Gauging interest for Digital Camera Battery

[Darren]

Hi all,

Just want to gauge general interest in a product called Digital Camera Battery - Click HERE for details!.

Mainly for Digital SLRs but can also power some film SLRs and a good number of flashes.

The estimated price of a DCB Kit (consisting of the battery, charger, power cable for DSLR, power cable for flash) will be in the region of S$900-S$1,000. Not cheap, but considering that you will be getting at least 500+ shots out of the battery (and/or more than 1,100 flashes) it will definitely be very useful for those (like myself) who do whole day shoots.

 

[Larry]

fwah, can power laptops as well!!!

good stuff... i'm definitely interested, just seems a little pricey...

 

[Darren]

FYI, I was researching alternative ways to power my D1x as the batteries seem to be dying faster and faster, even with regular battery conditioning.

Of my two EN-4s, one will die after approx 50-60 shots, while the other will give up after 100-120 shots (based on NEFs which are 7.2MB each in size). Hardly enough juice to fill up two MicroDrives ;p Suspect the first one is going to konk out soon also.

Considering that each EN-4 costs S$270 each, then the DCB is a good value when seen in that perspective (since it also provides power to the flash).

Oh yeah, and the fact that it can also power laptops, digital storage devices etc (with the proper cables) also is a bonus - imagine watching DVDs on your laptop while on that long flight without having to worry about the batteries dying after 1.5 - 2 hrs .....

 

[Wai]

i need something that can provide 18A @ 12V for 6 hours at least....

any idea which battery is suitable?

the highest end one is 120W and only produce 10A @ 12V....look like i need to get two pieces of these...

darren u want to MO?

 

[erwinx]

How about getting someone to DIY a casing utilising rechargeable Nimh batteries? multiple 'AA', 'C' or 'D' size running in parallel?

The digital camera battery is supposed to give 500+ shots doesn't sem that much for S$900?

after all, 4x1850 AAs can give 200+ shots on an S2 (D1x shouldn't be that much different?), so if one could DIY a casing holding 12x1850 AAs could be 'nearly' equivalent to the digital cam battery?

of course, size/weight will be quite a lot but cost savings can buy that nice light carbon fibre tripod

 

[Wai]

Originally posted by erwinx
How about getting someone to DIY a casing utilising rechargeable Nimh batteries? multiple 'AA', 'C' or 'D' size running in parallel?

The digital camera battery is supposed to give 500+ shots doesn't sem that much for S$900?

after all, 4x1850 AAs can give 200+ shots on an S2 (D1x shouldn't be that much different?), so if one could DIY a casing holding 12x1850 AAs could be 'nearly' equivalent to the digital cam battery?

of course, size/weight will be quite a lot but cost savings can buy that nice light carbon fibre tripod

hmm...i dunno if my calculation is correct or not...let me know if i am wrong...

let's say one NiMH battery produce 1.2V @ 2000mAH = 2.4W
which means i will need 50 of these batteries to produce 120W

also i have to arrange the batteries in parallel to produce 12V @ 10AH = 120W

and becos of internal resistance....some energy are wasted....

hmm....the size & weight of 50 pcs AA battries is too much for me....

 

[erwinx]

Originally posted by Wai


hmm...i dunno if my calculation is correct or not...let me know if i am wrong...

let's say one NiMH battery produce 1.2V @ 2000mAH = 2.4W
which means i will need 50 of these batteries to produce 120W

also i have to arrange the batteries in parallel to produce 12V @ 10AH = 120W

and becos of internal resistance....some energy are wasted....

hmm....the size & weight of 50 pcs AA battries is too much for me....

how about 9000 mAh 'D' size

http://www.zbattery.com/zbattery/gp900dhc.html

 

[Wai]

Originally posted by erwinx



how about 9000 mAh 'D' size

http://www.zbattery.com/zbattery/gp900dhc.html

:dunno:

can this work? any electrical engineer can verify??

