Where to get genuine Panasonic 3400mAh 18650?

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

Ncr18650b are not designed for 15A pulses. I suggest VTC5.

I agree with the others the NCRBs are not the way to go IMV even if the protection circuits allowed it the 15A bursts would not be good for the Bs

Go with high drain cells and charge them when the s’driver starts slowing/grunting.

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’ve handled mostly lithium polymers for my r/c hobby. Now lithium polymers don’t come with protected circuits so a common solution to over discharge would be to include a device that gives a live voltage, that way you know when to recharge. For example, http://www.ebay.com.au/itm/RC-helicopter-Lipo-battery-AKKU-portable-Voltage-meter-Tester-alarm-2-6S-AOK-/141151350792?pt=AU_B_I_Electrical_Test_Equipment&hash=item20dd46b008

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

based on panasonic NCR18650PF

that’s a much better option for your needs, take a look at mountain electronics to see more options, if you like

mountain electonics has a nice selection of higher quality cells, prices are decent too, but seems there are no options to delivery in EU, US only.

yes, sorry, i forgot to check your location…. are you interested of getting them from china, or you need them sooner than 1,5 months?

I don’t “need” them at all, I want them :slight_smile: it’s a hobby. It would be simpler and probably cheaper if I just bought a new Bosch screwdriver :slight_smile:

So - no, I don’t need to have them urgently, I can wait for china delivery.

Any suggestions where to get genuine ncr18650pf /based/ cells?

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.

sorry again. you can find them in fast tech, but shipping will be slow
11,47$ for a pair after BLF coupon

http://www.bgmicro.com/ur18650f-2000mah-rechargeable-lithium-ion-by-sanyo.aspx

I have ordered a few batches, and they are solid! Most of my gear is loaded with them and they have been working well for months.

Nice price, 10 cells are $17.5, but the shipping is also additional $17 for me (Sweden). Have you had a chance to test their capacity? i can’t find a review of those cells, only 2600mAh version comes up. Perhaps these are old 2600 cells which lost their capacity so they are now being sold as 2000mAh ? :slight_smile:

I have not tested them. They look identical to the laptop pulls I have found in the past. I forgot to test the voltage on the last batch I bought. If I recall my first batch they were around 3.8 volts when I got them (that depends on the meter you use too, lol). I can say that they took about a hour or so to fully charge up on the I4.

If all you’re interested in are 15A pulses, the Panasonic NCR18650BD might be a better choice. Maximum current may not be as high as the VTC5 - only 10A maximum continuous and 15A pulse (enough for your needs). But with 3200mAH, capacity is quite a bit higher - almost as high as the NCR18650B.