Newbie needs help with drop-ins!

Flashlight Modding and DIY Parts
1

Hi All

I bought a solarforce L2i and L2r in their recent sale, thinking I would buy drop-ins when I understood a bit more about battery choices and voltage etc...but my addiction to torches has become much more severe than I thought it would (very much helped by this site).

Now I must have drop-ins for them, but am getting confused about which ones to buy.

For the L2r I would like to be able to use alkaline, nimh or lithium AAs, I assume this means I need a low voltage dropin...but which one???

For the L2i I will be using 3AAAs or 1 18650. Any recommendations of what to buy?

I would prefer multimode for both, with no strobe/sos for the L2r. Stobe/sos is ok for L2i (I plan on using it on my bike).

If anyone could recommend good dropins for both I would be eternally grateful :)

2

"For the L2i I will be using 3AAAs or 1 18650" and if you need Strobe or SOS (I do not like the blinkmodes):

http://www.solarforce-sales.com/product_detail.php?t=RB&s=10&id=37

If you don't need Strobe and SOS, I would prefer this one (also for the L2r)

http://www.solarforce-sales.com/product_detail.php?t=RB&s=10&id=113

With the L2r can use alkaline, nimh (max. Voltage 4,2).

3

thanks for the help mate!

I'm going to order both of these :)

4

Just one more question - How many volts is 2 AA batteries going to be? Do you add the voltages together (2x1.5v) to get the total voltage?

5

1.5v x 2 = 3v

6

That was a good question.

Along those lines (without opening a whole new thread) what is the disadvantage of using a 3-18v dropin rather than, say, a 3-4.2v dropin?

If you are going to use 18650 batteries, does the 3-4.2 dropin give you longer runtimes or more lumens? Sounds to me like it just has a 'smarter' driver, but I'm an electronic idiot so I would like clarification as to why we don't just always order the 3-18v ones.

7

The narrower the voltage range and the smaller the difference from what the LED actually needs, the more efficient the driver can be.

The wider the range of input voltages, the less efficient the driver will be. And a lot of the extra voltage will just get burned off as heat.

8

See, that is why I come to this site. How's that for a concise answer to a question myself and every other person new to the P60 drop-in world needs to know.

bravoDonFoy

9

It's probably an oversimplification. After all, you could print out everything I know about electronics (admittedly in a very small font) and have 99% of the sheet of paper left.

10

Don, is it actually more efficient or is it just less complicated? It seems that a well-designed driver would be able to send the appropriate current to the LED regardless of battery voltage. I can't imagine that if you use an 8.4v setup compared to a 4.2v setup, that all the excess just gets burned off in heat. The driver should be able to compensate so that demand on the battery decreases and runtime increases.

But like I said, that is just my ramblings and has no basis in electronic knowledge...

11

It's rather dificult to design a driver that can take 3-18v and always put out 3.3v at 3A (for example) so what tends to happen is that corners are cut.

So what you often end up with is a driver that works well and puts out the current you would want only at the higher end of it's range, with the lower end disapointing.

It certainly can be done, but that is probably the diffrence between a $5 driver and a +$30 one.