Look familiar? Except for the black color, the BC-700 looks exactly the same as the better-known La Crosse BC-900 AlphaPower Battery Charger. Just like the BC-900, the BC-700 has four user-selectable operating modes: Charge, Test, Refresh, and Discharge. Trickle charge kicks in once the batteries are charged.

What’s the difference? The BC-700 charging current maxes out at 700mA in three steps (200mA, 500mA, and 700mA). The BC-900, on the other hand, can go up to 1000mA for 4 cells, or 1800mA for 2 cells.

Also, the BC-900 charger comes with eight NiMH rechargeable cells (4 AA and 4 AAA), eight C/D cell adapters, and a carrying case. To keep the price down, the BC-700 does not include the batteries or the carrying bag. Both chargers can handle voltage up to 240v for international use.

Which model should you get?

The difference in cost between the BC-700 and the BC-900, at Amazon for example, is about US$7.00. Giving up the ‘freebie’ batteries, is no big deal as they are Mignon batteries made by Ansmann AG. However, the travel case and the 1,000mA charging current are well-worth the extra seven dollars.

If you are in a hurry, fully charging a set of 2700 NiMH batteries with the BC-700 will take nearly 4 hours. With the BC-900, it will take less than 3 hours albeit with more heat generated.

Naming Confusion

Lacrosse uses the name ‘AlphaPower BC-700′ while Amazon calls the charger ‘Alpha Power BC700′. This difference makes searching for product information a bit confusing. We have used the name as the manufacturer has indicated.

The BC-700 has been available in the USA for about a year. However, it has been sold for several years in Europe under the name Technoline BL-700.

Robert’s Rating:

Late last year, Maha Energy – the maker of Powerex batteries and chargers, introduced a low self-discharge rechargeable battery called the ‘IMEDION’. The IMEDION batteries are compatible with NiNH battery chargers and are available in 2100mAh capacity for AA size and 800mAh for AAA.

Maha states that IMEDION batteries retain up to 85% of their charge even after one year of storage (at a room temperature of 20 deg C). This claim is similar to that made by Sanyo for their Eneloop batteries (see my post on Eneloop batteries).

Maha goes on to say: “the IMEDION batteries differ from the competition in that they boast a longer lifetime as well as increased power retention under warmer environments. The IMEDION batteries can be recharged for hundreds of times and perform extraordinarily well at elevated temperatures. In addition, the IMEDIONS feature a low-impedance design and can deliver a high burst of current”.

I purchased a new set of (4) IMEDION AA batteries from EastGear. To measure their discharge capacities, I used a LaCrosse AlphaPower BC-900 Charger (see my post with tips for using this charger here). I found the discharge capacity of the IMEDION batteries out of the package to be 1,784mAh. Unfortunately, I was not able to find a manufacturing date on either the packaging or the batteries themselves. It’s clear, however, that they are usable after purchase without charging.

After repeatedly discharging and charging the batteries until the capacity was stable (Refresh Mode), the final average capacity was found to be 2,208mAh with a standard deviation of 0.4%. The measured capacity of the IMEDION AA batteries exceeds the advertised nominal capacity (2,100mAh) by 5% giving them a slight advantage over Eneloops.

I mentioned in an earlier post that I now prefer to use low self-discharge batteries to power my Canon Speedlite flash. With low self-discharge batteries, I don’t have to worry whether or not my primary set or back-up set of batteries were charged the day before a photo shoot. Also, I have experienced performance problems with conventional rechargeable NiMH batteries often less than a year from the purchase date.

For a comparison of IMEDION batteries with other low self-discharge batteries, see information posted by Jeff Servaas.

Robert’s Rating:

While my initial capacity tests of Eneloop batteries were very positive, I chose to power my Speedlite flash and power pack with super high-capacity NiMH batteries such as Powerex 2700 or Sanyo 2500 batteries. After more than a year of field experience with these batteries, I am switching to Eneloop batteries.

