Solid state hydrogen storage experiments

Every fusor and fusion system seems to need a vacuum. This area is for detailed discussion of vacuum systems, materials, gauging, etc. related to fusor or fusion research.
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Rich Feldman
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Solid state hydrogen storage experiments

Post by Rich Feldman » Mon Nov 14, 2016 7:33 am

New title here. This is to continue a discussion that Corby Dawson, Rex Allers, and got into under "Any Swagelok Gurus out there?" viewtopic.php?f=10&t=11123

It's not the first time metal hydride storage came up on the forums, usually in connection with storing and transporting deuterium.

Like Rex, I got some "Hydrogen cores" sold under the Brunton brand. They go with a hydrogen fuel cell gadget that has a USB port for charging devices in the field. This consumer product system might not be made much longer. In the the other thread I reported picking up a Hydrogen Reactor and some cartridges at clearance prices. Get 'em while they last!

Brunton cores come filled with 10 liters of H2. That increases the weight from about 90 to 91 grams. Hydrostiks by Horizon Energy, sold for lab use, are compatible but are shipped empty. My inquiry last week brought a response including this advice: "Our HYDROSTIK is evacuated before shipping and there is a little bit of H2 to begin with." and this drawing:
stik.png
I'm planning to follow Rex's lead, and make instead of buy a Stik adapter fitting. The thread is a M6 x 1.0 mm, and the hole in the end admits a 0.071" round pin but not 0.072". The valve is held shut by an internal spring, that needs more than a few pounds of force from the mating device's "opener pin".

My fuel cell ran for the first time last night. It hosted a USB-A cable whose wire leads were broken out for a voltage logger and a load. Following directions, I inserted a full "core" and screwed it into place. Red LED flashed, there was a puff of gas sound, and blue LED came on. USB output, unloaded, had 5.00 volts on it. That dropped to about 4.95 V when 100 mA constant current load was connected.

I noticed occasional, momentary (100 ms?) voltage dips. My watch said they happened every 15 seconds. The voltage logger had been set up to sample every 5 seconds, so maybe it would catch some dips during the overnight run. The 100 mA load was left on for a bit more than 6 hours, theoretically using up about 1/7 of the hydrogen (core rating is 4500 mAh).

Logger was disconnected and plugged into computer USB port to upload the numbers. Sure enough, the voltage dip period was aliased from 15 seconds to 4 hours.
usb3a.PNG
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Here is a detail of the second dip in that log.
dip2.PNG
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Funny thing is, _both_ dips were caught on samples at 0, 15, 30, and 45 seconds after a whole minute, according to the voltage logger's clock, which is designed to keep time for many months. Must resist the temptation to give the Hydrogen Reactor's time base more attention than it needs. :-)
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Corby Dawson
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Re: Solid state hydrogen storage experiments

Post by Corby Dawson » Mon Nov 14, 2016 6:29 pm

Rich,

Do you know if you can refill the Hydrocores via a compressed gas bottle?
I have the instructions to do that with the Hydrostiks.

Cheers,

Corby
Last edited by Corby Dawson on Tue Nov 15, 2016 1:08 am, edited 1 time in total.

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Rich Feldman
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Re: Solid state hydrogen storage experiments

Post by Rich Feldman » Mon Nov 14, 2016 7:04 pm

Why would that not work? They use an AB5-class storage alloy, I bet the same as in Hydrostiks.

The Brunton product launch literature gives two ways to refill empty cores.
1. Exchange for full ones at the store. (which refills them in back room?)
2. Fill them at home with electrolyzer, which consumes distilled water and electricity, and can work at ~ 400 psi. I think Rex has one of those.

I have some parts on hand to make a little piston compressor. Then electrolysis or chemical reaction could run at atmospheric pressure, with temporary H2 storage over water or oil in inverted flasks, or in mylar balloons. H2 cartridge literature says the recharging gas should be very dry; any moisture degrades the storage alloy.

