REFLECTOR: Battery Isolator

[Andrew Ellzey]

Michalk
----- Original Message ----- 
From: "michalk" <michalk at awpi.com>
To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
Sent: Wednesday, January 03, 2007 9:15 AM
Subject: Re: REFLECTOR: Battery Isolator


>I don't have access to my schematics right now.  I can describe it
> easily enough though.
>
> There are three posts on the combiner.  One for each battery, and one
> for ground.  It's quite simple, just connect each post to a battery.
> The ground wire does not need to be very large.  For the battery
> connections, about 10 gauge should do it.  The alternator charges the
> essential bus.  When charging, the two busses are combined.
>
> I do see merit in the manual Nuckolls method.  It's a tradeoff.  I
> wanted it automatic, and less wiring.
>
> I have two battery busses, but one alternator.  My backup bus is not for
> engine cranking, so that battery is two motorcycle type batteries on
> each side of my main battery.  I plan to swap out a battery at each 
> annual.
>
> I do have a "join" switch, but it's for powering the essential bus off
> the main battery.  You can't start the engine with it.
>
> My essential bus powers the Autronic electronic ignition/injection, and
> avionics.  I did a load test, which is not entirely accurate because the
> load on the Autronic scales with RPM.  Accounting for that overhead with
> an estimated flying load, my batteries should keep the airplane flying
> for ten hours.  Make sure your battery capacity is longer than your fuel
> capacity.
>
> Even if the Autronic loses power, the backups would still work.  My test
> was with all of the gyros and radios working ... a worst case scenario
> minus the pitot heat.  If I turned off everything but the gyros I
> imagine my flight time would be extended beyond 20 hours.  However,
> that's not the main intent of multiple systems.  Redundancy is what one
> is after.  A failure analysis is interesting.  In my case, it's the fuel
> pressure regulator that is the weak link.  Finding data on failure rates
> of equipment can be difficult, so one has to make assumptions and make
> sure those components are frequently inspected or replaced.
>
> Anyway, I'm preaching to the choir here.  My plane is all electric.
> That means my systems need to have electrical redundancy.  Vacuum guys
> have a redundant system with it's own set of failure points.
>
> You still want that schematic?
>
> Alex wrote:
>> Hey Brian-
>> Can you send me a schematic of how you installed the West Marine 
>> isolator? I
>> have one also- and trying to make sure I get it in there correctly-
>> currently have separate relays for each battery installed, and I have a
>> cross over relay , but not sure if I will still need it or not......
>>
>> Alex
>> alex157 at pwhome.com
>>
>> -----Original Message-----
>> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
>> Behalf Of Michael Watson
>> Sent: Tuesday, January 02, 2007 11:51 AM
>> To: Velocity Aircraft Owners and Builders list
>> Subject: Re: REFLECTOR: Battery Isolator
>>
>> Thanks Kurt/Brian,
>>
>> Any comments AL.
>>
>> I was looking at the ASE Sure-Power 70Amp unit for $40.
>> Guess I'll buy and try it.
>>
>> Mike W.
>>
>>
>> On 1/2/07, Brian Michalk <michalk at awpi.com> wrote:
>>
>>>I'm using a marine battery isolator from West Marine.  Seems to work
>>>okay so far.  Not flying yet.
>>>I voided my warranty by opening it up to see the guts.  Simple
>>>comparator circuit with time delay which drives a relay.  When either
>>>battery is being charged, they are connected together.
>>>
>>>A person could easily make one, but for the $50 or so, it's not worth it.
>>>
>>>We use the solid state ones at work, and they seem to work okay.
>>>
>>>Michael Watson wrote:
>>>
>>>>Does anyone using dual batteries with an internal regulated
>>>>alternator, have a good source and part number for a battery
>>>>isolator? Thanks.
>>>>
>>>>--
>>>>Mike W
>>>>Velocity Elite RG
>>>>Franklin /IVO Electric CS
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>>
>>
>>
>
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