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D1X Tip: breaking in the EN-4 battery  
Tuesday, June 26, 2001 | by
My first experience with a high-capacity NiMH battery pack was in 1995, and the experience was not good. The pack powered the NC 2000 digital cameras issued to each of us then on the photo staff at the Calgary Herald. It quickly became apparent that some cameras could run all day on a single charge, while others were lucky to limp through a single assignment.

The reason for the battery performance disparity, we later learned, was in how the packs were being handled initially by the photographers. Those that were charged and discharged fully through the first few weeks of use provided many more frames per charge than batteries that were charged fully once, then charged on no particular schedule thereafter.

This finding was confirmed when the paper began purchasing rebuilt and brand new NC 2000/NC 2000e battery packs from John Falkenberg of Battery Rejuvenators. Falkenberg advocated putting NiMH packs through three complete charge/discharge cycles before their first use, and did just that to fresh NC 2000 packs using his company's professional battery conditioning equipment. The result? The number of frames per charge skyrocketed across the cameras receiving his conditioned pack.

That was several years ago. Since that time, Falkenberg's word on Kodak DCS battery handling has been golden with me. The arrival of a D1X and new EN-4 batteries earlier this month provided an opportunity to evaluate whether his triple-conditioning recommendation is equally valid for Nikon D-series cameras.

Nikon EN-4 battery for the Nikon D1/X/H

To that end, I tested three of the D1/X/H's 2000mAh NiMH packs, each of which was broken in differently when they first came out of the box three weeks ago. The results, as you'll see, confirm what I'd already thought to be true: to extract maximum performance from a NiMH battery pack, it must be run through three conditioning (charge/discharge) cycles when new.

Here's how the batteries were handled initially:

  • Battery 1 was prepped by Falkenberg's professional battery conditioning device. It was stepped through three charge/discharge cycles, and the pack's capacity was measured after each cycle. After one cycle, the battery had reached only 76% of its rated capacity. After two cycles, that number jumped to 95%. The third cycle topped the battery off at 97%. Since it's rare that any pack will rise to exactly 100% capacity, even when new, Falkenberg considered this battery to be fully ready for service at 97%.

  • Battery 2 was connected to Nikon's MH-16 charger, then put through three Refresh cycles back-to-back. The charger's Refresh function is a battery conditioner. It first discharges the battery to a specified minimum voltage, then charges it up again, in a manner similar to Falkenberg's pro conditioner.

Nikon MH-16 charger, set to Refresh

  • Battery 3 was charged up fully, once, by the MH-16 before its first use.

The three packs were then used normally, and charged as needed to ensure they were ready to go before extended shooting sessions. Just prior to testing, each was run through the Refresh function of the MH-16 one time, then left on the charger for about 12 hours. Finally, the number of D1X frames per charge that each battery could deliver was counted. The table below details the results.

Note: See the Product Testing Notes sidebar for important information on how the frame counts were derived, and how that relates to real world battery performance.

EN-4 battery capacity, Nikon D1X
EN-4 pack (2000mAh, 7.2v, NiMH)
Frames per charge -
Frames per charge -
Compressed RAW
Battery 1 (prof. conditioned)
Battery 2 (conditioned by MH-16)
Battery 3 (not conditioned)

The performance of each battery was essentially in line with how it was prepped when new. The professionally-conditioned battery led the way, but not by much, over the battery conditioned by the MH-16. Both batteries easily eclipsed the pack that was not triple-conditioned when new. That pack topped out at about 70% of the capacity of the triple-conditioned packs.

I've advocated during D1 training sessions that even if the photographer's EN-4 wasn't triple-conditioned when new it may not be too late to do it now. A triple-condition to try and jumpstart things really can't hurt and may help restore lost capacity. I tried doing just that, and the 70% capacity battery jumped up to about 80% after three rounds of the MH-16's Refresh function. This is still shy of what the battery is capable of, but better than not doing the triple-condition after the fact at all. While not tested here, my prediction, based primarily on Kodak DCS battery experience, is that the 70% EN-4 would jump up much closer to maximum capacity if conditioned by a professional conditioning device.

For breaking in the EN-4 when new, both the pro and MH-16 conditioning methods work well. The only real advantage to professional conditioning is the time saved breaking the battery in, since pro conditioners are several times faster than the MH-16. If you or your organization have a whack of new batteries, it may be simpler to pay US$10-15 a battery to have them conditioned, rather than go through the hassle of doing a stack of EN-4's with a handful of Nikon chargers.

Note: See the On Battery Conditioning sidebar for additional information.


For this test to be definitive, many more than three batteries would need to be evaluated. And yet, the results are roughly in line with what I've encountered in my travels to newspaper photo departments in the past 18 months: photographers struggling with lousy D1 battery life invariably had not triple-conditioned them at the outset. Conversely, those who reported no major battery performance problems cited some sort of procedure for breaking in the battery, including a Refresh 2-5 times when new, faithfully running the EN-4 dry in the camera before recharging, hitting Refresh on the charger each and every time, and so on.

All of these procedures may well get the battery to a good place initially, though it should be noted that conditioning more frequently than ever 10-12 cycles is almost certainly overkill. Based on anecdotal evidence, and the results of this test, my money is on refreshing the EN-4 three times when new. If you're about to pop for a D1X, I strongly recommend that you break in your new batteries just this way.

To do that, plug the battery into the charger lead, then hit the Refresh button. When the End light is illuminated (90 minutes to several hours later), press the Refresh button again. When the End light comes on a second time (again, several hours later), press the Refresh button one final time. When the End light illuminates, the triple-conditioning routine is complete.

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