Battery problem in EOS 5D grip - similar experiences?

On Sun, 06 Aug 2006 18:27:04 GMT, John Fryatt wrote:

> Actually, all the above made me think, and I tested both batteries in
> the grip but not attached to camera. The possibly-duff battery read
> 7.73V and the good one reads 8.16V. So, the grip itself seems to cause a
> voltage drop of about 0.3V. I guess maybe that's enough to cause the
> different readings on the battery state thingy.
> Same question though, really, any idea why the grip causes that voltage
> drop?

That 0.3 volts is pretty much the voltage drop across one silicon
semiconductor when it conducts more than a very small current.
Sometimes a diode will be used to provide protection in case
batteries are installed backwards. I'm not familiar with your
BP-511A batteries, but assume that it would be impossible to insert
them in the grip the wrong way. This leaves the possibility that
the BG-E4 is similar to Canon grips for other cameras in that it
also allows AA batteries to be used. If the grip was not designed
carefully, it could allow improperly inserted AA batteries to supply
a camera-damaging voltage to the 5D, which a single diode would
prevent. The camera wouldn't operate, but it wouldn't fry.
 >> Stay informed about: Battery problem in EOS 5D grip - similar experiences? 

ASAAR wrote:
> On Sun, 06 Aug 2006 18:27:04 GMT, John Fryatt wrote:
>
>> Actually, all the above made me think, and I tested both batteries in
>> the grip but not attached to camera. The possibly-duff battery read
>> 7.73V and the good one reads 8.16V. So, the grip itself seems to cause a
>> voltage drop of about 0.3V. I guess maybe that's enough to cause the
>> different readings on the battery state thingy.
>> Same question though, really, any idea why the grip causes that voltage
>> drop?
>
> That 0.3 volts is pretty much the voltage drop across one silicon
> semiconductor when it conducts more than a very small current.
> Sometimes a diode will be used to provide protection in case
> batteries are installed backwards. I'm not familiar with your
> BP-511A batteries, but assume that it would be impossible to insert
> them in the grip the wrong way. This leaves the possibility that
> the BG-E4 is similar to Canon grips for other cameras in that it
> also allows AA batteries to be used. If the grip was not designed
> carefully, it could allow improperly inserted AA batteries to supply
> a camera-damaging voltage to the 5D, which a single diode would
> prevent. The camera wouldn't operate, but it wouldn't fry.
>

Aaah... The grip does allow for AA cells. So, that means that a battery
which is marginal, in terms of charge status, will drop below the
threshold when in the grip. Makes sense.

Thanks for the advice.
 >> Stay informed about: Battery problem in EOS 5D grip - similar experiences? 

On Sun, 06 Aug 2006 15:50:50 -0400, ASAAR <caught RemoveThis @22.com> wrote:

>On Sun, 06 Aug 2006 18:27:04 GMT, John Fryatt wrote:
>
>> Actually, all the above made me think, and I tested both batteries in
>> the grip but not attached to camera. The possibly-duff battery read
>> 7.73V and the good one reads 8.16V. So, the grip itself seems to cause a
>> voltage drop of about 0.3V. I guess maybe that's enough to cause the
>> different readings on the battery state thingy.
>> Same question though, really, any idea why the grip causes that voltage
>> drop?
>
> That 0.3 volts is pretty much the voltage drop across one silicon
>semiconductor when it conducts more than a very small current.
>Sometimes a diode will be used to provide protection in case
>batteries are installed backwards. I'm not familiar with your
>BP-511A batteries, but assume that it would be impossible to insert
>them in the grip the wrong way. This leaves the possibility that
>the BG-E4 is similar to Canon grips for other cameras in that it
>also allows AA batteries to be used. If the grip was not designed
>carefully, it could allow improperly inserted AA batteries to supply
>a camera-damaging voltage to the 5D, which a single diode would
>prevent. The camera wouldn't operate, but it wouldn't fry.

Actually I would suspect & hope that there are 2 diodes in the
grip, 1 in series with each battery. These would be called isolation
diodes because they isolate each battery from the other.

Without isolation diodes, replacing just 1 drained battery
with a freshly charged 1 would cause that battery to try to equalize
(charge) the drained battery as well as attempt to power the camera.
This could be bad for both batteries because the fully charged 1 might
be damaged by trying to supply too much power too quickly & the
depleted battery might be damaged by being charged too quickly.
Additionally if 1 battery shorted out that would result in a massive
load being sensed by the other.

Never tested either of my battery grips to determine if they
use isolation diodes (300D & 30D) battery grips but either way I think
it's wise to try to use batteries in matched pairs so they are more
likely to perform longer & have a longer useful life span.

I don't always need the added power of having 2 batteries in
the grips but I like the added heft of the grip with 2 batteries to
counterbalance certain lenses.

