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  1. Mr Happy

    How hot does an NiMH really get when you charge it fast?

    The answer is not as much as you might think. Partly prompted by the common remark that "surely charging NiMH at lower rates is better?" and partly to investigate some mysterious behaviour from my AccuPower IQ-328 charger, I did a baseline test on one of the troublesome batteries to see how it...
  2. Mr Happy

    Freeplay Sherpa hand-cranked light in 2012

    I did a search for discussion of Freeplay lights and the most recent thread I found was from 2011. Having just bought a current edition of the Freeplay Sherpa light I thought I'd make one or two observations for anyone who is interested. The light easily disassembles by undoing a few screws...
  3. Mr Happy

    Large scale alkaline and other primary chemistry battery performance test

    tom66 over at EEVBlog forums designed and built a battery tester for his internship project at BitBox Ltd and used it to do discharge tests on as many AA sized batteries as he could lay his hands on. The results are here: The specific brands tested have a UK...
  4. Mr Happy

    Best quality Mag reflector replacement?

    I'm looking to source a metal reflector for a ROP and wondering what might be the best quality (available) option, but my searches are not turning up very much. Can anyone give me any hints? Has anyone done comparative tests with beam shots--looking at beam quality, profile accuracy, surface...
  5. Mr Happy

    Mag switch current handling -- it's conductive plastic?

    Dunno if this belongs here or with incan lights, so I'll try it here since a switch is kind of "electronic". I just disassembled a new Mag 3D and took the switch apart. I have previously seen comments that the standard Mag switch is good for 5-10 amps and I wanted to look at the construction...
  6. Mr Happy

    Dead Eneloop :(

    I had a set of four Eneloops in a kitchen scale, and today the scale wouldn't turn on. I checked the batteries and three were at 1.25 V, one was at 0.85 V. Uh oh. I wonder how that happened? These are 2006 vintage cells, and maybe one of them just upped and died? I guess even Eneloops might die...
  7. Mr Happy

    Panasonic HHR-3MPA NiMH 2050 mAh cells

    I thought I'd start a new thread about these cells, as they are interesting. They came with the Panasonic DMW-LZACKIT Accessory Kit for Panasonic digital cameras along with the BQ-321 charger. This was intended for Panasonic cameras LZ2, LZ3 and LZ5 that took AA batteries in the days (2005/2006)...
  8. Mr Happy

    A tale of Rayovac Hybrids

    I have four Rayovac Hybrid AAA cells that I picked up once, that had been sitting in a discharged state for a while. I was looking for some AAA cells to test chargers with, so I put two of them in my Duracell CEF-23 and the other two in my recently obtained Panasonic BQ-321. Well, one of the...
  9. Mr Happy

    What charger to buy depends on where you live

    A perennial question that comes up is What is a good NiMH charger to buy?, and when looking in shops in America it is hard to answer. There basically isnt one. However, in Europe there seem to be better answers. For instance, I just saw in Tesco an own brand 1 hour fast charger, with four...
  10. Mr Happy

    Excellent nickel battery charging videos

    I have not seen these linked here before, so here are a couple of very nice video blogs on battery chargers and charging that I just stumbled upon:
  11. Mr Happy

    How to squeeze a bit more precision from your multimeter

    One of the snags when measuring lithium ion voltages is that most inexpensive meters only read up to 1.999 or 3.999. If you want to read a voltage like 4.2 you have to switch to the next range up that gives you only 4.20 worth of digits rather than 4.200. The snag with this is that the last...
  12. Mr Happy

    Ni-Zn from UltraLast

    I made the mistake of going into Fry's and I saw these on the rack. Couldn't resist: I'll test them and see how they do. (Updated 12 May) Here are some preliminary test results. The cells are labelled 1.6 V, capacity 1350 mAh minimum. Size: diameter 14.3 mm, length 50.3 mm. Standard AA...
  13. Mr Happy

    Westinghouse LiFePO4 cell and Fenix LD10

    Following on from this thread, and also this thread where someone asked what these cells could be used for, I tested the Westinghouse LiFePO4 cell in a Fenix LD10 compared with a freshly charged Eneloop. I used each cell in each of the modes and measured the relative brightness with a light...
  14. Mr Happy

    Investigating the Westinghouse 3.2 V AA LiFePO4 cells

    These are the latest generation of "green" cells being used for solar lighting applications and can be found, for example, in the solar lighting section of Wal-Mart. I picked up a few of the 600 mAh AA/14500 variety to test and see what they can do. An add replaced the OP's images. Bill...
  15. Mr Happy

    Flammable vapors in metal tubes: a dramatic demonstration

    When there are stories of aluminum flashlights exploding I am reminded of the following rather interesting and eye opening demonstration. Do you think your lithium ion cells containing combustible organic solvents and sealed inside a metal flashlight tube might lead to an explosion as powerful...
  16. Mr Happy

    Analyzing batteries on a budget

    Some of us may want to estimate the capacity of our batteries, and either we don't own a CBA III (or I or II), or even if we happen to own an MH-C9000 we might want to test other cell chemistries than NiMH or NiCd. Well, there is an answer. If you can obtain a digital multimeter with a computer...
  17. Mr Happy

    Charging NiMH at high and low rates -- what can go wrong

    Using my newly assembled computer data logger (see here) I've been trying a few experiments. In the first experiment I looked at what happens when charging an NiMH cell at two different rates. It is often advised to charge small NiMH cells like AAA and AA cells at a rate of 0.5C - 1.0C...
  18. Mr Happy

    Playing with the RadioShack 22-812 Meter

    For anyone unfamiliar with it, this is a moderately good digital multimeter you can find in RadioShack for about $70, maybe less on sale. What is really neat about it is that it has a RS232 serial interface for connecting to a computer. This means you can use it for unattended data logging! (I...
  19. Mr Happy

    A new way to charge Duraloops? (Don't try this at home, kids!)
  20. Mr Happy

    Duracell Power Gauge CEF21 mod for improved charging of AAA cells

    Here is what the CEF21 looks like inside. This is the Duracell Power Gauge charger (Indicator Charger in Europe). Top view: Upper left is the mains power supply. Transformer TNY266B brings low voltage power over to the rest of the circuitry. Lower left there are four parallel power supply...