jkaness wrote: ↑
Feb 22, 2018 8:45 am
2. Four amps will charge much faster than one amp (my own is 2 amps). The only issue is the size of the cells and how they react to that charge current. I am not the expert for that subject. Recommend following what the manufacturer of your cells says about that.
Yes. Sometimes they use a low-current charger because they're cheap and small, and sometimes it's because the cells can't handle teh higher current well. (on some cells, it can cause fire if the charge current exceeds max spec by far enough).
3. For AUDiO applications it is desirable for the metal shell of the XLR connector to be connected to the system ground to keep hum and noise out of the audio. For battery charging applications I consider it optional if the metal shell (pin-3) is connected to anything.
It's actually safer to not connnect the shell in chargers, because you then cant' short the shell to the opposite polarity pin inside it by accidentally pushing the end agianst a metal object.
4. A personal comment: why this industry decided to use AUDIO connectors (XLR or RCA) for battery charging is a mystery to me. Of course, any 2-wire connector that can handle the voltage and current can be used.
Audio connectors are generally widely available, and often cheap because of that, and while not cheap like RCAs, XLRs are still common.
XLRs are large and easy to handlej, so they make good user-interface and are cheaper than connectors of similar handling ability that were intended as power-handling / charging connectors. (or at least, were when all this stuff started being used that way back then).
XLRs also have 3 pins, so you can have +, -, and a thermistor pin, which was important in the NiMH/NiCd days when these were more commonly used for charging. Or it could be used as a pack-ID pin so the charger wouldn't charge if it didn't detect the right resistnace on it, or the right zener diode voltage drop, etc.
Also, 3 pins plus a shell can actually be used as a four pin connector, or a higher-current 2-pin, by paralleling two of the pins and one pin plus the shell. Might also have been a factor in some designs' choices.
It oculd also have simply been the experience of the "engineer" that chose that part, having used them for other things before.
Or the company taht made some large batch of chargers (or bikes, or both) already had a warehouse full of those connectors, and said "use these or you're fired".