Archive for category Camera Batteries

Arduino Battery Capacity Tester

Ar2uinoBatteryIllustrationS  NOTE! This Arduino Battery Capacity Tester has been updated!
See the new, improved and simplified version of the
New Battery Capacity Tester!

 

Arduino Battery Capacity Tester CircuitTo automate the testing of (camera)batteries and to make the tests repeatable I came up with a small circuit controlled by a Arduino microcontroller  – you can see the UPDATED battery capacity tester circuit on the left. (If anyone is interested I can put up the Arduino program that controls it.) I have used this on my tests of camera batteries – check them out!

Someone was! 🙂  (Interested in the Arduino program!) Link at the bottom of this post! The program outputs measurements to the serial monitor.  I just copy it from there to Excel and do the calculations and graphics in Excel.

After some consideration about the measurement process I decided to try to approximate the real world picture-taking – but I also wanted a repeatable and reasonable easy and quick way of comparing different batteries. The circuit I decided on can handle the three most common batteries: 1.2 V NiMh, 3.7  and 7.4 V Li-ion by changing the load resistor. I wanted the load to mimic the actual taking of pictures by applying the load for a number of shorter times – like taking pictures.

For the 3.7 V Li-ion batteries on test here I decided that, as the battery according to Canon should give about 300 pictures, I would apply the load in around 300 short intervals. That ideally translated to a 5.2 ohm resistor giving around 500 mA load for 16 seconds each. Settled for a more standard resistor of 5.6 ohm. The load in this case is around 2.5 watts so use an appropriate resistor – with higher rating unless you want it to get very hot! 🙂  I also decided to let the battery “catch its breath”  for 16 seconds between each “picture” – again mimicking (very oversimplified) the real world behaviour while keeping the time down. Initially I wanted to follow a “real” standard like the CIPA one – but it was much to complicated for me and would involve far too much manual work. More to read about battery measurement in the CIPA document – but be warned it is very technical!

PEPs This 16 second 5.6 ohm load followed by a 16 second rest period just had to have a name so I called it Photoman Equivalent Picture samples (PEPs) – cool eh? 😉 NOTE that this is not real pictures taken but gives a good enough approximation – especially for comparing batteries! . The circuit takes into account the resistance of the MOSFET transistor used – just below 0.4 ohm – but it lowers the load a little bit. Running through the whole test takes about 3 hours per battery. Cut off voltage is 3.0 V for Li-ion batteries so that is where I stopped the tests. (This goes well with my Canon S95 that signals empty battery at that voltage.)

mAh My testing method also gives the capacity in mAh under the above “simulated real world picture-taking” conditions. Note that under other (“laboratory”) conditions these batteries can give other mAh capacities – but as I do it the same way in all my tests you can compare the results between the batteries that I test.

Here is a link to the Arduino program: BatteryCapacityTester

NOTE: Right click on the link and select “Save target as…” Due to limitations with WordPress this Arduino source code file has been given the extension “.doc”. After saving this to your disk rename the extension to “.ino”.

As usual if anything goes wrong or gets broken by using this information I am sorry – but all the decisions are yours!

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Canon NB-6L Compatible Battery Capacity

I have previously tested some of the electrical aspects of Canon NB-6L original and compatible batteries for my Canon PowerShot S95. These tests were sprung from a wish to minimise the risk of using a compatible battery. By comparing the electrical aspects I hoped to see if they were similar enough that I dared to use them in my camera! I am glad to say they were! I refer you to my previous post on NB-6L compatible batteries to read about the tests in more detail. (That test has now been updated to include the new Broadbattery battery mentioned below!) Maybe you will dare to try it as well? But remember that the risk is yours!

I was recommended a really low price and high-capacity (1600 mAh!) NB-6L compatible battery by one of my readers – thanks Francois! He found it on eBay at a shop called Broadbattery. Depending on where you live and how lucky you are in the bidding it can cost as little as $ 0.90 including shipping! (Which is a really super price!) I got mine for $2 + $2 shipping. It has just been delivered and I have now started the tests of this new battery – will update this article as soon as I have finished the tests – in a day or two!

As the selling point here was the high capacity I decided that just to measure the batteries under load was not enough – I needed a way to do battery capacity testing. Below you can see the results for all three batteries. Testing was done in a way as to simulate a real world picture taking.

For the technically curious

Arduino Battery Capacity Tester CircuitTo automate the test and to make it repeatable I came up with a small circuit controlled by a Arduino microcontroller  – you can see the UPDATED battery capacity tester circuit on the left. (If anyone is interested I can put up the Arduino program that controls it.)

