Charging Nimh batterires the right way.

<p>I few months ago I got 5 sets of NiMH along with a Duracell 15 min charger. Recently I noticed the batteries did not last long and some where dead even before they got to the flash ( I did not know they loose charge by sitting) so today I did some research and seems like I was cooking this poor assistants for the last few months. I got an extra charger (Rayovac PS3) it took the charger a good 8 hours to charged the Duracell and Energizer batteries I got and now I'll see if this makes it all better.<br>

Now the question is Would you recommend the MAHA chargers? they appear to be good and I'm ok spending the $$$ if this will extend the life of the batteries and one to two hours to charge does not seems too excessive to get fresh batteries.<br>

The other question is. would you recommend the use of NiMH exclusively if you're not flashing every day? What makes them better than the other kind of batteries? and one last thing what is the mAh telling me? I know the higher the better, but how that does translate to performance? Is it faster recycle times longer life or both?<br>

Thanks for your feed back<br>

Alex</p>

<p>Hello Alex:</p>

<p>You may find this useful:</p>

<p>http://www.batteryuniversity.com/</p>

<p>Cheers! Jay</p>

<p>I've got a LaCrosse BC-900, which I highly recommend. Everything I've read on the web says that the MAHA units are excellent, as well, but when I was searching, they were significantly more expensive, for very little extra functionality. A web search will find lots of info and customer experiences on these two units.</p>

<p>It's important to have a charger that individually charges and monitors each cell.</p>

<p>In answer to a couple of your other questions, the mAh rating tells the total amount of current the battery can store. That's important for the total number of flashes you can get out of the batteries, but it doesn't tell you much about recycle time. For recycle time, you need to know the internal resistance of the cells, or their maximum current capacity. That's not something that many battery makers make readily available. However, NiMH batteries tend to be much better than, say Alkalines in this regard. So I'd recommend NiMH for general flash use. If you're only using the flash infrequently, you may want a battery with very low self-discharge, so that it will hold its charge for a long time sitting on the shelf. Sanyo eneloops are a good choice.</p>

<p>An article on the benefits of NiMH in flash units is here: http://strobist.blogspot.com/2007/09/feed.html</p>

<blockquote>

<p>the MAHA units are excellent, as well, but when I was searching, they were significantly more expensive, for very little extra functionality.</p>

</blockquote>

<p>The price for equivalent units from LaCrosse and Maha is about the same at <a href="http://www.thomasdistributing.com/">Thomas Distributing</a> , which is the best place I've found for batteries and chargers.</p>

<p>Thank you all for your great information. I never tought the charger can influence the batteries this much.<br>

Hopefully I did not already kill those poor bastards with the 15 min charger. I guess this charger of mine will find it's way to the trash can in no time.</p>

<p>I can no longer find Energizer AA rechargeable Nimh's in my local stores that have at least 2500mAh required for my Pentax K100D.</p>

<p>All I can find are the 2400mAh's.</p>

<p>There's an Adorama SunPack battery ad appearing in this thread showing 4- 2650mAh Ni-MH's with 2 hour charger going for $20. Wonder how those are? Never heard of that brand before. </p>

<blockquote>

<p>I can no longer find Energizer AA rechargeable Nimh's in my local stores that have at least 2500mAh required for my Pentax K100D.</p>

</blockquote>

<p>Your camera doesn't require 2500mAh batteries. It requires AA batteries. As far as your camera is concerned if the voltage is right and it fits in the battery compartment its going to work. The term mAh is a measure of how much energy is stored in the battery. The bigger the number the longer the battery will last. 2500mAh is listed in the manual to tell you that the 350 normal recording number is based on a 2500mAh NiMH battery. A 2400mAh battery will work but you will only get about 338 pictures. </p>

<p> </p>

<p>I just went down this road myself. One great source of info and education came from amazon.com<br>

by the way of "NLee the Engineer". He must own and review every brand of nimh battery and charger.<br>

Here is a link: <a href="http://www.amazon.com/gp/cdp/member-reviews/AOEAD7DPLZE53/ref=cm_pdp_rev_all?ie=UTF8&sort_by=MostRecentReview">http://www.amazon.com/gp/cdp/member-reviews/AOEAD7DPLZE53/ref=cm_pdp_rev_all?ie=UTF8&sort_by=MostRecentReview</a><br>

My research has shown this:<br>

1) Maha, Lacrosse, and Ansmann make the best chargers<br>

2) Sanyo Eneloop batteries are probably the best nimh batteries...they are the newer "slow discharge" or "hybrid", etc battery. They can hold a charge for months and still be quite usable. There are new<br>

players coming on to the seen but the Sanyo's have proven themselves over and over<br>

