So, my rechargable NiMh batteries are wearing out...
 

First... I do not want to post this in Lighting and gadgets. The demographic is just too young, and there is way to much,,,, "Youthful bravado". I really want to say something else, but we'll keep it clean. :notamused:

So, I run a Busch and Muller Ixon IQ headlight. Had it about a year, and have used it a lot, including cloudy days, mornings, and late in the day. (Besides night) So, the factory supplied rechargeable NiMh batteries are finally getting to the point where they won't hold a full charge. I've got alkaline batteries for backups in my bag, should they be needed. These originals are rated 2100 milliamp/hours. Any suggestions on what I should replace them with? Or, any to avoid? Or, are the various brands of rechargeable NiMhs on the market all about the same? (Duracell, Everready, etc.) Suggestions and experience are welcome.

Eneloops are a hybrid, NiMh and something else. They can keep an 80% charge for a couple of years.

Not like typical older Nimh, that can lose 10% in a day. I have and use quite a few. And a good charger. All Nimh are not the same.

As stated above, the hybrid NiMH cells such as the Eneloops are much better at keeping their charge over time. Their drawback is that they have a slightly lower capacity - typ. 2000 mA-hr vs. about 2500 mA-hr for regular NiMH cells. So if you're using the cells almost every day and recharging regularly then the normal cells may work better for you. OTOH, if you have long periods where the cells are sitting unused then the hybrid technology is a big winner.

Sanyo's Eneloops continue to be good and reliable. Ray-O-Vac's original 'Hybrid' cells were also quite good, but they've replaced them with a different series which isn't nearly as good. Both Energizer and Duracell make good hybrid NiMH cells - I'd go by which one has the best sale at the time.

When I was still working and bike commuting I got my battery packs from www.batteryspace.com. The prices seemed good and I never had a problem with the batteries.

I use Energizers in my DiNottes simply because that's what they sell at Sam's Club. I charge them twice a week in Standard Time, once a week in Daylight Time.

I get about a year out of them in the front (steady) before they stop charging fully, then I rotate them to the back (blinking) for another year. I recycle them after that.

I don't know if that service interval is good, bad or indifferent, but I don't mind buying a fresh set every autumn and tossing a two-year-old set.

All rechargeable batteries have a duty period, this is the number of charge/discharge cycles that the battery can take, some will after this simply drop dead, some will slowly start to lose capacity. NiMH do not generally suffer from memory effect as much as NiCads, the problem with Bike lights is that you tend to not run the batteries to flat. You should leave your lights on until the light fails, then put them on the charger for 24 hours, about twice a month or so.

Slightly off-topic but not really.
I have a medical device that uses rechargeable batteries. After they went bad I looked up replacement packs for them. they wanted $130 for them!!. I took the pack apart to see what precious metal these things were made of :). Basically just basic batteries. took the pack to a local battery place and had them make me one. $12 later.....

I like the eneloops best, but I've found that these

http://www.batteryground.com/img/2/328.jpg

which I bought many years ago, have done very well in our Superflash Blinkies.

For photographic flash I've been very happy with the combination of Powerex Imedion batteries with a Maha MNC-8010 charger. The batteries hold a charge well on the shelf. The charger monitors individual batteries and does a life-prolonging soft charge when you aren't in a rush. The batteries also work well in my bike lights and their low power demands but others might do just as well.

Yeah you take the cartridge apart see that inside is a standard cell, and you wonder why the heck a battery costs $100, when the parts cost $5
... What gets me though, for my Camera, the battery from Canon is $149, a third party equivalent is $49... What really burns me though, you can buy a replacement battery for $13 in the US, and here with our dollar worth US$ 1.05, it costs me, $49 for that replacement battery.... :notamused:

What problem is the OP trying to solve? Self-discharge? inability to charge? low voltage (shorted cell)? "Wearout" for a battery usually means it's been charged and discharged as many times as it can be, and is not capable of providing an acceptable performance profile any more. All secondary or storage cells have a finite cycle life. Sometimes and for some battery technologies the cells can be reformed, but I'm not sure about current products.

If they've just had the stuffing used up, he just needs a replacement that at least meets the OEM specs, or to use up a lot of primary cells (alkalines or similar) making do without his recharging ability.

Despite the fact I'm an electrical engineer and have some experience in designing power systems that use batteries, I don't have a way of telling you what alkaline size or rating will give you acceptable service as replacements for your NiMh originals. I'd have to know your usage profile, how often you are willing to do replacements, and especially to have all the application curves for your old cells and a bunch of new alkalines. Even so, you might be able to use $.39 disposable cell for a while, but soon the replacement cost will be greater than the price of a new rechargeable battery that fits your light system. If you like the performance of the light, I'd suggest just get a new replacement battery of the right type, that will readily fit and work.

^^ Yep.

J

Thanks for all the advice, and all presented in a respectful manner. Wow! This forum is one of the few places left on the net where such a thing can actually still happen.

I use the light almost every day. In the fall, when it gets very dark very quickly around here, it stays on for a long time. The low, or "normal" setting is 10 LUX. I don't have a lumens figure. Let's just say the light is quite bright, and has good "fill". In this mode, it is supposed to run for 20 hours. The high setting produces 40 LUX. Bright? It's damn near blinding. I rarely use this mode. In absolute darkness, with no other light around, it's almost like having daylight in front of the bike. Good for areas where street lighting is poor, or non-existent. In this mode, you get five hours of light. This light is regulated. It does not get dimmer as the batteries discharge. a green/red LED on top of the unit lets you know if you are getting weak. I've always carried a spare set of alks, "just in case". The batteries are AA size, and easily replaced. No battery bag. (Battery bags drive me nuts. Can't explain it, they just do)

The factory originals are supplied by Busch and Muller. Now, it is possible that I contributed to their demise, because I'm a nutjob about making sure my batteries are fully charged.
My understanding is that NiMh battery technology is constantly improving, and that they now have gotten to the point where the "memory problem" and leakage has been just about eliminated. i.e. You may charge them as often as you want, and they won't suffer.

+1 on the Maha chargers.I use one as well and ultralast batteries...
Bud

An aside, when you need a back up that is reliable and will give you a reasonably time period before it goes out a medical duty dry cell works well. I got them when the home health care required them for an infusion pump I has for 7 months. The NiMH they came with were cheap and poor in cycle life. I have a few left and use them for headlights and electronics requiring an "AA" size cell.

Bill