.71959/post-986648

My 3-phase Fronius string inverter has an efficiency rating of 98%.

https://www.seplos.com/seplos-vertical-48v-230ah-lifepo4-lithium-phosphate-battery-pack-diy-kits-assemble-box-without-cells.html

I see nothing wrong with having two levels of overcurrent protection, one for low level events to provide basic overcurrent protection as well as one which can handle a much more severe fault (e.g. a battery short). Surely that depends on the quality of the breaker? Aside from fuses I use one...

You're allowed to have a fuse and a breaker. Breakers are very handy for taking a battery offline if required.

The charge/discharge - voltage curve for LiFePO4 is very flat, which means voltage is a poor reference for state of charge, excepting at the very top and bottom. Below 3.0 V / cell there is bugger all capacity left, above 3.5 V / cell there is bugger all room left to take more charge. Do not...

Both DIY batteries. Not clear to me from the photos I've seen on the OP's build thread whether the individual cells had an isolation barrier between them. It does not appear so: I noted they reported leaking cell a couple of years ago. Perhaps a portent of other issues...

SA has no data import feature I'm aware of. I view it mainly as a source of data for other systems rather than as a repository.

Efficiency above 50% load is generally very flat. It's below 40% load that efficiency drops away. For some generators efficiency drop as you approach 100% load. 2/3rd to 3/4 load is generally pretty good sweet spot. By going close to 100% I think you'll just burn more fuel and charge faster but...

Agree although I would say it's but one of multiple strategies required. Which is why I suggest keeping an eye on Australia (esp. Sth Aust). Multiple VPPs in operation. But definitely it's a developing area. VPPs started here in 2016, and now there is something like 500-700 MW under VPP...

Aside from volt-watt, PV inverters should also have Volt-Var management, adjusting the level of reactive power generation as needed, be it leading or trailing as the voltage determines.

Rooftop PV plays a minor but important element in strategies for reducing carbon emissions, and enables use of an idle asset (rooftop space) to contribute towards that. In that sense it has much wider value than just to the homeowner. It is after all the reason why there are incentives around...

That's for the grid's protection, not used as a tactical curtailment strategy. Tactical changes to demand and supply are used to adjust the grid's frequency, not the other way round. Put another way, if you wanted to curtail rooftop PV by employing a tactic of raising the grid's frequency...

Or use a means to reduce exports, or even production, to zero during such times. My inverter has export control, should that ever be required. But if prices are negative, then turn on discretionary controllable loads (e.g. water heater, EV charging) and get paid for consuming.

Pretty much all grid tied inverters have that but changing the grid's frequency is ASTONISHINGLY DIFFICULT and would never be a tactic ussed to throttle grid tied PV. There is MASSIVE inertia in the grid and grid operators work very hard to keep grid frequency within a very narrow band. They do...

People will buy them. There will be die hard off-grid lead acid set ups using 2V cells who need either more or replacement capacity. At worst they have scrap value, roughly $0.50 per kg of battery. Metal recyclers will take them.

The vast majority wouldn't. For those interested, watch the development on this stuff in the state of South Australia. They are the world's canary in a solar mine with solar PV meeting close to 1/3rd of the state's electricity demand and VRE (solar + wind) at 75% so for this year. Yeah it's...

It probably won't need to get quite that high. Check the volt-watt requirements for grid-tied solar PV in California though, I don't have that at my fingertips, but on the high side, I think when voltage exceeds 106% of the standard then the PV inverter's volt-watt mode kicks in and begins to...

You can if you allow grid voltage to rise high enough. Crude, indiscriminate as local voltages vary considerably, but it works. Better to have smarter control though.