Looking for a small EDC charger

[davidt1]

I have this Panasonic charger. I love it, but it only holds/charges 2 aaa batteries at a time. Would like to buy something similar in size that can charge 4 aaa at a time and 10440 and 14500 as well. Thanks.

 

[Mr Happy]

I can't imagine you will find such a thing. 10440 and 14500 are not consumer rechargeables. You will probably have to go with a second charger for the Li-ion chemistry and keep the Panasonic for NiMH.

 

[davidt1]

You are right. Forget the exotic batteries then. What's a really good small charger for aa and aaa batteries these days? I also use the charger to store the batteries, so it needs to hold 4 aaa in place. Thanks again.

 

[travelinman]

I use the Maha C401fsb cause I travel with as little luggage as possible. It's small, light, does 4 cells independently and most importantly has a slow charge mode that is causes very little stress on the cells. It also has an "international" power supply. You only have to remember to leave the plastic lid UP when charging, especially on the fast setting to keep things cool.

 

[davidt1]

Thanks, but it looks like the Maha charger requires an external power adapter which would be one additional item I need to carry.

 

[Marduke]

I use the Maha C401fsb cause I travel with as little luggage as possible. It's small, light, does 4 cells independently and most importantly has a slow charge mode that is causes very little stress on the cells. It also has an "international" power supply. You only have to remember to leave the plastic lid UP when charging, especially on the fast setting to keep things cool.

Slow charging can actually be quite damaging to cells due to missed terminations.

 

[Bones]

If you're okay with a 120 volt power supply, the Sanyo MQN05U could fit your needs.

It has fully independent charging channels, appears to terminate very reliably and its sliding cover will help contain your cells:

http://www.buy.com/prod/sanyo-batteries-mqn054 ... html

http://www.candlepowerforums.com ... post2281988

Please note that vendors often list the model number for the MQN05U when they're actually carrying the MQN06U, so it's prudent to verify before you buy. The latter model lacks fully independent charging channels and the sliding cover:

http://www.candlepowerforums.com ,,, post2778384
-

 

[davidt1]

Thanks, Mr. Bones.

The price is good, but shipping charge is nearly 50% of that. The description said it has worldwide voltage.

 

[Bones]

Thanks, Mr. Bones.

The price is good, but shipping charge is nearly 50% of that. The description said it has worldwide voltage.

The cost may be immaterial davidt1. A closer look at the product page revealed that the charger is actually the MQN06U, and the vendor's description is yet another that is misleading as to this fact.

Because the MQN05U is becoming increasingly difficult to find in North America, perhaps you should consider the Duracell Mobile Charger:

http://www.amazon.com/gp/product/B000XSA5WW/?tag=cpf0b6-20

It definitely has a 120/240 volt internal power supply, and it too has fully independent charging channels. It can also function as a mobile-booster via a built-in USB-A port, and it comes equipped with an auto-adapter and a cover of sorts.

They are commonly available at big box stores, and can be found bundled with 4 Duracell Pre-charged Rechargeable AA cells that are believed to be re-badged Eneloops.

The charger is also bundled with inferior pre-charged cells from China though, so here's a re-badged Eneloop checklist:

- States 'Pre-charged' or 'Active Charged' on the package.
- The positive post is surrounded by flat-white material.
- States 'Made in Japan' on the actual cell.

If they don't meet all of these criteria, the cells are not re-badged Eneloops.

 

[davidt1]

It turned out my old Panasonic charger is a smart charger. I tested it today by charging a used aaa Eneloop. It took over 2 hrs to charge. I took the battery out and charged it again an hour later. The second charge only took 10 minutes. I probably bought this charger 6 years ago, yet I am just aware of this capability now. I am keeping it.

 

[Radiophile]

You may still want to get a new charger. If it took more than 2 hours to charge a cell, then it's not getting charged at a .5C rate or greater, and that's best for peak charge detection.

In my opinion that's why the MQN05 charger is so good for everyday use. It charges at greater than .5C, but it does so in pulses that allow the cell to remain nearly room temperature. It takes about 8 hours for a fully flat cell to charge, but with as many cells as I own that's not an issue, and I'm sure they're treated well by the charger. I also have an MQN03 Eneloop fast charger for when I need fast charging, but I shy away from using it when I don't need them right away because the cells do get warm during charging.

