this post was submitted on 12 Mar 2025
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I actually know this! I used to work on an LVAD controller about 10 years ago. The technology is largely similar.
The pumps are centrifugal, they have to maintain blood pressure, and are largely waterproof.
The pumps spin with a brushless DC motor controlled by PWM. Depending on the specifics of the motor the RPM can be between 8,000 and 22,000. Because of the limitations of battery technology, you're stuck with using a LiPo battery. LiPos are annoying as all shit to deal with. You have to charge them carefully, discharge them carefully, and they're pretty big.
To give you an idea - FPV racing drone batteries can last several minutes: https://www.getfpv.com/batteries/mini-quad-batteries/cnhl-ultra-black-series-1050mah-150c-6s-lipo-battery-xt60.html On a really carefully tuned racer, you can get maybe 5 minutes out of a quad that would use that battery.
Edit: I was incorrect, the first battery I provided was not the battery that would be used in racing. LiPos are what I wanted to share. The battery now highlights what I wanted to.
Calling bullshit on that battery info RE: FPV drones matey.
That's a 4000mAh 4s Li-Ion pack. No racers use Lithium Ion, and definitely not 4AH.
That's a long range FPV pack, and it'll go for about half an hour to an hour on an appropriate LR quad.
A typical racing machine will run on 6s 1300-1500mAh Li-Po packs which are significantly lighter and smaller than your provided link, as well as higher voltage.
You are completely correct. It's been a while since I was flying.
I'm not actually sure what that battery pack is for. Maybe RC car?
It's for an LR drone. What people use for pushing the range limits on a quad. The 25mW Walksnail challenge for example.
Well, kinda. They'd make their own from bulk cells, but you get the idea 💛
Interesting, What about the change of heart rate a normal heart does in response to exertion? I assume this heart only runs at a single speed?
Nope! It has a range of speeds. The PWM signal it provides also produces something called "counter-electromotive force". I don't remember the exact specifics, but if this measurement falls (corresponding with a drop in blooded pressure) it will increase the pump speed (up to the maximum RPM permitted).
That is how our circulatory system works as well - a drop in blood pressure usually results in an increase to heart rate. I say usually, because I coincidentally have a nervous disorder where this is broken - an increase in heart rate will drop my blood pressure. A drop in blood pressure will also increase my heart rate, which then drops my blood pressure, which causes a runaway and I faint.
Very cool, thanks for the insights. Its really amazing how far prosthetics have come in the last years