Best double electronics XP-G configuration

[sosemot728]

Negating specific drivers...

What configuration would be best for powering two XP-G led's (1.5A ~3.5v) at very good efficiency.

i.e.

• LED's in Series, Boost controller, 3.7v double cell Li-ion (Difficult to build with good efficiency)
• LED's in Series, Buck-Boost controller, 7.4v double cell Li-ion (Larger driver component count)
• LED's in Series, Buck controller, 11.1v triple cell Li-ion (Larger battery pack)

 

[Th232]

IIRC, generally from most to least efficient:

Buck > Boost > Buck-Boost

But without the exact drivers, can't really say which will be more efficient. Still, I'd go for a buck driver if it was me.

I've also never seen a 7.4V buck-boost driver, all I've ever seen is 1.8 or 2.7 to 4.2 V. If you've seen one, I'd like to know where so I can possibly get one or two.

 

[MikeAusC]

Why not use an AMC7135 driver from 2S 18650s ?

It'll be as efficient as a Switchmode driver over most of the discharge range.

 

[DIWdiver]

Why not use an AMC7135 driver from 2S 18650s ?

It'll be as efficient as a Switchmode driver over most of the discharge range.

High efficiency, but at the sacrifice of decreasing light output as the batteries discharge.

D