Caleb Mayfield

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since Dec 15, 2016
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Western central Illinois
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Recent posts by Caleb Mayfield

I got into Linux about 9-10 years ago when I started learning about Arduino. It started innocently enough, just experimenting with Ubuntu, Puppy Linux, Tiny Core, and DSLinux on old Thin Clients. Pretty soon I was compiling my own custom configurations, ordering Raspberry Pi's and teaching myself Python scripting. My wife wasn't sure what to think. She was concerned I might need counseling, because who really gives away a free OS? and there's no way it's better than Mac. (She does graphic design and has a MacBook Pro).
I started to loath going to work where I was forced to grind along on a laptop running Windows. I configured a thumb drive to run Ubuntu and would secretly boot my work machine off of that when I really needed to get things done. The IT guy knew and tolerated it so long as I didn't create any problems for him.
Then it happened. The project I was on was moving into a new office and they couldn't access the keycard system. All three IT guys worked on it for a day and a half. On the second day, one of them popped his head in my office and told me what they needed, and that they were going to lunch. The Server room would be open while they were gone.
When they returned the key card system was accessed and our new cards were being programmed. Nothing was said, but he knew.

My wife has a smoldering love-hate for Linux after the numerous times I have converted client files or burnt discs for her when her "perfect, amazing, and faultless Mac OS" refused to do as advertised.

I just smile. She purses her lips and storms off. I may convert her yet...
1 week ago
Battery Testing and Sorting

Currently I have a baseline target of 104 batteries at 2600mAh. That will provide the total capacity that I am targeting, but I also need to evaluate actual power draw and cell load. I plan to cover that later, just know what it's something that needs to be factored in. Right now though I am collecting cells, testing them, and sorting them. So what do we test for? In general terms we are looking for the battery capacity, ability to hold a charge, and internal resistance as measured by AC Impedance. If you start digging into this there seems to be a lot of opinions on how to test and sort batteries, what is most important, and the order you should do them. I'm of the opinion the AC Impedance test should be done first. As Ken pointed out though, to make any meaningful determinations from this test you need to know what the AC Impedance is supposed to be to begin with. So far LG, Samsung, and Sony have the best Product Data sheets that I have seen with LG providing really thorough data for the batteries I have looked into. A good place to start is the Cell Database over at Second Life Storage. If they do not have your battery listed, and there is a number down the side of your battery type that into Google along with Product Data. If that doesn't turn up any results, I recommend looking for a battery you can test.

So, in my case I'm starting this build using LGABB41865 batteries. The LG Model number is ICR18650B4. AC Impedance is 70 mOhms or less for my cells.
To test the AC Impedance, you really need to invest in a unit that uses 4 wire testing at 1kHz AC. We could start a whole new thread on this topic alone, but I'm going to leave it at this more or less. The YR1030 units seem to be the best bang for your buck in terms of cost vs decent measurement. For $50-$75 it's a relatively cheap way to add a degree of safety to this project. Having a unit to take measurements with can also help you down the road in troubleshooting if you start having a pack that is giving you fits.

After collecting battery packs, I need to remove the individual cells, clean the nickel strips from the ends, and inspect for any physical damage. WEAR GLOVES AND SAFETY GLASSES. Set aside any that have dents or dings. Those go to the recycler.(Overview video. I advise against the "whack it on the ground" method) Now that I have a pile of cells, they need to be tested. By checking the AC Impedance now with the YR1030 I get cell voltage and a PRELIMINARY impedance value. I say preliminary because the product sheet specifies testing at full charge. Why not just charge the cells? Time. It can take a while to charge a cell, so I like to sort out anything I don't want to waste time on now. Yes, there will be more getting discarded at each level of testing, but his get's the bulk of them for me. In my first batch of 99 cells, 2 were DOA. Totally dead. 7 of them tested over 70 mOhms(over 85 mOhms at full charge). Of the remaining 90, they tested between 40.8 and 60.5 mOhms. I use a sharpie and write this preliminary value on the side of the battery.

