Ahhh ..... here comes my COMPLAINT ....... I am starting to get into power banks. I have been grumbling over the years about having so many USB wall chargers or extension power bars with USB ports to provide 5vdc to whatever electronics I have. Some of these come with USB-A some with micro-USB some now needing USB-C and all having 5vdc USB cords laying all around the place going to my electronics devices. From rechargeable flashlights, to rechargeable radios, and rechargeable headphones, recharging batteries for remote sensors for an alarm system, toping-up AA size batteries in Ni-Cad battery chargers for my solar lights (they never seem to get charged fully during the day), etc etc etc. I have the need still for C-cell batteries and for D-cell batteries for some of my electronics and don't get me started on rejuvenating my power tools, removing sluggish Ni-Cad batteries and or upgrading from Ni-Cad to Li-Ion or trying to keep up with power tool upgrades from 14.4vdc to 18v or 20v or 40v. Then I have my new toy, my drone, and having to work at managing the power pack(s) for it, and it goes on and on and on!

When I looked at buying to use the Li-Ion 18650 batteries within a portable battery pack, I was looking at this approach to get me over the humps when my mobile dies or my drone peters out right in the middle of me having some great Saturday fun, I was faced with yet more decisions of whether the 18650 I bought would be a button top or flat top, whether they would have protection built in or no protection, and how many mAh of a battery to buy. The concerns about if they get drained below 2.4vdc that they might then become yet another issue I would have to try and recover them from to again be a useable dependable battery within a portable power bank. Then there is whether the battery should be conditioned/reconditioned using a balanced charging system and whether the battery should be charged fully or only to 80% and making sure through battery management practices it does not discharge below 2.4v (who does this anyway with the D-cell alkaline flashlight sitting on the shelf in the garage .... when you go to use it and it is not very bright you fish out two newer D-cells and change them out before squinting for the tools on your work bench).

Then there are the cautions I read about regarding overcharging or charging to fast or having unbalanced cells being used together and whether they should be in series or parallel and cautions about them being a fire hazard and whether I should add a BMS to any portable battery pack I am considering or even does the portable battery pack already have a BMS in place and what type USB cable to use from the portable battery pack to my device.

Man, it sure was easier when we just went to the store and bought a few D-cells for the flashlight and a few C-cells for the portable radio or a few 9vdc for the smoke detectors or for my multi-meter or when we just put alkaline D-cells or C-cells into portable wireless speakers in the back yard to enjoy the family audio system on the deck when having a BBQ. Even when we had AAA or AA alkaline batteries for the stereo/TV system or in our portable in-house phones it sure seemed manageable. Now we have Ni-MH and Ni-Cad and Li-Ion or any of the newer battery types that are being proposed and the different connector type and battery materials/profiles/sizes/shapes/capacity/cost.

So, I make a decision. I find some reasonably cost manageable li-ion 18650 batteries around 2200mAh that won't break the bank and they are button top with no protection built in. Great. I buy them. Then I look for and find some reasonably cost effective portable power banks that have BMS incorporated within their cases, some take two 18650 and some take three. Some have an added ability to double as a 'flash light' with a single fairly decent LED bulb. So I purchase a few types of these portable power banks (they are very reasonably priced) to get a feel for what they have to offer and what they can do. The order for the 18650 button top batteries and a few of the power banks is sent and I patiently await their delivery.

They arrive (very fast .... only 7days or so) and what is it that I find? That the button top batteries are so tight in any of the portable power banks (and they were all manufactured by different companies) that the batteries will NOT go in! What I immediately notice is the positive side of the battery contact point within the power banks has a button or 'nipple' contact point profile to them (which is ridiculous). The negative side of the contact points for the batteries has the tension spring (which is good). Why do they manufacture power banks that an end user might want to put a button top or a flat top (the spring at the negative pushes the battery tightly/securely up to the positive end) or even an 18650 with built in protection into it? All three of these 'formats' of an 18650 have slight differences in their overall length. Some more so than others (button top vs flat top and even button top to button top but one has protection circuitry built in and one does not). I suspect that all 18650 batteries are NOT 'identical', particularly if they are coming from differing manufacturers as there may be a bit of a +/- difference in their manufacturing tolerances, not to mention the +/- tolerances that manufacturers of the power bank connecting terminals would have.