 

[travelinman]

You are right, the maha has an external charger. I've found for travelling that the "built in" prongs on chargers with internal power supplies will often not fit in wall fittings in foreign countries. They are often recessed as much as 1.5" into the wall. The external power supplies will often fit though, especially the newer switching ones.

The slow charge though works great, terminates every time properly and is much much easier on the cells. I have old Nicads that are still giving me 90% of their original mah after 11 + years of use because they are charged gently and properly. As far as I'm concerned if you can feel even a hint of warming on a charging cell, you are charging it too much.

I know I'm going to get flamed for saying that, but it's what I believe. :candle: If you are in so much of a hurry you have to physically force power into you cells so they heat up, get another set to use while you are charging the first set. Simple!

 

[Marduke]

The slow charge though works great, terminates every time properly and is much much easier on the cells. I have old Nicads that are still giving me 90% of their original mah after 11 + years of use because they are charged gently and properly. As far as I'm concerned if you can feel even a hint of warming on a charging cell, you are charging it too much.

I know I'm going to get flamed for saying that, but it's what I believe. :candle:

It may be what you believe, but it is very incorrect. Slow charging greatly increases the chances of missed termination. The cell actually needs that bit of temperature spike, as it's a function of the -dV signal a smart charger is looking for.

 

[davidt1]

You may still want to get a new charger. If it took more than 2 hours to charge a cell, then it's not getting charged at a .5C rate or greater, and that's best for peak charge detection.

In my opinion that's why the MQN05 charger is so good for everyday use. It charges at greater than .5C, but it does so in pulses that allow the cell to remain nearly room temperature. It takes about 8 hours for a fully flat cell to charge, but with as many cells as I own that's not an issue, and I'm sure they're treated well by the charger. I also have an MQN03 Eneloop fast charger for when I need fast charging, but I shy away from using it when I don't need them right away because the cells do get warm during charging.

Can you point me to a vendor that sells the MQN05?

Also, I have a travel waterpik that require 2 aa batteries to operate. I need to buy the most powerful nimh aa batteries for it. I don't mind recharging them every week. Any recommendations? Thanks.

 

[J_C]

It may be what you believe, but it is very incorrect. Slow charging greatly increases the chances of missed termination. The cell actually needs that bit of temperature spike, as it's a function of the -dV signal a smart charger is looking for.

Slow charging eliminates the need for termination. That's the whole point you don't need a termination if it is not charging at such a high current that it would cause damage, rather you have a leeway of several hours to disconnect them at your leisure.

For over two decades I have never had a problem charging below 0.5C with NiCd and NiMH. It's not belief, it's proof.

The cell does not need a temperature spike, different cells have different impedance and there are different ambient room temps as well as different charge levels when a cell is placed in a charger.

Further, I wish people would stop perpetuating the myth that charge rate needs to be above 0.5C. I have 3 separate chargers which charge between 0.25C and 0.4C, all of which never have a problem sensing Delta V termination with several brands of NiMH. Perhaps there was once a maldesigned charger or two, that through that maldesign did not work properly but that is no evidence of a charge rate threshold in general.

 

[Marduke]

Slow charging does hurt cells. NiCad is more tolerant to it, but stick a NiMH cells on a charger at 200mA and you will eventually cook it with repeated terminations.

The temperature spike is necessary, that is what causes the -dV signal for the charger to pick up on.

There is tons of evidence and testing to show that. Just because you have had an okay experience does not mean that it's that way in general. How do you know your cells are fine? Have you tracked their life cycles? Monitored cell health through time? Measured impedance and internal resistance? Others have...

 

[SilverFox]

Hello J C,

Unfortunately, the science of electro-chemistry does not support your ideas...

Many people use batteries for non essential tasks, but there are some that depend on them. When you can tolerate a battery failure as a minor inconvenience, you are free to charge batteries however you want to.

However, if your batteries are mission critical, it is best to treat them in the best way possible in an effort to get the best performance from them.

I am one of those people that is unable to complete my job if my light fails, so I have taken the time to do a lot of research on the best way to take care of batteries. I have also interviewed many chemical engineers involved in the development of batteries, and run many tests to verify the information they presented.

The result of all of this effort is that when dealing with NiMh chemistry, the best charge rate is in the 0.5 - 1.0C range. I favor 1C charging, but not all chargers are capable of that.

I have lost track of how many law enforcement and emergency services people have come to me complaining of poor performance of their battery operated devices. In reviewing their charging practices most of the problems disappear when we change from slow charging to charging in the 0.5 - 1.0C range.

