N Size Cell Charger


I got Lenmar's BCUNI3 NiMH charger along with N Size flattop cells today. The BCUNI2/3 specs are:

Power Source: 12VDC, 100-240V AC and DC car cord plus EU & USA plugs included.

Input current: 1000mA

Output charging Current: 1000mA max. (3.6V Li-ion Battery) 1000mA max. (7.2V Li-ion Battery) 1000mA max. (Ni-CD/Ni-MH battery)

USB output: 5v/1000mA max.

Charge Termination: 130mA max. (Li-ion Battery)

Negative Delta V detection (Ni-CD/Ni-MH battery)

Timing protection: Max. 7 hours (Li-ion battery) Max. 6 hours (NiCD/Ni-MH Battery)

The unit comes with the upper battery terminals being adjustable in width and height. The door slides down and is adjustable for battery length. I charged two N Size flattop cells in about 10 minutes (they we probably shipped almost fully charged). The batteries got a little warm but not too hard to handle.

The BCUNI3 also has a USB port for charging external devices and an LCD screen to show battery chemistry, battery voltage (1.2, 2.4, 3.6, 4.8, 6.0 or 7.2V), Fault, Capacity/Charging Status, USB Active and Power. The BCUNI2 doesn't have the USB charger port or LCD display.

I'm presently trying to charge a couple of Panasonic AA Ni-MH batteries rated at 2600mAh and they seem to charge quickly with the batteries getting a little warm. I like the battery charger because it can charge battery packs for Camcorders, Digital cameras and Mobile phones (that's why the upper terminals are adjustable) as well as external devices like iPods and iTouches with USB. One downside is that it will only do two N Size cells at a time. It also says it will charge one battery at a time in the right channel but the 'Charging Status' display just blinks. I'm not sure what to make of that. Note: Later the charger display took some time to update but it will support a single cell battery in the right channel at 1.2V.

Anyway, it does charge N Size cells quickly but I have to see how they'll work in my 41C, especially driving a card reader. I also remember that a 143 printer will power a 41c through its cable if the 41 has no batteries in it. I wonder if how NiMH batteries will affect an attached printer. I'm also wondering how these flattop N Size cells will work in a 41. They are a little shorter than the alkaline primary N Size cells, which I think is good as some of the springs in the 41 battery compartment are pretty stiff.

Stuff to play with. Let me know what you think,


Edited: 13 June 2011, 7:35 p.m.



Thanks for the nice review!

I may need to get one of these myself. I've got all sorts of ways to charge up batteries with external power supplies but this sounds really easy to use and very versatile. My only concern is that the the nicad/ni-mh charging rates seems excessively high for small capacity cells. But as long as it doens't cook them by seriously overcharging they should be fine.



Thanks Katie.

I tried the flattop N Size cells in one of my 41Cs last night and they are too short. Crap! Okay, time to modify the cells. I'm going to add beads of solder to each end and see if that works. I will probably go over to Newark and order some button top N Size cells.

In response to your concern about excessive charge current, the specs seem to specify a maximum current of 1A but I don't know if that's used throughout the charge cycle. I assume there is some algorithm in the uProc that tailors the current based upon the cell chemistry. Also, as the cell voltage increases that will reduce the charge current to help control the temperature of the cell. My initial impression so far is that the N Size cells don't get too hot. I believe the "Negative Delta V Detection" for Ni-CD/Ni-MH batteries means that it will stop charging a cell if the battery voltage drops over a period of time as charging current is applied. That's how the charger determines when the cell is fully charged.

Here, at work, we use Anton Bauer rechargeable battery packs (specifically the HyTRON 140 and Dionic 90) for our Panasonic P2 ENG HD field cameras. The associated chargers are amazing in how they can test, diagnose and try to repair problem batteries. The batteries recharge very quickly with the chargers monitoring the internal temperature sensors. There use to be white papers on their website explaining how their patented chargers worked but I didn't see them this morning. If you're curious take a look at http://www.antonbauer.com.



Edited: 14 June 2011, 2:55 p.m.


I wanted to update anyone interested in Lenmar's BCUNI3 NiMH charger that can be used to charge N Size cells. I received some button style N Size cells from Newark yesterday and ran them through the chargers last night. These cells must have been sitting for a while as the chargers reported a low initial charge but quickly charged them up. TOO quickly as when they were done, the N Size cells were almost too hot to handle. I one case, a cell making a sizzling noise and leaked a little during charging but none of the other 13 cells did that.

These freshly charged cells worked great in my 41cs and ran my new card reader just fine. I bought the reader from TOS really cheap (from a Canadian, Hey!) thinking I could do a rebuild based upon Geoff Quickfall's HHC presentation from 2 years ago (was it two years ago already?). But the card reader works as well as my original rebuilt card reader. And the new one is a version G so I'm happy.

Anyway, I would think twice about using this charger for N Size NiMH cells. It appears it uses too much charging current causing the cells to get hot. Bummer.


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