MH-C808M battery charger for rechargeable C and D batteries

Christmas is once again approaching, and for those people with kids, that means new toys, and new batteries to power them. While an increasing number of toys use AA batteries, many larger toys need the capacity of a C or D battery. The cost of powering those toys with disposable C or D batteries adds up, and contributes a substantial amount to landfill each year.

Rechargeable C and D batteries solve this problem, providing 3 times the power of disposable batteries, so the toys don’t need the batteries changed as often, and since each battery can be recharged hundreds of times, the landfill is substantially reduced by using rechargeable C and D batteries. Rechargeable C and D batteries are available in High Capacity Powerex C and Powerex D rechargeable batteries, and also as Accupower Low Self Discharge C batteries and Accupower Low Self Discharge D batteries. LSD batteries are great for toys and other devices which are not used regularly. The lower self-discharge rate of these batteries means they are ready to use when you need them, and are perfect for use in large Maglite torches.

To recharge C and D batteries, you need a battery charger capable of charging the C and D size batteries. While other C and D battery chargers do exist, the Maha Powerex MH-C808M C and D battery charger can charge 8 C batteries in 2.5 hours, or 8 D batteries in just 5.5 hours, and is also capable of charging AA and AAA batteries. It can charge any mix of different batteries at the same time, terminating the charge of each separate battery once the battery is full. By constantly monitoring the change in voltage (Delta V) of each battery, the battery charger ensures the battery is fully charged, but not over-charged. The status of the cahrge on each battery is also displayed on a backlit LCD screen, making it eacy for anyone in the family to use.

The MH-C808M includes a Conditioning feature to discharge batteries, which helps keep batteries heathey when they are not being used regularly. When conditioning/discharging with the MH-C808M, we recommended that you put the highest capacity cells toward the left of the charger as the heat from the discharge circuit is on the right. Higher capacity cells will generate more heat, so by keeping the higher capacity cells away from the heat, the charger and batteries will run cooler.

It is easy to see why Maha call the MH-C808M the “Ultimate Pro Charger”.

How to use BREAK-IN mode on the MH-C9000

The BREAK-IN mode ion the MH-C9000 is the perfect way to start your new rechargeable batteries lives. It helps to properly form the chemical structure inside the batteries by charging and discharging them gently, at a fixed charge and discharge rate, which is proportional to the capacity. BREAK-IN mode is also useful for rejuvenating old batteries that have not been used for several months.

Doing a BREAK-IN cycle on the MH-C9000 is a 39 hour process, irrespective of battery capacity. To do a BREAK-IN on your AA or AAA batteries, I recommend you discharge the batteries first. This is not necessary, nor is it mentioned by MAHA in the MH-C9000 user manual, it is just a personal preference. To discharge the batteries, place a battery into the first slot, then use the arrow keys to move the mode to DISCHG. Press the ENTER key, and press ENTER again to use the default discharge rate. Discharge on the first slot will start. Repeat for each slot. If your batteries are fully charged, discharge will take 4-5 hours. Once each slot shows DONE on the LCD next to the slot number, remove all batteries, and wait 5 seconds.

Place the first battery into the first slot. Use the Up and Down arrow keys to select BREAK-IN mode. Use the Up and Down arrow keys to set the battery capacity. Press the ENTER button. Repeat this process for slot 2, 3, and 4.

The charger will charge at 10% of the battery capacity. For 2100mAh IMEDION batteries, the charger will calculate the charge rate as 210mA (0.1C) and charge at that rate for 14 hours. After 14 hours of charging, it will rest the batteries for 2 hours, then discharge at 420mA (0.2C) until it detects the batteries are empty, which will take around 7 hours. It will then rest the batteries again for 2 hours, then charge them again at 0.1C for 14 hours.

At the end of the 39 hours, the battery capacity will be displayed. This mode of the MH-C9000 follows the IEC standard for measuring battery capacity

to measure a battery capacity as per the standards set out by the IEC (International Electrotechnical Commission).

Test results for AAA Low Self Discharge batteries

Following on from our write-up on AA Low self discharge battery test results, here are the results for AAA low self discharge batteries. These results are from archae86, a member of the DPReview forum. He tested 7 different brands of AAA low self discharge batteries over a period of several months. Of the brands tested, 4 brands are readily available in Australia. I have summarised the results into the below chart and graph. The tester found that the IMEDION AAA rechargeable batteries had a higher capacity than Sanyo eneloop AAA batteries, Uniross Hybrio AAA, and Duracell Precharged AAA. For full test details, click here to visit the DPReview forum.

