[WheresWaldo]

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Introduction:

Near the beginning of the year there were many questions about using cheap Chinese clone batteries in the K10D/K20D. I had some questions also, since I try to use the least expensive batteries possible, as long as they provide some reasonable value.

In light of the fact that genuine Pentax batteries are sold at a premium and many of the clones can be had for under $10 USD each, I set out to buy a few of the different clone batteries and compare them to the genuine article. You will find my initial conclusions in the following three threads:

https://www.pentaxforums.com/forums/camera-studio-accessories/44194-cheap-mad...rth-price.html
https://www.pentaxforums.com/forums/camera-studio-accessories/44863-chinese-k...round-2-a.html
https://www.pentaxforums.com/forums/camera-studio-accessories/46273-chinese-k...round-3-a.html

One of the main reasons for doing this was that much of the information here and in other forums throughout the net contain anecdotal information and assumptions were made based on gut feelings rather than empirical testing. While I cannot say that my testing methodology is any better than anyone elses gut feel I can say that it is repeatable and we can put some real world numbers behind each of the batteries tested.

Test Subjects:

There were three sets of batteries tested, all clones of the NP-400, all from China. Each battery was bought in the quantity of two and they had the following mAh ratings: 1400, 1800, 2000. All six cells have been in exclusive use since their purchase, I do have three genuine D-LI50 cells but other than using them during the initial tests and while waiting for the clones to arrive they have sat on the shelf in the same spot I placed them in months ago. This new round of tests only include the clone batteries.

Methodology:

All batteries were drained to 5.6 volts, as you will see from the attached PDF once they hit about 6.8 volts the drop to 5.6 is almost instant. Then all the batteries were fully charged on the clone charger that I purchased in January 2009. I used the clone charger since it takes about 20-30 minutes less time to charge the battery compared to the Pentax charger.

Each battery was then discharged using a constant discharge rate of 500mAh. This was the same rate used in the first round of testing and was chosen as a guesstimate of actual usage. Manufacturers do not test capacity this way when documenting the mAh for sale, they use .2C, where C s the total capacity, thus a 1400mAh battery would be discharged at a rate of 280mAh. Because of this we should actually expect to find that none of the batteries tested will meet the manufacturers claims, but rather be some percentage less.

The batteries were then fully charged a second time and discharged with the same parameters and the mAh capacities were recorded and graphed.

The Results:

First up, the 1400mAh batteries.


If you go back to the original thread you will see that these were advertised as 1750mAh but 1400mAh batteries were what was delivered, the price at the time was $15.10 for the pair. In the original test they managed 1330mAh. In this test we managed 1339mAh and 1352mAh. That is pretty good for some cheap batteries and these are currently still in use in both of my K20D's


Second we have the 1800mAh batteries.


These batteries cost at the time $16.00 USD for the pair shipped from Hong Kong. In the first round these had a rating of approximately 1200mAh. disappointing considering the lower rated batteries performed better. Even worse the new test revealed that these batteries simply cannot be reused over and over without significant loss of capacity. These two batteries failed in my estimation. They tested lower initially and lost significant capacity during use. the new results are that these batteries output 771mAh and 1031mAh respectively. These results indicate that cells used here are of inferior quality. Bottom line, stay away.

Lastly we have the 200mAh batteries.


In the initial tests the capacities of the pair were 1454mAh and 1476mAh, again less than the OEM but alright for a battery that only cost $18.00 USD shipped from California. These two batteries tested out very different. Some of this I attribute to the way I use batteries, generally I leave the grip on and select grip battery as the primary, then when I must switch to the internal battery I usually pop the grip battery out and recharge it. The battery in the grip goes through about three or four cycles before the internal battery needs to be recharged. I am currently rethinking this strategy in light of the following findings. One of the batteries performed about the same as it did initially providing 1446mAh of power. The second battery I consider a failure only able to produce 926mAh capacity. It too made it into the trash bin. This result was particularly disappointing since this battery claimed to use superior Japanese cells in its manufacture. I do not know if this is true, I may disect the battery just to see.

Test Chart:



Conclusion:

It is plain to see that these inexpensive LiIon batteries may not be the bargain they pretend to be, particularly in the higher output capacities. The 1400mAh batteries on the other hand seem to behave more consistently and have not suffered from the diminished capacity of their higher powered brethren. In my case if I needed more batteries I would look for the more standard sized 1400mAh clones as opposed to trying to eek out every bit of power I could by buying into the false economy of the high power clones. As with all of these types of test, please note that a sample size of two is very small and that your mileage may vary.

I do not own a K-7 but I would suspect that much of this data would apply to clone batteries for that camera also.

Please see the attached PDF for the actual test report.

Just as a side note, since three of these batteries were tossed out I do have two Phottix branded batteries on the way from Hong Kong. They claim a rating of 1500mAh. I guess we shall see.

Attached Images

0809_batt_test.pdf (52.0 KB, 367 views)

[maxwell1295]

I've had a very positive experience with some eBay NP-400 knockoffs. I haven't seen any real world difference between the Pentax battery and the eBay batteries. I picked up 8 or so batteries from this eBay seller: eBay Store - Battery: Charger, Digital Camera Batteries, Camcorder Batteries

I also have my K20D's set up to use the grip battery first. I shot a wedding last Friday with about 900 shots on one body. Then did some random shooting and a portrait session the other day with the same body. I got about 1200 shots in before having to switch out the battery.

[WheresWaldo]

If you are talking about these batteries then you will probably get very good service out of them,


Let's say that your set up gives 1 year of service per set of batteries, if you have two K20Ds and two grips that is four batteries. If you purchased all eight at once to save on shipping that's about $9.68 per battery. The current price of the genuine Pentax is $40 at B&H each, you could outfit your entire kit with spares you have for the cost of two Pentax D-LI50's.

This is the conclusion I drew, that even if you only get one year of service you can buy 4 years of clone batteries for the cost of one set of genuine Pentax D-LI50. In your instance that means 32 Chinese batteries vs 8 Pentax. By the time all these are unusable it will be nearly the time to replace your aging K20D's anyway and you will be forced to buy new batteries.

The 1400mAh-1500mAh seem much more stable than the higher capacity batteries as more than likely there are many more good cells in that mAh range. It would appear to me, and from what I have seen from anecdotal references such as yours, you will get much more life out of those batteries than just one year. every day, week, month or year is just that more you are saving. The most shots I have taken in a day was about 500, that with the clone batteries. The battery indicator, as inaccurate as it is still showed both batteries full.

I will test the 1500mAh Phottix batteries I get as soon as they get here. I may also look at these in the future.

The reason I went to the trouble of doing this test is that all the reports are just like yours, which is a good thing but very subjective. Just how much capacity does the battery contain? It is much too hard to determine that from just shooting pictures. You can make an educated guess, but that is all it is, a guess. This way we can put some numbers that make sense and not what some Chinese marketing person thinks we want to see and are willing to spend money on. I have dealt with Chinese batteries too long to trust what they put on the label is accurate.

[maxwell1295]

If you are talking about these batteries then you will probably get very good service out of them.

Yep, that's the battery.....I can't tell which battery is in the camera without looking. Performance appears to be identical.