So, I have a few things which use 18650 cells.
I also have a balance charger for hobby RC aircraft, an IMax B6AC to be precise.
Instead of buying an 18650 charger I went for the cheaper option of using the balance charger that I already own.
It comes with several outputs, one being two female bananna plugs. I've used this with crocodile clips (clipping onto the positive terminal and then using blu tack to attach a wire to the negative terminal for charging one cell at a time) this is obviously unreliable and I could only charge 1 cell at a time.
So a bought a dual 18650 cell holder and soldered some wire on so it (which I then insulated) could charge in parallel, it works fine but is still very much a prototype as I just clip the positive lead to the positive croc clip and the same for the negative lead. Yes I know there's a risk of shorting two 18650s out if the leads or clips touch during charging. I plan on putting a 3A or 5A fuse in my final design. The cells are rated to output 25A each so the fuse should blow before the cells do in the event of a short.
My question is, was wiring it up in parallel and just charging two cells as if they were one big cell the best choice? I've read online that charging in parallel can cause one cell to drain the other leading to overdischarge in one cell. However as there is no balancing feedback would series charging really be safer than parallel?
Also, should I build in any reverse polarity protection or just be careful when I insert cells?
Thanks
I also have a balance charger for hobby RC aircraft, an IMax B6AC to be precise.
Instead of buying an 18650 charger I went for the cheaper option of using the balance charger that I already own.
It comes with several outputs, one being two female bananna plugs. I've used this with crocodile clips (clipping onto the positive terminal and then using blu tack to attach a wire to the negative terminal for charging one cell at a time) this is obviously unreliable and I could only charge 1 cell at a time.
So a bought a dual 18650 cell holder and soldered some wire on so it (which I then insulated) could charge in parallel, it works fine but is still very much a prototype as I just clip the positive lead to the positive croc clip and the same for the negative lead. Yes I know there's a risk of shorting two 18650s out if the leads or clips touch during charging. I plan on putting a 3A or 5A fuse in my final design. The cells are rated to output 25A each so the fuse should blow before the cells do in the event of a short.
My question is, was wiring it up in parallel and just charging two cells as if they were one big cell the best choice? I've read online that charging in parallel can cause one cell to drain the other leading to overdischarge in one cell. However as there is no balancing feedback would series charging really be safer than parallel?
Also, should I build in any reverse polarity protection or just be careful when I insert cells?
Thanks