Low Self Discharge rechargeable AA battery test results

Just last week, Digital Photography Review forum member arcae86 completed a battery capacity test that took several months. The test measured the retained capacity of 8 different brands of AA low self discharge (LSD) AA batteries. The brands tested were Sanyo Eneloop, Duracell precharged, Hybrio, Powerex IMEDION. Battery capacity measurements were taken 1 hour after charging, and again after 1 week, 1 month, and 3 months. At all measurements periods saw the Powerex IMEDION AA battereis to have the highest capacity of all 8 brands tested.

Read all the details of the test here

For simplicity’s sake, I have taken the figures from the 4 commonly available brands available in Australia  (Sanyo Eneloop, Duracell precharged, Hybrio, Powerex IMEDION) and graphed the results below:

AA rechargeable battery test in a Nikon SB-800 flash

Glen from the DSLRusers.com forum recently did an extensive test of AA battery performance in his Nikon SB-800 flash, mounted on his Nikon D300 DSLR. I believe this is the first time a series of rechargeable AA batteries have ever been tested to see the real world results in a flash, and I am sure a lot of photographers will find this controlled test of real world value when choosing your batteries.

For the test, Glen compared four sets of 4 AA rechargeable batteries to see how many flashes could be achieved from each. Results are as follows:

Powerex 2700mAh = 266 flashes
Energizer 2500mAh = 242 flashes
IMEDION 2100mAh = 218 flashes
eneloop 2000mAh = 204 flashes

If you donʼt use your batteries as soon as you charge them, then test results are different. Some batteries are better at HOLDiNG their charge than others. Here are the results of the same test, 3 weeks after the batteries are charged.

Powerex 2700mAh = 250 flashes
Imedion  2100mAh  = 211 flashes
Energizer 2500mAh  = 208 flashes
eneloop 2000mAh =191 flashes

The Powerex 2700mAh have a higher energy retention rate than the Energizer 2500mAh. The Energizers were found to have a high self discharge rate, so much so that after just 3 weeks, the 2100mAh IMEDION batteries provide more flashes than the higher capacity 2500mAh Energizers.

Glen has noted that he is happy to conduct the test with other batteries if you want to know how yours compare to the four types already tested.

For capacity results and testing procedure details, read the full review here.

Visit Maha Powerex at PMA Australia Photography Expo May 30 – June 1 2008

The full range of Maha Powerex AA rechargeable batteries and battery chargers will be demonstrated at the PMA Imaging and Technology Show from May 30 to June 1 in Brisbane. If you live in Brisbane, or you are attending the expo, come by Stand 217 and say hello!

Which 9V battery for a radio microphone: 8.4V 300mAh or 9.6V 230mAh?

Older radio microphones needed the full 9V that alkaline batteries provided, so 7.2V and 8.4V NiCD and NiMH batteries did not last long before dropping below the minimum voltage needed by the microphone. In response to this need, MAHA developed 9.6V rechargeable batteries. More recently, newer mics have been designed to work with the standard NiMH battery voltages of 8.4V. As a result of this development, Maha released their 8.4V rechargeable battery. As they have 7 cells inside the battery instead of 8, each cell can be bigger, and the battery has a higher capacity of 300mAh.

If you have mics that are less than 3 years old, we recommend the higher capacity 300mAh 8.4V batteries which will give you around 5-6 hours from a full charge. If you have older mics, go for the higher voltage 9.6V 230mAh batteries to ensure compatibility with your microphones. The 230mAh 9V’s will still give you around 4 hours of runtime.

At One Community Church, a service is typically 90 to 120 minutes, plus a rehearsal of 90 minutes. The batteries are fine to run for the rehearsal time and the service. We use the 8.4V 300mAh batteries some of the radio microphones and in the wireless foldback headsets. Just last month we started using SHURE SLX radio microphones. We are using Powerex 2700mAh AA rechargeable batteries, and these are also lasting through rehearsal and the service. We recharge the batteries after every service, as the NiMH chemistry is fine to be topped up, and does not need to be fully discharged before recharging.