So what’s up? The self-discharge rate of conventional NiMH batteries is simply too fast. Especially in Singapore’s hot, tropical climate. In less than a month, half the battery capacity or more is gone without even using them. Before a shoot, I have to charge as many as a dozen batteries.

Eneloop batteries were specifically designed by Sanyo as a slow-discharge alternative to conventional NiMH batteries. Sanyo claims that the Eneloops retain 85% of their initial capacity after 1 year of storage at room temperature. Now with Eneloops powering my Speedlite, I don’t have to worry whether or not my primary set or back-up set of batteries were charged the day before a photo shoot.

Yes, the Eneloops have a lower nominal capacity (2000 mAh). However, the set of Eneloop AA batteries that I tested last year were found to have an actual capacity of 2100 mAh. Also, I found that the super high-capacity NiMH batteries don’t retain their full capacities after a few months of regular use. The Eneloops seem to hold up better.

So far, I haven’t noticed any increase in flash skipping during rapid shooting. I find the Eneloop powered Speedlite more than adequate for photojournalism or casual photography. If you are covering a wedding or fashion show, you will still need a power pack.

Resources:
Buy the Eneloop AA 4 Pack at Amazon.com.
Buy the Eneloop AA 4 Pack at Amazon.co.uk.
Buy the Eneloop AA 8 Pack at Amazon.com.
Buy the Eneloop AA 8 Pack at Amazon.co.uk.
Buy the Eneloop Charger plus AA 4 Pack at Amazon.com.
Buy the Eneloop Compact Charger plus AA 2 Pack at Amazon.com.
Buy the Eneloop AAA 4 Pack at Amazon.com.
Buy Eneloops batteries on eBay.

The Maha PowerEx MH-C9000 WizardOne Battery Charger & Analyzer was announced in November of 2006. This device was certainly designed by Maha to compete against the very popular LaCrosse BC-900 AlphaPower Battery Charger/Analyzer. The MH-C9000 is just now shipping to retail stores worldwide. I was able to purchase a unit at EastGear in Singapore. I have used it for about a week. Below are my observations.

Just like the BC-900, this device accepts only AA and AAA size NiMH and NiCd rechargeable batteries. It allows battery charging, battery matching, battery forming, and measurement of discharge capacity with independent operation of each battery slot.

Key features of the new MH-C9000 include:

• Four independent slots for AA or AAA batteries
• Large backlit LCD
• Digitally displays capacity, voltage, time and current
• Five modes of operations
• Special forming charge and cycle mode
• 30 Selectable charging and discharging speeds

I will spare you repetition of specs/marketing information and give you my impressions of this device compared to the LaCrosse BC-900. If you want to see specs and menu screen captures, go to the EastGear site or download the manual (see link below).

The MH-C9000 is a solid, well-built device. It is considerably larger than the BC-900 and therefore less portable. No pouch/travel kit is provided. The LCD screen is big and easy to read even in the dark (it’s backlit). However, there is no way to turn off the LCD backlight – it always on. At night, it’s bright enough to illuminate a small room. I find that a bit annoying. The viewing angle for maximum contrast is not straight up, but biased about 30 degrees down. There is a substantial loss of contrast off angle, however, the LCD is still easily readable as the characters are large.

There is enough space on the LCD screen to display either alternating information for all 4 slots separately or cycle through the information for all slots simultaneously. Instead, Maha chose to display a large single line with alternating/selectable information for one slot at a time. You can’t just walk over to it and see what’s going on with a glance. It takes a full minute to cycle through for all four slots. Those minutes add up. Much of the information displayed on the LCD screen for the five modes of operation (CHARGE, REFRESH/ANALYZE, BREAK-IN, DISCHG, CYCLE, 1, 2, 3, and 4) could have just as easily been imprinted on the plastic housing freeing space for more data.

Unless you are using the default settings, you need to enter the parameters on each ‘slot’ (battery) separately. You can do this on the BC-900 but the default mode allows setting all slots (compartments) simultaneously. The charge and discharge currents can be set independently in the MH-C9000. In the BC-900, the charge current is automatically set at 2x the discharge current.

