20D Grip Power Problems

Started Nov 11, 2004 | Discussions thread
Heng
Regular MemberPosts: 107
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See my measurements for my 20D
In reply to John, Nov 11, 2004

John wrote:

I tried a friends BG-E2 grip today and it seemed to use up both
batteries in less than 175 shots. When I put the batteries on
charge they seemed to be down to 25% by the blinking lights. Both
batteries were fully charged to begin with. When I put the single
battery back in the camera alone I got about 600 shots out of it.
Is there a problem with the 20D grip? I never had any problem like
this with my 10D add-on grip that seemed to be the same design
concept.

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I think this may be a design problem for using 2 BP511(A)s in the grip. In order to protect a short from one of them, a logic circuit (diodes) should be used to allow one-direction only current flows. The use of these diodes will further reduce the usable voltage of the BP511As in the grip. Thus, with just one BP511 in the camera (without the grip), you can take more than 1000 pictures. but with two BP511s in the grip, you can only take several hundred pictures.

I had done certain measurements with a lab power supply on my 20D. The following were the results:

1. A fully charged BP511(A) has a nonimal voltage of 8.4V.

2. The maximum current that a 20D with 80-200 f2.8L, 1 GB Sandisk CF card, shooting randomly and continuoulsy with Jpeg Large is over 1.1 amperes.

3. The 20D will not work when the lab power supply(PSU) is set to 7.3V and it will start working above 7.4V. With 7.4V supply and current limiting disabled, I encountered numerous lock-ups showing battery empty and one Err99 when shooting with conditions as in (2) above. Increasing the voltage above 7.5V or shutting down the 20D will not relief the lock-up. I had to switch off the PSU to reset the camera. The camera works normal again with 7.4V.

4. The camera works fine for voltages above 7.6V when shooting with conditions as in (2).

5. With a battery pack of 6 x fully charged AA 1500mah NiMH batteries (8.4V), lock-up occured just about 20-30 shots as in (2)( at this time the voltage had been instantaneously below 7.4V). But if shooting were halted after 10 shots, the same pack would work more than 100 shots.

6. With a battery pack of 6 x new AA Alkaline cells (9.8V), the camera would lock-up after 10-15 shots. Reset the camera and I could shoot another 10-15 shots for several runs.

My suspicion is that the NP-3E(12V) cell used in D1 Mk II would be more suitable for the 20D. In this case, I don't think the lock-up problem will ever exist.

But Canon wants the camera to be smaller and thus BP511A are being used and thus the lock-up problems. Furthermore, Canon likes us to buy the grip to get more money.

However, using 2 x BP511 with protection will reduce the shooting capability of the grip.

Would like you guys' opinions.

Heng

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