Now that I have sorted out the batteries I'm mostly interested in, I need to charge them and test them for capacity. I use an Opus BT-C3100 v2.2. There are others out there that in some respects are better, but I like the features of this one and it does well. There is a guy in the forums on Second Life Storage who has run numerous tests on multiple units of different makes and models. The Opus measures up well. I believe his review is in the FAQ now.
Four at a time, the batteries are loaded into the Opus and run through a test cycle. The cycle charges the battery up to full capacity, rests, then discharges it at a set rate until the voltage drops to a set voltage. It then calculates the capacity of the battery in mAh based on how long it took to discharge to said voltage. After it has completed the discharge test, it then charges the battery back to 4.2 volts and blinks between FULL and the mAh rating. I use a sharpie to write that value on the side of the battery below the mOhm value. The cells get set into a tray and the next 4 go in. I'm doing blocks of 36. When I get 36 batteries capacity tested and recharged I let them sit a few days, then run back through the AC Impedance test. If the value is +/-0.3 mOhms I call it good. If there is more that that I will remark the battery. I also check the voltage as the YR1030 provides that along with the mOhms. If any battery has dropped more than 0.5 volts since charging I pull it from the block and monitor it over the next few weeks to see if it really is self discharging or not. Anything that is self discharging gets pulled. Anything that tested over 65 mOhms during the full charge test may be usable in some projects, but I don't want to build it into the powerwall. Particularly when I have 70 battery cells testing 45.0 +/- 5.0 mOhms with capacities between 2650 and 2780 mAh.

So currently I have 70-75 batteries that are excellent and another 15-20 that are good to very good. If I can get another case or two in the few weeks to month I'll have enough to hit my target capacity.
1 week ago
Status Update. Use wood pellets sparingly.

I was in our local Menards a few weeks ago and strolled through the stove section where they keep all the wood pellets and such. They had two partial bags marke down to $3 each as they were damaged, and they were otherwise out of pellets. They also had these interesting compressed fiber logs, 6 for $2.39, and the pack weighed 21 lbs. I had 3 gift cards to use up, so I figured why not. We had some bitter cold in the forecast and if they worked well enough I wouldn't mind having some extra options. When I got home I prepared the starter wood like normal, 1/4"-1/2" splits, enough to fill the feed tube about 3/4 full. After shaving some fatwood in to the back side opening I lit it and let it get burning, then tipped about half the kindling back to create a kind of pocket right in the middle. I then dumped two cupped handfuls of wood pellets into said pocket. Within a few minutes I had the strongest pulse jet effect I've had and the barrel thermometer was climbing past 700. I found this exciting, but my wife was growing more and more concerned that the whole thing was going to suddenly lift off and fly right out the roof. It certainly sounded like it could. The temp seemed to stabilize at 750-760 for about 10 minutes before it finally started backing down. Now that it was good and hot I figured I'd test the fiber logs. I was pleased. They burned very consistently at 350 on the barrel thermometer, and it took almost 1.5 hours before I needed to add anything else.

After that we have just used the pellets as a booster if we let it die down and need to get it going again, or want a short burst of extra heat. SINGLE handfuls though.

In terms of overall performance I am extremely happy. Even with that bitter, -45 F windchill we had for a couple days the house stayed comfortable and the furnace didn't run any more than usual during the day. At night it did kick on more frequently, but only for a couple nights. I'm really looking forward to warmer weather when the ground thaws and I can finish cobbing the mass.
1 week ago

Dale Hodgins wrote:Turns out the salt soap that was meant for faces, is also an excellent laundry soap.



