 |
Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
|
| View previous topic :: View next topic |
| Author |
Message |
PaulR
Joined: 13 Nov 2008
Posts: 22
Location: Alabama
|
 Posted: Sun Jan 03, 2010 6:17 am Post subject: Battery Bus Location |
 |
|
I'm working on locating items on the firewall and have a question on location of the alway hot battery bus. I know that there is a length limit on the wire powering this bus and with that in mind, it seems the ideal location for the fuse block is on the hot side of the firewall.
Is this block and fuse combination okay to put on the hot side? Seems like it defeats the purpose of this bus if it's feeder line is fused and then put on the cool side of the firewall.
Thanks
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
_________________
Paul Rose
N417PR
RV-9A |
|
| Back to top |
|
 |
nuckolls.bob(at)aeroelect
Guest
|
| Posted: Mon Jan 04, 2010 8:21 pm Post subject: Battery Bus Location |
|
|
At 08:17 AM 1/3/2010, you wrote:
| Quote: | --> AeroElectric-List message posted by: "PaulR" <prose(at)panhandle.rr.com>
I'm working on locating items on the firewall and have a question on location of the alway hot battery bus. I know that there is a length limit on the wire powering this bus and with that in mind, it seems the ideal location for the fuse block is on the hot side of the firewall.
Is this block and fuse combination okay to put on the hot side? Seems like it defeats the purpose of this bus if it's feeder line is fused and then put on the cool side of the firewall. |
Where do you want to put it? Lots of fuse/relay boxes
go under the hood on cars. However, they're generally
covered. The Bussmann fuse-blocks are open. If
you want to put it inside, you can run the bus feeder
through the fire wall with some judicious attention
to support and insulation. Here's an example of a
small ceramic (thus fireproof) feed through insulator:
[img]cid:.0[/img]
This one is available from
http://www.surplussales.com/antennas/antennas-6.html
for about $5. Use fire-seal putty as an
installation sealant.
Bob . . .
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
| Description: |
|
| Filesize: |
9.96 KB |
| Viewed: |
7257 Time(s) |
|
|
|
| Back to top |
|
|
PaulR
Joined: 13 Nov 2008
Posts: 22
Location: Alabama
|
| Posted: Tue Jan 05, 2010 2:10 pm Post subject: Re: Battery Bus Location |
|
|
Bob,
Thanks for the reply. I'm not opposed to putting it outside on the firewall, I just didn't know whether the fuse blocks from B&C would be alright out there. I think you spell out 6" length on the feed wire. If I stick to that, which makes sense unprotected, then I would have to put it directly on the inside of the firewall which would be extremely difficult to get to for service. Hopefully none will be required, but it would be easier on the hot side.
The insulator would indeed be a good method to get the wire inside, but the length is still a factor.
Does most everyone else put them on the hot side?
Thanks
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
_________________
Paul Rose
N417PR
RV-9A |
|
| Back to top |
|
|
nuckolls.bob(at)aeroelect
Guest
|
| Posted: Tue Jan 05, 2010 3:33 pm Post subject: Battery Bus Location |
|
|
At 04:10 PM 1/5/2010, you wrote:
| Quote: |
Bob,
Thanks for the reply. I'm not opposed to putting it outside on the
firewall, I just didn't know whether the fuse blocks from B&C would
be alright out there. I think you spell out 6" length on the feed wire.
|
That's an idealized notion. If you need to make it 12"
or even longer to satisfy design goals, the world is
not going to come to an end.
| Quote: | If I stick to that, which makes sense unprotected, then I would
have to put it directly on the inside of the firewall which would
be extremely difficult to get to for service. Hopefully none will
be required, but it would be easier on the hot side.
|
Then put it in a location for ease of maintenance.
That would be my choice as well. Think about a
way to at least cover if not box-up the fuseblock
like they do under the hood of cars.
| Quote: | The insulator would indeed be a good method to get the wire inside,
but the length is still a factor.
|
The length isn't a REALLY BIG thing, just a
good practice design rule adopted by the TC
side of the house many years ago. How long would
the wire be for both extending the battery
feeder AND ease of maintenance?
| Quote: | Does most everyone else put them on the hot side?
|
Good question. How about it guys? Anyone out
there flying fuse blocks on the forward side
of the firewall?
Bob . . .
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
| Back to top |
|
|
jay(at)horriblehyde.com
Guest
|
| Posted: Wed Jan 06, 2010 1:08 am Post subject: Battery Bus Location |
|
|
I put one of my battery busses on the hot side of the firewall and the other
on the cold side (2 batteries). My reasoning was that I would rather have
the connection between the buss and the battery short on the hot side than
lead the wire to the cold side.
