What's New: Compact Battery Pack CP-E4N

May 11, 2016

Along with the updated Speedlite 600EX II-RT, Canon simultaneously is launching a refined external battery pack to provide faster recycle times and more flashes before battery replacement is needed — the Compact Battery Pack CP-E4N.

The updated Canon Compact Battery Pack looks virtually identical to previous external battery packs for speedlites. But it contains numerous internal upgrades, all designed to make it a best-match battery pack for the latest Speedlite 600EX II-RT. And, it remains fully compatible with older, high-end Canon Speedlites with a high-voltage socket for external battery packs.

This new external battery pack will replace the previous CP-E4 battery pack in the Canon line.  Like its predecessor, the updated Compact Battery Pack CP-E4N holds eight AA-size batteries, either alkaline or rechargeable Ni-MH type.  It uses the same type of connector to the high-voltage input socket on Canon’s 500- and 600-series speedlites, so it can be used with not only the latest Speedlite 600EX II-RT, but the previous 600EX-RT, 580EX II, 580EX, and even the long-discontinued Speedlite 550EX.

Upon first glance, this latest Compact Battery Pack appears identical to the previous CP-E4 version.  However, there are some noteworthy changes.

What's New?

The CP-E4N is designed to be a “best-match” external battery pack to use with the latest Speedlite 600EX II-RT.  Among the biggest changes in the updated speedlite are the increased number of continuous flashes that can be fired, and increased reliability in terms of heat resistance.  The CP-E4N battery pack mirrors those refinements, offering demanding flash shooters a battery pack that’s designed to match the continuous shooting performance of this latest speedlite.

•     Re-designed, heat-resistant circuitry within the battery pack, to minimize internal heat build-up during rapid, continuous flash firing and recycling

•     Internal temperature sensors to detect dangerous levels of heat, and prevent circuitry from damage during continuous, high-demand shooting

•     Special external power supply detection circuit, which can be read by Speedlite 600EX II-RT — this allows the speedlite to take full advantage of CP-E4N battery pack’s additional continuous shooting capability.  (If the 600EX II-RT does not receive this new signal, such as if it’s used with the older Compact Battery Pack CP-E4, the number of continuous flashes is controlled to minimize risk of heat build-up within the external battery pack.)

•     Flame-retardant, higher-grade exterior housing and battery compartment cover, to further resist both short-term and long-term risk of damage to battery pack from internal heat

•     Both ends of the coiled connecting cord to the speedlite are re-shaped, and stronger to resist bending, flexing, and long-term deterioration or breakage  (the actual connector for the high-voltage socket in compatible speedlites is unchanged)

•     Quieter operation during flash recycle, compared to previous CP-E4 battery pack

The compact battery pack concept

Unchanged is the basic concept of the compact battery pack for high-end speedlites.  With its eight AA-size batteries as a power supply, the idea is a pack that can noticeably cut flash recycle time, and extend the length of time a photographer can shoot with flash on-location or in the studio, before concerning him- or herself with needing to replace batteries.

Without risk of damage from truly high-voltage external power (as might be the case, in some instances, with certain third-party battery packs for speedlites), and in a very compact package, the CP-E4N continues the idea of an external power supply that adds to a speedlite’s performance, in a pack that’s small enough to carry in a typical dress shirt pocket.

Because it holds only eight AA-size batteries, a Canon Compact Battery Pack is a lightweight method to step-up the shooting performance of high-end Canon speedlites. And, this latest CP-E4N pack amplifies this, with added durability and heat-resistance to match the increased performance possible with the latest Speedlite 600EX II-RT.

With its connecting cord attached to the speedlite’s high-voltage battery input socket, the pack can be kept in a camera bag, or even the aforementioned photographer’s shirt pocket, during shooting.  And, it includes a tripod screw, allowing users to attach it to the base of their camera for one integrated camera/flash/battery pack unit (see the note below about directly attaching any of the CP-type battery packs to EOS digital SLR cameras).

