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by mhaberl
929 days ago
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If anyone is considering attempting this, please ensure you first educate yourself about thermal runaway. Using a collection of old lithium batteries like this can be extremely dangerous, and without exaggeration, it can kill you. When (yes when, it will happen) one battery overheats and catches fire, it will cause the others to do the same, leading to a significant fire.
During combustion, these batteries also emit gases, so put this into a box and you risk an explosion on top of the fire. |
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YES!.
That's why you should monitor a setup like this with a FLIR from all sides during the first month of operation or so, if no batteries ever run hot during charge/discharge cycle you may be good to go. But better keep an eye on that balance, especially in packs that are sitting at high voltage for a long time (like this one does) because you won't know how the pack behaves during discharge and recharge and that is likely when any problems will be most apparent.
Thermal runaway can happen very quickly once a certain threshold has been passed.
If you really want to do a project like this with Lithium Ion and you are not space constrained you would do better to have a bit less capacity and charge the batteries to 3.6 ... 3.8V or so. That would work much better in the long run.