NiteCore D2 LiIon charger max battery length

[Rick Law]

Hi Folks,

Anyone with the Nitecore D2?  I have a couple of questions.

My little charger boards with gator clip for connectors works well, but it is not something I want my family to use.  NiteCore D2 charger looks like a decent charger that a novice can use.

If you have a Nitecore D2 and don;t mind helping, I have two questions:

Q1:
My savaged laptop 18650 are a bit on the long side since I added multiple layers of insulation.  So I am concerned what is the max length battery I can squeeze in to the D2's charging slot.
Searching the web, I found two inconsistent buyer-comments, one at 70mm and the other at 68mm for the max battery length.
- If it is 72mm, life is good, I can just squeeze it in.
- If it is 70mm, I can repack by removing a layer of my 0.3mm insulation to just get it to fit.  I need to rework all my 18650 but they can fit.
- If it is 68mm, I can't get down that far easily.  I need to replace the round wire I use with something flatter and rework both ends for each battery.  That may be a show stopper for me.
So, knowing the max-length I can squeeze would help me decide.

Q2.
The specs implies there is thermo detection.  But it doesn't say explicitly that there is an over-temperature shutdown.  Do you know if it auto-shutdown when the battery got too hot?

Thanks for the info.
Rick

[Rick Law]

I left a similar post on a dead (old) thread on candlepowerforums.  I got a reply with a link to a review and I found the anwser in that review: 69.3mm max length.  Darn...  I was hoping it was 70mm and change.

This would have been a good solution...  Now I have to decide if I want to strip out the extra insulation I put on those old laptop 18650's.

I am disappointed!

[amyk]

Did you add a protection PCB to the cells? Otherwise I don't see how they could get longer...

[Rick Law]

Did you add a protection PCB to the cells? Otherwise I don't see how they could get longer...

Yeah, I added a protection board (1.7mm).  And I applied insulation liberally (.3mm each layer, with a layer of electrical insulation tape in between).

I did some calculation, even if I repack my 18650, I still can't squeeze it down to 69.3mm, but 69.9mm is a possibility (a very helpful candlelightforum users "RI Chevy" tried squeezing the max for me).
Top side: Flat top cover 1.5mm + insulation 0.3mm + wire 0.7mm = 2.5mm
Bottom side: protection board 1.7mm + insulation 0.3mm + wire 0.7mm = 2.7mm
Total = 5.2mm added with single layer insulation, plus 65mm for the cell, that is 70.2mm.

So if I can flatten the bottom-side wiring and make use of the vertical space of the protection board to route the bottom wiring, I could fit it.

I am a little reluctant to remove too much insulation.  The first time I repacked 6xSony from an old laptop, I noticed my gator clip sparked on occasion.  On closer look I noticed a very small nick on the shoulder of the cell's factory wrap likely made when I was removing them from the laptop pack's plastic casing.  So, it gets me a bit nervous without at least double lay of insulation.

Another user on candlelightforum "HKJ" did some reviews.  He pointed me to a few around 70mm to even 74mm max battery length.  I may consider those also.

With Nitecore or the other "longer" ones, I think I would miss my logging and the other features I added to my home-brew solutions.  So I am not sure what path I would take...

[alank2]

My D2 measures:

71.15mm
71.26mm

[Rick Law]

My D2 measures:

71.15mm
71.26mm

Thanks for the info!  Looks like it is a matter of luck of what I would get, 68mm (fasttech spec) to 71.26mm.

In searching for alternatives, I stumbled into the BT-C3400.  It is catching my eyes right now.  Since one of my goal is "user friendly" (to replace my gator-clip connected charger boards) so my family can use as well, the BT-C3400 looks best for the UI reason.  It has an UI exactly like the LaCross BC700 we have been using for NiMH last couple of years.  Its modes like "REFRESH DISCHARGE", "CHARGE TEST" are all already familiar and I would not even have to "retrain" them on how to use the BT-C3400.

A gentleman at candlelightforum tested it to take 72.5mm, so even if I do a +-2mm for manufacturing tolerance, I am still in the range.

Much as I like the Nitecore, for now, I am now switching over to BT-C3400 and see if it is what I expected.  It is > 3x the price of Nitecore D2, so my expectation is high.  Hopefully, my further research will not be disappointing.

Thanks for the input!  I don't feel I am in the dark with the help from folks here.

Much thanks
Rick

[amyk]

Those few mm of difference seem like manufacturing tolerances to me and it might be possible to modify the charger to fit longer cells.

[Rick Law]

Those few mm of difference seem like manufacturing tolerances to me and it might be possible to modify the charger to fit longer cells.

Ah, thanks!  confirming my line of thought there.  I think I will repack my cells with the thinner 1.5mm flat-top cover (waiting for shipment), and trim them to 70mm target 71mm max.  That should  do it.  But if not, I will take out a filer and fiddle with it a bit to get to 70-71mm if needed.

The BT-C3400 has my eyes now since its UI is exactly the same as the BC700 NiMH charger we have been using; so my family should adapt to it easily.  The BT-C3400 does pulse charging instead of flat CC and some folks doesn't like that.  I am researching and see what I can find out (pros or cons) about pulse verses a flat CC.  Barring any surprises, I think I will be in the company of a BT-C3400 shortly.

Thanks for your input folks!  I always learn things here.

Rick

[alank2]

I hope you like what you get Rick.  I really like the 18650 cells, better than the 16340 pair I was using before in my old light.

[Rick Law]

Oh, well... My impatience got the better of me. I was going to wait a bit to avoid buyer's remorse.

The eBay seller RDANA replied to my question and he measured the BT C3400 max battery length at 71.4mm. 71+ is a green light for me. I got my LaCross BC700 from him a couple of years back, and some of my NiMH-LSD cells came from him, so he is a known quality and I feel comfortable.

The BT-C3400 has almost exactly the same user interface as the BC700. The UI was the deciding factor. Same supported modes, same names for the same function, etc. makes the transition easy.  After all, making it easier for my family is the main reason I want to replace my various charger board solutions.

With his reply at hand, my limited patience started chewing on my ears, I hear the voice from somewhere: "Hey, you are not that young any more, do you want your charger before your first pension cheque or what? Forget the battery's expiration date, look at your own expiration date!" So, in panic, I hurried over to eBay and ordered hoping that this would not be the last thing I would ever do...

So now it is a done deal - Opus BT-C3400.

Joking aside... Thanks folks. You guys have been helpful and I feel I made a good decision with your help.

With thanks
Rick