3) Dont buy batteries based on amp/hour ratings alone. Ex: The popular Energizer 2500 ma/hour batteries you see in walmart have a horrible self discharge rate. Once charged they will loose thier charge in about a week. Something to do with the internal resistance of these batteries.<br>

4) lower/modest mA/hour batteries tend to last longer<br>

5) slow/gentle "computer controller" chargers are best. 15 minute chargers can cook your batteries<br>

and greatly shorten thier life span<br>

6) You may want to consider Energizer lithium (non rechargeable) type batteries. They have incredible shelf life, last a long time and in the end can cost less than regular alkaline batteries.<br>

7) Again, go to amazon.com and read everything that "NLee the Engineer" has to say, he difinately<br>

knows is stuff. He has about 123 reviews and many of them on batteries.</p>

<p> </p>

<p>You're right, Steven.</p>

<p>The manual only indicates the amount of images recordable with the given mAh rating. I don't know what gave me the idea that it was required. Guess I got the impression with all the specs and do's and don'ts listed in the manual that 2500mAh was some type of requirement concerning the electronics of the camera. I always think when tech docs get this specific, it has something to do with unknown electronic tolerances they're unwilling to divulge.</p>

<p>In that same section they indicate AA alkaline's won't allow certain functions on the camera to be used but don't list what those functions are. There's also a caution box that states:</p>

 

<blockquote>

<p>Nickel manganese batteries and rechargeable CR-V3 batteries may cause malfunctions due to their voltage characteristics. Therefore, use is not recommended.</p>

</blockquote>

<p>Wonder if there's anything else they've left out that we should know.</p>

<p> </p>

<p>Alex. As August mentioned, you should also keep some lithium and high energy alkaline batteries whenever you leave the house. Keep in mind that rechargeable NiMH and NiCad can only be charged to 1.2volts per cell. It does not matter much what the mAH rating is. Your camera needs so many volts to operate the internal electronics. Using rechargeables starts you off with a low voltage that gets lower pretty quickly. Say like my spousal unit's Canon P&S, 4 fresh alkaline or lithium batteries will start out at over 6 volts with a sloping discharge curve. She can take over 200 images, then the "LO BATT" warning and the camera will shut down. I have measured these spent batteries, and they are very consistent at 1.134volts (I keep these batteries for flashlights). The NiMH batteries also have a similar discharge curve but they start out at a much lower voltage (just above 1.2volts). She will get much fewer images if she switches to NiMH. When it comes to being prepared, I trust in primary (not rechargeable) cells. I do not count money saved when missing photographs. Don't get me wrong...I like rechargeable batteries for flashes, they tend to squeeze more juice from batteries.</p>

<p>Thanks, August, for the Amazon link and battery recommendations.</p>

<blockquote>

<p>There's an Adorama SunPack battery ad appearing in this thread showing 4- 2650mAh Ni-MH's with 2 hour charger going for $20. Wonder how those are? Never heard of that brand before.</p>

</blockquote>

<p>I had several sets of Sunpak 1800mA-H batteries. They discharged themselves faster than any 1500-2000mA-H cells I've ever owned, and after I acquired my first charger that could measure cell capacity (a Lacrosse BC-900. I now have three fo them, they're that good) I learned that they also didn't deliver anywhere near their rated 1800mA-H. Sunpak doesn't appear to care at all about the "factory of the month" that bears their name.</p>

<p>Best batteries I've ever used are Sanyo eneloops. They combine two features that I love:</p>

<ol>

<li> low self discharge means that they've always got a decent amount of power in them. Let them sit a month and they're still near 100% capacity. </li>

<li>low internal resistance means they efficiently transfer most of their power to the flash unit. The eneloops are only rated for 2000mA-H, but the low self resistance means that they transfer as much actual power (give as many flashes) to my Nikon SB-800 flashes as the 2700mA-H Sanyo "non-eneloop" batteries I used to use. They stay cooler in use (good for both the flashes and the batteries) and they stay cooler when charging.</li>

</ol>

<p>So I'm now a 100% eneloop user, in everything from my SB-800s to my maglite to most of the lab equipment. The only thing I don't run on eneloops is the x-Rite 414 densitometer: the eneloops are slightly too wide for it.</p>

<p>Paul, </p>

<p>During a warm day starting at noon and shooting until around 7pm with freshly charged Energizers NiMH's, I got 182 Raws that filled two 1GB SD cards with no blinking blank battery icon indicator afterward. I did get the blank battery icon with occasional half charge after first turning the camera off and on which soon returned to the blank icon.</p>

<p>I did a lot of chimping watching for blown highlights in the histogram shooting restored historical landmarks and houses around my town. I used the flash just one or two times as fill on shaded scenes.</p>

<p>And it's true these batteries don't hold a charge very long when they sit in the camera for a week without use. I got maybe half the amount of images over a fresh charge.</p>

<p>Wow again thank to every one for the great resources. I learned a lot from this post.<br>

