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Long lasting battery for DP2M/DP1M

peterb

Member
With all the advance mentions of how quickly the DP2M/DP1M rips through batteries I did a little experiment and may have come up with a possible solution.

When I ordered my DP2M from Sigma I also ordered their SAC-5 accessory that provides the camera with power in indoor (or power accessible) situations. Basically it consists of a power supply you plug into an AC outlet and a 'dummy' battery that fits in the battery compartment. The dummy battery has a cable that fits through an opening that's normally covered with a rubber gasket that covers the opening.

The end of the cable fits into a matching power connector at the end of the cable coming from the power supply.

I made two voltage measurements. The first was to measure the typical voltage the rechargeable batteries put out. The other was to measure the power coming out of the SAC-5. Interestingly enough the rechargeable batteries produced about 3.4-3.8v. But the SAC 5 unit produced 4.4-4.9v. Obviously Sigma felt the camera could handle that voltage.

The Sigma batteries have a rating of 1250 mAh (milliamp hours). Clearly what's needed for longer term usage is something that can put out a much higher amount.

I then went to RadioShack and found they had 1.2v NiMH Batteries rated at 5000 mAh. Which to me meant they had the potential of lasting 4 times as long as the battery that came with the camera.

I then purchased the following.

3 x "D" size NiMH batteries rated at 5000 mAh to provide 3.6v @ 5000 mAh (2 packages of 2 D Cells @ $14.99/package)
1 x 3 Bay Battery Holder ($2.79)
1 x Replacement Adaptaplug (Radioshack code 273-350) which is used to attach two wire leads to an adapter that fits any number of power plugs ($4.99)
1 x Adaptaplug "H" tip (to fit the cable lead from the Dummy battery) $6.99 (Note the tip has an orange 'O' ring)

I then soldered the leads of the adapter to the leads from the battery holder and wrapped them with electrical tape. NOTE: The red lead should be soldered to the wire with writing on it. That's the wire that connects to the (+) center of the Adaptaplug. This will insure that polarity is correct. But to be sure I tested it with an inexpensive Digital Volt Meter

When the whole thing was completed I now had a battery pack that provides power for really long periods of time.

The 3 rechargeable D cells SHOULD output 3.6v but I've measured it at 4.6v which is still within the voltage I measured off the dummy battery connected to the AC power supply.

I've attached photos to show you how the whole thing looks.

Note: you can see the dummy battery also clears John Milich' superb grip that he fashioned for the DP2M/DP1M

Last comment: RadioShack also has a superb charger that can handle 5000 mAh batteries including AAA, AA, C and 9v as well. It also has a car adapter for use on the road as well as a USB port for charging USB devices (like phones). When charging, individual lights for each battery in the one of four bays light either red (charging), green (charged) or blinking (defective/unchargeable).
 
Last edited:

scho

Well-known member
With all the advance mentions of how quickly the DP2M/DP1M rips through batteries I did a little experiment and may have come up with a possible solution.

When I ordered my DP2M from Sigma I also ordered their SAC-5 accessory that provides the camera with power in indoor (or power accessible) situations. Basically it consists of a power supply you plug into an AC outlet and a 'dummy' battery that fits in the battery compartment. The dummy battery has a cable that fits through an opening that's normally covered with a rubber gasket that covers the opening.

The end of the cable fits into a matching power connector at the end of the cable coming from the power supply.

I made two voltage measurements. The first was to measure the typical voltage the rechargeable batteries put out. The other was to measure the power coming out of the SAC-5. Interestingly enough the rechargeable batteries produced about 3.4-3.8v. But the SAC 5 unit produced 4.4-4.9v. Obviously Sigma felt the camera could handle that voltage.

The Sigma batteries have a rating of 1250 mAh (milliamp hours). Clearly what's needed for longer term usage is something that can put out a much higher amount.

I then went to RadioShack and found they had 1.2v NiMH Batteries rated at 5000 mAh. Which to me meant they had the potential of lasting 4 times as long as the battery that came with the camera.

I then purchased the following.

3 x "D" size NiMH batteries rated at 5000 mAh to provide 3.6v @ 5000 mAh (2 packages of 2 D Cells @ $14.99/package)
1 x 3 Bay Battery Holder ($2.79)
1 x Replacement Adaptaplug (Radioshack code 273-350) which is used to attach two wire leads to an adapter that fits any number of power plugs ($4.99)
1 x Adaptaplug "H" tip (to fit the cable lead from the Dummy battery) $6.99 (Note the tip has an orange 'O' ring)

I then soldered the leads of the adapter to the leads from the battery holder and wrapped them with electrical tape. NOTE: The red lead should be soldered to the wire with writing on it. That's the wire that connects to the (+) center of the Adaptaplug. This will insure that polarity is correct. But to be sure I tested it with an inexpensive Digital Volt Meter

When the whole thing was completed I now had a battery pack that provides power for really long periods of time.