The performance benefit of Compact Battery Pack CP-E4N

There’s a big difference in potential performance for the serious flash shooter.  Whether you’re working on-location events like weddings, shooting team or group photos, or using speedlites on-location with accessory light modifiers, the CP-E4N will make high-volume flash shooting less stressful for the demanding photographer.

Recycle Time, at full 1/1 manual power:
Speedlite 600EX II RT alone — approx. 5.5 seconds (alkaline AAs);  3.5 sec.  (Ni-MH)
600EX II-RT plus CP-E4N — approx. 1.8 seconds  (alkaline AAs);  1.2 sec.  (Ni-MH)

Number of flashes, at full 1/1 manual power:
Speedlite 600EX II-RT alone — approx. 100 (alkaline AAs);  approx. 112  (Ni-MH)
600EX II-RT plus CP-E4N — approx. 300 (alkaline AAs);  approx. 336  (Ni-MH)

Number of continuous, full-power shots before Level 1 protection engages:
600EX II-RT with previous CP-E4 pack — 45 to 70 flashes*
600EX II-RT with updated CP-E4N pack — 60 to 100 flashes*

* Number of flashes dependent on flash zoom position — at wide zoom settings, flash tube is closer to the front fresnel lens on speedlite, and fewer flashes are possible before heat protection is engaged.  Flash fired repeatedly, as soon as full-power ready light appears.

Note on other test conditions: 
— Recycle time is determined by using fresh batteries, firing flash at full power five times as soon as ready-light indicates full recycle, and then recording recycle time for 6th shot at full manual power. 
— Number of flashes determined by how many full-power, manual flashes can be powered, at 30 second intervals, before ready-light does not appear within 30 seconds (using fresh AA batteries).

Battery types for Compact Battery Pack CP-E4N

As indicated above, Canon Inc. recommends either alkaline type AA batteries, or rechargeable Ni-MH batteries.  The latter will tend to give faster recycle times, and roughly the same (or even more) total flashes before being depleted, as alkaline AAs.

Canon no longer recommends use of any AA-size lithium, disposable batteries — under hard, repeated use, tests have shown that some types of lithium AAs can develop dangerous levels of internal heat.  This applies to their use in Canon-brand speedlites (any type accepting AA-size batteries), and any external battery packs.

Canon also recommends that when a Canon Compact Battery Pack (such as the CP-E4N) is used with a Canon speedlite, that the same type of batteries be used in both the speedlite and external battery pack.

Batteries in the speedlite, when using a Compact Battery Pack

Four working and functional AA-size batteries are always required within a Canon speedlite, even when an external battery pack is attached to its high-voltage input socket.  Normally, the four batteries within the flash combine with the external battery pack to provide power to the capacitors for flash recycle, as well as provide power for flash-specific activities like zooming the flash head, illuminating the ready-light, displaying the LCD panel, and so on.

But because four internal batteries are combining with the external battery pack to recycle the flash after each shot is taken — the primary cause of battery drain in a speedlite — the four internal batteries will often be depleted before those in an external battery pack.  High-volume flash shooters (wedding shooters, etc.) may find that they’re changing the four internal batteries in the middle of a shooting event, even though those in the external pack are still performing OK.

High-end Canon speedlites have a flash Custom Function (C.Fn 12–1 on the 600EX RT-II, 600EX-RT, and 580EX II;  C.Fn 07–1 on Speedlite 580EX) to prevent the four internal AA batteries in a speedlite from being used for flash recycle when an external battery pack is attached.  This can be a huge benefit to high-volume users at events or in the studio, since it minimizes the need to replace the four internal batteries in the speedlite itself.  With C.Fn 12–1 (or 07–1) active, those internal batteries are used strictly for low-demand tasks like powering the LCD monitor, flash head zooming, and so on.  We strongly recommend users who invest in a Canon Compact Battery Pack consider at least trying the appropriate flash C.Fn on their speedlite when using a CP-series external battery pack, and see if this benefits them.