Low self discharge 9V batteries?

Is there such thing as a low self discharge 9V battery?

Well, no, not yet. But does it matter?

According to some people, the Maha 9.6V batteries are of a high enough quality, that they are in effect a low self discharge battery. Here’s a comment from a Maha 9.6V battery user in relation to using Maha 9V rechargeable batteries in smoke detectors:

“…I consider a smoke detector application to be low power such that
the self discharge characteristic of the battery will be the primary
driver as to length of use before recharging/replacement. With the maha
9.6v batteries in a various detectors, the run time is somewhere
between 6 and 12 months before the “replace battery” beeper kicks in -
all depending on the specific detector. The combo ionization/smoke
detectors or CO2 detectors draw more current than just ionization
detectors. Will those 9.6v batteries still supply sufficient current to
signal a _loud_ warning buzzer or beeping close to the end of their
useful charge? There was a CPF thread a while back that discussed that
aspect at some length. I tested a few of these specific Maha 9.6v
batteries under something I thought was close to end of charge – I had
to plug my ears to let the detectors sound off long enough to be
believable. No problem….

…While a 9V battery with the label of “low discharge” does not appear to
be available, in my experience the Maha 9.6v battery possesses
sufficiently adequate electrical/chemical characteristics to come close
enough to a “low self-discharge” battery for my usage.

BTW, you really need to purchase the Maha MH-C490F charger that charges
four 9.6v or 9V cells intelligently in a few hours, not all night as is
usual with 9V charging stations. and then leave the cells on trickle
charge after charge termination for longer than an hour. I credit that
charger for saving 4 existing older 9v batteries from the recycling
bin. It took a few charging cycles but the old 9V batteries were
sufficiently rejuvenated to become useful again.”
bcwang

IMEDION and eneloop performance review

Many customers ask “How do the new IMEDION AA rechargeable batteries compare to the eneloop AA rechargeable batteries?

Both are a low discharge technology, so they retain up to 85% of their charge after 12 months. But the eneloops have been available for a while, whereas the IMEDIONs are new. Has Maha been able to develop a better performer?

It would seem so. Test results have demonstrated IMEDION AA batteries outperforming the eneloop AA batteries in capacity measurements and discharge tests. Anders over on the Candle Power Forum has done many tests on the IMEDION AA batteries. The results of one of the tests, a comparison to the eneloop batteries, is shown below.

Update: Anders has noted that the eneloop graph is not correct. To see a more comparable graph, see the eneloop tests by Silverfox.

Here in Australia, several people have done their own tests and published the results on the whirlpool forum. Results by “Horrorking” can be seen here and IMEDION and eneloop performance tests in a Nikon SB-800 camera flash can be seen here

While the IMEDION AA batteries demonstrate a capacity advantage over the eneloop batteries, the other benefit of the IMEDION batteries is that they include a free AA battery holder, whereas the eneloop batteries do not.

EDIT: Fixed typo’s and added link to eneloop test results – sorry for misspelling your name Anders!

MH-C204W rapid charging and trickle charging process

Here is a question we received from a customer today. I thought it was worth sharing…

Hi,

I have MH-C204W battery charger I bought from you about 2 years ago. Its instructions sheet states \”do not mix batteries of different capacities ….\”. Your website states \”.. you can charge two different sets of two rechargeable batteries …\”. Is this true for all MH-C204W models or is this a later update to this product.

This is true of all MH-C204W battery chargers. The MH-C204W charges AA and AAA NiMH rechargeable batteries in pairs, and the pairs should match. However, you could have a different capacity and/or brand in slot 1&2 to what you are charging in slot 3&4. Similarly, you could charge a set of AA batteries in slot 1&2, and a set of AAA batteries in slot 3&4

I have also noticed that at the end of the quick charge cycle the batteries are only about 90% charged but leaving them on for another 2-3 hours adds another 8% or so to the voltage. Is this what should normally be done for a \”fuller\” charge\”?

The 204W will charge the NiMH batteries at a rate of 2000mA until they are almost full, approximately 97% of capacity. The battery charger then detects that the NiMH batteries are almost full by constantly monitoring the voltage, and it will switch to a 50mA trickle charge. If you leave the battieries in the charger for another hour or two, you will get another 2% or 3% charged capacity.