18650 battery recommendations for beginners?

Since the DevTerm requires 18650 batteries, I’ve been looking to get some before my Devterm arrives. I’ve never used 18650 batteries before, so I went to the forum to find more information. After some research, I realized that 18650 batteries are more complicated than regular batteries. I also realized that I don’t actually know where to start in terms of choosing batteries. Do any of you have recommendations or advice on which batteries I should get and where to buy them? Hopefully, seeing other’s opinions on this topic will help point me in the right direction. Thanks in advance for the help!


I researched a few different capacities… I may have bought to large a capacity not sure of capability with the charging circuit on the DivTerm but they are available on Amazon: 18650 Rechargeable Li-ion Battery 3.7V 9900mah Large Capacity Lithium Batteries Safe Accessories for LED Flashlight, Emergency Lighting, Electronic Devices etc. 4/8 Pieces (Yellow) (4 pcs) $13.98…(typically they are 3000 mah capacity…

Ther is a lot of info… and im giving you a lot to go thru… but it is my hope that after all this, you should feel al little more comfortable make a decision. If after all this study, you still have queries, I invite you to ask and we can start discourse.

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that sounds like a fake…
anything over 3500 is not likely real… :frowning:
do not buy from amazon. they are littered with fake cells.
check out the links and you’ll find better TRUSTED sources to obtain your cells from

can you name a few “trusted” sources please?

read everything in the two posts i linked and you would have found what you are looking for…
unless you want me to buy you the batteries too…

i used the search feature to pull posts that already contained detailed answers and link them for you… the least you can do is read them…

From what I can gather from the video sources you kindly together here

[check] protected cells
[check] capacity over 3800 mah fake…fake fake
[check] purchase wrapped cells(naked cells are dangerous) - re-wrap repurposed cells - same theme as folks on power walls suggest
[check] lipo batteries (18650) cells are dangerous - saw a video where someone put a nail through one and it lit off like fireworks (dont mishandle)

I prefer lipoFe batteries and have two power boxes (one I built) for two way radio/camping emergency that are 14.4 volts nominally - that’s the world I operate in…12, 24 and 90 volt DC nominal systems -

own numerous other consumer items with single cell lipo 18650 type cells they meet the criteria - not asking to be spoon feed here. just a short answer of trusted vendors… if Amazon is not a suitable vendor I guess I will watch all the videos and see who they recommend… Yes I know Amazon has counterfeit vendors (arduino comes to mind) (personal preference is Panasonic and LG brands for batteries we buy at work but these are typically NiCad and are used for industrial system memory backup) Rambling here but the goal is to have what is needed when the DevTerm arrives…

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Okay my browser compacts your lengthy post… managed to expand the post where it discusses vendors, dimensions… would not suggest unwrapped batteries to someone who wants to just put a couple in the unit and turn it on. Absolutely suggest getting a model with some internal protection. Lipo batteries can dump a great deal of current if they are shorted as in (you put one battery in the wrong way…) The DevTerm uses the lipo battery because of the energy density and has a built in charger for the type of battery so read the articles and also how to care for batteries when not installed in the unit - don’t put in a junk drawer with keys and other metial objects if they short they can dump current fast… (even if current limited they can spark and cause a great deal of heat)

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the first post i link to has a bunch of links… you caught most of it… but at the end, the last one… i mention thats where i get my cells from. :wink:

"battery guide (i actually get my batts from here)
Best 18650 Battery | 18650 Guide - Comparison Chart – "

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Got the cells I ordered per your recommended technical articles today … ordered a modest 2000 mah capacity with the better safety protection and best match for the load demand (as far as I can guess)

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Now all you gotta do is charge em up

Do we need to purchase an extra charger case for 18650 batteries for the new DevTerm? Can we charge them up while they’re inside the DevTerm with the type-c port of the device?

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that would be one way…
I personally do not know enough about the charging circuit to trust it 100% (as opposed to a dedicated circuit). Like how fast does the DT charge these cells? Does the DT have to be on to charge them?
In the links posted above, I did go through the trouble to actually recommend a decent charger and why.

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Let us see. battery types, sizes, ratings, knock-offs, chemistries, chargers, wrappers/labels, safety, rewrapping, protections, dangers…
did we discuss storage yet? i mean yea, sure. DT, Charger… check… but… now hear me out… what if you got 8 cells? like me? you gotta store them and safely too, right?

I have something like this…

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I’m closing this topic as there are already plenty about batteries for the DevTerm.

If you want continue the discussion please use this topic: Battery model recommendation

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