REVIEW: Pixel TD-382 Battery Pack

I recently picked up a Pixel TD-382 (for Nikon SB-900 flash) battery pack and decided to put it through its paces to see how it performed. Obviously with battery packs the two main considerations are recycle time and battery life. Some people deem one more important than the other and some consider them equally important. I’m in the camp of seeing both as equally important.

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The TD-382 looks much like any other pack of this type with similar housing, case, cable, plug and battery tray. Going beyond the cosmetics, the difference is in the circuitry and you can run the TD-382 on either 4 or 8 AA batteries.

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Method of Testing

The product manual for the TD-382 gives some stats based on using 4 Duracell alkaline AA batteries in the flash and 8 2400mAh NiMH batteries in the pack. I have Duracell AA’s and Powerex 2700mAh NiMH batteries so my results should pretty much replicate the numbers in the manual.

The Nikon SB-900 was connected to a Pocket Wizard Plus II and was triggered once every 30 seconds using the intervalometer in a Pocket Wizard Multi Max. Triggering every 30 seconds keeps the flash from overheating or shutting down due to the thermal protection circuitry. The manual also indicates that the flash was fired up to the point where it could no longer recycle within 30 seconds. According to the manufacturer they were able to get 577 pops under those conditions.

The test results in the manual are a bit misleading because in real world shooting I consider recycle times of more than 4 or 5 seconds unusable. If I was an event or wedding shooter I couldn’t possibly work that way. In a studio or for location work it might work but in reality I don’t see this type of battery as something that you use and run down like that. I tend to play it safe and once I see that initial drop in recycle time that means I should change batteries very soon and not wait. Once the recycle times do begin to change, the battery depletion is more rapid and recycle times increase dramatically. This is important and becomes quite obvious when comparing standard alkaline's to rechargeable NiMH batteries.

The Numbers

It should be noted that there is nothing scientific about these tests. The human element is introduced because I’m manually starting and stopping the stop watch. There is no real precision and I’m relying on my hand-eye coordination. Every timing was done five times and averaged to compensate for human error.

Recycle Time And Battery Life Using 8 NiMH Batteries:

• Full power - .9 seconds.
• Half power or lower - immediate with no perceivable delay.

In terms of battery life with 8 batteries in the tray, I stopped testing once the recycle time was what I considered an unreasonable amount of time and instead of a total number of pops I’ll present recycle time and change in recycle time over a number of pops.

Full Power Pop Test

• 1 – 100 pops : No change in recycle time.
• 101 – 200 pops : No change in recycle time.
• 201 – 300 pops : Recycle time increased from .9 to 1.32 seconds (.42 second change).
• 301 – 400 pops : Recycle time increased from 1.32 to 4.75 seconds (3.43 second change).
• 400 – 450 pops : Recycle time increased from 4.75 to 15 seconds (10.25 second change).

I didn’t see a reason to continue beyond 450 pops once I saw that the pack was struggling to recycle. For my purposes I consider 300 full power pops with acceptable recycle times to be quite good. Amazingly, the battery status LED didn’t start to indicate low charge until after 380 pops and that coincides with the drastic change in recycle time between 301 and 400 pops.

As a reference, the manual states that the fastest recycle time was 1.92 seconds but I never saw anything longer than about one second. The manual also states that they got 577 pops but you have to keep in mind that they kept counting as long as the pack recycled in 30 seconds or less.

The voltage of the NiMH batteries dropped from 1.29 to 1.18 Volts and the voltage of the alkaline AA’s in the flash dropped from 1.6 to 1.25 Volts. I did some additional testing and determined that the change in voltage of the batteries in the flash has no bearing on flash performance until those batteries are almost dead.

Since we are sometimes forced to shoot in less than perfect conditions or with backup gear I wanted to see the difference in recycle time between 8 and 4 batteries and also thought it was important to see how the TD-382 performed when using 8 alkaline AA’s in the battery tray.

Recycle Time Using 4 NiMH Batteries:

• Full power – 1.8 seconds.
• Half power or lower - immediate with no perceivable delay.

I only compared recycle time at full charge and did not test battery life or rate of depletion using 4 NiMH’s, as I only see this as a backup or last resort.

Recycle Time And Battery Life Using 8 Alkaline Batteries:

• Full power – 1.35 seconds.
• Half power or lower - immediate with no perceivable delay.

While those numbers are good, the results of the pop test reveal just how inefficient alkaline batteries are in flash guns and why it’s not cost effective to use them.

Full Power Pop Test

• 1 – 100 pops : Recycle time increased from 1.35 to 2.7 seconds (1.35 second change)
• 101 – 200 pops : Recycle time increased from 2.7 to 3.4 seconds (.7 second change)
• 201 – 300 pops : Recycle time increased from 3.4 to 5.4 seconds (2 second change).
• 301 – 400 pops : Recycle time increased from 5.4 to 7.7 seconds (2.3 second change).

After about 100 pops you’re already approaching that danger zone where recycle times are starting to get longer and you’re either missing shots or will potentially miss shots. The battery charge LED changed status after 50 pops, compared to 380 with NiMH batteries.

It’s great that in a pinch you can drop in either 4 or 8 standard alkaline AA batteries and continue shooting but it really has to be a last resort and is no better than just having 4 batteries in your flash.

In Summary

I really like the Pixel TD-382. Performance is quite good and gives me what I need for location work with Speedlight’s since I find myself using hot shoe flashes at full power quite often. If I’m working indoors at power levels of half or less and don’t have to combat ambient light then I can imagine amazing battery life with fast recycle times for hundreds of shots.

I got mine through CheetahStand.com rather than ordering from China. I'll gladly forego the better pricing and free shipping from China for US sales and support. Currently, CheetahStand is the only US distributor for Pixel Enterprises.

You can see the comparison of the Pixel TD-382 to the Yongnuo SF-18 here: COMPARISON: Pixel TD-382 to Yongnuo SF-18