April 18, 2021


Sony and Minolta SLR Weblog

Sony A700 battery life analyzed by engineer

Bart Pasquale, who last appeared on these pages with his insightful comments on the Sony Alpha Full Fame – Antishake question, is back with a detailed analysis of the Sony battery for the A700 Alpha and it’s lack of compatibility with the A100 batteries.

The complete text of Bert’s email follows:

Hello Tom!

Here’s some info regarding the new Alpha A700 battery, the NP-FM500H. As you may know, there is a grove in the new battery, and a ridge in the A700 battery compartment, which prevents interchangeability with the A100 battery. I contacted my usual 3rd-party battery suppler from eBay, and he said Sony has blocked the manufacturing of NP-FM500H compatibles. It was not clear weather this is legal/political maneuvering, or simply an issue being able to reproduce the circuitry required for A700 to display the % charge remaining, but he expected something out of Taiwan by January. What he did know is that one person reported to him filing out the ridge inside their A700, and the A100 batteries did NOT power the A700.

A700 Battery

A700 battery shown being loaded into new vertical grip. Notice the groove that allows battery to fit the A700 compartment.

Photo: Sony Corp, used with permission

Being the anti pay-for- proprietary-items consumer that I am, I find myself waiting it out to avoid buying a $80 Sony battery, understanding the implications of battery consumption suddenly became very important. So, I spent the past day and a half draining a fully-charged battery under controlled conditions. My goal was simple: take bursts of pictures throughout the day at various intervals, review the pictures, delete a few, and record the image count and battery charge remaining. Many batteries fall off very quickly once they indicate “half charged”, but SONY claims the new battery’s reported % is “accurate”, and the battery is good for 650 shots. Curiously, the second day I had the camera, I cranked off 900 pictures on a photo shoot, but the battery indicator still showed being more than half-charged. Let’s examine…

I began with a fully charged battery two days ago, At various intervals (a few hours to a few minutes) I would fire off 50-100 images, and review them, at a medium pace, deleting every few images as I went. I was shooting compressed RAW, anti-shake on, DRO standard. This simulates my camera use in the studio or shooting on location. After the first 50%, I continued to review the imagers quickly, but did not delete many images, as I might do to conserve battery power while on a shoot. The results are summarized in the following table:

Shots % Charge Charge Drain Rate
Day One: 0 100%  
  550 75% 1% = 22 frames
  1200 50% 1% = 26 frames
Day Two: 1800 25% 1% = 24 frames
  2600 1% 1% = 32 frames
  3080 Dead 1% = 400 frames

Over 3,000 shots from a single charge! I’ve never worked so hard to drain a battery. That was the battery’s third charge, so we’ll see how that changes after a couple dozen cycles, and how the generic versions hold up to that when they finally do come out. A few other statistics:

  • Reviewing 150 images uses 1% of battery charge
  • Leaving the display on for about 5 minutes uses 1% of battery charge
  • Overnight, the battery looses about 2%-3% of it’s charge
  • Straight shooting without reviewing images can achieve 30+ frames per percent at any phase in the charge cycle.
  • Once the battery indicates zero charge, you can still quickly eek out a few hundred shots!
  • This is about an extra 12% of charge not indicated in the charge level.

During recharge, the first 15 minutes were spent to achieve 1% charge status back. After that, it was pretty linear, adding about 12% every 15 minutes achieving 86% after 2 hours of charging. The battery indicated “100%” about 35 minutes later, but continued to take a charge for an additional 15 minutes to top it off. So, one could theoretically shoot 400 frames, recharge for 15 minutes while the model changes, and never run out of charge. Of course, YMMV; I don’t know how consistent one battery will be to the next. Happy shooting all!

– Bert Pasquale

BTW, I have a couple well-cared-for A100’s for sale! (With several extra batteries…)

Wow, that is a pretty exhaustive (no pun intended) sample of the battery life of the NP-FM500H when used in the A700.

I found it interesting that someone would actually go as far as removing the locking ridge from a new A700 to try to use the older battery. The fact that the NP-FM55H (used in the A100) would not power the A700 indicates to me that the ridge serves a purpose beyond an attempt to sell more batteries. It’s easy to point to an incompatibility like this and suggest it is being done to sell more batteries. I’ve found that manufacturers rarely make components less compatible just to move additional product. They have to stock additional components, manufacture additional components and distribute two lines of batteries instead of one. Usually is in the company’s best interest to stock and sell as many common items as they can, because that drives manufacturing and stocking cost down.

That said, several printer manufactures have taken great pains to make sure only their own cartridges work with their hardware. So who knows? This could be Sony’s attempt to eliminate after-market battery competition, but I doubt it. Usually when an electronic product carries a lock out ridge like the one described above, it is to prevent using a non-compatible item that might cause damage to the devise. The upshot is A100 batteries are NOT compatible with the A700 — don’t try to reengineer the camera or battery in attempt to make them work.

It Bert’s tests are indicative of how long a typical NP-FM500H will last, it seems like for most shooters a single battery will cover most assignments. A second battery, either used as a spare or inserted in the A700 Vertical grip should be more then sufficient power for most A700 shooters.

Thanks again Bert, this is a great report. If anyone is interested in Bert’s A100 gear, email me and I will get you in touch.

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