Nice post GuySonic, I look forward to your report! T+
OK, finally had a chance to open one of these devices up and do some tests. I am quite impressed with the engineering sophistication found inside.
Here are views of both sides of SM PCB board, and part of the test rig setup.MEASUREMENTS
:Switching circuit efficiency
= 78% to 95% (Efficiency depending on input voltage to device, and ampere current draw at output. Also found NO HOT RUNNING COMPONENTS on either side of the board even with ful .53 amp output. This indicates excellent engineering design)Amperage output
= .53 amperes/4.6 volts (~2.4 watt) output measured into Microtrack while charging +60% depleted battery.Device Input amperes
~0.9 amps/2.7 volts input with 0.51 amps/4.6 volts output (full applied MT charging power)
~0.5 amps/3.0 " " " 0.27 amps/5.3 " " (battery fully charged, MT in RECORD)Minimum Device input starting voltage
= 2.7 volts = 1.35* volts per AA cell
(*NOTE: Device may not start up with 1.25 volt rated
NiCAD/NiMH cells that are slightly discharged or not fresh off the charger to read 1.35 volts per cell. In other words, once device is shuts down or disconnected from powering deck, rechargeable cells are likely at nominal 1.25 volts that will NOT to start up again
even though nearly still fully charged)Minimum operating voltage
= 1.85 volts
(NOTE: Once started
, device will continue to work following
battery discharge DOWN TO 0.92 VOLTS per cell! That is as long as device is not shut off by disconnecting the output load where it demands at least cells having >1.35 volts per cell to start up again. This is where the lithium cells work well with this device as they start out at 1.75 volts per cell, and deliver +90% of their power before cell's voltage reaches 1.35 volts. Newer technology alkaline cells may also work fairly reliably delivering at least 70% of their +2 ampere capacity and still be able to start up this device, and if left connected to the load, will deliver +97% capacity before the device shuts down for good.)Other Noted Device features
1) Plugging in output power cord momentarily shorts the output to start up the switching boost circuitry. Applying a load with an already connected power cord does the same thing.
However, if there is NOTHING connected to the output to draw power, the device shuts down drawing almost nothing (<.0000001 ampere; the reason the two internal AA cells can still be good after for 10 years), AND WILL NOT START UP AGAIN FOR A FULL MINUTE even if reconnected to a load as there is 60 second internal keep off timer inside
that prolongs the 'sleep mode' for some reason I haven't figured out as yet.
2) Two blue flashing LED indicators show device is active, and will continue to flash until device either runs out of battery power, or the load is disconnected initiating the 'sleep mode.' Summary
So it looks like with AA Lithium cells having 2500 -2900 milliamperes capacity, recording time with already fully charged MT is as much as 5 hours, and maybe much as 3-3.5 hours with regular alkaline or more using newer 'OXY' alkaline formulations before MT's internal battery is tapped to supply power to the deck.
If you can get the Energi To Go device to start up with freshly charge 2700 MA capacity NiMH (for example) AND DO NOT DISCONNECT ANYTHING to continually run the MT(which draws ~.25 amps continually from external USB power even with fully charged internal battery/display off), then as much as 5 hours recording time might be possible before the MT's battery is again tapped to supply deck power.Conclusion
: Just out of the box, Energi To Go is an effective external MT powering device for having reliable power for at least 3 hour concerts using cheap alkaline cells, and up to 5 hours on AA photo lithium and (continually connected, high voltage) NiMH.
I'm now thinking to attach the (above pictured) test board to (2) C/D cell alkaline battery sleds to run for 4X/10X the estimated AA cell times for long duration field recording applications. That is if the board proves reliable for professional type remote work where failure is not an option.