Intro
I have used 2 types of LED torches: regulated and unregulated. The unregulated ones are the most common and they use some simple circuits for the LEDs, which means that as the battery discharges the light output gets lower.
The regulated ones use some circuit to maintain a constant current flow as the battery discharges, for as much as possible.
What about the Energizer hard case pro pivot plus?
This is an odd one. No, not because they needed 6 words to name it. As I swapped the provided alkaline batteries with rechargeable ones, I was surprised to see the same brightness – yes, a regulated torch!
If you would like to get one, please use this affiliate link which earns me a commission while you pay the same price.
But soon after, I noticed that as the light is kept on, it gets dimmer. In fact, leave it on for long enough and when you press the button while it is on, instead of going to the low level (30 lumens, or 10% of maximum), it stays the same, which indicates it reached 10% of max brightness.
But power it off and on again and it’s back. So it does not seem to dim due to heating. Ok, time to whip out the lux sensor in my office and use the data logging function.
How it actually runs
Here is the light intensity over time:
Each one of this triangles is a off and on again cycle. When the light is turned on, it starts at about 8000 lux* and linearly reduces to about 1000 lux in 15 minutes, than remains steady at 1000. Turn it on an off again and you get back to max. The torch achieves dimming through PWM, which is rather low frequency and I perceive it as flicker.
*I have a lux meter (measures light intensity) not a lumen meter (measures total amount of light).
During the last run it discharged completely. In total, the 2Ah rechargeable batteries could do 6 bunches of 15 minutes and another 90 minutes at low level. Far from the claimed 5 hours and far from the claimed max light level.
So the light is regulated, as it maintains the same light level as batteries discharge, at the start. But it dims itself on purpose, probably to get more battery life.
What’s inside
The circuit board contains 2 ICs and passive components. The bottom one is the LED driver, labelled CFC1B (or similar) for which I cannot find specifications. The top one is a controller, which has no marking.
Power consumption vs input voltage
I tested the power consumption at different voltages (when the light is just turned on) using my lab power supply. With over 4W of consumption, I suspect the LED used is below 100 lm/W.
Vin [V] |
Current [A] |
Power [W] |
3 |
1.47 |
4.41 |
2.8 |
1.54 |
4.31 |
2.6 |
1.92 |
4.99 |
2.4 |
2.15 |
5.16 |
2.2 |
2.0 |
4.4 |
2.0 |
1.93 |
3.86 |
1.8 |
1.87 |
3.36 |
1.6 |
1.8 |
2.88 |
1.4 |
1.74 |
2.43 |
1.2 |
1.6 |
1.92 |
1.0 |
1.23 |
1.23 |
0.8 |
0.8 |
0.64 |
0.7 |
0 |
off |
From 3V down to 1.8V the light remains constant, therefore it can squeeze out almost all energy from both alkaline and rechargeable batteries. Once the light is off, you cannot turn it back on below 2V, so it knows to protect rechargeable batteries from over discharging.
With such high power consumption, if the light would not dim down on purpose, the 2Ah rechargeable batteries that I used would be drained in less than 1h. With the dimming we can get to about double that, but it would still take very few on cycles to get to the 5 claimed hours.
A short review
It’s bright, dimmable, it’s though, runs on AA batteries, even rechargeable ones. This is a practical light to have in your tool box, if you do occasional work. It’s even regulated. If you would like to get one, please use this affiliate link which earns me a commission while you pay the same price.
But in a strange way, it dims itself on purpose so it can achieve the claimed 5h of battery. This feels quite a bit deceitful to me. Without the dimming, running at the max 300 lm it could probably hold only 1.5 hours on a set of alkaline batteries and a bit less on high capacity rechargeable.
What could be better: if it stayed 15 minutes at full brightness and then start the dimming process. That way there is still a chance to use it at full brightness by repeatedly turning it off and on.
Update
I have 2 other headlamps that behave in a similar matter, check out the new post.
Pingback: Another two troches with self dimming – Electro Bob
Are you sure it isn’t just defective?
Have you written to Energizer to ask them about the claims?
Though these days, you probably have to “tweet” at them to get their attention…
It’s not the only one doing this. Look at 2 others in the next post: https://www.electrobob.com/another-two-troches-with-self-dimming/