Someone was! 🙂  (Interested in the Arduino program!) It outputs measurements to the serial monitor.  I just copy it from there to Excel and do the calculations and graphics in Excel.
See a separate post on this!

After some consideration about the measurement process I decided to try to approximate the real world picture-taking – but I also wanted a repeatable and reasonable easy and quick way of comparing different batteries. The circuit I decided on can handle the three most common batteries: 1.2 V NiMh, 3.7  and 7.4 V Li-ion by changing the load resistor. I wanted the load to mimic the actual taking of pictures by applying the load for a number of shorter times – like taking pictures.

For the 3.7 V Li-ion batteries on test here I decided that, as the battery according to Canon should give about 300 pictures, I would apply the load in around 300 short intervals. That ideally translated to a 5.2 ohm resistor giving around 500 mA load for 16 seconds each. Settled for a more standard resistor of 5.6 ohm. I also decided to let the battery “catch its breath”  for 16 seconds between each “picture” – again mimicking (very oversimplified) the real world behaviour while keeping the time down. Initially I wanted to follow a “real” standard like the CIPA one – but it was much to complicated for me and would involve far too much manual work. More to read about battery measurement in the CIPA document – but be warned it is very technical!

PEPs
This 16 second 5.6 ohm load followed by a 16 second rest period just had to have a name so I called it Photoman Equivalent Picture samples (PEPs) – cool eh? 😉 NOTE that this is not real pictures taken but gives a good enough approximation – especially for comparing batteries! . The circuit takes into account the resistance of the MOSFET transistor used – just below 0.4 ohm – but it lowers the load a little bit. Running through the whole test takes about 3 hours per battery. Cut off voltage is 3.0 V for Li-ion batteries so that is where I stopped the tests. (This goes well with my Canon S95 that signals empty battery at that voltage.)

mAh
My testing method also gives the capacity in mAh under the above “simulated real world picture-taking” conditions. Note that under other (“laboratory”) conditions these batteries can give other mAh capacities – but as I do it the same way in all my tests you can compare the results between the batteries that I test.

NOTE: As usual if anything goes wrong or gets broken by using this information I am sorry – but the all decisions are yours!

NOTE! New and improved Battery Tester at my Ar2uino Blog!

Capacity Test Results

To not get your (and my) hopes up too high I include an excerpt from a comment I made a few weeks back: After testing a few different batteries I am sorry to say that I strongly doubt that the capacity ratings given on these (and on most other cheap batteries) are much to go by – expect them instead to most often be around or slightly below the original battery. Most manufacturers seem to use the same (probably most cost effective) production – making them very similar in capacity”

That’s enough tech talk … now over to the result of the tests. I charged all batteries before the test and allowed them to rest for 10 min before starting the tests. This is what I got:

Rather typical Li-ion discharge curves – first a slowly sinking voltage and then an abrupt plunge! But the batteries looks quite different! Up to about 180 PEPs the curves keep very well together. A quick look at the discharge curves shows that the best performer is the Canon original battery.

Canon original
The curve shows an unusual stamina after about 280 PEPs working hard att keeping the voltage up. It is quite clear that the Canon original battery gave quite a lot more PEPs on one charge. Canon gave 352 PEPs and a capacity close to its claimed 1000 mAh by reaching 950 mAh(It also says “min 940 mAh” on the battery.)

Broadbattery – Unbranded
The curve starts out high – actually a little higher even than the original but when it reaches its limit then it plunges very quickly! Broadbattery came second with a very small margin (more like shared second place) with 288 PEPs and 780 mAh. This was after all a “small” disappointment as it promised 1600 mAh! Would have been nice with a really high capacity battery for the Canon S95. The battery should really be marked with “800 mAh” or something … (I have been in contact with the pleasant people at Broadbattery to see if it just is my sample – but I would not guess so… if so I will of course update this info!)

Deal Extreme – GodP
The curve is like a standard typical LI-ion curve from a textbook. The Deal Extreme battery gave 284 PEPsvery close to the Broadbattery. The Deal Extreme battery is marked with 850 mAh but did not quite reach that with 770 mAh

Conclusion 

It is definitely a difference between the three batteries – but is it worth the extra price and the risk..? That is something you have to decide for yourself… (Tip: I have bought a few compatibles…) I can still not say that I have a corresponding real world capacity figure – I seem to forget all the time and just change the batteries as they run flat. What seems quite clear is that you get a little less capacity for a lot less price!

