I know linear BEC's are a pretty crude way to drive a servo in the age of compact UBECS and HV servos, but hear me out:
The Hobbywing 16BL30 is a neat little 2-3S, 30A brushless ESC with a "6V/1A BEC", and the manual specifies that it's a linear rather than switch-mode bec as is found on their larger ESC's. This means that it acts like a sort of variable resistor that 'burns off' the excess voltage between the input and the desired output. (switch-mode refers to dc-dc converters that typically achieve ~90% efficiency. I know all this will be redundant to forum regulars, but I figure I should include this for anyone unfamiliar with the jargon)
A 6V linear BEC on 3S is going to have to "drop" more volts within itself than it provides, which is kind of mind-blowingly inefficient. From that, though, I infer that the 1A limit is a worst-case scenario where it's running off a freshly-charged lipo at 12.6V, which would imply a ~6.6 watt average thermal limit.
On 2S, or even better, a 6-cell NiMh, the situation is a lot more favorable. The BEC would only have to drop a couple volts, less towards the end, achieving ~80% efficiency over the life of a 2S battery.
So, since the current limit to most electronic components, especially semiconductors, isn't a strict ceiling but rather an "average over time" limit primarily governed by heat buildup and dissipation, shouldn't the BEC be good for 2.75A on 2S, assuming a worst-case voltage drop of 2.4V? (6.6W / 2.4V = 2.75A)
I'll field-test my theory by driving two full-sized servos off a supposedly "1A" BEC in my souped-up bashing-crawler.
The Hobbywing 16BL30 is a neat little 2-3S, 30A brushless ESC with a "6V/1A BEC", and the manual specifies that it's a linear rather than switch-mode bec as is found on their larger ESC's. This means that it acts like a sort of variable resistor that 'burns off' the excess voltage between the input and the desired output. (switch-mode refers to dc-dc converters that typically achieve ~90% efficiency. I know all this will be redundant to forum regulars, but I figure I should include this for anyone unfamiliar with the jargon)
A 6V linear BEC on 3S is going to have to "drop" more volts within itself than it provides, which is kind of mind-blowingly inefficient. From that, though, I infer that the 1A limit is a worst-case scenario where it's running off a freshly-charged lipo at 12.6V, which would imply a ~6.6 watt average thermal limit.
On 2S, or even better, a 6-cell NiMh, the situation is a lot more favorable. The BEC would only have to drop a couple volts, less towards the end, achieving ~80% efficiency over the life of a 2S battery.
So, since the current limit to most electronic components, especially semiconductors, isn't a strict ceiling but rather an "average over time" limit primarily governed by heat buildup and dissipation, shouldn't the BEC be good for 2.75A on 2S, assuming a worst-case voltage drop of 2.4V? (6.6W / 2.4V = 2.75A)
I'll field-test my theory by driving two full-sized servos off a supposedly "1A" BEC in my souped-up bashing-crawler.