I too thought I was having excellent results with slow charging, but I have been amazed at how much better my cells perform when charging according to the manufacturers recommendations. When I started monitoring and testing the various chargers, I was pleased that the charger manufacturers incorporated various back up termination methods because the -dV termination signal was frequently not strong enough to terminate the charge. This results in a minor overcharge. Now the effects of this minor overcharge are minimal when the charging rate is at 0.1C or below, but once you get above 0.1C, damage is done to the cell. Most of this damage results in higher cell impedance, so unless you are testing or tracking it, it is not readily apparent. You just suffer reduced performance.

I am glad that you are pleased with you chargers, but it is no myth that you can get much better performance if you charge in the 0.5 - 1.0C range.

Tom

 

[J_C]

Slow charging does hurt cells. NiCad is more tolerant to it, but stick a NiMH cells on a charger at 200mA and you will eventually cook it with repeated terminations.

First, "eventually" is vague. I don't think anyone is talking about leaving it charging indefinitely, rather the common scenario is it may sit at 200mA for a few hours at most.

Now define "cook", it's a popular buzz word but just as a steak can be rare, medium, well-done and still be edible, "cook" is not sufficient to describe that all it's doing is keeping the battery pretty warm, but many batteries get similarly warm after ~85% of a rapid charge too.

The temperature spike is necessary, that is what causes the -dV signal for the charger to pick up on.

There is tons of evidence and testing to show that. Just because you have had an okay experience does not mean that it's that way in general. How do you know your cells are fine? Have you tracked their life cycles? Monitored cell health through time? Measured impedance and internal resistance? Others have...

How do you know they aren't fine, considering they still hold charge and last long enough? I mean really know because as I wrote, you may in fact suffer a dozen % degradation but that is acceptable.

It is not necessarily important to baby NiMH. It is not necessarily important to be a slave to a battery so you can get as close to 100% performance over it's life as possible. Instead, routinely it becomes better to replace a battery when technology improves cell performance and capacity over what was current at the beginning of a pack's life.

The VAST majority of electronics that recharge NiCd and NiMH do not do the idealized recharging proposed. The world keeps on using the devices regardless of the idealization because they just keep working until a few years pass and $3 worth of batteries are needed again.

 

[J_C]

Hello J C,

Unfortunately, the science of electro-chemistry does not support your ideas...

Really? Many battery manufacturers pose a suggestion but also give data for proper charging at lower rates. They would not do it if it were unacceptable. As I wrote in my last post, most electronic devices do slow(er) charge.

Many people use batteries for non essential tasks, but there are some that depend on them. When you can tolerate a battery failure as a minor inconvenience, you are free to charge batteries however you want to.

These are a minority, so it then follows that if a statement is made about the importance of a particular charge method, it is always the burden of the one making the statement to include this qualification.

Further, there is no reason to believe someone who depends on their battery cannot use a slow charge, in fact the only real issue is does the lifespan and capacity meet the need and in most cases it does. Quite a few devices do not follow the ideal charge method proposed, and aside from flashaholics you won't find the average emergency/security/etc personnel versed in how their devices handle charging beyond how long it takes and how long it runs.

However, if your batteries are mission critical, it is best to treat them in the best way possible in an effort to get the best performance from them.

Untrue. Mission critical does not mean one has to do anything except have equipment suitable for the mission. If this mission is long enough that having 85% versus 100% battery capacity really matters, the margins where too thin already and a different power source or replacement battery would be used.

Actually, the real critical uses tend to gravitate towards primary lithium cells not rechargeable.

I am one of those people that is unable to complete my job if my light fails, so I have taken the time to do a lot of research on the best way to take care of batteries. I have also interviewed many chemical engineers involved in the development of batteries, and run many tests to verify the information they presented.

This does not in any way disprove that slow charging works fine. People did their work and managed to survive for many years before modern battery capacity levels existed. To suggest it is really important to have the max possible capacity no matter what is rejecting the truth that either way we now enjoy more performance than ever before in history.

The result of all of this effort is that when dealing with NiMh chemistry, the best charge rate is in the 0.5 - 1.0C range. I favor 1C charging, but not all chargers are capable of that.

I could propose the best way for someone to walk, drive, part their hair and paint a house. Idealizations are a folly we can usually ignore, so long as the end result is acceptable. There is a middle ground between being a slave to some regimen and having an unusable device.

