kirksmith

The pumping cost constitutes a 1-2% total penalty on round-trip energy efficiency for a well-designed flow battery.

I take your criticism, but as for your comment that it's "a student project at best"... we do have PhDs (mine in flow batteries !) and manage this project in our spare time, at our homes...

Our small team is fully qualified to work at any flow battery company. Just give us some time and let us work on it full-time for a bit (which will happen soon). The linked post on top was a blogpost I cranked out in a few minutes one night, not something I ever expected to be on HN.

Hey, thank you!

The liquids are reusable, and are charged and discharged repeatedly without needing to replace the fluids. In other words the system is closed with respect to mass, only electrical energy (and minor amounts of thermal) are transferred in and out, reversibly. Flow batteries are similar to so-called reversible or regenerative fuel cells for this reason.

The answer to how long it lasts depends on many factors, and we hope to provide a clearer picture of that in our work.

In a well-designed system, they can last extremely long in comparison to, say, lithium-ion batteries. This is because flow batteries have different degradation pathways that are less severe and, if present, can usually be overcome through other solutions (e.g. electrolyte rebalancing, see ESS's "proton pump").

*typo: meant to say we have a grant from NLnet https://fbrc.dev/posts/NLnet-funding/ , which will cover a few months of full-time work (for one contributor)

Bingo, this is exactly the plan. Of course there are non-trivial engineering challenges when scaling up, but that's the rough idea.

Iron plating is a hydrogen evolution nightmare. It's interesting for sure, but not feasible for a simple demonstration system, due to pH issues and oxidation state drift from hydrogen evolution. We do plan to explore it in the future, and move onto larger cells/stacks that offer practical amounts of storage.

I agree... part of that frustration is why we're working on this project! See my short post on "Why you can't buy a flow battery today"

https://dualpower.supply/posts/motivation-OSHW-RFB/

Yeah I am self-hosting with a VPN and following all the best practices I know (not my expertise), not surprised there's some warnings going around.

It's in the graph image, CE: 88.7%

We are planning other electrolytes beyond zinc-iodine (including iron salts), but this one happens to be practical for getting started due to widespread availability, tolerance to oxygen (avoiding requirements of purging with inert gas), and low hydrogen evolution rates (quite unlike iron-salt systems, which are practically H2 electrolyzers!).

Thanks! This kit is for R&D and educational purposes only, because of the use of positive displacement pumps (peristaltic, diaphragm, etc) instead of centrifugal pumps, it will never be able to effectively work as a battery since the pumping energy cost is high.

Once we have materials and electrolytes validated with the kit, we plan to move to a much larger cell size which will be part of a flow battery stack, which would actually function as a battery for useful storage.

some context: https://dualpower.supply/posts/motivation-OSHW-RFB/

Wow, hi all, I am Kirk, the author of this blogpost, never thought my small ARM board home server would handle this much traffic!

Currently reading through these posts, feel free to ask questions. Great to see interest.

FYI, I am quitting my postdoc job in two months to work on this full-time, which should help the rate of progress, but my main source of income will stop. We hav ea small but it will only cover a few months of full-time work.

If you want to support the project financially we have an Open Collective here: https://opencollective.com/fbrc/donate

We'd really appreciate any support you're able to give, which we'll use to push this open technology as far as we can! We are planning to start work on a much bigger stack after the kit.