# Using Canon Battery Pack in Speedlite Flashes



## carlviens77 (Feb 19, 2011)

I was replacing AA batteries in my speedlite at the same time I was replacing LP-E6 battery pack in my 7D. And for the X time, I was wondering if it would be technically possible to make new speedlite flashes to use Canon battery packs. Physically, I think it would fit in size.

For power, 7.2v 1800mAh pack versus 6x1.2v 2500mhA rechargeable AA's, would that be enough? Replacing one single pack instead of 2x AA's heads up and 2x AA's heads down is much, much faster. I was recently using a Marshall monitor and it was also sing LP-E6 battery packs. So I thought that it would be convenient to use the same battery pack in everything.

What do you think? Would it be technically possible? Would it be relevent for you?


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## bvukich (Feb 19, 2011)

So you want to replace $10 worth of rechargeable batteries, with a $65 battery that has less capacity?


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## Flake (Feb 19, 2011)

Sheesh !! Don't put that idea in Canons head!! LP-E6 batteries are over Â£50 each a set of four rechargeable AAs are about Â£5 and if they run out & you don't have spares with you most local shops have them. This is why battery grips come with a AA battery tray, for emergencies.

If you want more power companies like Yongnuo or PXL make lookie likie versions of the CP-E4 battery pack which hold 8AAs in addition to the 4 in the flash, and cut recharge times in half, plus giving twice the capacity. Because they have the Hi voltage built in they deliver the power direct to the flash head. 

(Now I wonder if pocket wizzard have thought of trying that out!)


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## Admin US West (Feb 19, 2011)

The reason the Li-on battery packs are not advisable for use in a flash is the high rate of discharge required to recharge a flash unit after firing it. Li-on is great for low current applications, but not for high current. 

1. The effective usable capacity would be lower before the cells electronics shut it down

2. The battery would age very quickly and die much sooner.

A battery pack designed for high current by placing several li-on batteries in parallel couldwork, but thats a whole different design.



Here is a little more of the technical discussion quoted from wikipedia.

Internal resistanceThe internal resistance of standard (Cobalt) lithium-ion batteries is high compared to both other rechargeable chemistries such as nickel-metal hydride and nickel-cadmium, and LiFePO4 and lithium-polymer cells

Internal resistance increases with both cycling and age. Rising internal resistance causes the voltage at the terminals to drop under load, which reduces the maximum current draw. Eventually increasing resistance means that the battery can no longer operate for an adequate period.


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## 1D Guy (Mar 23, 2011)

The reason for using the battery pack is so the flash recycles faster, so why would you want to eliminate using it?


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## 7enderbender (Mar 23, 2011)

I wouldn't like that. I like the idea that in a pinch I can put in AA batteries pretty much anywhere in the world. That was one of the reasons I bought the original Canon grip for my 5DII that comes with the AA tray. If I ever forget to leave the house/hotel without charged LP E6 packs or they fail on me I can always go to the next gas station and buy batteries.

I wouldn't mind, however, if they came out with a similar interchangeable design for their speedlights where you could stick in a designated power pack or a little cage with AA batteries. Think Metz 45 series. For those I always have a loaded second battery cage with me and you don't have to sit there with a flash light trying to figure out which of the 6 batteries go up and which go down.


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## zalmagor (Mar 23, 2011)

7enderbender said:


> I wouldn't like that. I like the idea that in a pinch I can put in AA batteries pretty much anywhere in the world. That was one of the reasons I bought the original Canon grip for my 5DII that comes with the AA tray. If I ever forget to leave the house/hotel without charged LP E6 packs or they fail on me I can always go to the next gas station and buy batteries.



I bought a grip for the 450D for the same reason. When I upgraded to the 5Dmk2, I opted for the cheaper & lighter options of buying 2 extra LP-E6 batteries, and keep them in my camera bag.


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## prestonpalmer (Mar 23, 2011)

I just use AA Lithiums in my 580's They will last for 3 camera batteries or more. I generally change them every OTHER wedding.


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