View Full Version : CR2016 VS CR2032 batteries

08-29-2010, 23:01
I have a dead Photon Micro-Light II that takes two CR2016 batteries, 3 volts each. I replaced them with a single CR2032 battery, 3 volts, because that's all I have. I'm surprised that now the photon micro light works just fine. It still has a blinding bright light. But I'm guessing that it is not as bright as the original because I'm only using one 3 volt battery instead of 2, but don't know for sure. Maybe it will last longer, I don't know. what do you think.

note: a single CR2032 is the same physical size as two CR2016 batteries put together.


08-29-2010, 23:18
It'll work just fine according to photon - http://www.photonlight.com/pages/Battery-Replacement-Instructions.html

There must be a really small voltage regulation circuit hidden iin there somewhere.

The Old Fhart
08-30-2010, 06:25
The Photon link does not say the Photon II will work fine if you replace the 2 CR3016 batteries with one CR3032. What it says is that your Photon II will require one or two batteries depending on the color output of the LED.

LEDs are not like incandescent bulbs where you just paint the bulb a different color, different color LEDs require different voltages to work properly. If you check this site (http://www.oksolar.com/led/led_color_chart.htm) it will show the voltages required for their different color LEDs, which is pretty representative.

Replacing the 2 batteries with 1 will probably give you much less life that the original 2. If you check the discharge curves for the CR3032 (http://www.jlsener.com/products/spdpn/CR3032/$FILE/CR3032.pdf) you will see the initial voltage starts at at about 3.3 volts but quickly drops down to about 2.7 volts where it will stay for a long time. You will also notice that the voltage output drops with temperature as well so your Photon II you put 1 battery into may work for a very short time and also may not work at lower temperatures. The 2 cells were used to maximize the amount of energy you could get from the batteries while getting constant light output.

CR30xx batteries are quite cheap on Ebay so I'd replace the batteries with the same type and number of cells. Photon put 2 cells in for a good reason

08-30-2010, 09:29
If you use two batteries, you get a longer run time than just using one battery. The voltage will be the same, you hust have more of a reserve. That is the reason large trucks use more than one twelve volt battery. The circuit is still twelve volts, but the starters need a larger reserve of battery power so the manufacturers use more than one battery.

Only John

The Old Fhart
08-30-2010, 09:56
OnlyJohn-"If you use two batteries, you get a longer run time than just using one battery. The voltage will be the same, you hust have more of a reserve. . ....."Wrong in this case. These batteries are in series so the voltages add but you don't get more current. To get more cranking power for a starter you either get a larger battery or put 2 in parallel so you get the same voltage but higher current capacity.

Pedaling Fool
08-30-2010, 10:49
I agree with the old fhart.

When trying to imagine what voltage and current do it's sometimes helpful to think of water, such as flow rate and pressure as an analogy to current and voltage. Think of how water flows through different scenarios and how flow and pressure are effected.

08-30-2010, 13:00
I sent an email to Photon teck support and this is what they said:

Tom, putting a single Cr2032 will work fine for your white Photon. Light output will be decreased but you will get a much longer run time; probably around double (no actual testing as the lights designed for two batteries). Regards, Rudy.
Panzer (alias Tom)

08-30-2010, 17:05
There must be a really small voltage regulation circuit hidden iin there somewhere.

Photon LED runs on 4.1 volts max. I found the following on another forum to explain why the LED doesn't burn out when used with two 3 volt batteries.

None of the Photon Lights run on 6 volts and there are no resistors in the Photons 1 & 2. It is the limited amps(effective internal impedance) of the 2016 cells that protects the leds and allows the current to "load down" the cells to around 4 volts.(As Bryan noted.) This is why, if you use a full 6 volts from another power source, you will overload the led. Unless you add more resistance to make up for the difference, the LED will draw too much current from the power source. Even if all you use is two 2032 cells, an un-modified Photon may draw too much current from those two batteries and will likely overdrive the LED and the controller chip, perhaps to distruction.

08-30-2010, 17:11
Also, found this by the same author to explain why the cr2032 will run longer that the cr2016.

I believe you will also find that the Red, Orange, Yellow, & IR LEDs are not normally run on 4.1 volts, but closer to 2.2-2.6 volts. This works well with the 2032 cells when they load down the cell to that level. Their long running time is due to the increased millamp/hour rating of the 2032 cell over the 2016 cell.


08-31-2010, 01:47
You all went and dragged The Old Fhart into a battery argument.
We are never going to hear the end of it now.