As I said before, the low cost cartridges and fuel cells might not be available a year from now,
so get 'em while they last. "Reactor" is on sale for $59 here, for example:
https://www.bhphotovideo.com/c/product/ ... ellow.html
Last edited by Rich Feldman on Mon Nov 14, 2016 7:25 pm, edited 1 time in total.
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Richard Hull
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Re: Solid state hydrogen storage experiments

Post by Richard Hull » Mon Nov 14, 2016 7:16 pm

The core post here was the kind of post that is so rich and informative. Thanks to Rich Feldman for this exposition on the H2 storage and fuel cell operation with extensive data.

Richard Hull
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Rex Allers
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Re: Solid state hydrogen storage experiments

Post by Rex Allers » Mon Nov 14, 2016 11:22 pm

Glad Rich is getting into this too. I think it was Corby that brought up the idea of using these about a year ago.

I've been planing to write up details of what I've done so far, but haven't got to that yet. Since Rich seems to be ready to make his own adapter fitting, I thought I'd share a few quick pics and notes now.

The original designers and sellers are (I think) Horizon Fuel Cell. They are the same people who sell the small plastic-cased PEM fuel cells that others here have used to make D2 from D2O. There are other posts here that have covered that.

This page shows the basics of the products Rich has described.
http://www.horizonfuelcell.com/minipak
As mentioned Brunton also sells a version of this stuff. On the top of the Horizon site pages there is a link to their Online Store. There are old and new versions of their Stiks and Chargers. The newer versions have a little more capacity but I think the old ones will be fine for our purposes.

The prices on their store page are scary high. The cartridges both new (Pro) and original are $39. The new Pro charger is $729 and the older charger is $419. Almost a year ago (Dec 1015) I bought one of the Hydrofills, I think from Jameco, and I think I paid about $230 for it. The store also shows the small inline adapter/regulator for $130.

I plan to use my own home-made fittings and I have a small standard regulator for low PSI out.

Until Rich's post, I hadn't realized the original Hydrostiks don't come filled. That certainly explains why the one I connected to my valve had zero pressure. Glad I also had a 4-pack of the Brunton Hydrocores; these measured in the vicinity of ~280-290 psi.

Here's a sloppy drawing I made of the cartridges for planning my fittings.
Hydrostik details 1.png
Hydrostik dimensions
And another sketch of the dimensions of the fitting I turned to screw onto the Stiks. I used an 010-sized o-ring to seal between the adapter and the Stik.
my Stik mount.png
Stik adapter connector
Here's a close pic of the Stik output end.
hydrostik end.jpg
Hydrostik output end
The solid "plug" in the center of the opening is the valve. I made a little button with a thin rod to press into the valve. On the empty Stik, I measured about 60 oz force to open the valve. I didn't try to measure it on a full cartridge; I assume the force would be higher.

I made my own adapter fitting with a homemade valve that presses a pin to open the Stik valve. Without going into much detail, here's a pic of my valve.
full valve-adapter.jpg
My adapter and valve
The "body" of the valve started out as a brass 1/4" compression fitting. A bit of lathe work was involved. Turning the knob on the top, pushes a 1/8 rod with the end turned down to fit in the stik opening. Here's a view of what's in the valve I made. I'll try to write up a more detailed version later.
valve parts.jpg
Internals of my valve
My next plan was to try to learn about the charging cycle of the Hydrofill I bought. I plan to turn an adapter that I can screw into the Hydrofill so I can have a Y and monitor the pressure during a charge cycle. Looking into the charger unit, I don't see any pin that would press the valve in the stik. I assume the as the pressure gets up to or above 300 PSI, that the gas just forces past the valve.