A dab of color paint on the end of each battery makes it easy
for me to keep them paired up. This all may be overkill on my part
but it's very little added effort & thus far it's worked out just fine
for me. It's something others may wish to consider.

Now you have gone & made me curious to know if my battery
drips use isolation diodes in them or not so I may have to get out my
multi-meter & test for them. I suppose it's also possible that said
isolation diode could be built into the battery pack itself with a
charge circuit bypass too. When 1 of my batteries fails, I will have
to open it & see what if anything is inside it other than the
batteries.

Just my long winded 2 cents worth!

Respectfully, DHB
"To announce that there must be no criticism of the President,
or that we are to stand by the President, right or wrong,
is not only unpatriotic and servile, but is morally treasonable
to the American public."--Theodore Roosevelt, May 7, 1918
 >> Stay informed about: Battery problem in EOS 5D grip - similar experiences? 

On Mon, 07 Aug 2006 02:00:48 GMT, DHB wrote:

> Actually I would suspect & hope that there are 2 diodes in the
> grip, 1 in series with each battery. These would be called isolation
> diodes because they isolate each battery from the other.
>
> Without isolation diodes, replacing just 1 drained battery
> with a freshly charged 1 would cause that battery to try to equalize
> (charge) the drained battery as well as attempt to power the camera.
> This could be bad for both batteries because the fully charged 1 might
> be damaged by trying to supply too much power too quickly & the
> depleted battery might be damaged by being charged too quickly.
> Additionally if 1 battery shorted out that would result in a massive
> load being sensed by the other.

> Now you have gone & made me curious to know if my battery
> drips use isolation diodes in them or not so I may have to get out my
> multi-meter & test for them. I suppose it's also possible that said
> isolation diode could be built into the battery pack itself with a
> charge circuit bypass too. When 1 of my batteries fails, I will have
> to open it & see what if anything is inside it other than the
> batteries.

What you said in the top two para's. makes too much sense for you
to need to test it. Trust the Force, Luke! I doubt that isolation
diodes are in the battery packs, since the OP have probably would
have had the same problem with the defective battery, whether it was
used in the grip or in the camera, and its measured voltage
differed, depending on whether the readings were taken in or out of
the grip. From this, I'd assume that if someone is using a battery
grip in the field with no spares and runs out of power, the camera
might be able to limp along for at least several dozen more shots if
the batteries are removed from the grip and placed in the camera.
That might be worth testing. I'd certainly be foolish enough to do
so if I had a battery grip.
 >> Stay informed about: Battery problem in EOS 5D grip - similar experiences? 

John Fryatt wrote:
> Hi,
>
> I have a Canon EOS 5D and battery grip BG-E4.

There was a problem like this with the BG-E2 grip for the 20D/30D. Canon
offered a free repair. Perhaps the same problem is present in the BG-E4.
 >> Stay informed about: Battery problem in EOS 5D grip - similar experiences? 

SMS wrote:
> John Fryatt wrote:
>> Hi,
>>
>> I have a Canon EOS 5D and battery grip BG-E4.
>
> There was a problem like this with the BG-E2 grip for the 20D/30D. Canon
> offered a free repair. Perhaps the same problem is present in the BG-E4.

Hmmm. Possibly. I'll see what Canon support say.

However, the other reply suggesting a diode (and hence 0.3V drop) to
protect against incorrectly loaded AA batteries seems to make sense.
 >> Stay informed about: Battery problem in EOS 5D grip - similar experiences? 

Canon support replied. Sadly they are much like many support departments
and don't really address the issue you raise thoroughly.
They say that my symptoms suggest that one battery if developing a
fault, which seems to make sense, but they completely ignored my
question about differing status readouts when the battery was in the
camera or in the grip.
Fortunately ASAAR suggested what the answer most probably is for that
issue. Thanks for that.
Just to finish off the subject, for the benefit of futre Googlers
perhaps, I found this...

During my messign around with the batteries and a voltmeter, trying to
understand what was happening, I reloaded the battery into the charger.
The LED came on solid almost immediately, seeming to confirm my theroy
that the battery was faulty and could not hold full charge. (i.e. the
charger saw it as full but it's capacity had diminished).
FOr some reason, I removed the battery and then put it back in the
charger almost stright away (within 20-30 seconds) and this time the LED
cameon blinking, and stayed that way for some time. It now seemed that
the charger could tell that the battery was not fully charged, and was
putting some more in. At the end of the charge cycle it now reads full
on the camera status indicator and also measures full voltage.
I used the battery yesterday for a day out shooting and it worked fine.
So... the end result is that I learned a couple of things, but don't
know why that battery played up that way.

John
 >> Stay informed about: Battery problem in EOS 5D grip - similar experiences?