Observations about output of the Vamo V3

[LeoRex]

Now, the only real technical info I've seen on the Vamo is a really good video put out by Matthew Olmstead, showing how with a single 18650, the Vamo V2 pretty much peters out at 12w.

But I've seen nothing on the V3.... I played around with mine a bit and this is what I found.... I only have two devices that I can get a decent reading off... a 1.25 (metered) RSST and a 1.5 (metered) IGO-l. Three configs: single IMR 18650, single IMR 18350 and stacked IMR 18350.

IGO (1.5)

Both singles peaked at 4.55v at the posts... and it was like hitting a wall, anything from 4.5-6v was no difference.
Stacked 18350s hit a wall at 5.6v.

RSST (1.25)
Both singles peaked at somewhere between 4.1 and 4.2 at the screws (fluttered back and forth), so I'll average that out to 4.15v
Stacked 18350s.... 5.6v again.

So a single battery, regardless of size, had a max POWER output of around 13.8w.
But stacked, it is VOLTAGE limited (at least on the LR stuff I have in my arsenal) at close to 5.6v.... worked out to a max output of 25 watts.

Has anyone hooked it up to something a little fancier than my little hand held MM? And with something higher up? From the looks of it, it looks like it performs similar to the V2, just with a higher ceiling. (4.5v vs 4.2v, 13.8w vs 12, etc.)

 

[Eddie.Willers]

You're barking up the wrong tree by thinking about voltage and wattage here.

The Vamo chip - whatever version - will be limited by AMPERAGE. That is, the amount of CURRENT that the circuit can handle. The current draw of the circuit will be determined by the resistance used and the voltage/wattage selected.

Example: assuming a 1.5ohm coil and a 4A limit, the maximum voltage the circuit could handle would be 1.5*4= 6 volts. This would have a power consumption of current*voltage (4*6)= 24 watts. However, this is by calculation and may not reflect real life - YMMV.

Now, the only other thing that will affect the power delivery of the circuit is the ability of the batteries to handle the demand being placed on them. In this respect, two batteries in series will have a greater capacity to run at higher-loads for longer. Example: running a pair of 800mAh batteries will give you better 'peak' performance, but shorter life, than a single 1600mAh.

 

[WarHawk-AVG]

nice writeup...much easier to regulate down than boost then regulate down

 

[LeoRex]

nice writeup...much easier to regulate down than boost then regulate down

Yeah... pretty much... at no point am I anywhere near amperage limits, so it has to be limits to boosting voltage.

No biggie, that is still a fairly high power for a VV device anyhow. If I wanted to give it the spurs, I'd go sub-ohm and put it on my K100.

Still... when will these guys start using chips like the DNA20??