Why are power banks not engineered/designed/manufactured so that they could accommodate 18650 Li-Ion batteries that are either button top or flat top or that come with or without built in protection and that come from different manufacturers? I mean if they got rid of the positive terminal connection point metal strip 'button' / 'nipple' all together or make the power strip 'button' about 1/3 of the height of how they are doing it now or even make it just as a 'flat' that is (IMO) 2x the thickness of the positive terminal strip itself and with a small 'dimple' in it to accommodate some retention of the 18650 button then the power bank would be universal and be able to accommodate (IMO) 99.99% of all 'formats' and 'manufacturers' of an 18650 Li-Ion battery. Now wouldn't that be great because it would remove some of the 18650 battery management issues we (in today's world) have to face!

Anyway, what I ended up doing to get over this 'issue' was I temporarily removed from one of the power banks the positive end terminal strip (some de-soldering/soldering of the battery lead may be required) and used my Dremel with a grinding disk to grind down the 'button' / 'nipple' that was there for each of the 18650 battery positions so that it was (about) 1/3 as high as it was. This allowed me to install the 18650 'button top' batteries I had purchased (at a very reasonable price). They fit snuggly and also securely into the portable power bank. There was no issue putting the power bank case back together and now I will have to do the same to the other three portable power banks I bought to allow me to fit the 18650 'button top' batteries into them.

I suspect, but have not tried, that an 18650 'flat top' battery will also fit after this modification I made with no issue because the spring at the negative side of the portable battery pack holder seems to exert enough force (IMO) to force the flat top against the positive terminal strip and there is still a 1/3 sized 'button' / 'nipple' remaining on the terminal strip after my grinding.

 

Welcome to AAC.

Please don’t take this the wrong way, but I find it hard to have any sympathy for your “complaint”.

The first half is the story of your frustration with how many details there are in something that you chose to do. It’s really just learning about the technology but it reads as if something is being done to you. Yes, there are a lot of details but that‘s what the subject matter looks like.

As far as your claim (in the title) that the “Industry NEEDS to Streamline Things”, I think you are confusing the needs of industry and your desires. Whether any of us likes it or not, what the industry NEEDS is to maximize shareholder returns. This is how things stand right now, and for the foreseeable future.

You might argue that making things better for the consumer will increase the bottom line—but that‘s only true for market segments that are not price sensitive and have knowledge to distinguish improvements, or are served by retail outlets that have sales staff who can inform them.

Why are power banks not engineered/designed/manufactured so that they could accommodate 18650 Li-Ion batteries that are either button top or flat top or that come with or without built in protection and that come from different manufacturers?

It’s the outcome of value engineering. We live in a world where shaving cents from the BoM (Bill of Materials) will have a detectable impact on margins, and so on the bottom line. This is even more true for single digit dollar priced items.

It turns out there are flexible compatibility battery boxes if you look for them—but they cost more. To borrow an aphorism: “good, cheap, flexible—pick two”. That you can purchase a battery box that works for only a few dollars is actually a minor miracle. The economies of scale that make it possible aren’t structured to “streamline” your experience, they work because the manufacturer streamlines their process.

In the end, yes—there are a lot of details involved in Li-Ion cell technology, and alkaline cell technology is a false analogy. If you want the “convenience” of old cell technology it’s easy to get: just use old cell technology. But, it will be at the cost of having the benefits of the new technology—you just have to choose what you want.

Good luck with your future power bank projects. I hope you come to an accommodation with modernity.