Rechargeable CR-V3

[firedogut]

i've been reading the posts in underwater photography and i have only read one post on the Rechargeable CR-V3.

Walk into any camera shop or a best buy and they will tell you there are no Rechargeable CR-V3.

if your camera can take the CR-V3 you might want to look at these two pages

http://www.batteryx.com/product/Document/012-PV001/012-PV001.asp?ProductID=1069

http://www.steves-digicams.com/2003_reviews/rcrv3.html

i would have bought these except i only wanted to spend $30.00.

 

[Dee]

Thanks for the link.

 

[ShoalDiverSA]

Hi again firedogut,

I thought it might be interesting to get some feedback from other Board members after my PM to you this afternoon.

I performed a test on my camera last night to test what the cutoff voltage is. I used the cells in the camera - they had been in use for a couple of days. I fired off about 12 shots in a dark room to deplete them quicker with the full power flash. The low battery warning came on and the camera switched off. I quickly removed the cells from the camera and measured the voltage - it was 1.23V per cell. I reinserted the cells into the camera and tried to switch it on - nothing. So this rough test shows that the cutoff voltage for this camera is about 2.5V.

Does anyone know the cutoff voltages of their cameras? I am particularly interested to hear from those with two-cell cameras, as these have the greatest susceptibility to voltage-related switch off without utilising the cell capacity.

A NiMh cell is considered to be fully discharged at 1V. According to the GP Batteries NiMh Technical Handbook, the 1.2V threshold is reached by a room temperature cell with 60% remaining capacity. At 10degC this voltage is reached with roughly 85% remaining capacity. So your 2100mAh cells are behaving like 840mAh cells at room temperature and like 315mAh cells at 10degC! I know that this is gross oversimplification of the science, but the conclusion seems vaild (to me at least ).

The issue here is that with a two-cell camera with a cutoff voltage higher than 2V, you stand a good chance of severely under-utilising the capacity of your cells when using NiCad or NiMh cells. I am curious to find out if this is unique to this camera (Samsung) or if it is a general issue. From an Electronic design perspective, I understand the difficulties of designing for low-voltage applications and 2V is extremely low. I am sure that the users with three or more cells won't have this problem.

It seems that the best option is to use LiIon cells in the two-cell cameras.

Sorry for the meandering post.

Cheers,

Andrew

 

[ShoalDiverSA]

[Retyping my looong post after IE crashed ]

After many disappointing moments with "LOW BATTERY" shutdowns of my camera, I finally took the plunge and bought two sets of RCR-V3 batteries.

I charged one of the batteries and installed it in the camera before Saturday's dive. The camera was switched on for the full duration of the dive (1 hour). I took about 50 photos and 2 video clips. We went to a show on Saturday evening and I took another 20 or so photos and another two short video clips. Lots of reviewing (bragging!) of the dive shots with friends on Saturday and Sunday. Took some more shots of my (cute) daughter on Sunday. After downloading the shots from the cameraon Sunday evening, I forgot to turn the camera off. It shut down some time after this. While this is by no means a controlled, scientific evaluation of the performance of the battery, by comparison my 1800 mAh NiMh cells were barely lasting a single dive (if that). I would with confidence use this battery for two dives without a recharge in between.

[Select All, Copy, Paste to Notepad, Save. Mutter, mutter...]

Granted, my NiMh cells were not the best quality available, but the issue here is not the capacity of the cell, but rather the nominal cell voltage.

In fact, this discussion is probably of very little value to those of you who have cameras which take 3 or more AA cells. The "flat" (fully discharged) voltage of a NiMh cell is quoted as 1V. My camera shuts down below 2.5V. I would expect similar values for other cameras as the electronics is probably rated for a nominal operating voltage of 3V (but I am guessing). So if your camera has 3 cells, in an almost fully discharged state, the total voltage will still be 3V, which is above the shutdown voltage of the camera.

This means that you will be able to utilise the full useful energy storage capacity of the cells before the camera switches off.

Free advice #1: If you are considering purchasing a digital camera, buy one which takes three or more AA cells. It makes a lot of sense.

With two-cell cameras, the scenario is quite different. The discharge curve of a fully charged NiMh cell dips below the 1.25V level quite quickly (see previous post) and this results in very little of the available cell energy being utilised before the camera shuts down. This expected performance correlates well with my experience using NiMh cells. I was utilising somewhere in the vicinity of 300mAh of the 1800mAh capacity.

The capacity of the RCR-V3 batteries is quoted as being in the 1100 to 1300mAh range. The nominal voltage is roughly 3.2V. This means that I am now getting the full 1100mAh before the camera shuts down.

To say that I am pleased with the performance of the RCR-V3 batteries would be an understatement.

Free advice #2: If you own a two-cell camera which can use CR-V3 (non-rechargeable) batteries, get the RCR-V3 battery. Link to list of compatible cameras

The fully discharged battery takes about 3 hours to recharge.

Please excuse me if I indulge in a quick plug. Most Internet battery retailers either do not ship to S.A. or charge a fortune in shipping. If you live in USA, Thomas Distributing is probably the best bet. I shopped around a bit on the 'Net and found HKDCPlus on eBay. I placed my order for two sets and within a week and a half, the parcel arrived from Hong Kong. This is exceptional! The shipping cost $23 for two complete sets. The charger and battery kits sell for $32. I thought that this price was very reasonable. The charger is universal, so it will work on 110 or 220VAC mains. The response to email queries was polite and quick.

I hope that this quasi-review (revision B!) is of use to someone.

Cheers,

Andrew