The Discharge Mode is different in the MH-C9000. Unlike the BC-900 Discharge Mode, it just discharges and does not charge afterwards. Therefore, the Maha unit is more useful for measuring how much capacity is lost from self-discharge. You can measure discharge capacities in the Discharge Mode with the BC-900. However, you must note the discharge capacities before the charge cycle is complete.

The MH-C9000 Refresh & Analyze Mode (charge, rest, discharge, rest, repeat) only goes through two cycles which might not be enough especially for breaking-in and testing a new set of batteries. It would be better if the MH-C9000 had a auto-cycle Refresh Mode like the BC-900*. The MH-C9000 Refresh & Analyze Mode is more like the Test Mode in the BC-900 as it starts with charging and goes through two charge/discharge cycles. Also, if you wanted to do what the MH-C9000 Refresh & Analyze Mode does now, you could simply select Cycle Mode for 1 cycle albeit without the rest periods.

In the Refresh & Analyze and Cycle Modes, the MH-C9000 does not display the most recent discharge capacitiy until the subsequent rest step (one hour) is over. If you remove the batteries prematurely, data are lost.

The MH-C9000 has a battery Break-In Mode (IEC 61951-2 Capacity Analysis). This mode applies a 16-hour 0.1C charge, one-hour rest, followed by a 0.2C discharge, rest again, and finally a 16 hour 0.1C recharge again. It would be useful if the MH-C9000 had a way to do a 16-hour forming charge without doing the entire IEC Test Cycle. Sometimes you only need to form the cells without the wait period which triples the time needed.

The default 1A charge and 500mA discharge rates are typical for 2000-2700mAh cells (0.5-0.4C and 0.4-0.2C, respectively) which eliminate the need for entering parameters for each slot. The BC-900 uses a default charge current of 200mA which is too low and most likely a legacy setting. Just like the BC-900, the MH-C9000 will revert to charging at the default rate after power is interrupted.

Before starting any cycle, the MH-C9000 goes through an impedance check of each battery. If any battery fails the test, ‘HIGH’ is displayed and the program is terminated. The BC-900 has the same feature and simply displays ‘NULL’.

Not mentioned in the manual is a “TOPOFF CHARGE” which is applied in certain modes after rapid charge termination to top off the battery. The rate is typically 0.1C ( approx. 200mA ) and is applied for one hour. After that, an indefinite trickle charge is applied, usually at 0.005C (so around 10mA for AA rechargeable batteries) using modulated pulse trickle charge. The trickle charge assures good battery performance even if the batteries are left in the charger for an extended period of time. The BC-900 also applies a trickle charge after charging is complete.

The MH-C9000 has an issue with charge termination – discussed in depth on the CandlePowerForums. I experienced it charging set of Sanyo 2700 AA batteries at the default 1,000mA charge current. The final charge capacities were 2,253, 3,440, 3,587, and 5,680mAh. The batteries became hot toward the end of the cycle. Keep in mind these are charge capacities not discharge capacities. Still, they should not be this far from the nominal capacity**.

A simple metal bracket (lift rod) pops out from the back of MH-C9000 raising the unit off the supporting surface, probably to help air flow for cooling. Heat is well-controlled even at high charge currents.

Some users have reported that the terminals on the MH-C9000 can tear the battery wrappers on removal unless some care is taken. I have not experienced this problem with PowerEx, Sanyo, or Varta batteries. The batteries fit quite tightly in MH-C9000 which could be a problem with batteries that have thin, easily peelable wrappers such as GP batteries.

Neither the MH-C9000 nor the BC-900 have an on/off switch. To restart either device, you need pull out the power cord. Both devices have an international power adapter (input: 100-240V 50/60Hz ) and 12V car adapters (not included).

An overdue and desirable feature would be a USB connection to a PC with a software interface that would allow control of the device and data storage. An PC interface also would allow for easy firmware updates. How about it Maha or LaCrosse?

Download the MH-C9000 User’s Manual here. It is worth noting that User Manual is quite brief. For more information and FAQ, checkout this thread on the CandlePowerForums.

