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BP-21 vs BP-22... what?!?

Started Dec 3, 2013 | Discussions
Don Strimbu
Don Strimbu Regular Member • Posts: 467
BP-21 vs BP-22... what?!?

Just received my SD1M and noticed that a BP-22 battery (and BC-22 charger) shipped with the camera. (The camera is gorgeous, by the way... can't wait to get some shots on it!)

Looking at my SD-15's battery vs the battery that shipped with the SD1M:

SD15 == BP-21 - 7.4v, 1500mAh, 12Wh

SD1M == BP-22 - 7.4v, 1200mAh, 8.9Wh

Same size, same weight... same chemistry?  Seems like it, but I have to ask: Is this a giant step backwards?  Or was the BP-21 "overrated" in terms of capacity?

I am assuming that the BP-21 is the battery of choice for any Sigma DSLR at this point... but I could be incorrect.

Your comments welcomed.

-Don

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Don Strimbu | Marin County, CA USA
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Sigma SD1
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mike earussi Veteran Member • Posts: 9,440
Re: BP-21 vs BP-22... what?!?

Don't know anything about a BP-22 but I've used plenty of my SD15 BP-21s in the SD1M without problems.

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xpatUSA
xpatUSA Forum Pro • Posts: 23,016
Re: BP-21 vs BP-22... what?!?

Assuming that the contacts are also the same and of the same polarity, there is a missing parameter in the comparison. That would be the time period for which the capacity is stated. Like vehicle batteries, e.g. 47Ah at the 20-hour rate.

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"For every opinion, there is an equal and opposite"
Ted
SD9, SD10, GH1 and a lens or two

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Don Strimbu
OP Don Strimbu Regular Member • Posts: 467
Re: BP-21 vs BP-22... what?!?

Thanks for the reassure, Mike.  Figured that, since the voltage is the same, it would be fine but it's good to hear from a user.  Still a bit distressed by the reduction in battery capacity, though.  I think I'm gonna hold onto my BP-21s...

If I get rambunctious, I'll do a battery life comparison...

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Don Strimbu | Marin County, CA USA
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Don Strimbu
OP Don Strimbu Regular Member • Posts: 467
Re: BP-21 vs BP-22... what?!?

Thanks, Ted.  The hour rating isn't on the battery pack - at least not in English.

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Don Strimbu | Marin County, CA USA
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SigmaChrome Forum Pro • Posts: 15,728
Re: BP-21 vs BP-22... what?!?

Hi Don.

I use my BP-21 and BP-22 interchangeably with the SD15 and SD1M without any problems.

And, yes, you will love the SD1M once you get to know it.

Don Strimbu wrote:

Just received my SD1M and noticed that a BP-22 battery (and BC-22 charger) shipped with the camera. (The camera is gorgeous, by the way... can't wait to get some shots on it!)

Looking at my SD-15's battery vs the battery that shipped with the SD1M:

SD15 == BP-21 - 7.4v, 1500mAh, 12Wh

SD1M == BP-22 - 7.4v, 1200mAh, 8.9Wh

Same size, same weight... same chemistry? Seems like it, but I have to ask: Is this a giant step backwards? Or was the BP-21 "overrated" in terms of capacity?

I am assuming that the BP-21 is the battery of choice for any Sigma DSLR at this point... but I could be incorrect.

Your comments welcomed.

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Ceistinne
Ceistinne Veteran Member • Posts: 3,256
Re: BP-21 vs BP-22... what?!?

Don Strimbu wrote:

Just received my SD1M and noticed that a BP-22 battery (and BC-22 charger) shipped with the camera. (The camera is gorgeous, by the way... can't wait to get some shots on it!)

Looking at my SD-15's battery vs the battery that shipped with the SD1M:

SD15 == BP-21 - 7.4v, 1500mAh, 12Wh

SD1M == BP-22 - 7.4v, 1200mAh, 8.9Wh

Same size, same weight... same chemistry? Seems like it, but I have to ask: Is this a giant step backwards? Or was the BP-21 "overrated" in terms of capacity?

I am assuming that the BP-21 is the battery of choice for any Sigma DSLR at this point... but I could be incorrect.

Your comments welcomed.

-Don

Don,

Mine came with a BP21 , havenn't heard of a BP22 until now. Anyway the voltage is the same but the BP21 would likely have longer shooting life.

I think the change might be due to new battery regulations in Japan in the fairly recent past. Nikon & others had to make similar battery changes also.

S

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SigmaChrome Forum Pro • Posts: 15,728
Re: BP-21 vs BP-22... what?!?

SigmaChrome wrote:

Hi Don.

I use my BP-21 and BP-22 interchangeably with the SD15 and SD1M without any problems.

