Canon BP-511 battery: specifications?

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Henry Law - 03 Jan 2005 13:12 GMT

Does anyone know what the specifications are for the Canon BP-511
battery that's used in the EOS 300D (Rebel) and - I believe - in some
others? I know the voltage but what about the current requirements?

And what are the "B" and "D" contacts on the case for? There's no
voltage across them but there is between "B" and the "+" terminal: but
about 0.6v less than the main voltage, which sounds like a diode drop.

The Canon AC Adapter is £50 in the UK, and I'm wondering if buying a
dead cheap BP-511 from eBay and using it as the in-camera end of a
home-made adapter, with a decent stabilised power supply, would be a
cheaper option. I Googled for anyone doing the same without any hits.

Signature

Henry Law <>< Manchester, England

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bin-slash - 03 Jan 2005 15:44 GMT

>Does anyone know what the specifications are for the Canon BP-511
>battery that's used in the EOS 300D (Rebel) and - I believe - in some
[quoted text clipped - 8 lines]
>home-made adapter, with a decent stabilised power supply, would be a
>cheaper option. I Googled for anyone doing the same without any hits.

----------------------------------------

B = 97k - 101k ohm
D = 73.5k - 76.5k ohm

B is essentially useless and more likely a legacy connector.

D is probably a thermistor based on its values

The rest of the details on the BP-511 battery:
7.4vdc @ 1100mah

I currently own an OEM BP-511 and a import (ebay) BP-511 rated at
1500mah. Even though the 3rd party BP-511 is rated at 7.2vdc, it works
fine and the .2 vold difference is within the OEM voltage high/low
spec.

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Henry Law - 03 Jan 2005 17:04 GMT

>B = 97k - 101k ohm
>D = 73.5k - 76.5k ohm

Thanks, but I don't understand: these resistance measurements are
between the named terminal and where?

>B is essentially useless and more likely a legacy connector.

Interesting; I know that this format of battery is in pretty wide use
for digicams and such. Maybe they use it for something.

>D is probably a thermistor based on its values

Used for what, would you say? Is it maybe associated with the
flashing lights on the charger? Or maybe an over-temperature cutout?

>The rest of the details on the BP-511 battery:
>7.4vdc @ 1100mah

Mmmm, yes. But that could be 1.1A for an hour or 1.1mA for 1000
hours. What I need is the maximum, though - I've read that it could
be up to 1Amp when the flash is charging.

>I currently own an OEM BP-511 and a import (ebay) BP-511 rated at
>1500mah. Even though the 3rd party BP-511 is rated at 7.2vdc, it works
>fine and the .2 vold difference is within the OEM voltage high/low
>spec.

Good to know; I'm planning to buy a third-party battery: the Canon
ones are UKP50! (USD90-ish these days)

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Henry Law <>< Manchester, England

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Nigel Clark - 03 Jan 2005 20:24 GMT

>>I currently own an OEM BP-511 and a import (ebay) BP-511 rated at
>>1500mah. Even though the 3rd party BP-511 is rated at 7.2vdc, it works
[quoted text clipped - 3 lines]
>Good to know; I'm planning to buy a third-party battery: the Canon
>ones are UKP50! (USD90-ish these days)

Try 7dayshop.co.uk, I've been using a couple of 3rd party batteries
from there for the last 12-18 months with no noticably difference over
the original Canon item. They're recently brought the price down even
more to GBP 9.99

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bin-slash - 03 Jan 2005 20:39 GMT

>>B = 97k - 101k ohm
>>D = 73.5k - 76.5k ohm
>
>Thanks, but I don't understand: these resistance measurements are
>between the named terminal and where?

Those were internal (schematic) ratings.

>>B is essentially useless and more likely a legacy connector.
>
>Interesting; I know that this format of battery is in pretty wide use
>for digicams and such. Maybe they use it for something.

More likely the situation. It gives manufacturers the option for
future designs additions without having to "re-invent-the-wheel"

>>D is probably a thermistor based on its values
>
>Used for what, would you say? Is it maybe associated with the
>flashing lights on the charger? Or maybe an over-temperature cutout?

Could be all the above and more.