In summary, the MH-C9000 could be serious competition for the BC-900. It needs a few firmware changes (esp. 4-slot display) and better charge termination at slow charge rates.

Robert’s Rating: (first rev. firmware)

Resources
Shop for the Maha MH-C9000 on eBay.
Shop for the LaCrosse BC-900 on eBay.

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*The MH-C9000 Users Manual states that the Refresh & Analyze Mode can be repeated up to three times. However, it is not done automatically.
**I then placed the same batteries in the BC-900 using the Discharge Mode (1,000mA/500mA). The final charge step gave charge capacities in the normal range (2,500-3,000mAh).

European consumer battery maker VARTA, founded in 1904, was acquired by Rayovac (now Spectrum Brands, Inc.) in 2002. Spectrum Brands sells rechargeable NiMH batteries under the Rayovac label in the USA. In Europe and Asia, the Varta brand is still used. I purchased a 4-pack of Varta Power Accu AA 2700 NiMH batteries at Mustafa in Singapore. I measured their discharge capacity using a LaCrosse AlphaPower BC-900 charger. (See my earlier post for tips on using this excellent charger/tester effectively.)

The batteries were found to have a discharge capacity of 2,670mAh +/-1% with an end voltage of 1.45V. Varta claims the batteries have a nominal capacity of 2,700mAh. A previous study of lower capacity rechargeable AA NiMH batteries yielded capacities often well below their nominal capacities. Some credit goes to using the charger/tester in the refresh mode. I noticed that the batteries did not reach maximum capacity until they had been through several discharge/charge cycles.

Looks like Varta has a winner on their hands. These batteries are close enough to their nominal capacity to earn a 5-star rating from Robert! Kudos to them for honesty.

Important: The LaCrosse BC-900 charger performs [discharge + measurement] in the Refresh Mode immediately after fast-charge termination, which means there’s still a little bit of capacity left that could be filled by extra time spent trickle charging. The capacity could be boosted by an additional 50mAh or more by leaving the battery on tickle charge for an hour or so after the initial charging is finished.

More batteries will be tested and added to the Battery Round-up page.

Robert’s Rating:

Notes: Batteries were tested using the LaCrosse BC-900 in the ‘Refresh Mode’. I used a charge current of 1,000mA (about 0.4C) and a discharge current of 500mA (about 0.2C). Capacity (C) is measure by discharging the battery to an end voltage of 0.9V under constant load. Batteries were repeatedly discharged and charged until the capacity was stable. The discharge current is similar to that used by the manufacturers to spec their batteries. Sometimes, manufacturers use a lower charge current over a longer time period. IMHO, not practical for routine use. And, the results are not indicative of the real world.

There is very little independent data on the discharge capacities of popular AAA NiMH batteries. Most of the attention has focused on the AA size batteries. Yet, AAA size batteries power an ever-growing list of gadgets that include not only cameras but MP3 players, Bluetooth headsets, cordless phones, remote controls, etc.

There has been a tremendous improvement in NiMH rechargeable battery chemistry in recent years resulting in higher effective capacities. However, measured capacities of NiMH batteries still often fall short of nominal (named) capacities. This shortfall has been well-documented previously by other investigators studying the AA size. Prior to the availability of low-cost chargers with testing circuitry, consumers often were left in the dark as to the gap between nominal and discharge capacities. In the table below are results for five batteries from four different manufacturers.

As expected, the major brands (Sanyo and Maha PowerEx) turn in the best performance. However, not as good as with the AA size batteries where Sanyo and PowerEx are getting closer or actually hitting their nominal capacities.

Why not test Sony, Energizer, or Kodak batteries? These brands are typically re-labeled Sanyo batteries. Look for the ‘HR’ stamp on the bottom of the battery that indicates it is a Sanyo OEM.

More batteries will be tested and added to the Battery Round-up page.

