Switched's battery FAQ

[Vaporologist]

Hey PT, I have two WF-138 chargers and just tested them both for you.

I mostly use them at the 3V setting for my AW LiFePO4s and never hear a buzzing sound but decided to set them up at 3.7V and attempted to charge one partially drained AW 16340 IMR battery. I got the buzz sound from both chargers. It wasn't really bad or really loud but definitely noticeable, especially when my ear is about a foot away from the charger. If you've heard others say that it's normal to hear the buzzing sound at the 3.7V setting I wouldn't worry too much. The odds of all three chargers between yours and mine having a defect would be pretty slim...

If someone out there has some real data conflicting with these findings, your advice would be greatly appreciated.

 

[VaporMadness]

Hey PT, I have two WF-138 chargers and just tested them both for you.

I mostly use them at the 3V setting for my AW LiFePO4s and never hear a buzzing sound but decided to set them up at 3.7V and attempted to charge one partially drained AW 16340 IMR battery. I got the buzz sound from both chargers. It wasn't really bad or really loud but definitely noticeable, especially when my ear is about a foot away from the charger. If you've heard others say that it's normal to hear the buzzing sound at the 3.7V setting I wouldn't worry too much. The odds of all three chargers between yours and mine having a defect would be pretty slim...

If someone out there has some real data conflicting with these findings, your advice would be greatly appreciated.

Mine don't buzz, at least not in a frequency that I can hear. Caveat, I think my hearing may be damaged from that super-loud Pretenders show I saw in the 80s

 

[Pyloric Thinker]

Mine don't buzz, at least not in a frequency that I can hear. Caveat, I think my hearing may be damaged from that super-loud Pretenders show I saw in the 80s

Hahaha. I do have dog-like hearing so that may be part of the problem here. I was fortunate to have an over-protective dad that always made me wear ear plugs when we went to concerts so my hearing was salvaged despite many great shows with him. Our latest was Roger Waters performing The Wall at HP Pavillion! I'm not sure if you've been but they built a huge HD projection screen that spanned the width of the arena! It was one of the best shows I've ever seen. More theatrical than musical, but a great show nonetheless. Thanks for the tips, I don't think it's dangerous after doing a little more research, but I wish I knew what was causing that damn hiss/buzz/whistle

 

[Switched]

Totally off topic but dealing with chargers. My makita charger for my cordless drill goes through a song and a dance when the battery is first plugged in. I attribute it to a fast boost charge and there is a fan that comes on as well. This last about 15-20 seconds. It is normal for this charger.

Could be that the wf138 has a boost cycle as well. I am not familiar with charger as stated before, but if the charger is not getting hot nor the batteries, and the charger is not over charging the batteries, it would seem that all is well.