DC Converter/Regulator efficiency?

[TomCatt]

I see a lot of comments on the efficiency of the various dc converters / regulators used for mods. It seems to me that while this aspect of converters/regulators is something to keep in mind, exactly how important is it? I ask this because I've been using a LM2596 buck converter module I got off of eBay, which has been pointed out a number of times that this one has a low efficiency.
Yesterday I vaped from ~6:30am to ~9:30/10:00pm when the batteries cut out. (Yeah, I know , just wasn't paying attention.) I have 2 14500 Trustfire Flames 900mAh batts in this mod. Seeing as how this was the ACDC, I just switched over to the AC adapter power and kept on vaping. I would guestimate that I vaped around 3mL before the shutdown.
I also don't vape at high(er) wattage - usually in the 6-8 watt range; so I'm aware that this affects run times.

So, if I vaped at say 10 watts, how much less run time would I be looking at?

 

[BJ43]

Using the same setup, regulator and batteries, at 10 amps I was getting about 10 hrs and I vape hard, two draws each time. I haven't really checked battery duration lately as I mostly use my smaller only PT mod.

 

[CraigHB]

For a rough idea, you can equate efficiency to run time. So a regulator with 10% better efficiency will give you roughly 10% more run time. It's not something that typically makes a huge difference, but a difference of 20% can be quite noticable. The bigger the battery the more noticable. 10% of 16 hours is a lot more than 10% of 6 hours. I probably wouldn't nitpick efficiency differences of a few percentage points but differences in double digits are for sure worthy of consideration.

 

[srolesen]

if your regulator is only 80% effective then your looking at 20% reduction in vaping time+whatever reduction from the internal battery resistance from increased power draw
so if the discharge rate of batteries is a concern,and you like high wattage vaping, then you really need to go for an effective regulator, but if you use imr batteries or more than 2 ah in total battery power then it probably wont be very noticable at all.

i'd guess if you were vaping at 10 watts you wouldnt notice any increased loss from regulator, but a 10% loss in net watt hours applied to atomizer from battiers beeing heavily used, but that's a total guess on my part

 

[CraigHB]

That sounds reasonable.

One other consideration is heat which can be a problem with lower efficiencies. For example, a regulator that's 90% efficient requires 11W input for 10W output. That extra watt is dissipated as heat by the regulator. As effeciency goes down and power output goes up, heat increases exponentially. For that reason, heat can be a major problem for a less efficient regulator such as the linear type. They're typically only 70% efficient, but that can decrease quite a bit as disparity goes up between input and output voltage.