Notes: Batteries (new) were tested using a LaCrosse AlphaPower BC-900 in the ‘Refresh Mode’. I used a charge current of 500mA (about 0.5C) and a discharge current of 250mA (about 0.25C). Capacity (C) is measure by discharging the battery to an end voltage of 0.9V under constant load. Batteries were repeatedly discharged and charged until the capacity was stable. The discharge current is similar to that used by the manufacturers to spec their batteries. Sometimes, manufacturers use a lower charge current over a longer time period. IMHO, not practical for routine use. And, the results may not be indicative of the real world but help in comparing batteries.

In the quest for the perfect power source for my Canon Speedlite 580EX, I purchased a new set of Maha PowerEx 2700 NiMH rechargeable batteries from EastGear here in Singapore. Then, I measured their discharge capacity using a LaCrosse AlphaPower BC-900 charger. (See my earlier post for tips on using this excellent charger/tester effectively.)

The batteries were found to have a discharge capacity of 2,698mAh +/-2% with an end voltage of 1.45V. Maha does claim the batteries have a nominal capacity of 2,700mAh; however, they also give a minimum capacity of 2,500mAh. A previous study of lower capacity rechargeable AA NiMH batteries yielded capacities often well below their nominal capacities. Some credit goes to using the charger/tester in the refresh mode. I noticed that the batteries did not reach maximum capacity until they had been through several discharge/charge cycles.

Looks like Maha has a winner on their hands. These batteries are bang on! They could have rated them higher and gotten away with it. Kudos to them for honesty.

Anything Robert doesn’t like about the PowerEx 2700 batteries? My only issue although somewhat picky is the labeling. The PowerEx 2500 and PowerEx 2700 batteries look exactly the same except for the small print. If you have sets of both batteries, it will be easy mix them by mistake. The handy little plastic box that comes with the batteries helps keep them together; still Maha should consider redesigning the label.

Important: The LaCrosse BC-900 charger performs [discharge + measurement] in the Refresh Mode immediately after fast-charge termination, which means there’s still a little bit of capacity left that could be filled by extra time spent trickle charging. The capacity could be boosted by an additional 50mAh or more by leaving the battery on tickle charge for an hour or so after the initial charging is finished.

PowerEx 2700 NiMH rechargeable batteries are also available from Amazon.com and Amazon.co.uk.

More batteries will be tested and added to the Battery Round-up page.

Notes: Batteries were tested using the LaCrosse BC-900 in the ‘Refresh Mode’. I used a charge current of 1,000mA (about 0.4C) and a discharge current of 500mA (about 0.2C). Capacity (C) is measure by discharging the battery to an end voltage of 0.9V under constant load. Batteries were repeatedly discharged and charged until the capacity was stable. The discharge current is similar to that used by the manufacturers to spec their batteries. Sometimes, manufacturers use a lower charge current over a longer time period. IMHO, not practical for routine use. And, the results are not indicative of the real world.

Robert’s Rating:

Maha Powerex NiMH 4 Rechargeable AA Battery w/Case

US $14.00 End Date: Saturday Feb-11-2012 20:58:27 PST Buy It Now for only: US $14.00 Buy it now | Add to watch list

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The La Crosse AlphaPower BC-900 Battery Charger has been getting rave reviews from users. The term ‘charger’ is a bit of a misnomer. That’s because it’s not only a battery charger but also a battery tester and battery refresher. It has four modes: charge mode – slow or fast charging with selectable current; discharge mode – fully discharges the battery before charging; refresh mode – discharges and recharges up to 20 times to bring old batteries back to life; and test mode – measures a battery’s discharge capacity. All modes switch to trickle charge at the end of the cycle.

Before the BC-900 came on the market, photographers were at the mercy of the battery manufacturers. Whatever was printed on the battery label, we assumed to be the capacity. The fine print was always suspicious. Terms such as ‘nominal capacity’, ‘typical capacity’, and ‘minimum capacity’ were rarely defined. Only a few geeks with expensive or homemade test equipment were posting independent test results. We had only field experience to go by. Now all that has changed!

