Get a DMM. I strongly suspect that your wires are crap. Those can drop the voltage by a huge margin and might get warm at a 3A discharge. Or your cells are crap (although the fact that you still read a voltage of 3.021V after 10minutes backs my theory about your wires up). Only one way to find out -> DMM.
I just assumed that if you buy a hobby charger for 100 bucks you wouldnt go cheap on the cables..
Did I mention that you should get a DMM? Thats essential when handling LiIon batteries.
I just took one apart with the intent to strip and re attach.
The banana plug end has a "Binding post"? connection and there was no exposed wire.
I tried to strip an end and the wire just snaps, when you bend it, it breaks.
Since I already have the ends, what kind of wire should I get?
can I use one of the wires inside of an ethernet cable?
You can’t be serious about using wire from an Ethernet cable, that’s a data cable!
Go to your closest hardware store and get thick but felixible cable that can handle 10amps, this will be ideal low resistance cable for measurements or charging.
You could use a pair of them, though! They’re arranged that way and twisted for you. Maybe a couple of pair would be better. Maybe more, if you want to flow some decent current. Be sure to solder the ends together before wrapping them around that post! Cat6 Ethernet isn’t widely available as scrap yet, so you’re likely looking at Cat5. Either way, a dedicated, full-size wire would work better. If it has to move any, ever, use stranded wire, if it can be hot-glued into place, solid works fine.
If you have a computer repair shop nearby, ask for a dead Power Supply from their trash… Lots of wires there!
I would recommend 14 AWG high strand count silicone wire, very flexible stuff and is usually what hobby charges are supplied with. You can find it on ebay if you prefer that route. DMM leads are usually silicone wire also, but are usually around 18AWG wire. The larger and the shorter the wire you use the less v-drop you will see especially at higher currents.
Depends on the battery, the newer Panasonics can be discharged down to 2.5v. Member HKJ usually discharges down to 2.8v for his graphs. The datasheet of a particular battery usually contains the current draw and the ending discharge voltage of their test, to check the advertised capacity. Most of us test at what actual current draw we will be using the battery at, to determine the runtime or capacity in actual use.