A place users can post their projects. If you have a small project and would like your own dedicated place to post and have others chat about it then this is your spot.

User avatar
By lethe
#8816 I would strongly discourage you from using these cheap battery boxes with more than one 18650 battery. As you can clearly see from the pictures, they have the batteries connect in parallel without any protection. If you put in batteries that don't have exactly the same voltage, one battery will discharge directly into the other. Since 18650s typically have very low internal resistance, this means that you will easily pump several Amps from one battery to the other, even if the difference is only 100mV.
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By Aonko
#8826 As long as the 18650 batteries are from the same lot and are protected cells, and charged to identical voltages I don't think it would be that much of a deal. However if you are mixing batteries of different age/manufactures or using non-protected cells then I can see there being a problem. That being said there are also problems with counterfeit batteries and substandard lithium battery manufacturers, no one wants a lithium metal fire. :shock: Do your research.

Also to amend my previous post I did get 1 other working by using a heat gun to reflow the available solder. So overall I have two working units even if it did take some work. I guess not terrible considering they are less than $2 a piece with shipping.
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By gerardwr
#8836
lethe wrote:I would strongly discourage you from using these cheap battery boxes with more than one 18650 battery.


Good idea for using such a box if you have a battery operated device in it.

Just use it with 1 battery in it, the space reserved for the 2nd battery can be used for other parts :-)
User avatar
By alonewolfx2
#8854 two 18650 battery voltage max 4.2x2=8.4v , min 3.5x2=7v if it series and it could be fine with ldo. but parallel connection 4.2v full and 3.5v min. which ldo can handle this ? i think its not good option parallel connection, am i right?