I have had a BC-900 for about six months now so I can offer you some advice to shorten the learning curve. Here are some tips:

Tip #1: Use 500mA as your standard current for charging high capacity AA batteries. The BC-900 default charge current is 200mA. In my opinion this charging current is just too low (less than 10% capacity for 2,500mAh batteries) and probably is a legacy setting.

Do you really want to wait 14 hours to charge a set of batteries? At 500mA, charging takes about 5 hours and generates minimal heat. Even 1,000mA is still below the current used by most ‘fast chargers’ on the market. Once the batteries are charged, the BC-900 automatically applies a trickle charge current so you can leave a set in the charger ready for quick use.

Tip #2: Use the refresh mode to test battery capacity. It has been established that a new set of batteries require several charge/discharge cycles to achieve full capacity. The BC-900 will do this for you automatically. (Note: Discharge capacity can only be measured in the Test Mode or the Refresh Mode.)

I recommend setting the discharge current to 500mA, and then the BC-900 will automatically set the charge current to 1,000mA. Thinking about lower currents? Think twice! Even with discharge/charge of currents 500mA/1,000mA, a new set of NiMH AA batteries can take 2-3 days to reach a consistent capacity. Ok, if you don’t mind waiting nearly a week – use 250mA/500mA. Worried about excess heat ruining battery life? The BC-900 has a temperature sensoring circuit that interrupts charging at 127^oF until the batteries cool to a safe temperature.

Tip #3: Use the measured capacities to sort your batteries. The better ones can be grouped together and used for more critical applications. For example, I measured the capacities of (8) Sanyo 2500 AA batteries. They ranged from 2,420mAH to 2,520mA. Four of the eight measured over 2,500mAh.

Regardless of the time required, one might ask ‘what are the test conditions that best simulate real life applications’? Digicams drain batteries continuously at low currents during use. A Speedlite flash, however, grabs power at the max discharge rate briefly to refresh a capacitor. No test protocol will perfectly simulate the various discharge conditions required by different devices. That said, a discharge current of 500mA applied continuously will drain a set of 2500mAh batteries in about 5 hours. This is a reasonable simulation of real life. And, applied consistently to different batteries will allow us (at least) to evaluate which batteries will last the longest or which batteries offer the best price/performance ratio.

I won’t list minor complaints about the BC-900. You can find those in the photography forums. Only one glitch is worth mentioning though. The BC-900 refuses to charge over-discharged batteries. That is, batteries with less than zero volts. The BC-900 simply displays ‘NULL’. You need to charge them for a few minutes in (yes) some other charger.

For me, the reasonable price of BC-900 offsets the minor design and operation flaws.

The BC-900 is available at EastGear if you live in Singapore or from Amazon.com if you are in the USA or Canada. The power supply is universal (100-240v, 50-60 cycle) so (with a plug adapter not included) you can use this device anywhere in the world. It comes with a nifty black travel bag as well as ‘C’ and ‘D’ size battery adapters. Included in the box are also a set (4) AA La Crosse 2000 and a set of (4) AAA La Crosse 700 (Mignon) rechargeable batteries.

A copy of the La Crosse BC-900 Instruction Manual (pdf format) can be download here: Instruction Manual.

Shop for the BC-900 on eBay.
Are you in the UK? Go here.

Robert’s Rating:

Photographers have learned that rechargeable NiMH batteries are the best choice to power an external flash. Charging the primary set of batteries prior to a ‘shoot’ is not a problem. However, there is rarely enough time to charge the back-up sets which can sit in a camera bag for weeks or months. This can be quite a problem because of the well-documented self-discharging of conventional NiMH batteries.

SANYO Electric Co., Ltd. has developed a new NiMH battery technology that reduces self-discharge and operating voltage loss so that the batteries keep at least 85% charge even after one year. The new battery called ‘Eneloop’ was released in Japan in December 2005 in AA size. The AAA size was added to the line in late January 2006. In a break with convention, the batteries are labeled only as ‘Eneloop’ without Sanyo in the name and without a nominal capacity (at least in large font). The small print on the Eneloop AA size battery says: [2,000mAh typ/1,900mAh min]. The Eneloops are rated to withstand about 1,000 discharge/recharge cycles.

