powering a hasselblad H3d back

[Peter Devos]

On location i had a H3dII body stop working. Whatever i tried, nothing got it working again. Luckely enough i had my spare H1 with Ixpress 384 with me. However, the client really insysted on 39Mp images. So this is what i macgyvered: I screwed a quick release mount to the hasselblad H clamp. Then I glued the quick release plate to my ImagebankII. Thei took my H1, put a piece of paper over the contacts, attached the H3d back. I connected the back to the image bank, attached the image bank with battery under the camera ( about a 15cm stac :-(     ), put the back in Flash sync mode  and then continued shooting. 
Now i am looking for a FW powersupply that works on a simple 7,2 battery. I hope the to attach that instead of the little unused flash on top of the prism finder.

[Weldon Brewster]

I'm not sure if they are still in business but there was a company Big Power Wave that had a battery product called Titan I.  It had a firewire power port.

[rolad]

if these are not available commercially - and as you seem quite handy - perhaps give DIY a try:
(disclaimer - i am no electrical engineer - try at your own risk...    )

cut a FW cable, identify the power wires (pinouts available on the net) and then mcgyver these to i.e. a standard rechargeable LiIon 7.4V video battery with enough mAh.
or get a couple of 18700 LiIon cells (equiv of 18650s with protection circuitry built in) and hook these up.

i will try to pimp a spare CR123 battery grip by inserting two 18700 cells next week, btw - to see how far it much it ld boost battery life.

[John.Williams]

...or, try this:

HD+ FireWire Power

John

[Peter Devos]

if these are not available commercially - and as you seem quite handy - perhaps give DIY a try:
(disclaimer - i am no electrical engineer - try at your own risk...    )

cut a FW cable, identify the power wires (pinouts available on the net) and then mcgyver these to i.e. a standard rechargeable LiIon 7.4V video battery with enough mAh.
or get a couple of 18700 LiIon cells (equiv of 18650s with protection circuitry built in) and hook these up.

i will try to pimp a spare CR123 battery grip by inserting two 18700 cells next week, btw - to see how far it much it ld boost battery life.

That was the thing i was looking for. I have the FW800 layout, so that is not the problem but wat is the Voltage used. Nowere it is mentioned as 7,2 volt. Mostly between 12 and 25Volt. Ideal would be the 7,2 volt battery. I would then remove the flash from the prism and make a battery mount instead.

My Question: What is the Voltage needed on the FW cable to power the Back ( Voltage and Watts)

[rolad]

FW voltage definitions do indeed apparently specify a range of 8-33V with the device being responsible to regulate as needed.

i measured 8.6V on a original LiIon battery grip fully charged and 9.5V on the CR123a grip.
as the std batteries deliver within range of FW spec they ll be ok - yet you could use higher V via FW - like the commercial FW power battery mentioned.

i would personally go for a min. of 1,850 mAh - as stated in the battery specs for the digital capture unit (H3DII manual pg 123) - and not having to change that often.

[ced]

John that is okay for an emergency to save the day but not a lot of juice to keep working under pressure...