The 3 rechargeable D cells SHOULD output 3.6v but I've measured it at 4.6v which is still within the voltage I measured off the dummy battery connected to the AC power supply.

I've attached photos to show you how the whole thing looks.

Note: you can see the dummy battery also clears John Milich' superb grip that he fashioned for the DP2M/DP1M

Last comment: RadioShack also has a superb charger that can handle 5000 mAh batteries including AAA, AA, C and 9v as well. It also has a car adapter for use on the road as well as a USB port for charging USB devices (like phones). When charging, individual lights for each battery in the one of four bays light either red (charging), green (charged) or blinking (defective/unchargeable).
Looks promising Peter. A smaller package that could be fitted to the L bracket (bottom or side) on John's grip would make a nice portable power supply.
 

peterb

Member
Thanks Carl,

I keep it in a smallish fanny pack (which I typically use for the camera itself) and let the leads run along my arm.

A smaller pack could easily be made using three rechargeable AA batteries. They have capacities up to 2300 mAh giving you the potential of double the power time of the standard Sigma battery.

P
 

Quentin_Bargate

Well-known member
Great idea!

An external pack is exactly what these cameras need. It woud be easy for Sigma to manufacture something, or maybe a third party product that could be slipped in the pocket, along your lines Peter. They are half way there already with the AC adapter.
 

scho

Well-known member
If you use a tripod a lot (I do) then it would be easy to just tape your battery pack to one of the legs. I don't know if you saw this link from DPR. Translation is really bad, but the pictures are self explanatory.
 

pophoto

New member
...if there was a way for those who use tripods, to somehow use the tripod legs to store the batteries (removable), and some sort of universal cable for cameras!
 

scho

Well-known member
I have an external USB power supply (Anker Astro 3, 10000 mAh) that I use for emergency power with my iPhone, iPad, and laptop when traveling so I just tried it with the SAC-5 in the DP1M and it works fine as an alternate power supply. I used a 3 ft StarTech USB2TYPEH 5V DC power cable to connect the Anker USB port I (there are two USB out ports, both 5v, 2 amp) to the lead from the SAC-5 in the camera. Just power on the Anker, turn on the camera and shoot. If you have the DP set to automatically power off after a set time it will also shut off the Anker power supply. I haven't checked actual output voltage to the camera yet, but will do so when I have access to a meter. Here is a (poor quality) iPhone shot of the set-up.



Mirror 2 sec timer portrait taken with DP1M with Anker power supply on tripod. The power unit is in a small mesh carry pouch hanging on the tripod.

 
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scho

Well-known member
I have an external USB power supply (Anker Astro 3, 10000 mAh) that I use for emergency power with my iPhone, iPad, and laptop when traveling so I just tried it with the SAC-5 in the DP1M and it works fine as an alternate power supply. I used a 3 ft StarTech USB2TYPEH 5V DC power cable to connect the Anker USB port I (there are two USB out ports, both 5v, 2 amp) to the lead from the SAC-5 in the camera. Just power on the Anker, turn on the camera and shoot. If you have the DP set to automatically power off after a set time it will also shut off the Anker power supply. I haven't checked actual output voltage to the camera yet, but will do so when I have access to a meter. Here is a (poor quality) iPhone shot of the set-up.
Voltage measured at the SAC-5 from the Anker is 4.8-5.0 V.
 

peterb

Member
Hi Carl,

That's about what I measured too. I looked at some 5v P/S's but was concerned that like batteries what's printed on the outside wasn't would might actually get. (Sorta like your mileage may vary.) The battery I set up seemed to be coming in around 4.2v even though it should have been 3.6v! so I was nervous considering the higher voltage battery for fear it would go over 5v and do some damage to the camera.

Glad it's working out. I like the 'cleaner' package.

P
 

Millsart

New member
Not sure if I'm missing the point (other than a cool DIY) but this device looks far more awkward and bulky to carry than just a few spare batteries.

Under what type of conditions would this be used ? I used to use external battery packs shooting weddings, as I didn't want to miss shots changing batteries, however, the last place I would expect a Merrill to be used is in fast paced shooting. Can't think of a worse camera for that type of work honestly lol

For me, its a composed shot, landscape camera, where I end up taking a handful of shots, mainly because of file size and the fact I don't want to have to work with SPP all evening because I snapped away like a mad man.

I could of course see going on a 2 day hiking trip or something, where one battery might not be enough, but in that case, it again seems easier to carry a few spares, which would take up less room and be lighter in the pack.
 

adsf

New member
Charging of NiMH Batterys ends somewhere over 1.4V. They drop down fast when using. Thats normal.
Your original Sigma Battery will also have another Voltage than 3.6V after charging it. Probably about 4.1V

I guess i would use a single Cell LiPo or LiIon Battery for making an external battery Pack.

Buying some cheap aftermarket Chargers for mobile 12V use (availability is good cause the battery-type is pretty common) and coupling them for synchronous charging is also a good idea to keep it (the camera) more handy.
 
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