Sanyo has yet to release the batteries worldwide. There were limited quantities available at an IT trade show in Singapore in March. As the official launch in Singapore is not scheduled until June, I sourced a set of four Eneloop AA batteries (date code: 12/2005) from Yodobashi Camera in Osaka, Japan.

I used a LaCrosse AlphaPower BC-900 Charger to measure capacities (see my post with tips for using this charger here). I found the discharge capacity of the Eneloop batteries out of the package to be 1,857mAh. After repeatedly discharging and charging the batteries until the capacity was stable, the final capacity was found to be 2,105mAh with a standard deviation of 0.4%. Quite amazing! After 4-5 months, the batteries had retained 93% of their nominal capacity and 88% of their true capacity.

It is clear that Sanyo’s modifications to their conventional NiMH battery chemistry to reduce self-discharge has also reduced the battery’s maximum capacity. The Eneloop AA batteries hold about 25% less capacity than Sanyo’s newly released 2700 batteries. Perhaps the slightly lower capacity is worth the trade-off (certain applications) for such a low self-charge rate and to use them the first time without charging. Next is to see how they perform as a primary set of batteries in my Canon Speedlite 580EX.

Sanyo offers a new compact USB charger that will charge Eneloops or any AA/AAA NiMH batteries in any PC via the USB port. However, this charger is not necessary to charge Eneloop batteries. You can use any NiMH battery charger.

Any negatives? I only wish the capacity was a bit higher.

Resources:
More product photos are here.
Buy the Eneloop AA 4 Pack at Amazon.com.
Buy the Eneloop AA 4 Pack at Amazon.co.uk.
Buy the Eneloop Charger plus AA 4 Pack at Amazon.com.
Buy the Eneloop Compact Charger plus AA 2 Pack at Amazon.com.
Buy the Eneloop AAA 4 Pack at Amazon.com.
Buy Eneloops batteries on eBay.

Robert’s Rating:

Robert has read claims that PowerEx 2500 AA NiMH rechargeable batteries are conservatively rated or under-rated with respect to their nominal capacity. These batteries are being advertised as the best in their class. Marketing phrases such as “ultra high performance” and “true capacity plus” are being used by distributors and dealers. On Maha’s website, they state: “PowerEx AA NiMh 2500mAh Rechargeable Ultra High Performance Batteries have 2500mAh true capacity”.

Eastgear in Singapore just received a new shipment of these batteries from Maha in Japan. Being of a curious nature, I decided to put a set of four of them to the test. I used the same procedure and settings that I used to test the Sanyo 2500 and Sanyo 2700 batteries (see my earlier post). With my standard settings (charge/discharge current of 1,000mA/500mA), the PowerEx batteries gave a measured capacity of 2,335mAh +/-3%. Then, I tried changing the charge/discharge current to 500mA/250mA. With these settings, the batteries gave a measured capacity of 2,395mAh +/-1%.

Important: The LaCrosse BC-900 does its discharge measurement in the Refresh Mode immediately after fast-charge termination, which means there’s still a little bit of capacity left that could be filled by extra time spent trickle charging. The capacity could be boosted by an additional 50mAh or more by leaving the battery on tickle charge for an hour or so after the initial charging is finished.

Notes: Batteries were tested using a LaCrosse AlphaPower BC-900 in the “Refresh Mode”. I used a charge current of 1,000mA (0.4C) and a discharge current of 500mA (0.2C). Capacity (C) is measure by discharging the battery to an end voltage of 0.9V under constant load. Batteries were repeatedly discharged and charged until the capacity was stable (normally 2-3 cycles). These parameters should simulate normal use – medium/fast charge and a discharge period of about 5 hours.

The PowerEx 2500 batteries are also available at Amazon.com.

Robert’s Rating:

Maha Powerex NiMH 4 Rechargeable AA Battery w/Case

US $14.00 End Date: Saturday Feb-11-2012 20:58:27 PST Buy It Now for only: US $14.00 Buy it now | Add to watch list

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