 

[roygoh]

OK, Wai, here's a full-time electrical engineer at your sevice.

In you earlier post, you mentioned you require a power source that can deliver 18 amperes at 12 volts (dc) for minimum 6 hours.

To me, that means that:

1. The device you are powering consumes 18 * 12 = 216 watts.
2. The batter capacity you require is 18 * 6 = 108 AH (or 108000 mAH)

Hypothetically, if you wish to construct such a battery pack using AA NiMH cells with 1800mAH capacity at 1.2V, you will need to:

1. connect 10 batteries in series to give you 12V, this will give you 1800mAH at 12V. The voltage adds when you connect in series, but the capacity remains the same.
2. connect a total of 108000/1800 = 60 sets of the 12V assembly described above in parallel to give you the total capacity of 108000 mAH. The capacity adds when you connect in parallel, but the voltage remains the same.

So the total number of AA batteries required is 600.

Even if you go to 9000 mAH 1.2V D size batteries, you will still need to connect 10 in seriese to get 12V, and then 108/9 = 12 "tubes" of the 10-in-series connection in parallel to get the 108 AH capacity. That means a total of 120 batteries.

The only suggestion I can give you is to look at car batteries.

May I know what devices you are trying to power? I am curious about the 18 ampere requirement. Driving that kind of current will heat up the cable to very high temperature due to cable resistance. You will need cables that look like jump-start cables for cars.

- Roy

ps. sorry for going OT, Darren. could not resist an electrical discussion.

 

[roygoh]

Wai,

The 120W version is rated at 10 AH when set to 12V output.

In theory if you draw 18 Amperes from the battery it will last you slightly more than half and hour.

In practise, the device will not deliver 18 amperes safetly. It is actually rated at a maximum current of 5 amperes.

Connecting multiple devices in parallel in theory increases the capacity as well as output current capability. However, this is not safe, as each device has its own voltage regulator (a circuit that tries to maintain its outout voltage at the set level). connecting 2 or more devices in parallel directly means that they will have to "fight" to control the output voltage. This will result in a hazardeous condition as one battery may end up charging the other battery.

My question again, what exactly is your application? My curiosity is killing me!

- Roy

ps. Sorry again Darren.

 

[mpenza]

12V-18A is a lot of power!!! Just wondering what devices are to be powered....

 

[roygoh]

Originally posted by mpenza
12V-18A is a lot of power!!! Just wondering what devices are to be powered....

Exactly...in normal life situations I can only think of starting a car that uses that kind of current.

Of course, there are air conditioners, hair dryers and stuffs like that that uses pretty high current.

Unless Wai is actually adding up the power consumptions of a few different devices.

 

[roygoh]

Originally posted by erwinx
How about getting someone to DIY a casing utilising rechargeable Nimh batteries? multiple 'AA', 'C' or 'D' size running in parallel?

The digital camera battery is supposed to give 500+ shots doesn't sem that much for S$900?

after all, 4x1850 AAs can give 200+ shots on an S2 (D1x shouldn't be that much different?), so if one could DIY a casing holding 12x1850 AAs could be 'nearly' equivalent to the digital cam battery?

of course, size/weight will be quite a lot but cost savings can buy that nice light carbon fibre tripod

If you do not need the variable output voltage that the DCB unit can provide, my suggestion is to look at building a casing around a high capacity LiIon battery for camcorders. Capacities up to 3AH at different voltages are available.

For my CP995, I built a case around a Lenmar DLS550H (compatible with Sony NPF550) and added a voltage monitoring circuit to show battery status. The battery is 1850mAH at 7.2V. Got the battery for US$35, and a LiIon charger for US$39. Provides 3 times the capacity of the internal EN-EL1 battery.

You should be able to get the capacities of the 30W version DCB with D-sized NiMHs or camcorder LiIons relatively easily. The cost of the DCB is mainly for the dual variable voltage output for the purpose of powering the camera and flash from the same power supply.