Author: <gmcjetpilot@...> Time: Wed Aug 24, 2005 12:20 pm PDT Link
Dear Mr. Linn Walters:
I will not go line by line, but I am sure Lucky appreciates your defense an external Jump Jack. No doubt Lucky has a mind of his own and will do what he wants. I just was pointing out the pros and cons.
However several things you wrote about are really quite improper, even dangerous.
FLYING WITH KNOW DEFECTS?
In your example where you are flying around in an aircraft in poor maintenance ("elder battery) and than made the decision to fly with out the alternator (because the battery maintain a charge to excite the alternator). To me that is poor judgment and is in violation of FARs, regardless of whether you needed your radio or not. Low wing? What about the boost pump? Mechanical pump failure? Even though a radio is not needed at an uncontrolled airport does not mean it is a great idea either? You can fly in 3 mile visibility and call that VFR. That's not a good idea either, but it is legal. A little aircraft does not have a MEL (min equip list) like a big plane that says it is OK to fly with out part of the aircraft systems. To fly with out the battery (which you knew was bad before you flew the plane in the first place) and with out the alternator intentionally, taking off with a known maintenance issue, is a big no-no. May be it could be considered legal (I guess if you placard every
thing inop), but I know you can not fly knowing your boost pump is inop, which it was without a battery.
WEAK BATTERIES ARE DANGEROUS
You are wrong about a battery in a low charge (volt) state. You will put more drain on the battery. The jumping battery will excite the alternator and from then on the alternator will usually be self sustaining, and may even continue to work disconnected from the battery. However in your case your battery was really dead apparently and the alternator would not come on line; However with a weak battery and the alternator does come on line , operations may be unstable without the buffer of a strong battery. HERE IS THE KEY. Electrical system safety is dependent on a good strong battery.
Battery resistance has nothing to do with it. When the alternator starts to put out 14.5 volts the battery will charge. The amount of amps the battery (wants to draw) draw is a function of the charge state of the battery and the voltage/current (power) supplied to it. The battery will take as much power as it can take limited by chemistry and temperature, and that may be as much as 10-12 amps or more. In fact people who have poor batteries and turn on all the lights right after starting, load the alternator. With this high electrical demand and demand from a weak battery they pop their alternators output (B-lead) circuit breaker, which is pumping out its max capacity. The combo of normal electrical load with the added load of charging a weak battery caused the overload. Of course the simple process of reducing load and resetting of the CB would solve the problem, but why cause the problem in the first place.
Look at your alternators load or amp meter after starting, before turning on any electrical load, you see the amp meter showing many amps being drawn from the alternator, that is the battery being charged. The current goes down as the battery charges and reaches it full charge state. To say a discharged or low voltage battery does NOT draw more current form the alternator shows a lack of system knowledge.
WHY?
Again to repeat, if your battery has been discharged you should charge it before flying, but that is just me. Your comment:
"However, that Piper plug does something your trickle charger won't do .... start the engine from an external source.....Lucky will be long gone while those with a trickle charger cable wait impatiently on the ramp."
Who cares, wait. If you are dumb enough to leave the master on or fly with a known weak battery you deserve to have to wait. I don' t care how remote an airport is or how bad you have to get home, flying decisions should be based on safety (airworthiness) not personal need, but that is just me. In conclusion I find little use for a jump jack, because I see no need or would ever use it to jump a dead battery.
If you are flying a plane with an electrically dependent engine (dual electronic ignition or electronic fuel injection used in auto conversions) you are foolish to fly with a jumped dead battery to "get-er-done". Sure it was done back in te day but we know better now. Regardless of whether your engine is electrically depended or not, flying with known maintenance issues and a weak battery is asking for trouble.
Lucky, figure the weight, it is several pounds to add this feature; Lynn is doing it, but than he likes to fly with dead batteries. If you want it, put it on, but consider the uses. In fact the last story I heard about jumping a GA plane was at a FBO, who jumped the plane with 24 volts and blew several expensive items in the electrical system.
Cheers George
vansairforce@yahoogroups.com wrote:
From: "jmtipton"
2. Re: Re: AeroElectric-List: recharge/jump start receptacle
________________________________________________________________________
________________________________________________________________________
Message: 2
Date: Tue, 23 Aug 2005 09:41:29 -0400
From: linn walters
Subject: Re: Re: AeroElectric-List: recharge/jump start receptacle
gmcjetpilot wrote:
>Lucky: how much are you going to need a JUMP?
>
When you need it, it only takes once!
>If the battery is dead (presumably from leaving the master on) you
>need to charge it first. Jumping a dead battery and going flying in
>an airplane is not a great idea. It also loads the alternator, which
>can put a strain on it.
>
Whoa. If you jump the battery an just start it, there isn't enough
'charge' in the battery to get the alternator to generate voltage.
Charging an almost dead battery won't place any more strain on the
alternator than an almost fully charged one. Actually, the almost dead
battery will be less strain because of it's higher internal resistance.
>I suggest if you drain the battery you use a small plug (cigarette
>lighter) and wait an hour or so to get a charge on it. You don't need
>thick wire to charge. I understand the need to charge, but you don't
>need a high amp exterior jack to do that.
>
We're back to how long you want to wait on the ramp while you trickle
charge the battery with a cigarette lighter cord. In order for this to
work, the cigarette lighter needs to be hard-wired to the battery (which
most aren't). Having any 'loads' connected upstream of the main
contactor invite that dead battery.
