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Old Jul 26, 2008, 6:38 AM   #1
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Here is the story.

1 Week ago, i ordered my new camera, and2 CR-V3 Batteries and a charger from a "Respectable, UK Battery Dealer"(Batterystore.co.uk)Camera arrived, and it works super, excellent camera!

Next day, package arrives! But... Import Tax? What? I had to pay import tax for an item i had ordered from a"Respectable, UK Battery Dealer!" In fact the batteries had arrived from a company named "ESPOW" Based in Hong Kong! So i reluctantly payed import tax and opened up the package. Expecting 2 Batteries and a Charger, What acctually arrived were 3 batteries, and a charger! i had to pay also for an extra battery which i didn't order.

I was pretty annoyed at this, and just wanted to take some pictures. So i put them in and everything was working lovely until about 25 shots in, after each shot it shut off and the most aggrevating thing is it shuts off whilst the picture is saving rendering it "Un-readable!" . It turns off, no lens retraction. I pulled out the CR-V3 and the contacts were boiling hot!

Fed up and angry i rang Batterystore.co.uk for a refund, but they claimed i had never bought anything off them! I rang Espow, the Hong Kong dealer, who i have not heard about before the package arrived on my doorstep, and they said if i sent it back they would give me a refund. I decided to do this until they mentioned that Shipping to my house, Return shipping, and import tax at my house and import tax into hong kong were not refundable! It would cost more to post it back than it costed to buy the batteries in the first place!

Angry, i asked well known camera and battery genius Alan T. I tested their voltage, against other similar batteries and it was much higher. I investigated also that manypeopleare usingCR-V3s with no problem.I then went a step further. I opened up the battery and guess what i saw?

The "CR-V3" is acctually 2 Ni-MH batteries stuck together and with a bit of plastic covering the contacts at the top! I am sure this is very dodgey! Below are the pictures i took, Amazingly, the camera cut out a further two times whilst taking these pictures! Sorry for shaky pictures, but you get the idea.





Any ideas on why? This is so frustrating! The moral is... DO NOT buy from Espow or Battery Store UK!

- Sim
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Old Jul 26, 2008, 7:01 AM   #2
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SimmiS wrote:
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...i asked well known camera and battery genius Alan T.
No, I'm not, though I'm flattered. I'm just carrying on as an informed amateur in my late father's and my own semi-professional footsteps.

My Dad used regularly, in spite of my imprecations, to overcharge non-rechargeable cells with inevitable consequences, using his own lashup power supplies. It wasn't that that killed him, I hasten to add. I'm a retired electrochemist & general jobbing chemist/scientist from a major UK research centre, which is still going strong, but much smaller in the modern, privatised world. There are folk here who know much more about batteries than I.

I did stress that I was speculating about the Ni-MH/Li-ion counterfeiting. Has anyone else takenrechargeable CR-V3 apart? Sim is to be congratulated for his investigative boldness.

I have asked that question here before, because I measure, and use as a battery-monitoring measure (also current under under standard load as well),3.8V across the camera contacts, and 4.2V across the charger positive and camera negative terminals, on a fully charged, genuine, rechargeable CR-V3 battery. This is presumably to avoid over-voltage on 2xAA cameras. I want to know how they do it. Is it just an energy-wasting resistor, or is it a sophisticated voltage regulating circuit?

I await comments with interest.

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Old Jul 26, 2008, 7:15 AM   #3
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After taking the battery apart, there were two AA sized Batteries with 680mAh stamped on the side and nothing else. It may not be a Ni-MH but it was very similar.

Very interesting. I will either Buy a real Kodak Charger and 2 Klic-8000 or a couple of reputable CR-V3s.

Sim
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Old Jul 27, 2008, 2:37 PM   #4
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Quick update :-

I ordered some nice Uniross CR-V3s and a charger. I have had unirosses before, one set i bought in2003 and arestill going strong! My new batteries are Li-Ion unlike my dodgy NiHm ones and hopefully they will be much better!

