# Flow Batteries



## PhantomPholly (Aug 20, 2008)

I think that almost any chemistry can be made into a flow battery.

I also think all of the flow batteries in existence are in laboratories.

Good idea, though - recharge at home when able, replace the goo at a filling station for long trips. Best of all worlds.


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## PZigouras (Jun 5, 2010)

Nevermind... I figured it out.

Apparently, lead-acid flow batteries are NOT rechargable. The lead plates turn into lead-sulfate as the fluid passes through, but it cannot be changed back into pure lead (unless you stop the flow and recharge it with the liquid not moving).

They do use flow batteries in certain applications, but it's rare. I was only able to find one installation in all the research I did...

- Paul


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## Coulomb (Apr 22, 2009)

PZigouras said:


> Apparently, lead-acid flow batteries are NOT rechargable.


Ah. So you could still recharge your own goo at home, but with the extra time and space and mess and fluid losses... it doesn't seem very attractive. Possibly also a fire risk.

So those that are rechargeable *and* replaceable at a fill station are of more interest.


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## Crash (Oct 20, 2009)

This may be more appealing to you as far as flow batteries go:

http://dvice.com/archives/2011/06/battery-goo-cou.php


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## dirtfarmer (Jun 13, 2008)

I am strongly considering making a flow battery. Flow batteries have the reaction taking place in the liquid instead of the metal so the metal DOES NOT DEGRADE and there's very little solid metal involved. Complete discharge to zero does not hurt them at all so there's much more usable current. I'm sure everybody's fully aware that most normal metal batteries have 80% of their capacity that you cannot use without damage. Capacity is also increased by simply increasing the tank size (small battery, large tanks). Making the battery looks much easier than converting the car. They're supposed to last thirty years. Repairs should be easy to go another thirty.

There seems to be two main kinds--vanadium or zinc-bromide. Vanadium has the advantage that both sides are the same chemical. Zinc bromide is cheaper. Vanadium seems to be a more dangerous chemical but more powerful, but I guess all batteries that contain acid are somewhat dangerous. Research "vanadium redox flow batteries". I think I'm going to make the vanadium kind since that seems to be the most common.

I don't have an electric car yet but plan to have one someday. I hope to make the battery power my home first, but have tanks large enough to pump to the future car when it's built. You could even charge more electrolyte at home while you're driving the car. There has been talk of future service stations offering to exchange electrolyte just like pumping gas.

If anybody else is working on this approach I'd like to compare notes with you. I am also putting together DC refrigeration but that might be off topic for this group.


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## Roy Von Rogers (Mar 21, 2009)

What do you mean by dc refrigeration, using a dc compressor ??

That, already exists.

Roy


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## dirtfarmer (Jun 13, 2008)

No..I'm certainly not reinventing DC compressors. I'm just building a super insulated a chest freezer using a Danfoss 12v compressor powered by solar panels (I didn't invent those either). I'm hoping our solar panels will power a few necessary household items and a car via a flow battery.


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## Roy Von Rogers (Mar 21, 2009)

dirtfarmer said:


> No..I'm certainly not reinventing DC compressors. I'm just building a super insulated a chest freezer using a Danfoss 12v compressor powered by solar panels (I didn't invent those either). I'm hoping our solar panels will power a few necessary household items and a car via a flow battery.


The reason I asked was because do hvac and refrigeration, in case you need some help, just send me a pm.

Roy


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## dirtfarmer (Jun 13, 2008)

I appreciate that. I am not very good at hvac. I can get the job done if it's not too complicated. 

This battery thing has me really motivated though. I really think flow batteries are the way to go for both cars and homes. I think it can be done by the do-it-yourselfer. We are going to have to be more energy self-sufficient. I don't have any confidence in "the system" working very much longer.


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