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Old 10-20-2017, 07:19 PM
rv7charlie rv7charlie is offline
Join Date: May 2006
Location: Pocahontas MS
Posts: 3,338

Originally Posted by rv7charlie View Post
You do realize that PM alternators are being installed on the other end of experimental engines, too, driven by belts at their original design rpm? This is most likely to be done by those obsessing over weight; the same people that will be drawn to lithium chemistry batteries.
Of course, there is many different combinations, builds, set ups in the experimental aircraft market.

OK, I guess I should be more explicit. Those installations will not be limited to 20 amps by low rpm, yet your blanket statements ignore that fact.

I ask the above question because if the BMS is *blocking* the voltage, it's removing the load, which will allow voltage to rise (probably a lot). On the other hand, if it's *shunting* the current to ground, it's *supplying* a load to hold the voltage down. So, which? .
Please see our manual or previous posts concerning this.

OK, so it is blocking the voltage. What controls voltage rise?
Please understand that I'm asking these questions because I can't get some of the earlier answers to line up with a couple of careers worth of experience herding electrons. I want the new tech to work, but we need to understand all the differences from the old tech to have confidence in it.
We can appreciate you trying to understand how the BMS works and the MOSFET technology that is used within the BMS, which is definitely in the newer realm of technology advancements.

I guess it is relatively new; It invented over a decade after transistors (transistor in 1947 to MOSFET in 1959)

We have spent years developing the BMS, (9 to be exact) and we not only have the electrical and mechanical engineers at EarthX, but we have also the expertise of the engineering departments from companies such as Vans Aircraft, Rotax Engines, Viking Engines, and the engineers of the many aircraft companies that have implemented using the EarthX brand into their aircraft builds that have helped us design a robust BMS for aircraft. Plus we design to the FAA certified aircraft requirements and commercial product certifications as previously mentioned.
Fly Lightly,


As a corollary to what scard posted, I might have just fallen off the turnip truck, but I didn't land on my head.

I missed the answer to this one; was it in there?:
For the wound-field models that B&C & others sell for the vacuum pad: Are you saying that your engineering dept has spun one at vacuum pad rpm with the output feeding the field, minimal-to-no load, and the voltage never rises above your 60V threshold?

If you'd like to get above that 40V (or 60V) limit, here's a link to some 150V+ MOSFETs:

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