just ordered 2 of these from (edit:removed shop name), so 4 cells total.
edit:removed link of purchase because I am in potential dispute regarding wrong battery shipped
I have an imax b8+ so I’ll test discharge them when they arrive.
I need one of them for a handheld screwdriver which can request some 10-15amps in bursts, so I hope the protection can handle it, otherwise I’ll have to put few of protection board in parallel.
The gold plated variant seems new to me, perhaps you will be the first to review them? However typically protected circuits for ncr18650b cuts off around 7amps. If you really did need such high currents, perhaps unprotected cells would be a better option?
I need overdischarge protection so I don’t ruin the cells.
It should be possible to put a few protection circuits in parallel, right? Perhaps they need to be identical though, so that the current is divided equally between them.
Yeah I guess over discharge can be a big problem. Have you considered unprotected cells, but also adding a protected circuit to the device? This way I think is easier as you can adjust the high current threshold.
Yes I have but they were too expensive for higher current circuits.
Another option perhaps is to increase the number of FETs, harvest them from a few cheap battery protection circuits and add them to one protective circuit
You better buy other cells. Panasonic 3400 are not high drain cells, they were designed to provide the maximum capacity, not max amps. You don’t want to ruin your cells, so you buy protected ones to avoid over discharge, but then you want to trick it to let it discharge at higher amps… That doesn’t make sense to me
I would have to agree with you guys, however I thought the OP wanted something that would hold up under 15A bursts? I’m sure the NCR18650B’s can handle 7a bursts (anyone have data on this?). Now what might be important to know is what are the typical current the device will be drawing. I would hardly think an electric screwdriver would draw that high currents continuously.
I’ve got plenty of high drain liPos since I also do RC flying, but aren’t NCR18650B’s tested above 10 amps and favored by e-cig folks? I’m also pretty sure they can do more than 7A bursts, perhaps not their protective circuits.
For accu screwdriver I need only over discharge protection, I don’t need overcurrent protection. If it turns out to be too complicated, I’ll just run them without protection and look for torque reduction as end of charge signal.
I’ll do a review and high current test when they arrive.
edit: yup, I got something mixed up, in my head. They are not recommended for 10A currents.
I don’t quite see how to modify the above linked device for 1 cell, you need 2 more or in series to use that device. Now I’m guessing it wouldn’t be too hard to adopt this idea for these cylindrical cells. Perhaps this would be another option, that way you don’t have to mess with protected cells.
I got plenty of those voltmeters and low voltage notification thingies from hobbyking, with light and/or sound, and voltmeter readings, but I wanted more of a fully automated disconnect circuit that would simply stop supplying current when input voltage is below 3V.
edit: to have sort of a conclusion for reference, this seems like a very good high drain battery, up to 30A
it’s not an easy task to find high drain protected cells with a circuit capable if providing more than 7 amps without tripping
if you really need protected and need that current, I can’t tell you any cell other than that one you linked, maybe other have an idea, i don’t, sorry
I think you misunderstood - I’d like to buy unprotected or protected NCR18650PF based cells, if they’re protected I can remove the protection if it will be tripping.
I’m only asking where to buy genuine NCR18650PF cells.