>>The rest of the details on the BP-511 battery:
>>7.4vdc @ 1100mah
>
>Mmmm, yes. But that could be 1.1A for an hour or 1.1mA for 1000
>hours. What I need is the maximum, though - I've read that it could
>be up to 1Amp when the flash is charging.

As you know, battery life is related its given load. The load on the
battery can easily be measured with a ammeter across its negative
lead.

If I had to make an educated guess, I would say max load is at shutter
lift then tapers off from there (unless internal flash is used). Even
still, I can't see peak (spike) load going over 0.6amp. The natural
impedence (high) of this battery will easily absorb any and all
spikes.

>Good to know; I'm planning to buy a third-party battery: the Canon
>ones are UKP50! (USD90-ish these days)

The only thing you don't want to do is, if you use a battery grip
(that uses 2 or more batteries), DO NOT mix batteries. Not even old
OEM's with newer OEM...Certainly not from different companies. A
weaker or older battery will always pull down the better battery!!

-Just another bloke born & from the U.S.A ;-)

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MarkH - 03 Jan 2005 23:06 GMT

> The only thing you don't want to do is, if you use a battery grip
> (that uses 2 or more batteries), DO NOT mix batteries. Not even old
> OEM's with newer OEM...Certainly not from different companies. A
> weaker or older battery will always pull down the better battery!!

So where did you get this information from? Which battery grip is this
information specific to?

I have the 10D with BG-ED3, I have read that it draws current from one
battery or the other, whichever has the higher voltage (IIRC). I certainly
have had no problems in using 2 OEM batteries together which are different
ages. Of course my 2 Power 2000 1500mAh batteries run longer as you would
expect.

I am not so sure that any of Canon's battery grips use a straight parallel
connection between the 2 batteries to double the capacity.

Signature

Mark Heyes (New Zealand)
See my pics at www.gigatech.co.nz (last updated 12-Nov-04)
"There are 10 types of people, those that
understand binary and those that don't"

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Skip M - 04 Jan 2005 13:42 GMT

>> The only thing you don't want to do is, if you use a battery grip
>> (that uses 2 or more batteries), DO NOT mix batteries. Not even old
[quoted text clipped - 13 lines]
> I am not so sure that any of Canon's battery grips use a straight parallel
> connection between the 2 batteries to double the capacity.

I certainly haven't had any problems using my BG-E2/20D with a BP-511 and
BP-511A combination.

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Skip Middleton
http://www.shadowcatcherimagery.com

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bin-slash - 04 Jan 2005 18:05 GMT

>> The only thing you don't want to do is, if you use a battery grip
>> (that uses 2 or more batteries), DO NOT mix batteries. Not even old
[quoted text clipped - 12 lines]
>I am not so sure that any of Canon's battery grips use a straight parallel
>connection between the 2 batteries to double the capacity.

I never said they will not work. I'm speaking from an ideal
standpoint. Just because 2 different batteries work doesn't mean its
at their potential.

Batteries are essentially capacitors with its given impedence (high).
If the 2 batteries are from same source....different age...but both
are equally healthy...the 2 batteries will work at or near their
efficiency (> 90%).

None of this is battery grip specific. Its battery specific ;)

These battery grips are wired in parallel so the output voltage remain
constant dc (7.4). I seriously doubt that any of the "grips" alternate
its power from one battery to another. Doing it this way is far less
efficient than having them in parallel so both contribute to the vdc
output.

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MarkH - 05 Jan 2005 08:24 GMT

> These battery grips are wired in parallel so the output voltage remain
> constant dc (7.4). I seriously doubt that any of the "grips" alternate
> its power from one battery to another. Doing it this way is far less
> efficient than having them in parallel so both contribute to the vdc
> output.

You may be correct and I may be failing to remember correctly what I have
read.

However what you say is contrary to what I recall reading about the BG-ED3.

I also do not believe that there is any need to share the amp load between
2 batteries, my 10D worked fine before the battery grip with just one
battery.

Also there is the point you made about problems with 2 different batteries,
which would explain why Canon might design the grip to alternate between
the 2 batteries rather than a straight parallel link.

