Interview With Mooch315: The Battery Tester We Need. Not The One We Deserve.
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Mooch315 has been actively testing batteries and publishing the results for almost a year. Many reports have been shocking and we learn more everyday about the misinformation out there. Mooch is here to set the record straight as we learn why and how he does what he does.
What do you do when you’re not testing batteries?
I design and build power management electronics such as power supplies, battery chargers, energy harvesters, battery management/protection systems, and electronic loads for battery testing. My clients range from the US Gov’t to large corporations to small start ups. Most of the work involves designing and building small numbers of high-reliability devices for abusive environments.
You’ve been posting battery ratings and reports on Reddit/e-cigarette-forum.com for close to a year now, what is your motivation to post these and how did you come up with the idea to start?
I’ve been testing batteries as part of the work I do for my clients for many years now. The two friends of mine who helped me start vaping asked me to test some batteries they had. I was stunned to see how exaggerated the ratings were. As I learned more and more about the batteries vapers used, and how ridiculously they were rated, I got angry. Really, really angry. Since I already had the battery testing equipment I decided to start testing every vaping battery I could find. I wanted vapers to know about these crazy ratings.
How do you test each battery?
The equipment I use includes…
• West Mountain Radio CBA IV Pro battery analyzer.
• Custom constant-current electronic load, rated 150A/400W. A second load is available, if not
being used for other testing, if I need to discharge at over 150A (up to 300A).
• Adjustable 5A/30V CC/CV power supply for charging the battery.
• Omegaette HH308 dual type-K thermocouple thermometer.
• 20A, 100A, and 200A current measuring shunts.
• Fluke 8846A 6-1/2 digit DMM.
• Fluke 87 DMM.
• Heat-resistance cell clamping rig.
• Safety glasses, fire-resistant apron, fire-resistant gloves. I wear all when doing destructive
testing or if I think the cell temperature will rise much above 100°C. Otherwise just the safety
glasses.
The setup…
• The CBA battery analyzer handles 10% of the discharge current and creates the graphs. The
custom load handles 90% of the current.
• The battery has its wrapper removed so the thermocouple can be placed directly against the
metal can to sense temperature.
• The thermocouple is tightly taped to the battery with the thermocouple positioned halfway
down the battery.
• All discharges, unless noted, are constant-current to within +/-1% of the stated value.
Confirmed via +/-0.25% tolerance current shunt.
• All measured temperatures were rounded to the nearest degree-C. Only the highest
temperature for the discharge is recorded.
• The battery is placed in an insulated fireproof container with a lid loosely placed on top. The
container is left open at the top to allow heat to escape during discharge.
• The cell holder is a non-conductive c-clamp using a 1″ x 1″, 0.040″ thick copper plate to
connect to the bottom of the cell. A 1/4″ diameter copper rod is used to connect to the top of
the cell. Both the top and bottom connections have 10AWG and 12AWG silicone-insulated
wires soldered to them. The 10AWG wires go to the 400W load and the 12AWG wires go to
the CBA, directly soldered to the CBA circuit board.
What process do you go through?
Each pair of batteries I buy are first checked for basic functionality and consistency and then
one is tested at various constant-current discharge levels to determine its continuous rating. The
other battery is then tested at various pulsed current discharge levels to show its performance
when vaping.
The continuous current testing involves the following steps…
• Remove the wrap and photograph the case, top, and bottom.
• Attach the thermocouple (temperature sensor) halfway down the battery with heat-resistant
tape.
• Clean the test rig contacts with a Scotch-Brite pad and then a 90% alcohol wipe.
• Mount the battery in the low-resistance test rig.
• Charge 18650’s and 26650’s to 4.20V at 2.5A until the current drops to 100mA. 18350’s are
charged at 0.5A unless the manufacturer specifies a higher rate.
• Run three constant-current (CC) discharges down to 2.80V to check basic functionality,
including capacity and temperature. 18650’s and 26650’s are discharged at 10A.
18350’s-18500’s are discharged at 5A.
• If all three discharges are essentially identical then I continue. If something keeps changing for
each discharge I keep running them until the performance has stabilized. So far, every battery
has stabilized within three discharges.
• Run CC discharges, down to 2.80V, at every 5A increment above that until the battery reaches
100°C or the voltage just quickly collapses.
• Note the maximum battery temperature reached for each discharge.
• After each discharge let the battery cool to below 40°C before recharging.
• Recharge to 4.20V, stopping when the charge current has dropped to 100mA.
