I have 2 18 650 Samsung 25r batteries that I charge as a couple always yesterday one of the batteries read 4.21 volts and kept charging on a smart charger is that bad what was going on is it the battery is bad or the charger is bad please answer before something bad happens I asked a guy on YouTube that does reviews on batteries and said it happens sometimes up to 4.5volts?


closed as unclear what you're asking by winny, Lundin, Scott Seidman, Dwayne Reid, MCG Jan 8 at 15:47

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  • \$\begingroup\$ My guess is your multi meter is less accurate then the charger... \$\endgroup\$ – MadHatter Jan 7 at 14:30
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    \$\begingroup\$ This isn't really answerable unless you provide more details. Modern chargers have NTC supervising and shouldn't charge past the specified voltage for a single cell and/or battery pack, as in this case. \$\endgroup\$ – Lundin Jan 7 at 14:44
  • \$\begingroup\$ the battery should not overcharge at all Do yourself a favor and go to YouTube and search batteries exploding or li-ion battery overcharged If you suspect that your charger or the battery could be faulty try another multi-meter or try another battery or charger do not let the batteries heat up in the charger by over charging it \$\endgroup\$ – Tjaart van aswegen Jan 7 at 18:16
  • \$\begingroup\$ It was the charger the zanflare C2 too bad it was such a small cute compact charger with real time reading now I had to get the new Nightcore I forget the name but it's the new one it'll be here a couple days also I had to go to a company that's authorized dealer for the batteries and chargers which is very hard to find but I did it so anybody new to chargers and batteries always pay the extra money to get a better smart charger battery could be the difference between tragedy and safety \$\endgroup\$ – Tony Jan 9 at 22:45

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