It sounds like you are only basing what you say on an assumption that the
batteries are linked in parallel, which is not what I have read.

Signature

Mark Heyes (New Zealand)
See my pics at www.gigatech.co.nz (last updated 12-Nov-04)
"There are 10 types of people, those that
understand binary and those that don't"

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Lionel - 05 Jan 2005 18:48 GMT

>I also do not believe that there is any need to share the amp load between
>2 batteries, my 10D worked fine before the battery grip with just one
>battery.

That's correct. Only a very incompetant electronics engineer would wire
multiple batteries directly in parallel. If they did, even the slightest
difference in charge levels or manufacturing tolerances between
battery-packs would harm the batteries, & possibly the grip. The
batteries will isolated from each other by diodes, at the very least.
The nett effect of this is that the camera will be running from
whichever battery has the highest terminal voltage at the time, so I
would expect the batteries to run down at aroun the same speed.

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W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------

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MarkH - 05 Jan 2005 22:45 GMT

>>I also do not believe that there is any need to share the amp load
>>between 2 batteries, my 10D worked fine before the battery grip with
[quoted text clipped - 8 lines]
> whichever battery has the highest terminal voltage at the time, so I
> would expect the batteries to run down at aroun the same speed.

That would agree with what I read about how the BG-ED3 works. I can't
remember exactly where I read it, but I think it might have been something
that Chuck Westfall said on a forum.

Signature

Mark Heyes (New Zealand)
See my pics at www.gigatech.co.nz (last updated 12-Nov-04)
"There are 10 types of people, those that
understand binary and those that don't"

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jean - 04 Jan 2005 03:56 GMT

> >Does anyone know what the specifications are for the Canon BP-511
> >battery that's used in the EOS 300D (Rebel) and - I believe - in some
[quoted text clipped - 16 lines]
>
> D is probably a thermistor based on its values

The batteries are somewhat more complex than that, there are a couple of ICs
and misc parts on a small circuit board. I had one go bad when it was
dunked in water. The battery being charged made a mess of the circuits and
even popped the plastic case open, that is how I peeked inside.

Jean

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Lionel - 04 Jan 2005 07:02 GMT

>Does anyone know what the specifications are for the Canon BP-511
>battery that's used in the EOS 300D (Rebel) and - I believe - in some
>others? I know the voltage but what about the current requirements?

1 Amp should be fine. You might want to put a big electro in the dummy
battery case to deal with transients, but I doubt it'd be necessary.

>And what are the "B" and "D" contacts on the case for? There's no
>voltage across them but there is between "B" and the "+" terminal: but
>about 0.6v less than the main voltage, which sounds like a diode drop.

That sounds reasonable. It's common practice to use a small-signal
silicon diode as a cheap temperature sensor. It's also possible (but
much less likely) that it's for reverse polarity protection.

>The Canon AC Adapter is £50 in the UK, and I'm wondering if buying a
>dead cheap BP-511 from eBay and using it as the in-camera end of a
>home-made adapter, with a decent stabilised power supply, would be a
>cheaper option. I Googled for anyone doing the same without any hits.

A generic 7.2V supply & a dead, gutted BP-511 would probably be a cheap
& effective option. I doubt very much that the camera uses anything but
the + & - terminals.
(I've got a couple of dead BP-511 clones, so I've considered making one
of these adapters for my 10D, but I haven't got any pressing need for
one, so I haven't bothered yet.)

Signature

W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------

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S Lee - 04 Jan 2005 13:21 GMT

Lionel <nop@alt.net> choreographed a chorus line of high-kicking electrons
to spell out:

>>The Canon AC Adapter is ?50 in the UK, and I'm wondering if buying a
>>dead cheap BP-511 from eBay and using it as the in-camera end of a
[quoted text clipped - 7 lines]
> of these adapters for my 10D, but I haven't got any pressing need for
> one, so I haven't bothered yet.)

For reference, my EOS AC adapter here has just the +, -, and D
terminals only... though my plan would have been to use the dummy battery
as a pass-through for a body-mounted battery pack--better for cold days.

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__)|| | |(_)| \ "...and then, the squirrels attacked."

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