Regards<br>

Alex</p>

<p>There appears to be a lot of misunderstanding about NiMh batteries. First off, in general they will last longer then alkaline (much higher mAh rating). Next off, their discharge slope is much, much gentler then Alkaline batteries (Li Ion is better however as well as having more capcity).</p>

<p>Next there are two basic types of NiMh batteries, and the differences are important. Regular NiMh batteries behave similar to NiCad with two important differences, they don't tolerate fast charging well unlike NiCad and they also have no memory issues with charging (they also store a lot more amperage). The next type of NiMh is a hybrid NiMh. Unlike regular NiMh and NiCads, hybrid NiMh has a very, very low self discharge rate. Not as good as alkaline, but still very good. A regular NiCad of NiMh is will self discharge around 1% per day, so after 30 days you've lost nearly a third of the batteries charge. Hybrid NiMh have a self discharge rate of between one third to one fifth that of regular NiMh batteries. This comes out to around 5-10% per month, instead of 30% per month.<br>

The big advantage of regular NiMh is that they have lower internal reisistance and tend to have slightly higher mAh ratings (around 10% higher). This means when at 100% they will last just a bit longer and recycle a flash just a hair faster (on a 10 sec charge cycle, maybe 1s faster). The downside is that they are not a battery you can just leave in your flash if the flash doesn't get much use, they'll be dead when you need them otherwise. Hybrids if you only use your flash a few times a month are going to probably last you a long time before you need to charge them. Hybrids are suitable for not only high drain applications, but also low drain or sitting on shelf applications. Heck, hybrids are perfectly usable in wall clocks and TV remotes so long as you don't mind maybe needing to charge them every 6-12 months (where as with the super low self discharge of alkaline, you might get 2-3yrs of use before needing to replace them).</p>

<p>Personally I use my Vivitar 285hv maybe 10-15 times in a month with the occasional event where I will 'hammer' on the batteries with 50 or 60 or more flashes. Hybrids work great for this because I am not going to go an grab my flash after not using it for a month or two and find that the batteries died while they were sitting there. Plus I have much faster recycle times then alkaline, more flashes on a set of batteries and they are rechargable.</p>

<p>Anyway, long story short. Unless you use your flash a heck of a lot and need the absolute maximum capacity, or for a digital camera that you use all the time and need the maximum possibly capacity, don't get regular NiMh batteries. They self discharge way to quickly. Heck, even if you'd normally burn through a set of batteries in say 2-3 weeks the self discharge of regular NiMh batteries is going to offset the slight capacity advantage over hybrids. Check out the Rayovac or Sanyo (Eneloop) NiMh hybrid batteries. Great life, very low self discharge and at least with the Eneloop they come with their own (very good) charger. I'd say from a full discharge something like maybe 4-5hrs for a complete charge on the Eneloops.</p>

<p>Matthew, thanks for the insight.</p>

<p>Just bought (4) pack AA 2000mAh Eneloops with its MQNO6 charger off Amazon for $21.</p>

<blockquote>

<p>The big advantage of regular NiMh is that they have lower internal reisistance</p>

</blockquote>

<p>I'm not sure what you mean, here. Regular NiMH have a higher internal self resistance than eneloops and a higher self resistance than old fashioned NiCads.</p>

<p>Higher resistance then NiCads yes, but I was under the impression that they had a lower internal resistance then eneloops.<br>

As for the eneloops, they have been working out great for me and my wife. I was using a set of 4 in my 285hv with great success. I had gotten them for my wife for her older sony superzoom digicam, but she had already bought a pack of Lithium batteries. Well the lithiums finally wore out so now she has bogarted my eneloops from my flash. On Alkaline she was probably getting something like 100-150 pictures with flash including plenty of reviewing, etc. About 3 weeks of use on a set of alkalines. She hasn't run down the first set of eneloop yet and she has been using them for at least 6 weeks now and they still say full charge (though the battery meter isn't to accurate, it tends to say full charge until batteries are about 75% depleted and then drop to half and then quickly to nothing).<br>

I need to get at least another 4 pack soon so that I can leave a set in my flash and still leave her with a pair for the camera and a spare pair.</p>

<p>Duracell also have these slow drain rechargeable<br>

<a href="http://www.duracell.com/precharged/">http://www.duracell.com/precharged/</a><br>

I've seen them at local Target as well, while I've never seen Sanyo Eneloop locally. My unscientific observation rate them about the same in terms of performace, much better thatn regular NiMh.</p>

<p>Duracell also have these slow drain rechargeable<br>

<a href="http://www.duracell.com/precharged/">http://www.duracell.com/precharged/</a><br>

I've seen them at local Target as well, while I've never seen Sanyo Eneloop locally. My unscientific observation rate them about the same in terms of performace, much better thatn regular NiMh.</p>