gmcjetpilot
Joined: 04 Nov 2006
Posts: 170
|
 Posted: Thu Dec 14, 2006 2:45 am Post subject: Alternate feed to Lightspeed (easy fix) |
 |
|
Kaluza: That would be fine to drive the LSII from the
main bus and AUX battery with a Schottky diode. Here
is Klaus diagram I modified as I think you described.
http://img218.imageshack.us/img218/7803/presentation1wm4.jpg
(you may get by with less than a 4.5 amp/hr battery,
depending on your endurance needs)
Skytec also has suggestions: http://www.skytecair.com/EI.htm
(notice the capacitor solution, independant of using the Aux
battery, a 50,000 mfd cost about $36.00. I like the battery better
if you already have it and its suitable.)
Is the rocky mountain really up to charging the
battery? You may have to decided that. There is no
reason why you can't let the airplane charge it is there?
What kind of aux battery is it?
The reason you may have got a kick back after 360
hours is your main battery is starting to get weaker
(from age) and possibly cold weather is affecting it.
Also the starter may be draining more with cold
weather starts, lowering the voltage during start. Never
the less having the ignition w/ AUX pwr during start will
fix it. AUX does not drive the starter so voltage stays up.
No EI is immune from start kick back with super low
supply voltage. The lightspeed happens to be one of the
best for starting because it takes very low voltage to
work, like 6 to 8 volts. Most planes should maintain
that during start.
Any EI on the market will have a problem including
the E-mag which has also had kick backs, if the voltage
is too low. On RV's we use a small battery and light
weight starters that take almost 300 amps to crank.
With permanent magnet starters (which have high
current demands) and small Odyssey batteries we use in
RV's, you can get start irregularities. You can get a
bigger main battery or different starter as alternative
solutions.
Wire wound starters uses less current. I highly
recommend the SkyTec High Torque or new NL model.
You probably have a Flyweight PM skytec?
A bigger battery may not be possible or practical but
that may solve the issue as well with the starter.
The wiring of the Aux to the Lightspeed Plasma II is
the best option in my opinion.
Feel free to ignore Bob's comments:
| Quote: | >"not designed to work in the real world of airplanes.
>In this case, a software fix to the product in question
>would prevent inadvertent kick-backs."
|
It is not a software fix. That's 100% wrong. Bob has no
clue what he is talking about. The product is excellent,
in service for over a decade, very mature and works in
the real world of airplanes. Absurd comment, it's the
nature of any CDI ignition that relies on external power;
it needs min voltage. The lightspeed is no different.
Also Bobs other comment can be ignored:
| Quote: | >"you need to be able to shut EVERYTHING down
>without having the engine quit
|
You have one mag so the engine quiting is not an
issue. You can always turn the EI off to save power.
I don't recommend Z-30 or ABMM for your simple needs.
| Quote: | >Adding an aux battery per Z-30 has always been
>the universal Band-Aid for this phenomenon.
|
This adds weight and complexity of a large contactor (relay).
Bob loves to add wires, weight and switches. LOVES IT!
ALL YOU NEED IS TO KEEP EI VOLTAGE UP DURING START.
Cheers George (no space shuttle solution, simple is better)
| Quote: | We have 360 hours on our RV6A with one mag and
the Lightspeed II unit which has worked well. We
have had one kickback when starting on the
Lightspeed with a low battery. Spoke with Klaus
about using my backup battery as an additional
power source for the unit. He thought it would be
fine as long as I used a Shottky diode (90SQ030) to
prevent back feed from the auxiliary battery to the
main. The engine starts better on the Lightspeed but
we have been starting on the mag since the
kickback. I am debating using power from the E-Bus
which I have activated during start vs. running the
Aux. power direct from the Aux. battery. The second
option would allow better charging of the Aux.
battery. I worry about excess current flow if the Aux.
battery is low causing the 5 amp fuse
on the Lightspeed to blow. Any advice?
|
| Quote: | The Aux. battery is currently charged through my
Rocky Mountain monitor.
|
| Quote: | >Time: 10:11:40 AM PST US
>From: "Robert L. Nuckolls, III"
<nuckollsr(at)cox.net (nuckollsr(at)cox.net)>
|
| Quote: | >Subject: Re: Alternate feed to
>Lightspeed
|
| Quote: | >This issue (and others like it) have surfaced dozens
>of times over the past 15 years. There are some
>products not designed to work in the real world of
>airplanes. In this case, a software fix to the product
>in question would prevent inadvertent kick-backs
>due to low bus voltage or any other stimulus.
|
| Quote: | >Adding an aux battery per Z-30 has always been
>the universal Band-Aid for this phenomenon.
>Further, it offers an opportunity to run other
>electrically-dependent engine accessories from a
>"protected" supply.
|
| Quote: | >No diodes needed (therefore no charging issues).
>Battery may be any practical size needed to
>address your endurance needs. Closing the
>contactor may be automatic.
|
| Quote: | >or manual or manual with warnings . . .
|
| Quote: | >Any item needed to keep an engine running should
>be operated from an always-hot battery bus . . . if
>you got bad smells in the cockpit, you need to be
>able to shut EVERYTHING down without having
>the engine quit.
>Bob
|
[quote][b]
| | - 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 |
|
|
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
