Lately I've been looking into the MM+ board due to its low price and abundant stock. Would like to get a couple of these but don't know much about its characteristics and merits.
Anyone has good experience with this driver? How does it compare with the BBNG and GD in terms of performance and efficiency, especially in a typical 2xAA setup? Is it a good candidate for such a light setup? Does it maintain constant output at 700mA? Is it compatible with single LiIon (eg. 14500) power source? Any special precautions when assembling this board into custom modules (eg. is potting absolutely necessary)?
The MM is a boost only and assuming a Vf of 3V-3.5V on most LEDs a li-ion battery voltage would be higher than the Vf putting the driver in bypass mode and risk possible damage to the driver.
MM is not a CC regulator like the NG or GD. It will be brighter on a fresh set of batteries and get dimmer as the battery goes down.
It is a great driver if you want to milk the most out of a set of alkaline batteries as the driver will work down to 1V or so.
If you are using rechargeable especially NIMH then this may not be good as over-discharging NIMH degrades this type of batteries as they don't like to be deep discharged.
If you want to use different cell topologies in one light you will more than likely need a buck/boost driver like the GD.
Personally I would stick to GD for my 2xAA applications, but for friends and relatives the situation is different. Gave them flashlights as presents a few years back, and since their lights are now "underperforming" (ie. can't keep up with the competition in terms of brightness) I intend to prepare module upgrades for them in an economical way. They're all non-flashaholic audience so probably aren't picky on battery choice (ie. no L91s, oxyalkalines or other premium AAs, not even NiMHs, just standard grade stuff) and thus the MM+ seems like a good candidate for the cause.
Have also considered BBNG but its unit price is not low enough. Probably would stick to 750mA level but realize that premium AAs would be necessary to deliver good performance, and that the system might not run cool enough. 500mA seems to be too low and may deliver only little advantage over the stock 350-400mA module in terms of brightness performance.
If you are upgrading from the older Lux3 generation LEDs that alone would be a major upgrade. Todays XR-E, Rebel, Seoul or others are almost twice as bright for the same drive current.
So, a 500mA driver and a newer LED vs a Lux3 is a good upgrade as is.
You don't need to drive the current generation LEDs very hard to get a ton of light. Most are over 100lm/W or if driven at 350mA generate over 100lm of light output. So, driving at 500mA is well over 100lm of light output.
It's so impressive nowdays I received a light that has a 1/2W LED and it performs on par with the old sandwiches I made driving lux3 at 750mA.
MM+ driver question
Reply With Quote
