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Rechargable Batteries


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I've had good luck with Rayovac Hybrid and Sanyo Eneloop. Amazon.com, Target, and even Kroger (grocery store chain) have lower prices on batteries than the local Wally-Worlds.

 

Try to find a slow charger (ie - one that takes 2-4 hours to charge), the 15-minute quick chargers are hard on batteries. Duracell has started offering low-discharge AA batteries, the Duracell CEF23DX4N combo of batteries and charger has gotten good reviews but it comes with 2 AA and 2 AAA instead of 4AA.

 

I've used a 4 pack of Rayovac Hybrids and an inexpensive charger that came with them for a couple of years now with good luck, I think the combo was around $15-20 at Target. I recently stepped up to a Maha MH-C8005, a much better charger. It was around $50 but it will charge up to 8 AA/AAA batteries at a time and monitors each battery individually. I do a good bit of photography and burn through AA cells pretty quickly in flashes and cameras so I needed something that could charge more than 4 batteries at a time, there are less expensive 4 battery chargers out there that do a good job.

Edited by jopasm
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My favorite battery / charger combo seems to be out of stock due to a recall (the LaCrosse BC-9009).

 

Depending on your type of use, some rechargables may be more suitable than others.

 

1. Regular NiMH. Higher capacity, but loses significant part of its charge if stored for a few weeks. Not all bundled chargers are the same, I avoid them, but that's because I already have a few good chargers. I really don't know what is a good brand right now.

 

2. Hybrid NiMH (e.g. Eneloop) that has lower capacity but holds its charge well for months. Costco occasionally has a 8 battery set with charger.

 

3. NiZn. Fairly new, available from Amazon. Some people here have used it and are reasonably happy with the performance, especially in cold weather.

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Try to find a slow charger (ie - one that takes 2-4 hours to charge), the 15-minute quick chargers are hard on batteries.

I thought "slow" usually refers to C/10, which takes 10 hours to fully recharge a completely drained batteries :) But a good charger can do 2 to 4 hours without damage to batteries.

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Try to find a slow charger (ie - one that takes 2-4 hours to charge), the 15-minute quick chargers are hard on batteries.

I thought "slow" usually refers to C/10, which takes 10 hours to fully recharge a completely drained batteries :) But a good charger can do 2 to 4 hours without damage to batteries.

 

Some people say that a very slow charging might be a problem in terms of detecting the right time to stop the charge, it's more prone to stopping the charge process much earlier.

 

Regards,

 

WF

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Some people say that a very slow charging might be a problem in terms of detecting the right time to stop the charge, it's more prone to stopping the charge process much earlier.

That depends entirely upon the charging algorithm and the precision of the analog to digital converter of a good charger.

 

The process most often used for knowing when to stop charging NiMH cells is called "negative delta V". While using a constant current charger, the voltage across the cell is being monitored.

 

The "-dV" method watches the cell voltage increase during charging, noting that the voltage begins to plateau, and finally that the voltage begins to drop, and using that drop (a good one will detect this as little as a 0.05V drop) as an indication of a completed charge.

 

A properly designed charger that is expected to deliver a 0.1C charge (or C/10, or 1/10C or whatever one prefers to call it) must also be designed with an analog to digital converter with enough resolution so that the processor can accurately gauge the changing voltage of the cell when that voltage is moving very slowly. Moreover, a well designed charger should not make assumptions about the cell capacity as is the case with less expensive units -- explained in a moment.

 

What you refer to is a older charger design (or a new and poor design) where the voltage appears to have ceased to increase and yet no decrease is noted either. When that condition is detected, most charging firmware will stop the process after a fixed amount of time as a precaution against battery damage.

 

One problem with this "time out" is that many of the older chargers made assumptions about how fast the voltage on the cell would rise based upon typical cell capacity. As we know, the capacity of a AA cell has increased a great deal since the "old days", and using the same current, the voltage curve over time is significantly less steep as a result. With a fixed current charger, higher capacity cells need more time to charge completely. The better chargers require that you supply information about the cell capacity and the charger will then adjust any preventive time-outs accordingly.

 

The other problem with some of the older chargers is that they had poor analog to digital resolution -- which is to say, the resolution with which they could monitor the cell voltage was poor. As a result, they were unable to realize that the voltage on a higher-than-planned capacity cell was still rising -- slowly -- during the charge. Detection of a long period of voltage plateau (never seeing the voltage drop show up) was another way of shutting down the charge.

Edited by ecanderson
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I have the same problem, i have about 20 Durracell 2650mAh recharables, which i purchased less than 12mths ago and in the last month or so when i have put them in my gps found all to be flat, even after recondistioning them less than a week ago. I use a PowerEX MH-C9000 Charger to charge and condition the batteries but even after than they do not hold a charge for more than a week sitting (not in a device). Just kind of strange that all the batteries being less than 12mths old are all doing this, yet i also have some old Energiser 2100/2400mAh rechargables which do hold their charge. Has anyone contacted Durracell about this, as now i its not just a one off occurance i may just do that, but i guess without a reciept anymore taking it back to K-Mart would be out of the question.

