Do you know of any that actually put out more then 500mA to the LED, and bonus if its a constant boost till battery exhaustion and has several modes
I got a few of those cheapy AA zoomies from WB when they were on sale. The drivers are 15 mm, Hi-med-strobe modes, and one I got cranking at 2.05A on a Sanyo 14500. I noticed an R390 resistor connected right before the - LED wire, so re-wired the - wire to before the resistor and that boosted the amps from about 1.2A to 2.05A.
Not sure what size, or what boost capability you need. I tested an Eneloop on it and it still works at 1.7a though - about 1/4 the output the 14500 has (75 lumens vs. 323 lumens) running a XP-G2 on a Noctigon.
This claims 700-800mA
http://dx.com/p/700-800ma-3-mode-regulated-led-driver-circuit-board-for-diy-flashlight-3v-pair-128086
From this thread https://budgetlightforum.com/t/-/17498
I’m looking for one eneloop AA, no 14500s, and something confirmed high output, for example HKJ tested one and it was something like 200mA linear
Those boost drivers are difficult to find to be completely linear until the battery is flat. the 7880 Driver is the only single AA ( 1.5 volt) boost driver i really tested and used in modded lights.
The one I currently EDC uses this driver from FT. I gave up on the idea of using AA LSD cells however, and now use the Nitecore protected 14500 or the Sanyo unprotected 14500 cells in it. And while it is rated at 3.6V, I have been using it that way for months and the tailcap readings are 2A at 4.2V, and no problems so far. It became my EDC because I love the output of the XM-L2 T4 5C emitter I put in it. Subjectively it looks like I get about 650lm from it.
I have also been considering this
rather more expensive $9.00 one from IOS, as it says 650mAh for one AA cell but is rated for up to 3V. I’m tempted to try it with one AA LiFePO4 cell and see what happens.
it was tested by HKJ, did great on 2AA, but crummy on 1AA
and they are 17mm, SK68 is 15mm I believe
Thanks, going to have a look at that review now.
I should mention another reason I prefer to use the 14500 cells: cold weather. In spite of the fact that they claim the newer Eneloops have improved and are good to –20C (from the previous –10C), that is not what we have found in real world Rocky Mountain ‘head down, bum up’ conditions. So then the only (expensive) option has been Energizer Lithium Primary cells. I look at Eneloops as something I use around the house in my toothbrush and remote controls. When I am in the real world where the word ‘inconvenient’ can qucikly become ‘life threatening’, I have no interest in the heavier Eneloops, or more affordable and equally good Recyko cells.
you’ll be hard pressed to get more than 350mA to the LED from a single AA as the driver will be drawing 1.7-2A from the cell at that current. To get 500mA you’d have to have either a very efficient driver (these small boost drivers are pretty inefficient) or draw 3A+ from a NiMh cell, neither of which are trivial or cheap.
The problem is low efficiency and the battery current. You will need to boost the voltage about 3 times, i.e. you need 3 times the current from the battery with 100% efficiency, but in real life the efficiency is more like 50% to 60%.
My next driver review is a decent driver for one or two AA batteries, it limits the battery current draw to about 2A and will stabilize when battery voltage is above 1.5 volt with 700mA to the led.
At 1.25 volt it has 500mA to the led.
There will be many people looking forward to that review.
FWIW I’ve installed a DX 7880 (17mm driver) into an SK68. It wouldn’t fit into the driver pocket, but it did fit behind the pill just fine.
The 7880 is a pretty weird driver, I’m not endorsing it - just pointing out that 17mm drivers can be crammed into at least some SK68’s without much trouble.