Further, there is no evidence that merely deviating from what is claimed the best is really a problem. The battery manufacturers themselves sell chargers that deviate from this! Most people buy the off-the-shelf chargers that deviate from this, most devices which recharge deviate from this, and NiCd or NiMH battery failure from modern chargers are exceedingly rare, most often the failure come from devices which allow draining the cells too far and reverse charging one in series.

I have lost track of how many law enforcement and emergency services people have come to me complaining of poor performance of their battery operated devices. In reviewing their charging practices most of the problems disappear when we change from slow charging to charging in the 0.5 - 1.0C range.

This goes against science. There is nothing that keeps a battery from fully charging at a lower rate than 0.5C. Seems they merely had poorly designed chargers or insufficient knowledge of when the battery is fully charged.

I too thought I was having excellent results with slow charging, but I have been amazed at how much better my cells perform when charging according to the manufacturers recommendations. When I started monitoring and testing the various chargers, I was pleased that the charger manufacturers incorporated various back up termination methods because the -dV termination signal was frequently not strong enough to terminate the charge.

That typically means the charger needs replaced, not that a different charge rate is needed. As I've mentioned in a past post, randomly picking 3 chargers with charge rate below 0.5C, all have no problem terminating charge. Perhaps many years ago this was more of a problem, but today, as in many industries, more info has been gathered to the point that chargers can detect below 0.5C rate, AND batteries are designed to allow for sitting on a slow charger and topping off.

There are still problematic devices, those made cheap but only intended to last through the warranty duration so they reduce charge time with an excessive rate, but such devices are becoming more and more rare, segmented into the cheapest of type products.

This results in a minor overcharge. Now the effects of this minor overcharge are minimal when the charging rate is at 0.1C or below, but once you get above 0.1C, damage is done to the cell. Most of this damage results in higher cell impedance, so unless you are testing or tracking it, it is not readily apparent. You just suffer reduced performance.

I agree if the overcharge duration is long enough but slow chargers are typically 0.1C or below, medium ones at least have a timer shutoff (but this type of charger best avoided), and any higher rate, yet still below 0.5C, can and will detect the Delta V threshold and terminate the higher charge rate.

Perhaps you too closely followed the suggested practices and haven't much used typical chargers in recent years? I and many others do routinely and can assure you they work fine.

I am glad that you are pleased with you chargers, but it is no myth that you can get much better performance if you charge in the 0.5 - 1.0C range.

Tom

It is a myth. Ask any battery manufacturer plainly if you leave a battery charging below 0.5C, will it still reach full possible capacity. The answer is yes, and many do outline lower charge rates in datasheets. The reason they promote higher charge rates is to cover their own asses, to shift the burden to charger manufactures because no matter how clearly they define other charging parameters, the more latitude and options that are presented, the more ways they will find someone ignored an important part of the puzzle and they suffer battery RMA and reputation issues.

There is a threshold below which a charger shouldn't use Delta V detection but today that threshold is below 0.5C. There is also a region of charge rate a battery shouldn't be constantly subjected to if one wants to avoid immediate damage which is above 0.05C, and a region in which the battery needs to be disconnected from the charger within a few hours which is between 0.05C and 0.1C.

ALL of these methods are capable of completely charging a NiCd or NiMH. ALL have exactly the same performance if the battery is left charging until full. ONE of them, extended overcharging close to 0.1C, will reduce cell life by about a dozen percent.

These facts are not isolated to one battery brand and model or one charger, they are seen all day every day by the majority of battery users. While there is a wrong way to design a charger and it certainly happens, there are also plenty of devices out there which demonstrate sufficient performance without a 1-2 hour charge rate.

I always wonder why there are two camps, those who pose a theory and those who actually do it without problems. Probably the charger, try a different one just as someone would do if they picked a different 0.35C charger to replace a faulty one instead of a 1C charger.

 

[travelinman]

I have noticed that many of the battery manufacturers, who produce their own chargers, have charge rates that are high enough to make their cells hot enough to make them uncomfortable to hold. I have a couple of them in my "electronic stuff I probably won't ever use but won't throw away" cupboard.

I also find it interesting that my BC 700/900 recommends 200 ma as the preferred charge rate to prolong battery life.

I wonder if the battery manufacturers could have some form of motivation for insisting everyone "cook" their cells every time they charge them. hmmmmmmm