[NSRCA-discussion] HV Direct Drive

[Anthony Romano]

You have to be very careful with this because you can create a floating ground. I used tap of one 5s and grabbed the wrong one frying the ESC.


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From: NSRCA-discussion <nsrca-discussion-bounces at lists.nsrca.org> on behalf of Scott McHarg via NSRCA-discussion <nsrca-discussion at lists.nsrca.org>
Sent: Tuesday, October 16, 2018 8:38 AM
To: Tim & Janet Pritchett; General pattern discussion
Subject: Re: [NSRCA-discussion] HV Direct Drive

There are quite a few folks that do this.  It works just fine and certainly eliminates weight.  John Gayer showed me this technique and actually gave me several adapters.  My only complaint is that this technique still gives you a single point of failure.  If something happens to your motor pack (as a whole) and it's rendered useless in flight, you've lost the ability to land your airplane.  I still run a 350 mah 2S pack for redundancy and then the primary is the 2 cells of the 5S pack.  All you have to do is set your voltage regulator on one to a lower voltage than the other.  This should result in your RX pulling the current from the higher voltage path and the other is simply a backup in case of failure.  This is the lightest way to have redundancy.


Scott A. McHarg

Takeoff is optional.  Landing is mandatory!


On Tue, Oct 16, 2018 at 7:21 AM tim pritchett via NSRCA-discussion <nsrca-discussion at lists.nsrca.org<mailto:nsrca-discussion at lists.nsrca.org>> wrote:
A friend of mine suggested that with high voltage equipment, a dedicated battery is not needed for the receiver and servo's.  Plugging in the balance leads from the 5s power packs directly into the on/off switch to the receiver provides the same voltage.  This is true; the red/blue wires (on my packs...) in the balance leads produce 8.4v.  A simple 5s plug and a two wire harness could be easily made to supply power to the controls, and could even be 'doubled up' to supply power from both 5s packs.  My flight pack usually only drains ~30mah per flight, so that equates to ~7mah per cell in the power pack per flight - almost unnoticeable.

So the question; is anybody doing this with success, and is it recommended?  It eliminates some complexity maintenance and weight, so it seems worth asking. The math seems to work...
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