OK, enough for now. Hope some of this helps.
Rex Allers

Corby Dawson
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Re: Solid state hydrogen storage experiments

Post by Corby Dawson » Tue Nov 15, 2016 1:07 am

I've been looking at the pictures of and the user manuals for the Brunton Hydrolyzer and the Hydrostik Hydrofill Pro Hydrogen generators. These are used to recharge the Hydrocores and Hydrostiks, as well as to provide Hydrogen for other uses.
The Hydrolyzer runs $250.00 and the Hydrofill Pro runs $600.00.
It sure looks to me that they might be identical inside !
The Hydrofill manual says it produces 99.95% purity and the Hydrolyzer manual says 99%.
They both use PEM electrolyzers.
The Hydrofill Pro mentions using Malic acid powder to regenerate the PEM unit if needed.
Since the Hydrocores are shipped full and one in my application should last years it's probably cheaper not to invest in a refilling unit!
Just wondering what the difference in cost gets you?
Cheers,

Corby

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Re: Solid state hydrogen storage experiments

Post by Jim Stead » Tue Nov 15, 2016 1:30 am

The Hydrocores contain Hydrogen, not Deuterium. If you plan to use them for a Fusor, you will need to evacuate the supplied Hydrogen and replace it with Deuterium.

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Re: Solid state hydrogen storage experiments

Post by Rex Allers » Tue Nov 15, 2016 2:41 am

Jim,
I thought the H2 vs D2 in these things was obvious so no one has mentioned it recently. I think Corby's current application is other than Fusor -- Hydrogen Maser? (am I right)? I think both Rich and I are hoping we can use them for a bunch of Fusor runs from one cartridge charge. I've thought, if nothing else, maybe the cartridges could be a way for someone who gets a D2 tank to share by filling some of these cartridges and thereby sharing and dividing the cost of purchase. This assumes many who get a tank of D2 will have more than they really need and might be willing to share some for a price, if we can come up with a workable design and procedure.

Corby,
The recharger device I got is one of the Horizon Hydrofills (not the Pro). I do not know, but I would guess the Horizon and Brunton versions are nearly identical. I don't know how different the Pro vs. original versions are. As I recall from the specs, the PRO runs to higher pressures. I wasn't aware of the reconditioning (my term) option you mentioned. That could add complexity to the design.

I've never seen any other unit than the Hydrofill I bought. Of course, as a certified nerd, the first thing I did was open it up to see what's in there. The PEM cell is a little bigger and much sturdier that the blue plastic fuel cells we have seen posted on this forum before. I looks to me that all the pressure (>300 psi I think) comes from the electrolysis -- no pump in there. The plumbing is mostly ~1/16" OD stainless tubing. The path from the cell passes through two cylinders about 1" dia and 3" long. They are not the same. The first one has a low pressure plastic tube coming out the bottom. It seems to go to a solenoid valve that gates into a (?) small water expulsion tank on top of the unit. (My best guess so far.) The second cylinder just has a simple 'in' on the bottom and 'out' on the top. Both are with the stainless plumbing.

I don't know exactly what is in these two cylinders but I assume it is probably to get water out of the gas. In the long run of trying to convert from H to D, I'm a bit concerned how hard it will be to purge the H and keep the D pure. Then, so far, I'm not sure if the design is willing to waste some H2 in its water expulsion. That would be bad for our precious D2. I still need to look closer and try to figure out how this thing works, in detail.

So the design is fairly sturdy and complex. For a low-volume custom design, I don't think the ~$200 price I paid is out of line. The other higher prices for most sellers now, and the very high premium for the Pro versions seems a bit too much for me.
Rex Allers

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Rich Feldman
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Re: Solid state hydrogen storage experiments

Post by Rich Feldman » Tue Nov 15, 2016 10:09 pm

Nice work there, Rex.

My first cartridge ran out of gas during fuel cell load test, after 2300 mAh at about 5 volts. Almost 11½ watt hours -- not bad IMHO. Test loads were a 100 mA current source, a 100 Ω resistor, and current source modified for 280 mA. All probably accurate within 5%.
first_gas.JPG
Estimates in small-fuel-cell literature are in the same ballpark.
15 Wh here. http://resources.arcolaenergy.com/docs/ ... TW0719.pdf
13.3 Wh here, from the fuel consumption spec: http://www.fuelcellstore.com/edustack-junior-fcsu-32
Horizon Minipak http://www.horizonfuelcell.com/minipak claims "1 watt for 10 hours", and says most AA primary cells last less than 1 hour at 1 watt. Not really a fair comparison, because 1 watt is a very heavy load for a single AA alkaline cell, even more so for a single LeClanche.

