I bought a companion power supply PCB with a 3 x 18650 battery holder soldered on (2/3 down the web page for the main board). I need to supply the main board with at least 12V. I bought 4 batteries labeled 4.2V on the idea that 3 x 4.2 = 12.6V is enough (as the web page states). (The full label is "GTL GtIenrgy® Li-ion, 18650 4.2V 9900mAh.") noticed that most of the 18650 Li-Ion batteries on Amazon are 3.7V. The batteries came charged to 3.7V and I popped 2 of them into my $5/no useful markings/very bad English 18650 charger and it looks like they aren't going to charge over 3.8V. (I've tried to go cheap because I do not anticipate working with 18650 Li-Ion batteries in the foreseeable future.)
There are a variety of different chemistries for Li-Ion batteries. Do some produce 3.7V and others 4.2V? Do I need to buy a 4-battery holder or get a charger for 4.2V Li-Ion batteries?
In trying to figure this all out, I am lead to ask, how do I interpret the voltage readings my multimeter is giving for Li-Ion? I wouldn't wonder, except—How come my MM/Battery Tester has three different dial selections for measuring battery voltage (other than the general "V" setting)?
1. AAA/C/D
2. AA
3. 9V
There are a variety of different chemistries for Li-Ion batteries. Do some produce 3.7V and others 4.2V? Do I need to buy a 4-battery holder or get a charger for 4.2V Li-Ion batteries?
In trying to figure this all out, I am lead to ask, how do I interpret the voltage readings my multimeter is giving for Li-Ion? I wouldn't wonder, except—How come my MM/Battery Tester has three different dial selections for measuring battery voltage (other than the general "V" setting)?
1. AAA/C/D
2. AA
3. 9V
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