Please note that even if the appropriate speedlite Custom Function is active, four working AA batteries will always be required inside of a speedlite if an external battery pack is attached.

Directly attaching Compact Battery Packs to EOS cameras

An important note about direct connecting a Canon Compact Battery Pack (any version) to the base of an EOS digital SLR:  it’s possible for electromagnetic “noise” from battery operation and recycling to create interference and visible artifacts on actual digital image files.  An attached battery pack needs about 2 inches (5cm) of distance between the pack and the actual camera baseplate to ensure this doesn’t happen.  Canon therefore suggests:

•     Canon EOS-1D series, and EOS-1Ds series cameras:
Because these cameras have their own battery chamber beneath the actual camera body, Compact Battery Packs for speedlites can be directly attached to the camera baseplate, without further worries.

     All other Canon EOS D-SLRs:
We recommend using a Canon Battery Grip attachment (optional accessory) on the camera, and then attaching the Compact Battery Pack for speedlites to the base of the battery grip.  Or, consider having the Compact Battery Pack in an alternate location.  Directly attaching it to the camera baseplate, without a camera battery grip in place, can definitely result in the patterned noise and interference mentioned above.

Canon recommends if you want to directly attach any Canon Compact Battery Pack (for speedlites) to a camera, that the camera have an optional battery grip attached. Pictured here is a Canon EOS 7D Mark II, with its dedicated Battery Grip attached. The CP-E4N (or any other Canon compact battery pack) could be safely attached to the bottom of this combination. Since EOS-1D (and previous EOS-1Ds) series models have an integrated battery compartment in their bodies, a CP-E4N pack (or equivalent) can safely be attached directly to the bottom of those cameras.
Can I use older CP-type battery packs with the latest 600EX II-RT?

Absolutely.  The connection socket for high-voltage input is the same on all Canon EX-type speedlites that accept external battery packs, so they plug right in.  Users who currently own older CP-E3 or CP-E4 battery packs for speedlites can continue to use them, even with the latest Speedlite 600EX II-RT.  And, as mentioned above, this latest CP-E4N battery pack can likewise be used on older EX-series speedlites, going back to the earliest high-end unit, the Speedlite 550EX.

The only limitation with using older CP-type battery packs with the latest Speedlite 600EX II-RT is that the speedlite will sense that a pack with lower capacity for heat during repeated, fast shooting is attached.  Accordingly, the 600EX II-RT itself will engage heat protection sooner, if and when you shoot rapid, repeating flash pictures.  When the latest battery pack CP-E4N is attached to the companion Speedlite 600EX II-RT, the speedlite receives an identification signal from the pack, and extends the range of possible shots before heat protection kicks-in during rapid, demanding shooting situations.


As Canon’s digital SLR customer base becomes progressively more experienced, more and more users are taking advantage of the shooting performance modern D-SLRs possess.  We live in a world where even entry-level models can often shoot at five frames per second.  Not too many years ago, it took a top-of-the-line professional SLR, with an optional (and expensive!) motor drive, to provide that level of speed.

This evolution of expectations has extended to flash photography as well.  Pros, advanced amateur enthusiasts, and even to some degree more casual users have realized the benefits a modern, dedicated speedlite can bring to their photography in many instances.  With the introduction of the new Speedlite 600EX II-RT, Canon makes a significant gesture toward a wide range of users who want features, wireless capabilities, and performance in their flash photography.

Supporting this is the updated Canon Compact Battery Pack CP-E4N — matching the increased performance of the 600EX II-RT, and providing a wide range of users a relatively light and unobtrusive means to further leverage the performance of their cameras when shooting flash pictures.  The Compact Battery Pack concept has been well-received for years by Canon shooters;  this latest incarnation changes nothing in terms of the size and portability of an external battery pack for flash, but makes even more possible if and when it’s attached to the latest, high-performance Speedlite 600EX II-RT.

The CDLC contributors are compensated spokespersons and actual users of the Canon products that they promote.


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