Here are my figures from fundamentals.
Hydrostiks and Cores are supposed to hold "10 normal liters" of H2. Depending on whose Normal temperature they follow, that's about 0.89 or 0.83 grams. The FAQ link above implies the former, in cartridge lifetime discussion -- weight change dropping below 0.72 grams. I bet the capacity value does _not_ follow the lecture bottle convention, where nominal content includes residual gas at atmospheric pressure, accessible only to apparatus that sucks.
gas_works.JPG
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Coulometrically, there's about 23 ampere hours of fuel. 16 watt hours at 0.7 volts per cell. Lossless DC:DC conversion could deliver 3200 mAh at the 5 volt USB output. I see no way to match Brunton's 4500 mAh claim, for charging mobile devices, except to use 3.7 volts -- the nominal voltage of mobile device battery. Need to neglect conversion losses, and actual Li-ion battery voltage during charging (4.1 to 4.2 volts).


Last night I bought a compact digital scale with resolution of 0.01 gram, that came with a 100 gram reference mass. Didn't need a Mettler or other fine brand. Real shopping is better and faster than online shopping, so I visited Monsters of Rock on the way home from work. It's a smoke/vape shop and body piercing parlor, and the most prominent display shelves are loaded with exotic glass pipes. They have a whole cabinet full of compact digital scales. :-)

[edit] Guys, here's a pic the so-called reactor & core. Also a close-up of the parts where they conjugated.
DSCN0059.JPG
DSCN0068.JPG
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Rex Allers
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Re: Solid state hydrogen storage experiments

Post by Rex Allers » Wed Nov 16, 2016 2:09 am

Rich,

Good details. Using the hydrogen for fuel cell for electric energy isn't what we really want, but I do get that how much they hold is important. I hadn't really thought about getting the last little bit out of them. It remains to be seen if that will be something to care about.

I do have a couple of the small plastic electrolysers too. If I used them, I had planned to use a small mylar balloon as the intermediate, room pressure reservoir for D2. I might try that too, eventually.

I also recently bought a small digital scale, but mine was from ebay china seller. Unfortunately, the one I bought only goes to .1 g resolution. I guess not good enough to trust any difference due to gas in the cartridge. I weighed the 5 cartridges I have here and the total weight seemed to be about 105 to 107 g.

Nice pictures you took. There seems to be three lines of info etched on the bottom of the cartridge. I assume they are: serial number, mfg date, use-by date. I looked at the 5 I have here and they all seem to have exactly the same dates as yours; no difference between the Bruntons and the Horizon one. So, if I am interpreting right, they must have all been made in a big batch on Dec 20, 2013 and are rated for 10 years of use. Out of curiousity, I compared that first number (S/N ?) on the 4 Bruntons that came in the same box; they were far from sequential. Not important, I just found it interesting.

You got a nice clear picture of the port that the cartridge screws into. It looks very much like the output port in my Hydrofill recharger, except on yours the pin that opens the valve on the cartridge is easy to see. As I mentioned earlier, the Hydrofill doesn't have a pin.

Here's the output port in the Hydrofill...
Hydrofill port.jpg
Hydrofill output port
The white gasket looks the same. I pried the gasket out and made a sketch of it and the port dimensions, as best I could.
Hydrofill out port.png
Hydrofill gasket and port
I've never seen a gasket like that, not a simple shape. I assume it is a custom design. The material is white and pretty soft "rubber". I'm not well versed on plastics but it seemed a lot softer than something like Viton, more like vinyl.

Oh, BTW, that picture you got from Horizon of the cut-away view of the cartridge was nice to see. Too bad it didn't include any of the internal valve. Looks like it could have been there originally, but that area was erased before sharing.
Rex Allers

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