Awesome! I recently started making my own soap and am really glad I did. I discovered different amounts of extra coconut oil (superfat) created different properties. I made a table with 3 different units of measurement to make it easy to batch the ones my family likes are;

Laundry Soap, 1% Superfat
OuncesGramsParts by weight
Oil33.00935.55.59
Water12.00340.22.03
Lye5.90167.31.00


Shampoo Bar, 12% Superfat
OuncesGramsParts by weight
Oil33.00935.56.20
Water12.54355.52.36
Lye5.32150.81.00


Body Bar, 20% Superfat
OuncesGramsParts by weight
Oil33.00935.56.83
Water12.54355.52.60
Lye4.83136.91.00


We have really enjoyed adding some Cedarwood Essential Oil right before they go into the mould.

Loving the updates!
(Edited to correct Parts by Weight)
3 weeks ago
Pearl, I would second Ken's recommendation on how to assemble your own "Powerwall", be it lithium or lead-acid based, although deep cycle lead acid batteries are hard to wall mount. (Yes, my sense of humor is a touch dry). There are a few people starting to get their hands on reclaimed Tesla battery modules from cars and using them more or less as is to create a powerwall. This video is the first one that comes to mind. It can be done.

Personally I think it's difficult to put a hard definition on what system is 'safe'. I believe a lot of 'safe' depends on the user and the application, and on hazard identification and mitigation.
Lead acid batteries can be extremely dangerous. You still hear of incidents where a battery melts down or blows up. Lead acid batteries also the require routine maintenance of adding pure water to a cell. That means a routine exposure to acid. The reason you add water is the charge and discharge cycle generates hydrogen gas. So you have to ensure adequate ventilation to make sure you don't end up with a hydrogen explosion. There are risks. They can be mitigated.
Ken has given a good overview on the lithium hazards and what should be incorporated into a system. Again, there are risks and I believe they can be mitigated if you take the time to research and understand the systems and operate within the design criteria of your components. Even then, I believe the design must incorporate critical failure safe guards, regardless of which one you decide to use because there are aspects of ANY system that are beyond your control.

I believe that at the end of the day each individual is going to have to assess their own application, evaluate the options, and decide on which set of risks and hazards they want to live with and mitigate.

Obviously in my case I have decided I do not want to mitigate the lead acid risks. I believe that in my application, the lithium battery bank will be safer and more manageable power supply.
3 weeks ago
Wow. Gone for a few days and I feel like the train has gone off the rails.

Ken, thank you for pointing out my error. The way I stated that was poor.

Dillon, my apologies. Ken has correctly stated that there are other chemicals in 18650 batteries that contain fluorine. In the case of my batteries it is a constituent of the electrolyte that represents a maximum of 3% of the net contents of the battery. So technically there is still a risk of HF exposure in the event of a rupture.

Ken, thank you for taking the time to explain what you have. It is very valid and well written, and I appreciate that. What I have issue with are statements like

Ken Zemach wrote:
I am betting you don't have a calgonate kit on hand in case you get some electrolyte on your skin.  I'm betting you don't know how HF goes into your skin, and then effectively continuously leaches calcium out of your bones which if it happens to a large enough extent is painful, debilitating, and completely untreatable once it happens (unless you treat with calgonate quickly). Which is why no one in our cell chemistry lab is allowed to work with or open cells until they've taken HF training along with specific cell safety training.  


and

Ken Zemach wrote:
... but from what I'm reading here, just don't think for a second that your build is going to be 'safe.'  I'm not saying that it's not going to work and possibly work well for years, but that doesn't mean it's inherently safe.



I have issue with that because as far as I am aware you don't know who I am, and have a very limited view based on what I have had time to document here. Which is very little, relatively. Yes, I made an error and I appreciate you identifying it. I don't mind owning my mistakes and learning from them, but I hope you are not really a gambling man as you would have lost both bets. If you were directing that to any reader in general then you are most likely correct. Most people are not going to have a kit and know much about HF. Then again most aren't going to be working with large numbers of lithium cells. building their own powerwall, or working in a Cell Chemistry Lab with a much greater chance of exposure to larger quantities of dangerous chemicals.
I think a recommendation on having a calgonate kit on hand, a link to where to get one, and a description on how HF goes into your skin would be a great addition to the Safety aspect of this thread.

