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Old Jan 14, 2006, 9:05 AM   #1
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I was thinking about my sony hvl 32x flash, and it is a 6v battery. (well 4 aa totall) and I thought why not make a custom battery pack, something that you wear on your hip that would recharge instantly (like any high end flash would have available)

My question is how many miliamps is necessary, and what is the may rating you can get?

Maybe even an explanation on how it all relates to speed or recharging (for next flash picture) etc??



thanks for your time
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Old Jan 14, 2006, 10:56 AM   #2
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mA is is unit of current. (or actually 1/1000th of it)
For flash to give certain output it draws certain amount of electrical charge which is measured in mAh. (current multiplied by time)
So if that same charge is needed to transfer faster current must be bigger.

So for faster recharging NiMHs (and other rechargeables) would be better because they can output much higher current than any alkalines.
But if flash doesn't have connector for external batteryback it's propably itself capable to drawing only certain amount of current and big high capacity external batteries wouldn't make it any faster than using NiMHs and for faster recharging best solution would be better flash. (small cheap flashes are generally slower)
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Old Jan 14, 2006, 11:37 AM   #3
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Hello Dashboardgyno,

To design a battery pack for your flash, you need to know the voltage it should run at, the current demand, and how many flashes you can reasonably expect before recharging.

You have indicated your system runs on 6 volts. The current is measured in milliamperes or amps. The number of flashes you can expect is related to the capacity of the battery and is given in milliamp hours, or amp hours.

I would lean toward taking what you already have and looking for an improvement. Some batteries are capable of delivering lots of current while maintaining a higher voltage. Other batteries offer high capacity, but can not sustain high current rates while maintaining a descent voltage level.

You probably can not do much with the voltage. The flash circuit is probably not capable of higher voltages, so you have to work within the 6 volt range.

If your current batteries are high current/low capacity, you can get more flashes by changing to higher capacity batteries. That is batteries with higher mAh results from testing. Please note that the mAh rating on the label may not reflect the cells actual capacity. There seems to be some inflation of capacity numbers these days...

If your current batteries are high capacity, you may be able to improve the recharge time of the flash by changing to high current batteries.

By going to an external battery pack, you can get the best of both worlds by configuring it with high current cells and by using many of them you can also get high capacity.

Clear as mud?

Tom
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Old Jan 14, 2006, 10:07 PM   #4
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would we have any idea what an alkaline battery (not rechargeable) would rank in mA?

Currently that is what I use for my flash. At first the recharge isn't long... but after a bit it does slow down, I am not sure how many flashes I would actually get but... The alkalines were cheap that is why I did it..... the whole reason my question arises, is because I got a flash bracket on Friday, and during my testing (learning and playing I found the flash to be very dim, which made me think the bracket had changd the output somehow. Then I came back to life, and realized that the batteries must have been old, and all was well....

Would Sony be able to provide any insight on current draw for their flash?



thanks for the feedback so far!
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Old Jan 15, 2006, 5:12 AM   #5
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dashboardgyno wrote:
Quote:
would we have any idea what an alkaline battery (not rechargeable) would rank in mA?

Currently that is what I use for my flash.* At first the recharge isn't long... but after a bit it does slow down
In milliamperes or in amperes (current) any alkalines rank extremely inferiorly, no matter what super hyper ultra make they are.
Their capacity (mAh) is only worth in low constant current situation but big current (like what digicams and flashes draw), regardless about fact that it's drawn only short continuous time at once, crashes down their voltages and draws them empty very fast.
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