Thanks -

Sim
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Old Jul 27, 2008, 3:15 PM   #5
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SimmiS wrote:
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....Uniross CR-V3s and a charger...
Well, my Uniross one is 15 months old and going strong, so you should be OK at last. I suggest you could keep records of when you charge and recharge vs filename number and date, and then you'd know how well they were doing, under various duties.

I'd still employ my list of energy-saving measures that I mentioned in the Kodak forum as well, if I were you.

Happy shooting!


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Old Jul 27, 2008, 7:07 PM   #6
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Hello Sim,

AA sized cells work out to a metric size of 14400. Li-Ion cells are made in this size. They aren't sold individually because people would put them in NiMh AA sized slots and burn out their electronics because of the voltage differences.

A NiMh AA cell has a nominal voltage of 1.2 volts. An AA sized Li-Ion cell has a nominal voltage of 3.7 volts.

A CR-V3 battery is made up of 2 of the 14400 cells in parallel. If the cells have 650 mAh of capacity, the battery will have a capacity of 1300 mAh. This battery should come off the charger at about 4.2 volts.

I am not sure why your battery was heating up, but that is a danger sign with Li-Ion cells. If a pack heats up beyond mild warm, I would not recommend using it.

I have a GPS unit that uses the CR-V3 battery. The battery that came with the unit died within a month, but the replacement battery has lasted several months and is still going strong. I think there may be some quality control issues with these batteries as I have heard of several problems with them. However, once you get a good one, it seems to work fine.

Tom
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Old Jul 27, 2008, 8:08 PM   #7
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I hoped you'd arrive, Tom, knowing you'd shed some light.

What's going to happen if the two Li-ion cells are in parallel, and one's in better shape than the other? I'm not bad at Ohm's Law, but that's getting a bit tricky for me. Sim's cells do indeed look the same way up, and strapped together, therefore in parallel.

Are you able to explain why I can measure on open circuit 3.8V across the terminals exposed to the camera, but 4.2V across the negative and the centre terminal used only by the charger? That's on a charged battery; when used upit's about 3.6V and 4V. Presumably this is due to some control and safety electronics. But where's the extra potential coming from? Are there circuit diagrams for these things anywhere, please?

I remain bemused, but hopeful.
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Old Jul 28, 2008, 12:31 AM   #8
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Alan T wrote:

Are you able to explain why I can measure on open circuit 3.8V across the terminals exposed to the camera, but 4.2V across the negative and the centre terminal used only by the charger? That's on a charged battery; when used upit's about 3.6V and 4V.

The difference is probably the voltage drop across a diode installed to provide reverse current protection.

brian
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Old Jul 28, 2008, 11:48 AM   #9
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Hello Alan,

As Brian has indicated, there is a protection circuit inside the battery pack. This protection circuit limits the high voltage of the cells (4.2 volts fully charged) to something the camera, or GPS, can handle without damage (around 3.7 - 3.8 volts). This 0.4 volt drop means that as the cells reach their nominal 3.7 volt operating range, the camera is only seeing 3.3 volts. This is more in line with what you would get with 2 NiMh cells.

In order to fully charge the battery pack, special chargers are used that charge to a higher voltage than those used for Li-Ion cells without this type of protection circuit. These chargers should only be used with the batteries they are bundled with.

In a parallel circuit, the voltages remain the same for each cell. If a cell gets a little weak, your overall capacity will drop, but with Li-Ion chemistry, the cells will remain in balance. The biggest concern comes from the condition where one cell dies and the other is worn down a lot. If a maximum draw is placed on a battery in this condition, it could exceed the recommended maximum draw on the individual cells and they would heat up. It appears that this may be what Sim encountered with his pack.

Tom
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Old Jul 28, 2008, 12:40 PM   #10
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Thanks for all your help! Hopefully my new batteries should arrive soon!

-Sim
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