Pixel Enterprise Limited, Hong Kong, has released a new battery pack for Canon Speedlites - model TD-381.
Disclaimer: I have no connection with Pixel, other than as a customer. These are the people who have released a beta of their TR-332 TTL Flash Trigger for Canon. The commercial version of the TR-322 is due for release around 14 February at a price nearer the Nikon version. (EBay user name pixelhk; web www.pixelhk.com.)
Purchase: I bought a Pixel Power Pack through eBay at US$56.80, shipping free, on 20 December. The item was received in New Zealand on 5 January, good for Christmas, New Year and four national holidays in that period. Packaging was adequate.
Contents: Pixel TD-381 Flashgun Power Pack with attached cord, fabric slip pouch, 1/4x20 attachment screw. No straps, warranty or instructions. Edit: Instructions should have been included, and Pixel sent one to me.
Connects to: Canon Speedlites 580EXII, 580EX, 550EX, MR-14EX, MT-24EX.
Batteries: A set of 4 or 8 Alkaline, NiMG or Lithium AA batteries can be used. 8 batteries will recharge the flash faster.
Charging System: A new type of dual circuit charging system, charging the flash capacitor faster than other battery packs. Due to Canon's control system, there is a small standby drain when attached to a flash which is switched on. The LEDs are bright when charging, twinkle rapidly on standby or slowly when battery is low. A graph on their website indicates 1.24 seconds recharge with 8 freshly-charged NiMH AAs, extending to about 5 seconds after 500 1/1-power flashes, then a rapid fall-off.
Physical: Similar to the Canon and other battery packs. Cable to flash: 60cm; 140cm stretched. Weight: 168gm; with 8 AA batteries: 450gm. Length: 170mm. Width: 72mm. Height: 25mm.
Likes: Great price. Smart appearance. Fast recharging of flash. Versatile battery configurations. Dual charge circuits provide backup if one circuit or battery fails. Dual thermal protection of charging circuits. Rubber waterproofing sock on plug. Multiple strap mountings on slip case and battery case.
Concerns: The batteries are inserted into a tray which is clipped into the bottom of the pack, and I am uneasy about the strength of the latch. The battery tray can be inserted two ways, but only one can be latched. It could be a fiddle to change on location and in low light, but at about 500 full-power shots, it would be a long session that would require a change. The slip pouch has a velcro'd opening at the top, and a domed flap at the bottom. The dome is poor and likely to part and let the battery pack drop out! Some soldering is poor, and as a result a small number of units can be expected to fail sooner or later.
Performance: My rough timings with 8 batteries and a 580EXII indicate that 1.2 seconds at 1/1 power is about right. At 1/4 power, the Ready light is on continuously. There is no perceptible delay on power-on or wake-up. Experience will tell...
Because some posts have dismissed power packs as expensive battery cases, I have included photos of both sides of the dual voltage-trippler/control board. There's a lot of design and manufacturing in that, and it is the heart of a flash battery pack.