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I have noticed that my Duracell rechargables wont hold a charge any more. So in short I need to replace. Any suggestions on a good quality battery? I noticed Wally World had Kodak brand on sale for 20.00 4 batteries with charger.

Thanks for the help

BillMc

I use the Sanyo Enloops and also the Kodak Hybrids. Walmart has the Kodaks, but for some reason Kodak doesn't call them Hybrids on the package, but if you read the package they are called digital camera batteries and the package says pre-charged so I'm almost positive they're a hybrid battery.

 

As far as chargers I wouldn't buy the batteries that come with a charger. I use a couple of different Maha chargers. The one I use the most for the day to day charging is a Maha MH-C801D which I bought from Thomas Distributing.

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I would bet if you bought the PowerEx charger and put them through the reconditioning cycle (about 24 hours) they would be returned to like new. I have run into the loss of time many times over the years and it does great. One of the reasons to buy the good chargers is so that you save money on replacing batteries.

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I have used nicd and nimh for years. I now use only low discharge nimh like Eneloops and the Duracell low discharge cells. They work great in my Vista HCx, lasting for many days of geocaching and bike rides. They don't lose their charge in between weekend adventures either. I charge with the popular LaCrosse BC-9009 charger and its replacement power adapter (recent recall) . Couldn't be happier!

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I personaly think you are crazy if you don't buy the 2500mAh Energizer NiMH rechargable batteries. The new similar Duracel may also be good, not sure.

Not that I doubt your professional psychiatric evaluation, but could you explain the reasoning behind your thought? :surprise:

 

My experience with any other brand is that they quickly loose energy after a few charges. I have been using my Energizer NiMH rechargables for over a year, and they still hold (close to) their original charge. and lets face it 2500mAh is very high. I use 4 of those (giving me 4.8V) to charge my cell phone (HTC Touch). That gives me 2 full charges.

 

And yes, my professional psychiatric skills include psychic diagnosis. For example, I can tell that Chrysalides is definatly crazy (that is a technical term that means not right in the head). :ph34r:

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I personaly think you are crazy if you don't buy the 2500mAh Energizer NiMH rechargable batteries. The new similar Duracel may also be good, not sure.

Not that I doubt your professional psychiatric evaluation, but could you explain the reasoning behind your thought? :ph34r:

 

My experience with any other brand is that they quickly loose energy after a few charges. I have been using my Energizer NiMH rechargables for over a year, and they still hold (close to) their original charge. and lets face it 2500mAh is very high. I use 4 of those (giving me 4.8V) to charge my cell phone (HTC Touch). That gives me 2 full charges.

 

And yes, my professional psychiatric skills include psychic diagnosis. For example, I can tell that Chrysalides is definatly crazy (that is a technical term that means not right in the head). ;)

I have a set of Energizers that wouldn't hold a charge after about 1 year / about 25 recharges. Might just be a bad set, or a bad batch from Energizer. I had bad experience from Duracells too. Both were purchased about 3 to 4 years ago. I've even tried to refresh them on the LaCrosse charger, no luck.

 

My Eneloops have been working well though. So have the batteries that came with my LaCrosse, but I haven't used them for a year yet. My Eneloops actually see more use in my camera flash than my GPSr, and they work extremely well in them.

 

I even have a pair of AAA Eneloops in my wife's wireless mouse. She uses it every day, and the batteries last about 4 to 5 months between charges, far exceeding my expectation.

 

As for my mental condition, you're absolutely correct! :surprise:

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I also use the PowerEX MH-C9000 charger. Just received it so have only been "refreshing" my existing Duracell 2300mah, Fujifilm 1700mah and GP 2600mah. None of them were exhausted yet but the new charger certainly put some more life back into them. Also bought 8 of the Powerex 2700mah AA's. They've received great reviews. Haven't tried them yet so can't comment. I certainly recommend the PowerEX MH-C9000 charger though.

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I was reading today that the NiZn batteries will be available in AAA sometime before June.

 

I can't wait. The 1.6V will mean a lot of saving on AAA for me.

 

As for the rechargables, I am using Rayovac and Lenmar in a cheap Lenmar charger. So far I have 20 cycles which means it's paid for. Anything beyond now is gravy. And I've yet to need to change out a set of batteries while caching unless I restart it with low batteries. A full charge still gets me 8 hours of night caching.

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I personaly think you are crazy if you don't buy the 2500mAh Energizer NiMH rechargable batteries. The new similar Duracel may also be good, not sure.

Not that I doubt your professional psychiatric evaluation, but could you explain the reasoning behind your thought? :surprise:

I had eight of the Energizer 2500mAh batteries that didn't have more then about 3 or 4 days of shelf life, so Energizer replaced them and the new ones still aren't anywhere as good as my Enloops.

 

There was an article I read somewhere about NiMH batteries above, I think it was 2300mAh not being a good thing. I wish now I would have saved it.

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