And, yes, you will love the SD1M once you get to know it.

Hang on...now that I think about it - I don't have a BP-22, just the old BP-21.

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Don Strimbu
OP Don Strimbu Regular Member • Posts: 467
Re: BP-21 vs BP-22... what?!?

That probably nailed the reason for the change - thank you! Probably points to some of the Li-Ion battery issues that the laptop computer makers had last few years. They might be limiting energy density to reduce fire risk, hence the lower total power rating.  That's kinda sad, as the Sigma DSLRs aren't the most power-efficient.  One more reason for the PG-31 power grip, I guess.

Oh, and there is a BC-22 charger, too. The casing is a bit "blockier" than the BC-21 - the big chamfer around the bottom of the case, and the big round fillet at the top of the upper case cover are gone... other than that, functionality seems to be exactly the same.

Headed down to Carmel, CA tomorrow; not sure if I'm more excited about the trip, or taking the SD1M with me!

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Don Strimbu | Marin County, CA USA
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SigmaChrome Forum Pro • Posts: 15,728
Re: BP-21 vs BP-22... what?!?

Don Strimbu wrote:

<...>

sad, as the Sigma DSLRs aren't the most power-efficient. One more reason for the PG-31 power grip, I guess.

Get one. It's worth every cent.

Headed down to Carmel, CA tomorrow; not sure if I'm more excited about the trip, or taking the SD1M with me!

The latter, without a doubt!

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xpatUSA
xpatUSA Forum Pro • Posts: 23,016
Re: BP-21 vs BP-22... what?!?

Ceistinne wrote:

I think the change might be due to new battery regulations in Japan in the fairly recent past. Nikon & others had to make similar battery changes also.

S

Now that makes sense; may I post a theory?

If the regulations have the effect of increasing the batteries internal resistance (so it doesn't 'splode or ketch fahr if it's short-circuited) then the reduction in capacity would be explained. In other words, the BP-21 and 22 are identical in all respects except for internal chemistry (say).

Remember that the nominal voltage of a battery is stated for the no-load condition, so both batteries are still 7.4V nominal. But the battery terminal voltage of the 1200mAh battery becomes lower (by comparison) as soon as the camera is switched on and thus the camera chip detects 'low voltage' sooner.

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Ted
SD9, SD10, GH1 and a lens or two

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rick decker
MOD rick decker Forum Pro • Posts: 19,097
Re: BP-21 vs BP-22... what?!?
1

According to Sigma Japan:

The charger was change due to some regulation changes (as was speculated by at leat one person here) and the new batteries must be used with the new charger.

Rick

ju_ju
ju_ju Senior Member • Posts: 1,077
Re: BP-21 vs BP-22... what?!?

I do remeber this change in law at the time. One of the reasons was historically there was a new battery for nearly all new cameras produced. The idea is to stop the producers making too many battery types and more batteries that are interchangable into newer models of cameras. It was about waiste and the enviroment as much as anything, in the hope batteries would not become redundant , therfore being used again in newer cameras purchased. Obviously this does n ot apply to cameras alone. I belive it is going to be a world wide move.

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atom14
atom14 Veteran Member • Posts: 3,301
That's weird...

I've got a BP21 with my SD1M and ordered and got a 2nd.

atom14.

bensonga New Member • Posts: 7
Re: BP-21 vs BP-22... what?!?

rick decker wrote:

According to Sigma Japan:

The charger was change due to some regulation changes (as was speculated by at leat one person here) and the new batteries must be used with the new charger.

Rick

I recently received a SD1M which came with the BC-22 charger and a single BP-22 battery.  I've ordered some Wasabi BP-21 batteries (I couldn't find any company that would ship the Sigma BP-21 batteries to Alaska) and a Sigma BC-21 charger.  It looks like the batteries will arrive before the charger.

Does anyone know if I can correctly and fully charge BP-21 batteries in the Sigma BC-22 charger?

Thanks.

Gary

Ceistinne
Ceistinne Veteran Member • Posts: 3,256
Re: BP-21 vs BP-22... what?!?

bensonga wrote:

rick decker wrote:

According to Sigma Japan:

The charger was change due to some regulation changes (as was speculated by at leat one person here) and the new batteries must be used with the new charger.

Rick

I recently received a SD1M which came with the BC-22 charger and a single BP-22 battery. I've ordered some Wasabi BP-21 batteries (I couldn't find any company that would ship the Sigma BP-21 batteries to Alaska) and a Sigma BC-21 charger. It looks like the batteries will arrive before the charger.

Does anyone know if I can correctly and fully charge BP-21 batteries in the Sigma BC-22 charger?

Thanks.

Gary

I would think that you can.

S

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