As far as this build being 'safe', can I ask you to you withhold judgement until I've actually had a chance to explain how I'm building it? Because I would greatly appreciate your input, if you're willing, as this build continues. Your response to Pearl's question is spot on. The 3 points you layed out have me asking if you're telepathic.
3 weeks ago

Dillon Nichols wrote:Linked below is a thread detailing the experience of a very unlucky person who had a pair of CR123A flashlight batteries blow up in the same room as him. These are 1/2 the size of an 18650; while the chemistry differs, both have the potential for hydrofluoric acid poisoning as described in the linked thread.

http://www.candlepowerforums.com/vb/showthread.php?340028-Flashlight-Explosion



Dillon, That is a scary story indeed and worth reading. Particularly SilverFox's comments. One thing to note is that both types of batteries have a different chemistry and only Primary (non-rechargeable) cells based on the Li-(CF)x chemistry can produce Hydrofluoric Acid as that is the only current Lithium based chemistry with Fluorine atoms. Batteries like CR123 batteries with a nominal 3 volts have this. Page 3 of that thread starts to discuss it. Li-ion rechargeable 18650's do not. They do have their own hazards though, HF is not one of them thankfully.
3 weeks ago

Staci Kopcha wrote:

Hi Caleb,
 Thank you for the suggestions!
Maddening enough, there was NO wind! Crazy.  They issued the burn ban due to the stagnant air.  I could understand high winds being a factor, but none..? Weird.
I appreciate the comment on using the smaller wood straight off.  I have noticed that too, when I am impatient to not want to babysit with smaller pieces, and instead add thick pieces... impatience does not pay off in best heating results.
Staci



That makes sense. Sounds like a significant inversion layer which would hold in the smoke from less efficient fires and would keep warm air from rising. Depending on how low it was it could create drafting issues.

Hope it starts burning well for you!
4 weeks ago
My feeling is weather, and possibly wind, is the primary culprit. I've been noticing with my RMH that winds from a particular direction will cause it to draft differently (slower) and that some days it seems like it just won't heat up like it does at other times. High, gusty winds, or damp/high humidity days seem to do the same. It does heat up, but we really struggle to get it roaring. The wood isn't the driest either. Another year with it split would be spectacular in my case.

Anyway, I also have noticed a trend on mine that if I start it hot, it will burn hot. Meaning I start it with a load of stuff split down to 1/4"-1/2" and use a good handfull, maybe two, of fat wood shavings it will fire up hot and fast, then I feed it smaller stuff for the first 5-10 minutes. That gets my drum upwards of 600 F (hot for mine). Then I start feeding it normal 1"-2" sized stuff and it chooches right along between 550-600 F.

If I load it up with larger stuff off the bat, or less fat wood it takes longer to get warm and I struggle to get it up to 500 F. It gets warm and gives off the heat we need, and looking at the chimney it's burning clean, just not as well as a good hot start.

Just a thought.

Good luck!
4 weeks ago
Merry,
My mother went through the same thing. In her case the solution was to wipe the laptop and install Windows 8 back on it, the original OS that came on the laptop. About 6 months later she bought a new laptop that runs on Windows 10.

Personally, I dual boot with Windows 7 Pro and Ubuntu Linux on a Dell Latitude E6420. I replaced the original hard drive with a 256 GB SSD and partitioned it equally to run my OS's off of. I replaced the CD/DVD drive with a hard drive caddy and placed a 1TB traditional hard drive in it to store my files on. The idea being if the SSD goes it just takes the OS with it. A new SSD, reinstall the OS, and all my files are ready to go.

There are many flavors of Linux. I must warn you, once you go linux nothing else will be forever disappointed with anything else.


4 weeks ago