REFLECTOR: [c-a] Re: COZY: 24 Volts VS 12 Volts

[Clayton Chase]

I'd prefer to go with 24V but have chosen to use a 12V system because of
the depth of pocket required to go up to 24V.  The equipment isn't any more
expensive to make, however since there is not a demand for it like there is
for the 12V equipment.  Due to the auto industry, almost everything you
could want in a 12V part is mass manufactured.  Therefore I'll be using 12V
in my plane even though it will add some weight in wires.


On Mon, Oct 7, 2013 at 9:37 AM, Dave Philipsen <velocity at davebiz.com> wrote:

> Heh, heh...nice techno-humor!  The only point I'm trying to make with all
> of this is that, yes, there are some benefits with a 24v system.  There
> would be even more benefits with a 48v system and even a 96v system. But at
> some point the advantages of increasing the voltage diminish to a point
> where they are not really practical.  Obviously, for automobiles, the
> engineers decided almost universally that that point was at 12 volts. I
> believe that for our experimental aircraft the point is also at 12 volts.
> But, others with perhaps deeper pockets and a desire for slightly greater
> reliability and dependability may arrive at the point of 24 volts.
>
>
> Dave Philipsen
>> Velocity STD FG
>>
> N83DP
>>
>
> On Oct 7, 2013, at 11:08 AM, Don Johnston <numa at comcast.net> wrote:
>
> You are forgiven.
>
> Now go say 50 "Hail Tesla's" and sin no more. :-)
>
>
> On Mon, Oct 7, 2013 at 10:35 AM, Dave Philipsen <velocity at davebiz.com>wrote:
>
>> I messed up on the 24v calculations. Strike out the paragraph below and
>> change to:
>>
>> The same scenario with a 24volt 100 amp starter would work out to a 290
>> milliohm total resistance (starter is 240 milliohms and solenoid contacts
>> are 50 milliohms). The circuit will now draw 82 amps and you will see 19.86
>> volts across the starter and 4.13 volts across the solenoid contacts.  This
>> is a better scenario than the 12v system but not as exaggerated as the
>> scenario you stated below.
>>
>>
>> Dave Philipsen
>> Velocity STD FG
>> N83DP
>>
>> On 10/7/2013 10:15 AM, Dave Philipsen wrote:
>>
>>> The same scenario with a 24volt 100 amp starter would work out to a 170
>>> milliohm total resistance (starter is 120 milliohms and solenoid contacts
>>> are 50 milliohms). The circuit will now draw 141 amps and you will see 16.9
>>> volts across the starter and 7.1 volts across the solenoid contacts.  This
>>> is a better scenario than the 12v system but not as exaggerated as the
>>> scenario you stated below.
>>>
>>
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