Series connecting MCE & R2

[trout]

I am planning a mag mod for a bike light and would like to use 2 MCE and 2 R2 leds
and drive them as 2 strings of 5 emitters with a maxflex

Is it ok to connect all 5 emitters from 1 MCE and 1 R2 in series

or is there another way :thanks:

 

[znomit]

Yes trout but you are limiting the R2 to the 700mA MC-E current limit.
You can run the two MC-E in parallel at 600mA off the maxflex followed by the two R2s in series at 1200mA(who cares about the 1A current limit ).
Not sure which setup would be brighter.

 

[2xTrinity]

Yes trout but you are limiting the R2 to the 700mA MC-E current limit.
You can run the two MC-E in parallel at 600mA off the maxflex followed by the two R2s in series at 1200mA(who cares about the 1A current limit ).
Not sure which setup would be brighter.

All 5 in series as the original poster specified is far more sensible. For voltage boost drivers, it's usually a better idea to have a lower total Vf for your strings. so 1.4A @ 17V (23.8W) will be more efficient to produce than 1.2A @ 21V (25.2W)

Brightness will be close. The latter will have more power, but will be driving the R2s at a muhc less efficient level. When you overdrive an LED you hit diminishing returns. This will be largely offset by dropping the MC-Es from 700mA to 600mA. Certainly if you're looking for the most lumens per watt (from the battery), the 5S 2P with MC-E connected to 1 R2 is the best way.

May I ask -- what sort of battery will you be using? Depending on your answer it may be a better idea to do something like wire all the MC-Es into parallel strings of two, and also run the XR-Es in a parallel string of 2. (eg, if you're using 2 LiIon cells you might be able to pull off a more or less direct drive setup doing that).

 

[trout]

Thanks for the advise

this is the early stage of the light

The battery will most likely be a 14.8 Li Ion pack .

I did think about using 2 drivers a maxflex for the MCE s and a buckpuck for the R2s
but this adds to the cost and complexity .

 

[znomit]

I did think about using 2 drivers a maxflex for the MCEs and a buckpuck for the R2s but this adds to the cost and complexity .

I like that. Maxflex + Bflex with a two way mom switch so you can tailor the beam pattern.