[NSRCA-discussion] Main battery redundant lead for receiver

Mon Jan 23 14:05:56 AKST 2012

Peter,
   To be honest, I'm struggling to make 5000g with my second De Ja Vu that
I bought from a guy IF I want to run redundant packs.  I use some 800mah
packs in the primary De Ja Vu but that has no weight issues at 4885.  I
took off the APC prop, stuck on a Falcon and added an 800mah pack for
redundancy with a 2nd regulator.  Those items weighed about the same that I
saved switching to the Falcon prop.   The APC was 128g and the new Falcon
was 62g.  The 2nd rx battery and regulator was 76g so I'm only 10g heavier
with redundancy.  On the 2nd De Ja Vu, it has painted wings and stab and
weighed in at the Nats at 4960g.  I do still need to switch receivers in it
(I have an 8 ch and a 14 ch receiver).  The 8 ch is in the primary but I'll
switch that out to save a few grams.  The 2nd DJV was not running a switch
or an arming switch which I feel is important.  So...to make it all happen,
a Falcon vs. APC and then am running two 350mah 2S packs (Sky Lipo).  They
only weigh 26g each.  The 800's were 46g each.  Now, with these pigtails, I
am under 5000g finally.  WOOT!

On Mon, Jan 23, 2012 at 4:56 PM, Peter Vogel <vogel.peter at gmail.com> wrote:

> Ah.  Now that's a good idea + point.  And then, in my case, where I'm
> running HV, I don't even need a reg.  That would provide true power
> redundancy for almost no weight penalty, though it does run the risk of
> yanking your RX out if your main battery ejects, or, even if it doesn't
> yank the Rx (which is held in by 6 servo leads after all, it could yank the
> redundant battery lead loose and the main system battery is of course
> yanking itself, so you are left with no radio...
>
> Scott, how do you come up with 20g savings?  What size Rx battery are you
> running?  My TP 1350's weigh 76g, even 900's are in the 60+g range.
>
> Peter+
>
> On Mon, Jan 23, 2012 at 2:51 PM, Keith Hoard <khoard at gmail.com> wrote:
>
>> Only tap off two cells of your main pack. You can then use a regular
>> regulator (as opposed to a non-regular regulator).
>>
>> Keith Hoard
>> Collierville, TN
>>
>> On Jan 23, 2012, at 16:49, Peter Vogel <vogel.peter at gmail.com> wrote:
>>
>> And, of course, with a non-switching BEC off a 10s or even a 5s pack you
>> would have massive heat issues as it tries to step down the voltage from
>> 18.5 volts to 7.2 or 6 volts, depending on whether you are running an HV or
>> standard voltage setup, so the regulator would probably need a fan or heat
>> sink of some sort, which likely negates any weight savings from not running
>> with a second battery.
>>
>> Peter+
>>
>> On Mon, Jan 23, 2012 at 2:30 PM, Scott McHarg <scmcharg at gmail.com> wrote:
>>
>>> You have to be careful using the BEC, especially from CC because it is a
>>> switching regulator which cannot be run in parallel.  It's really best not
>>> to use the BEC and set up a truly separate system.
>>>
>>> Scott
>>>
>>>
>>> On Mon, Jan 23, 2012 at 4:28 PM, George Kennie <geobet4evr at gmail.com>wrote:
>>>
>>>> Could a CC BEC also be used instead of a reg.? I don't know how much
>>>> curent is passed by a reg.
>>>> Sounds good cause it's a bummer trying to solder an extra lead to the
>>>> Deans.
>>>>
>>>> G.
>>>>
>>>> On Mon, Jan 23, 2012 at 5:09 PM, Scott McHarg <scmcharg at gmail.com>wrote:
>>>>
>>>>> Guys,
>>>>>    Chris Moon just e-mailed me about some leads that were done at the
>>>>> factory.  These leads run off your balance leads to a voltage regulator and
>>>>> allow your main battery pack to be utilized as a redundant receiver
>>>>> battery.  It is NOT meant to be a primary but it will save 20+ grams if
>>>>> you're running 2 rx batteries.  You still have to run the 2nd regulator for
>>>>> true redundancy but you eliminate the 2nd battery.  These leads are factory
>>>>> made and eliminate the need to make them yourself with the concern about
>>>>> plugging in to the wrong cell.  I know in my article, I was pretty much
>>>>> against doing this as a backup but, with Chris having this made at the
>>>>> factory, he has all but eliminated making a mistake by tying to the wrong
>>>>> cell.  I have the link that I'll e-mail you off-list or you can just go to
>>>>> his website.  I don't want to break the NSRCA list rules by advertising for
>>>>> him even though he advertises with the NSRCA.  The leads are only $3.99
>>>>> each and are found under the Connectors/Adapters listing.
>>>>>
>>>>> Thank,
>>>>> Scott
>>>>>
>>>>> --
>>>>> *Scott A. McHarg*
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> NSRCA-discussion mailing list
>>>>> NSRCA-discussion at lists.nsrca.org
>>>>> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
>>>>>
>>>>
>>>>
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>>>
>>>
>>>
>>> --
>>> *Scott A. McHarg*
>>>
>>>
>>> _______________________________________________
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>>> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
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>>
>>
>>
>> --
>> Director, Fixed Wing Flight Training
>> Santa Clara County Model Aircraft Skypark
>>
>>
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>
>
>
> --
> Director, Fixed Wing Flight Training
> Santa Clara County Model Aircraft Skypark
>
>
>
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-- 
*Scott A. McHarg*
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