An extra comment on the battery from Broadbattery is that apart from that they claim a much too high capacity – the battery seems to be very similar to the Deal Extreme one – so if you live somewhere to where they do free shipping and if you are a bit lucky at bidding  – this might still be a real bargain!

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Canon NB-6L Compatible Battery

This is a test and comparison of the electrical characteristics of three NB-6L batteries for Canon PowerShot S95 (original and compatibles).

After a very long wait (25 days for the shipping) for batteries the two NB-6L compatibles finally arrived from Deal Extreme. Priced at just 3.6 EUR/$5 each including shipping they are really a very cheap alternative to the original which are 15 times as expensive here in Sweden!

I also ordered one NB-6L compatible battery from an eBay shop called Broadbattery. Depending on where you live and how lucky you are in the bidding it can – at the moment – cost as little as $ 0.90 including shipping! I got mine for $2 + $2 shipping (2.7 EUR/$4). It arrived much quicker after “just” 12 days!

Having bought a set of compatible batteries that has worked very well – so far – for my Canon EOS 550D (Read my test of LP-E8 compatible battery here!) I decided to go about it the same way – testing and comparing the batteries as far as I could – before putting them in the camera!

The Deal Extreme batteries came very well packed in separate blister packs with a lot of “quality inspiring” text: 100% Compatible Original, Intelligence Protection, New Technology, Longrun Lithium, NO Memory Effect and IC Control. (Second one sure is scary! 😉 )
The Broadbattery one had less fancy packaging but was still well packed in a padded envelope with an extra plastic “bubble” bag  around it! All batteries arrived in perfect condition!

I must admit that I always feel a slight worry 😦 about these compatible batteries – so I try to be as “sure” as I can before I give them the GO! I feel that there are two different areas which to consider: First of all is whether the battery is safe – voltage and current wise – that is if all voltages are reasonably close to the original. This I can measure! Secondly, most (all?) Li-ion batteries contain some sort of protection circuitry for short-circuit, overloading and over charging – and this I will not be able to access and therefore can not comment on!

NOTE! This test of compatible batteries just shows the results from the samples that I got and that I give NO GUARANTEE that any batteries bought by you will work as the ones I got! Any tests that you make are your own responsibility!

My Canon PowerShot S95 seems to really eat battery power! So having a pair of extra batteries is something I would recommend to anyone – especially at these ridiculously low prices! Also having extra high capacity is quite tempting…

The original Canon NB-6L is specified as 3.7 V, 1000 mAh (min 940 mAh) and the NB-6L compatibles are specified as Broadbattery 1600(!) mAh and Deal Extreme 850 mAh so if these specifications are to be trusted – the compatible batteries should give around 60% more or 15% fewer shots.

A funny observation I have made with the original is that it seems to “recuperate” to some extent after the camera has switched itself off. Just a few seconds later I can take maybe 5 more pictures – and I can repeat this 2-3 times… One more observation – the original battery goes from full via 2 stripes to empty very quickly – it is not as if the stripes indicate some sort of proportionality….

As you can see from the picture the Deal Extreme compatible is of a completely different design from the original Canon and Broadbattery ones! But size measurements are within 0.1 mm of each other – so size wise there should be no problem! The weight differs very slightly – the original weighing in at 19 grammes and the compatibles at 18 and 19 grammes. All have a good, light but very solid feel to them!

After charging all three batteries I set about to measure them under different loads – before even considering to put them in my Canon S95. Charging proceeded similarly for all three of the batteries!
NOTE! After getting a “normal” response  from all three batteries in the capacity test I redid the following Load tests!

The different measurements that I did show VERY SIMILAR results from the original and all of the compatibles! They are so close to the original that it is impossible to pick out the different curves in the diagram! They are like identical twins – measurement wise! This at least convinces me that there should be very little risk in putting the them in the S95! 

After brooding for a few minutes – first thinking about what could go wrong I then thought about the similarities. All of them the exact same size – should fit well in the camera! They had fit well in the charger – but that is not such a tight fit. Then – as far as I could measure – the voltages under load were the exactly same – so that should pose no problem! The weights were also very close! The text on the package about “100% Compatible” seems to be correct – according to my measurements!

The question that is left is that about the protection circuitry – should one trust or laugh at the text about this: “Intelligence Protection” and “IC Control”. It sounds as if it has the relevant circuitry … Bad english can be forgiven – but to find out if these statements are true I would have to open the batteries and this I will not do!

Finally I put the Deal Extreme battery in the camera and switched it on … and it workedI am very glad to say! 🙂 The fit was perfect – as it should be with such close size! Then I repeated it with the Broadbattery – and again it worked – I am again very glad to say! 🙂

For capacity measurements of these batteries look HERE!

