Hello, I have 18 or so 18650 batteries that I have sitting around and I wish to use them in projects. I don’t really know how dangerous they are, but I have heard they must be charged properly along with used correctly otherwise they may combust.
Are there any boards available that allow you to charge 18650 batteries? These 18650s are probably badly over discharged as they have not been touched for 2-3 years but some still have 1.5 volts, others have 0.0 volts and a few have 3-3.8 volts.
Oh yeah, is there also a way to use them in a project without having them over discharge?
This is a good article on safety for 18650 Lithium batteries.
Depending on the condition of the ones you have are would depend on whether they should be used or disposed of. Some of these batteries have protection circuits some don’t. You cannot tell by looking at them, unlike the flat LiPo’s.
The circuit would need to monitor the condition of the battery and switch off when the battery charge is too low. A simple way to do this is to check the voltage, but it is not a good indicator of charge level.
Lithium batteries should be stored at about 50% charge, they should never be completely discharged. The flat LiPo’s should have an over discharge circuit, but I have lost a few by running them to zero charge by not monitoring the project correctly. A rule of thumb for my phone and tablet devices, charge when it says 30% to at least 80%. And don’t charge to 100% if it is not going to used.
Hmm, might have to take some of my batteries somewhere to get disposed of. So using TP4056 like @lia262073 suggested, but with discharge and overcharge protection, do you think that would be best for projects like an led light that is rechargeable, autonomous RC car, indoor weather station unit, etc…?
Hi Lost
I would suggest starting from square one here.
Firstly I would get a commercial small charger. I have a Powertech single cell device that will charge a multitude of cell types.and double up as a 500mA 5V power source with a lithium cell fitted.
Mine is a MB3700 which appears to be no longer stocked. A good replacement would be the MB3635 dual cell unit.
Secondly sort your cell types out, Nominal 3.7V (Li- Ion) or Nominal 3.2V (LiFePo4). Do not mix in the same project or cell combinations.
Attempt charging.
Discard PERMANENTLY any that fail to charge or indicate a faulty cell. I would guess that the ones currently measuring 0V would probably be dead.
THEN start playing around with permanently wired charger/discharge management and protection devices within a project.
If you don’t start out with a known good set of bits you will probably end up going in circles with devices of unknown status causing no end of strife. Believe me if you don’t start with most of the bits of known status troubleshooting (especially remotely) can be a bit of a nightmare. And a good place to start is your power source. Make sure it is up to the task you have on the go.
Cheers Bob
It sounds like you have a few batteries that should be disposed of rather than trying to revive.
I’d also be very careful with trying to charge any with a voltage below 2.7V.
I do agree with Bob on checking them with a proper charger before attempting to use them in a project.
I’d also recommend doing some reading into voltages, charging and discharging Lithium based batteries. Battery University goes very deep but it can be really useful information
As for solutions for your projects, Looking at a system like this one could be helpful for keeping the batteries in a safe condition while also providing regulated voltages.
You have to be a bit careful here. If you have the nipple type cell (won’t call it a battery. A battery is several cells connected together to form a “battery” of cells) especially the ones with built in discharge protection these could be up to 69mm long. Some holders are built for cells 65mm long and the longer ones just won’t fit.
Believe Core only stock the unprotected “flat” type cells which are 65mm long.
I don’t see why no mention of this is in the product description for some of these cell holders. I have a few of these of various flavours, some from core and some elsewhere, and none will accommodate the longer cell.
They are still designated 18650 though. A bit misleading. The same applies for the AA sizes.
Cheers Bob
Thanks for bringing this to our attention because you are absolutely right, our 18650’s are the flat top variant as that’s what we mainly find to be openly compatible with the holders we stock too, but it isn’t the worst idea to be more transparent about that.
Hi Blayden
No fault of Core. It gets down to the cell manufacturers still labelling their cells 18650 when in fact the protected ones are nearly 70mm. Also the holder manufacturers implying by omission that their product will accept any 18650 cell. When you have a 60k round trip to the nearest stockist of these things it can be a damn nuisance.
Cheers Bob
