Discussion Batteries

How good are we talking? 18650s usually are like $25 or so for 4.
 
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Ok I wired up a charger port to the pcb but it won't charge the batteries my battery charger led stays green doesn't even turn red when it suppose to charge the batteries or does this pcb need a special charger I know it can't be my wiring I put red wire to the P+ And black wire to P- any suggestions?
 
EN probably stands for "Enable". You need to connect that either to P+ or P-. Before doing that check the resistance between EN and P+ and also the one between EN and P-
 
The resistance between P- and EN .387 for P+ and EN .190
 
Yeah that's what I'm getting off of 2M on 20M it's 3.76 for P+ for P- it's 2.52
 
Has anyone used these PCMs? http://www.batteryspace.com/PCB-for-11.1V-Li-Ion-Battery-Pack-4.0A-limit-----PCM-L03S04-559.aspx

I connect it exactly as it says in the instructions, but for some reason the P+ and P- are always 0 volts. I bought 4 of them and tried connecting the batteries to all 4, and I get the same result. Here's a picture of how I've been connecting it.

View attachment 1525
Connecting the charger for a moment or shorting b- and p- can reset it.
 
I've got a question. So if you are employing the charge and play strategy, you have 12v ac or use 4 3.7v batteries in series for 14.8v, what do you do if you have a screen/fan that runs off of 12v? It's fine on ac power but if you switch to battery power is this going to be a problem?
 
It's generally best to not order batteries straight from china as there are alot of knockoffs produced. These are popular among the community and from a known reputable seller, plus slightly cheaper.
 
About what voltage would a PCB for 18650s at 7.4v (like the one in the BOM) cut off at? I just checked my battery's voltage and it is at 6.1v and still supplying it, so I'm pretty concerned.
 
About what voltage would a PCB for 18650s at 7.4v (like the one in the BOM) cut off at? I just checked my battery's voltage and it is at 6.1v and still supplying it, so I'm pretty concerned.
http://www.batteryspace.com/hi-powe...2-24wh---ncr18650b-0-93---un-38-3-passed.aspx
  • Nominal Voltage: 3.6 V
  • Charging Voltage: 4.2 V
  • Minimum Voltage: 2.5 V
This PCB from battery space shuts off at 2.3v for each cell, I'd say you're good.
http://www.batteryspace.com/PCB-for-7.4V-Li-Ion-Battery-Pack-3.0A-Limit.aspx
 
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