Now I have all the NB-6L batteries that I need for my Canon PowerShot S95 – for a very low price!

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Canon EOS 550D Compatible LP-E8 Battery

Here in Sweden the original batteries LP-E8 for the superb Canon EOS 550D/Canon Digital Rebel T2i are priced quite high at around 600 SEK/€ 60/$80 so I googled after some lower priced alternatives and I came upon Deal Extreme Compatible battery (SKU 35588) for only 10% of the original battery cost (free freight) … and after some consideration I ordered two. After waiting close to two weeks the batteries arrived! In the meantime I had read on several forums about “compatible” batteries and there seemed to be different opinions about whether the batteries were really compatible or not and whether they could actually damage the camera or not

NOTE! This test just shows the results from the two samples that I got and that I give NO GUARANTEE that any batteries bought by you will work as the ones I got! The fact that I got two different capacities might indicate that batches have different properties! Any tests that you make are your own responsibility!

This “make or break” was a worry on my mind and I did not dare to put the batteries in the camera when I got them!  I decided to try to compare them to the original battery. The two batteries I got were stamped with different capacities as you can see in the table below.

The batteries arrived boxed in small red&yellow boxes (above). They were also put in small plastic bags and had on their underside a snap-on cover. All in all they had a trustworthy feel to them. The plastic seemed as sturdy as the original. No text at all on the top. The grey colour were ever so slightly darker grey i colour than the original.

Turning them over they were printed with voltage, capacity and other info. The contacts were also visible and looked very much as the originals except that you could see the “gold-plated” contacts glimmer a little clearer than on the originals.

Now I set about checking weights and sizes. The compatibles weights were 18% and 4% lighter than the original. No visible difference in sizes. Having done this I thought it worth the risk of charging them. Charging them with the original charger posed no problems and after less than an hour they were both fully charged. (I guess they were partially charged from the beginning.) To get comparable results I charged the original battery also.

Not knowing that much about battery science I googled to try to find out what the different specification voltage meant 7.2/7.4 Volts. I found no easy to understand explanation – might depend on different materials for anode/cathode – but it is still a little of a mystery to me what the voltage actually stands for

These were the results I found when measuring the voltages under different loads.

As the no-load voltage of all three batteries were the same with 8.32 Volts I decided I would test them in the camera. Also helped was the fact that the the difference under load was just 1-2%!

I tried them and there was no problem with fitting, all three batteries felt similar in fitting them in the camera so I (with some excitement) turned the camera on – and it worked as usual! 🙂

I have now been using them for a few weeks and I have seen no real difference between the batteries – original or compatibles. I have not really measured or kept a proper eye on capacity – but my feeling is that the batteries last the same time. (If I get curious I might do a proper capacity measurement…) I have read comments by other buyers that the low charge warning does not work so well with the compatibles. I do not know if it is like that – I tend to not notice the battery charge indicator until I see the flashing red low battery indicator – and then I change battery! I will try to keep an eye on that in the future and report back here with an update! With three batteries I tend not to worry too much – when one goes flat I just change to a new one! 🙂

Canon original battery lasted an impressive 827 pictures total – spread out over a rather intense 4 hour photo shoot – checking most pictures on-screen. Of the total about 50 was flash pictures.

UPDATE!

After a few months of rather intense use I can now report the following average capacity figures for the above batteries – both compatible and original. Used by what I would describe as a “keen” photographer (me).

Normal usage, lots of focusing (without taking pictures),  checking the majority of the pictures on-screen for 1-2 secs (no automatic image review), info display switched off, a mixture of lenses used but mostly the 18-55 mm kit lens and just 1-5 flash pictures per charge, camera never switched off. I have taken 300-500 pictures each day so this was much less intense then the above mentioned photo shoot.

Original battery lasted 1000 pictures – with two battery level warnings at 2 bars with 200 and at 1 bar with 100 pictures before empty.
Compatible battery lasted 800 pictures – ONE battery warning at 1 bar with 10 pictures before empty.

It was no surprise that the original battery was the (slightly) better of the two – but at a 10 times higher price …  

The battery level indicator works well with the original battery and there is not really any warning with the compatible – it just goes flat! BUT as I usually – in practice – have the info screen switched off I am as surprised with both batteries when they run flat! Having the info screen on I would definitely have a better chance of picking my moment to change the battery – if I have the original. Either way I would really appreciate a more forceful way of warning for low battery – one that is seen even when the display is switched off!

Till next time…

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