What is direct drive?

Before the flames start, I tried the search function without fully understanding what the term means. I am looking at ordering a Solarforce L2 with the capability of using 18650 batteries. I want to use Gene's MC-E pill, too. What does direct drive mean?

It simply means there is no buck or boost circuit and that the voltage from the battery goes straight to the LED.

Direct drive means that the emitters positive and negative connections are connected to the battery supply with no current/voltage regulation in between.

Basically, what it means is that the output of a light varies as the voltage of your battery goes down.

It will be brightest with fresh batteries and go down from there.

On a regulated flashlight, there is a circuit board that keeps the light at a set level until the battery craps out, or goes to a lower level(moon mode).

At least that is my take on it.

By the way, welcome to CPF. This place is like the latest book on flashlights. There aren't any stupid questions here. I know because I've asked a bunch of them and always received intelligent answers.

It just means, on a runtime chart, you draw a straight line from 100% to 0%. Unregulated. :welcome:

rockz4532 said:

It just means, on a runtime chart, you draw a straight line from 100% to 0%. Unregulated. :welcome:

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I've noticed that Direct driving with NiMh Eneloops that they will maintain constant voltage for about 80% of their runtime then drop right off , li-ion's cant do this.

lightforce2 said:

I've noticed that Direct driving with NiMh Eneloops that they will maintain constant voltage for about 80% of their runtime then drop right off , li-ion's cant do this.

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Yeah, direct drive performance varies among the different battery types. The discharge curve is fairly flat with NiMH and Li-Ion batteries, but not the case with Alkalines. There is great debate on whether regulation really provides that much more of a flat discharge curve as compared to direct drive from NiMH or Li-Ion batteries. Depending on the application, it's fair to say that Alkaline battery setups benefit the most from regulation circuitry.

bourmb said:

Before the flames start, I tried the search function without fully understanding what the term means. I am looking at ordering a Solarforce L2 with the capability of using 18650 batteries. I want to use Gene's MC-E pill, too. What does direct drive mean?

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I am waiting for my MC-E direct drive P60 from Gene. The lumen output will be dependant on the cell. The bigger the battery the longer it can hold those high amp draw ratings. With an 18650 the MC-E Gene mentioned will be at least 1000 lumens at 3.5amp draw: for around 10 minutes. He said it settled down at 2.8amp draw.

With regulated MC-E the output is more linear, but in a DD (direct drive) it will be more of a curve.

Note: Due to the high amp draw of the MC-E you should look into getting the IMR 18650's. I use these batteries for 500 lumen plus incan lights and the P7/MC-E LED's. My regular 18650's gere getting killed with high amp applications, but now the IMR 18650's can handle anything I throw at them. Regular 18650's are not designed for high amp draw applications. Don't worry about the low mAh advertised on the IMR cell they are great and more honestly reporting mAh.

:welcome: