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dkirk

Vivitar 2000 (DF500 board) Energy Study

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Here is some slave flash energy consumption numbers for those of you that wear pocket protectors.

 

I've wanted to measure the total amount of energy that is used to charge slave flash units in order to better estimate battery life, and finally put together some hardware to make the measurements.

 

Here are some initial data points, and will probably provide more data and a model at a later time for estimating battery life (it gets complicated due to many different factors).

 

Energy required to charge a Vivitar 2000 (DF500 board version, fully modified, 0.57 ohm series resistance)

0 to 274 volt charge, 30 second charge time = 80.5 Joules (typical of charging totally discharged unit)

61 to 279 volt charge, 30 second charge time = 66.0 Joules (typical of charging slave after firing it)

60-213 volt charge, 10 second charge time = 43.4 Joules

211-260 volt charge, 10 second charge time = 16.1 Joules

258-286 volt charge, 10 second charge time = 15.4 Joules

 

Total energy available from a four pack of 2100 mAh batteries (assuming no self discharge and an average terminal voltage of 1.2 volts per cell)

(2.1 Ah)(4.8 V)(3600seconds/hr) = 36288 watt-seconds = 36288 Joules

 

Notes:

1) I estimated the wasted energy in the 0.57 ohm series resistance, and came up with the worst case number of 5.7% which happens when we charge for 30 seconds from a totally discharged unit (average current during this 30 second charge time was 0.516 amps). The amount wasted in the series resistance charging from 258 volts to 286 volts is more along the lines of 1.0%. The energy numbers shown above are total system energy, so they include the amount wasted in the series resistor.

2) I used a 0.1 ohm series "shunt" resistor for my energy montioring hardware, and also used a 0.47ohm series resistor to limit the peak current. This is why the total resistance was 0.57 ohms in the above data.

3) The resistors used were not wirewound.

4) The above tests were done using energizer AA 2100 mAh batteries, and the open circuit voltage was 5.2 Vdc.

5) The above data is just from one unit, so it's just a sampling to show approximate energy consumption.

6) The Vivitar 2000 under test was a DF500 board version with the DF501 board removed, and the low power mods implemented (all debounce circuits disabled).

 

Sorry to bore most of you with this info (as usual).

 

Don

Edited by dkirk

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Here is some some slave flash energy consumption numbers for those of you that wear pocket protectors.

 

I've wanted to measure the total amount of energy that is used to charge slave flash units in order to better estimate battery life, and finally put together some hardware to make the measurements.

 

Here are some initial data points, and will probably provide more data and a model at a later time for estimating battery life (it gets complicated due to many different factors).

 

Energy required to charge a Vivitar 2000 (DF500 board version, fully modified, 0.57 ohm series resistance)

0 to 274 volt charge, 30 second charge time = 80.5 Joules (typical of charging totally discharged unit)

61 to 279 volt charge, 30 second charge time = 66.0 Joules (typical of charging slave after firing it)

60-213 volt charge, 10 second charge time = 43.4 Joules

211-260 volt charge, 10 second charge time = 16.1 Joules

258-286 volt charge, 10 second charge time = 15.4 Joules

 

Total energy available from a four pack of 2100 mAh batteries (assuming no self discharge and an average terminal voltage of 1.2 volts per cell)

(2.1 Ah)(4.8 V)(3600seconds/hr) = 36288 watt-seconds = 36288 Joules

 

Notes:

1) I estimated the wasted energy in the 0.57 ohm series resistance, and came up with the worst case number of 5.7% which happens when we charge for 30 seconds from a totally discharged unit (average current during this 30 second charge time was 0.516 amps). The amount wasted in the series resistance charging from 258 volts to 286 volts is more along the lines of 1.0%. The energy numbers shown above are total system energy, so they include the amount wasted in the series resistor.

2) I used a 0.1 ohm series "shunt" resistor for my energy montioring hardware, and also used a 0.47ohm series resistor to limit the peak current. This is why the total resistance was 0.57 ohms in the above data.

3) The resistors used were not wirewound.

4) The above tests were done using energizer AA 2100 mAh batteries, and the open circuit voltage was 5.2 Vdc.

5) The above data is just from one unit, so it's just a sampling to show approximate energy consumption.

6) The Vivitar 2000 under test was a DF500 board version with the DF501 board removed, and the low power mods implemented (all debounce circuits disabled).

 

Sorry to bore most of you with this info (as usual).

 

Don

 

 

WOW great work Don, now if it only was in english and not chinese... :P:P:P

 

You have been a great asset to Hags house Don you da man!!!!

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Don,

 

If I am Understanding you correctly then on average that would compute to approx a lil over 500 flashes with the 2100's, But then again that would be total discharge of the 2100 batteries available Joules which would certainly not be possible as well as no natural bleedoff.

 

What did you find the cutoff point to be for the batteries ability to perform? in both voltage and flash count.

 

Also I wonder if it was a continous use test or realistic say 30 flashes per nite test factored over time, where the drawdown would be less significant than say continous use.

 

Great work on the findings, stuff like this really gives great Insite as to longevity people can expect on there setups.

 

Thanks alot

 

Dan

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Dan,

 

My numbers are just energy to charge, and they are all just done on the bench top today.

 

One of the data points I listed was the energy used to top off the flash unit (from 256 volts back up to 286 volts), and this takes 15.4 joules (trying to look at what it takes when we refresh the flash due to the capacitor leakage current). This is the kind of information that will help us build a battery life model.

 

Much more work to do, but wanted to let you guys know what I am working on long term.

 

Can also do the same thing on cameras (amount of energy consumed from turn on to turn off, energy consumed per picture taken at day and at night, etc.).

 

I am going to be doing a lot of travel for the next month, so this project will take a back seat for a little while.

 

Don

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