For the second battery, which is located in the cargo compartment, I had to
lead a long fat wire to the front, as per my previous mail. The battery bus
is located where the fat wire ends at the firewall, on the contactor for
that battery. As Bob pointed out, this is not ideal as it means that you
have a long fat wire (now protected by an inline fuse as described in my
last mail) between the battery and the contactor. The rational for this is
that the routing between the front and back is not easy and I would rather
have 1 mechanically robust wire than several smaller wires that might be
subject to chaffing and damage- the fat wire is much easier to protect
mechanically. Not ideal, but adapted to the situation that I have...
Jay
--
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
| Back to top |
|
|
PaulR
Joined: 13 Nov 2008
Posts: 22
Location: Alabama
|
| Posted: Wed Jan 06, 2010 8:00 am Post subject: Re: Battery Bus Location |
|
|
| Quote: | The length isn't a REALLY BIG thing, just a
good practice design rule adopted by the TC
side of the house many years ago. How long would
the wire be for both extending the battery
feeder AND ease of maintenance? |
I think I could get by with 18-24" depending on how "easily maintainable" it is.
While it's really too cold to heat the shop up for a couple hours, I think I'll see if I can find a covered fuse block until I'm back in the shop over the weekend
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
_________________
Paul Rose
N417PR
RV-9A |
|
| Back to top |
|
|
nuckolls.bob(at)aeroelect
Guest
|
| Posted: Wed Jan 06, 2010 9:15 am Post subject: Battery Bus Location |
|
|
At 10:00 AM 1/6/2010, you wrote:
The length isn't a REALLY BIG thing, just a
good practice design rule adopted by the TC
side of the house many years ago. How long would
the wire be for both extending the battery
feeder AND ease of maintenance?
I think i could get by with 18-24" depending on how "easily
maintainable" it is.
While it's really too cold to heat the shop up for a couple hours, I
think I'll see if I can find a covered fuse block until I'm back in
the shop over the weekend
[/quote]
Think about building a cover. The fuse-blocks mount with 4
screws. The "nut" for each of those fasteners could be a
thru-hole, threaded spacer of sufficient height to just clear
the tops of the fuses.
Four thumb-nut screws would be used to mount the cover
down to the tops of the spacers.
A cover might be nothing more than a sheet with four
folded down edges having notches for clearing
wire bundles. I've been thinking about having some ABS
covers made. A friend of mine does deep vacuum forming as
a part of his manufacturing operations. Another option is
to make the cover out of copper clad. See:
http://www.aeroelectric.com/articles/cladboard/cladboard.html
http://aeroelectric.com/Pictures/Data_Acquisition/Weeder_Module_DAS_1.jpg
http://aeroelectric.com/Pictures/Data_Acquisition/Weeder_Module_DAS_2.jpg
I've built robust enclosures out of this stuff. You only need
to cut some accurate rectangular pieces, fixture them
against square corners for soldering, run a bead of solder
down the inside corner for assembly. Single sided clad
gives you a fiberglas/epoxy outside surface that takes paint
very nicely.
Bob . . .
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
| Back to top |
|
|
nuckolls.bob(at)aeroelect
Guest
|
| Posted: Wed Jan 06, 2010 9:31 am Post subject: Battery Bus Location |
|
|
| Quote: | <snip> I would rather
have 1 mechanically robust wire than several smaller wires that might be
subject to chaffing and damage- the fat wire is much easier to protect
mechanically. Not ideal, but adapted to the situation that I have...
|
The legacy rationale for incorporating an always hot wire
into an airframe recognizes the limited ability of circuits
protected at 5A or less to start post-crash fires.
Extending the battery bus on a long feeder calls for
protection of that feeder at some current level larger
(and SLOWER) than total draw of accessories fed by the
battery bus. Further, one should consider the dynamics
of interaction between fuses at the bus and protection
at the source end of the feeder. Bus feeders are generally
CURRENT LIMITERS with high tolerance to overload. If a
fast fuse is used upstream of a bus of fast fuses, one
needs to make sure that popping a bus fuse doesn't take
the upstream fuse too. Remember that the upstream fuse
is "pre-heated" by total loads on the battery bus.
Faulting one of the 5A fuses on the bus could trip a
20A feeder protection and take the whole bus down.
When the case is finally adjudicated, I'll be able
to share how a stack-up of "little details" about fault-
trip dynamics brought down a nearly new, very expensive
airplane while getting folks hurt in the process.
If the battery bus is back in the tail, then any
feeders coming forward don't need extra-ordinary
protection. They're lightly fused and risks for
faulting any single feeder are low. Once the bus
feeder turns into a fat wire, the legacy design
philosophy for always hot wires is worthy of
consideration.
Bob . . .
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
