Revice some dead Camera Battery (Nikon EN-EL3e) - Page 1
Forum section: electronics / repair

author: nightfire
author_rank: Frequent Contributor
timestamp: April 16, 2021, 10:28:40 pm
content: Short Backstory: As I am doing photography, I still have some old Nikon gear lying around, that I intend to reuse for tinkering or some "high-risk" shots, where damage of the gear i no big concern due to low value.On ebay I sourced some 3rd party batteries for a decent price, that are of the old type (LiION, 7.4V nominal voltage =2 cells internal) and no digital coding, only a small internal PCB for charge control and balancing. (And reporting back on a 3rd terminal the charge status to cameras with respective contacts like the D200 etc.)Sadly, out of 5 used batteries only 2 were showing 7.4V, the three remaining were dead from the outside- my DMM showed 0.0xx Volts.I cracked one open, and the cells measured 2.5 and 2.8 Volts, so they were about deep discharged.As they were not only intended for powering a camera, but also to power (as second usage) some breadboard power supplies for tinkering (and eliminating power supply ripple...) I also might de-solder the 18500 cells inside and use the cells separately.I mean those el cheapo power converters that can be clipped onto a breadboard and with 7.5V-9V input voltage they will provide 3.3V and 5V output- perfect for some things I will do some work with- and with a battery there cannot be ripple from a SMPS...Questions:- How good are my chances to manually revive those 18500 cells?- Any good Li/Ion charger that could be recommended for usage with 18500 and 18650 cells? (Preferrably below the 50 €€€ mark...)- What about manual charging via lab power supply?- Any tips where to get in germany some 18500 battery holders (preferrably in one piece, no separate clamps for soldering onto a PCB)?

author: RoGeorge
author_rank: Super Contributor
timestamp: April 16, 2021, 10:42:05 pm
content: All consumer Li-ion batteries have internal protection against over-discharging, a MOSFET that disconnects any output when the internal voltage is too low. Most of the time this is why Li based rechargeables show 0 volts.Just let them in the charger for a couple of hours, and they might start charging normally. It takes a while, so take patience, just let the battery pack in the charger and wait for it to start taking charge.If you plan to replace the internal cells only, beware that some ballancing circuits won't work any more (will brake an internal fuse) if it detects a cell has zero volts internally (or disconnected).

author: nightfire
author_rank: Frequent Contributor
timestamp: May 22, 2021, 09:58:03 pm
content: Well, for 2 of them it did the trick, as they were able to get revived.At least one of the pack is still playing dead, as I opened it I got 2x 18500 cells inside, that seem to be still ok and could be re-purposed for other use.Problem: Here in germany I can't find any battery holder that will natively fit themQuestion: Any tips where to obtain a fitting 18500 battery holder OR any hints on how to fit/adapt those cells into somewhat more standard, like a standard C cell/26500 size?Or are there any spacers to prolong the 18500 to 18650 holders?

author: DC1MC
author_rank: Super Contributor
timestamp: May 22, 2021, 10:20:01 pm
content: Quote from: nightfire on May 22, 2021, 09:58:03 pmSure they are id foy don't mind the price, this site has "variable" (adjustable) loaders for 1, 2, 4, 6 and 8 cells, that fits a whole bunch of models, here is the loader for one cell:https://akkuplus.de/Efest-SLIM-K1-Intelligent-Charger-Ladegeraet-fuer-1x-Li-Ion-ZelleCheers,DC1MC

author: nightfire
author_rank: Frequent Contributor
timestamp: May 22, 2021, 11:09:03 pm
content: Thanks!These models have an integrated USB charger that I don't need- and what is probably making them expensive- But they also have some 3D-printed adapter rings from 18mm->26mm.Thats exactly what should fit the bill here- with this mechanical adapter, a 18500 cell should fit into a standard battery holder of C Cell batteries, that are standard stuff.

author: tooki
author_rank: Super Contributor
timestamp: May 24, 2021, 01:43:07 pm
content: Quote from: nightfire on May 22, 2021, 09:58:03 pmJust get PCB battery contacts like Keystone 54 (Conrad and Reichelt carry them). Then just install them at the distance you need.

author: nightfire
author_rank: Frequent Contributor
timestamp: May 24, 2021, 02:44:04 pm
content: Yes, I also thought about that as I was browsing through the Reichelt catalogue- but as I try to be a bit lazy about self-manufactured stuff (and still wonder why there are so many ready-made 18650 holders out there, but no 18500) I wanted to have some existing model...I think I might end up with a standard C cell holder (length should be the same) and add 1 or 2 rings around the 18500 to make it up to a 26500 so that it will fit snugly.Found some O-Rings with 18mmx3,5mm and will see how they hold up...

author: tooki
author_rank: Super Contributor
timestamp: May 24, 2021, 04:49:59 pm
content: Quote from: nightfire on May 24, 2021, 02:44:04 pm...maybe because 18650 is hands-down, by a wide margin, the most common cylindrical Li-Ion cell size, while 18500 is an unusual size that didn’t become popular the way 18650 did?

author: nightfire
author_rank: Frequent Contributor
timestamp: May 25, 2021, 12:52:37 am
content: Thats ok for me, but in such cases I would suspect that there is a (small) niche market for adapter stuff and such- especially when manufacture of mechanical adapters is no rocket science and the 18500 is "only" a bit shorter that the 18650...

author: amyk
author_rank: Super Contributor
timestamp: May 25, 2021, 03:00:19 am
content: Quote from: nightfire on April 16, 2021, 10:28:40 pmThat's not deep, that's usually the end cutoff voltage for lion cells. Below 2V is a deep discharge.

author: nightfire
author_rank: Frequent Contributor
timestamp: May 31, 2021, 08:31:33 pm
content: Update: Got my hands on some Nitrile O-Rings (18mm/3.5mm) and they fit quite well- put that stuff into a standard C-Cell holder (basically a 26500 type) and it worked like a charm.Now I only have to look for a way to get those rings a bit fixed/sticky, but that should be no big issue...Now I only need to solder some 4mm test leads on the contacts and I am set :-)

author: nightfire
author_rank: Frequent Contributor
timestamp: June 12, 2021, 09:40:16 am
content: So, final test: Bought myself my first "real" Lithium charger- a Xtar VC4L, which is simple as it gets, but displays voltage and current- both abovementioned cells were charged to 4.15 Volts open circuit voltage according to my trusty multimeter, and the charger reported somewhat above 1200 mAh- so seems good, and with a bit of luck i have some good cells for cheap ;-)