• Determine the continuous discharge rating (CDR) by noting the current level that brings the
temperature closest to the 78°C average (74°C-82°C range) I measured for the Samsung,
Sony, and LG batteries I tested at their CDR.
• Run an additional two CC discharges at the CDR to check for voltage sag, loss of capacity, or
increasing temperature. These are all signs of damage and indicate that the rating is too high.
• Run additional CC discharges at above the CDR to check for voltage sag, loss of capacity, or
increasing temperature. These are all signs of damage and indicate that it’s being discharged
at beyond its rating. It also gives us an idea of hard it can be abused.
• Take the second battery, run the three initial discharges, and then discharge at 10A and at the
CDR. If the results are within 2% of the first battery then the first battery’s discharge graph is
used. If the discharges of the second battery are different from the first I do not post any test
results until I can source another set of battery’s to test and compare.
The pulse current testing involves the following steps…
• Discharge the second 18650 battery at 30A, each pulse is 5 seconds on/30 seconds off, down
to 2.50V. 26650 batteries are started at 20A. 18350-18500 batteries are started at 10A.
• A lower cutoff voltage is used for the pulse testing to give those batteries that have a
significant increase in voltage when hot (due to lowered internal resistance) a chance to warm
up.
• Run pulsed current discharges, down to 2.50V, at every 5A (for 18350-18500) or 10A (for
18650-26650) increment above that until the battery reaches 100°C or the voltage drops to
2.50V for the first pulse.
• After each discharge let the battery cool to below 40°C before recharging.
• Recharge to 4.20V, stopping when the charge current has dropped to 100mA.
• Note the maximum battery temperature reached for each discharge.
What is your background?
In 1992 I went into business for myself modifying photographic equipment and designing remote control systems for professional photographers. This quickly expanded and I started doing work for different types of companies. Since most of these devices used batteries I became more and more involved with them. This quickly grew to include battery charging, testing, protecting, etc. Almost all of the work involves designing high-reliability devices for high temperature, high shock/vibration environments. Over the years I have spent thousands and thousands of hours researching and studying the technologies, devices, and components I could use to solve the problems my clients bring to me. I love what I do!
You made a post bashing efest (rightfully so), why do you think companies such as them lie about their ratings? Do you think it’s on purpose?
I don’t know whether it’s done on purpose or not. But I suspect most vaping battery companies don’t have a very good understanding of what a battery rating is and how to test for it. This can lead to confusion between a battery’s rating and just a capability of the battery. For example, the Samsung 25R can be continuously discharged at over 30A. But that doesn’t mean it can be rated at 30A as it gets incredibly hot when doing that. It’s still a 20A battery
Were you ever contacted by efest because of that article or for any other reasons?
Not that I can remember. I’ve been contacted by a couple of other companies regarding the results of my tests though. They were not happy.
Have you had any batteries explode while testing?
I’ve had batteries go into thermal runaway and burst open during testing but those were not vaping batteries. They were all batteries I was destructively testing for clients. I’ve only had two vaping batteries even vent, out of over 250 tested, and that was months ago. But I have safety limits in place that, for the most part, keep me from bringing the battery to a high enough temperature to vent. Unless you short-circuit a battery it is very hard to force it into thermal runaway, where it can shoot sparks/flames and even burst open. The explosions we’ve been hearing about are, I believe, caused by the expanding gasses from a battery in thermal runaway being constrained by the mod. This can cause the pressure to build up to the point where the mod basically explodes. If the battery was in a mod with a pop off panel I feel that what happened in those cases would have been a lot less destructive.
If you could say one thing to someone just getting into vaping, what would you tell them?
This is something that is really tough to do but it’s what I’ll always recommend. Stop and read. Read a LOT before buying anything. The forums, web sites, etc. Study Ohm’s Law, battery safety, and the things that need to be learned to vape safely. Then dive into vaping and all the great things you can get involved with.
I think a lot of people would like to see a Mooch website to browse batteries and you’re work. Is there a plan for this anytime soon?
It’s in the works but it’s coming along slowly. Hopefully I can dive into it full time soon
What set up are you currently using? Hand check?
I don’t have an all-day-vape or setup so I bounce around a lot. My favorites include a Nobunaga Mini on a Phantom, Bellus on a Treebox Mini, Velocity V1 clone on a Lavabox or VF Stout, and a Sapor on an iStick 40W for tasting.
I believe I speak for a lot of people when I say, Thank you. Your work has been incredible and I hope you continue to test batteries.
Check out Mooch’s Recommended batteries.
Check out all his posts on the forum
source: http://vapedesk.io/mooch315-interview/