>As was pointed out, cost, weight, and build time TO benefit favors
>not installing a high amp jump plug in my opinion. There are some
>ways to access the battery (under cowl or behind baggage compartment)
>for charging.
>
However, that Piper plug does something your trickle charger won't do
.... start the engine from an external source. You can get the engine
started and wait until the alternator kicks in before unplugging. And
it's a standard connection. You have to carry an adapter, and Lucky
carries his installed plug (albeit maybe with less weight.) Lucky will
be long gone while those with a trickle charger cable wait impatiently
on the ramp.
>So how many times have you really NEEDED to jump an airplane. Having
>to wait to charge the battery for a short bit is a fair punishment
>for leaving the master on.
>
I can't speak to Lucky, but in my case I was on a cross country .... on
my way home ...... when I overnighted. The plane was a little hard to
start, but the elder battery chose this opportunity to tell me it needed
replacement. We pulled the top cowl (Grumman AA-1B) and jumped it with
battery cables from a car ..... it's Sunday morning and the place was
deserted except for this fellow and his dog that stopped to help. We
got the engine started and ran it for a while, shut down and put the
cowl back on. Started the engine, but couldn't get the alternator back
online. It was an uncontrolled field, and so was my destination. I bit
the bullet and flew home. The only thing I really missed was my radio
because I couldn't give and receive position reports in the uncontrolled
patterns. I musta looked like an owl as I scanned for traffic.
Bottom line, for just a little weight penalty, Lucky has received some
piece of mind and ability to quickly extract himself from a poor
situation rapidly. As you can guess, my -10 will have an external
ground start capability ..... and it'll probably be the Piper part.
Linn
>George
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
[Non-text portions of this message have been removed]
------------------------ Yahoo! Groups Sponsor --------------------~-->
Get fast access to your favorite Yahoo! Groups. Make Yahoo! your home page
http://us.click.yahoo.com/dpRU5A/wUILAA/yQLSAA/1yWplB/TM
--------------------------------------------------------------------~->
Online help on this group at:
http://help.yahoo.com/help/groups/
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/vansairforce/
<*> To unsubscribe from this group, send an email to:
vansairforce-unsubscribe@yahoogroups.com
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
Author: linn walters <lwalters2@...> Time: Thu Aug 25, 2005 3:00 pm PDT Link
I will admit to not being perfect, and I did not provide the info for
guidance. My point was that had I had one, a ground power jack would
have name this a non-event.
gmcjetpilot@yahoo.com wrote:
>Dear Mr. Linn Walters:
>
>I will not go line by line, but I am sure Lucky appreciates your defense an external Jump Jack. No doubt Lucky has a mind of his own and will do what he wants. I just was pointing out the pros and cons.
>
>However several things you wrote about are really quite improper, even dangerous.
>
>FLYING WITH KNOW DEFECTS?
>In your example where you are flying around in an aircraft in poor maintenance ("elder battery) and than made the decision to fly with out the alternator (because the battery maintain a charge to excite the alternator). To me that is poor judgment and is in violation of FARs, regardless of whether you needed your radio or not. Low wing? What about the boost pump? Mechanical pump failure? Even though a radio is not needed at an uncontrolled airport does not mean it is a great idea either? You can fly in 3 mile visibility and call that VFR. That's not a good idea either, but it is legal. A little aircraft does not have a MEL (min equip list) like a big plane that says it is OK to fly with out part of the aircraft systems. To fly with out the battery (which you knew was bad before you flew the plane in the first place) and with out the alternator intentionally, taking off with a known maintenance issue, is a big no-no. May be it could be considered legal (I guess if you placar
>
>d every
> thing inop), but I know you can not fly knowing your boost pump is inop, which it was without a battery.
>
Well, I never said I was smart. I wouldn't have departed home in that
condition for sure. I will consider myself chastised.
>WEAK BATTERIES ARE DANGEROUS
>
To who? You never know that you have a low battery until you crank a
little longer than usual or some other problem occurs.
>You are wrong about a battery in a low charge (volt) state. You will put more drain on the battery. The jumping battery will excite the alternator and from then on the alternator will usually be self sustaining, and may even continue to work disconnected from the battery.
>
Well, we'll just agree to disagree. With a jumped dead battery
(jumpee?), the 'dead' alternator will see the 12+ volts from the jumping
battery (jumper? great mental picture there) Now you disconnect the
jumper and the full 13.7Volts (or whatever the regulator is set at) goes
across a battery with high internal resistance which will limit the
current initially. As the battery charges the current will rise to
whatever the normal steady state current is .
> However in your case your battery was really dead apparently and the alternator would not come on line; However with a weak battery and the alternator does come on line , operations may be unstable without the buffer of a strong battery. HERE IS THE KEY. Electrical system safety is dependent on a good strong battery.
>
You need to read my email more closely. The reason I couldn't get the
ALT online was because I had to shut down, disconnect the jump and put
the cowl back on. I DID NOT HAVE AN EXTERNAL POWER JACK. Sorry.
External power would have saved the day. After I cranked and got the
engine started, there wasn't enough voltage left to excite the ALT.
>Battery resistance has nothing to do with it.
>
I beg to differ.
> When the alternator starts to put out 14.5 volts the battery will charge.
>
That's a little high, I think, but yes, it will charge albeit slowly at
first.
> The amount of amps the battery (wants to draw) draw is a function of the charge state of the battery and the voltage/current (power) supplied to it. The battery will take as much power as it can take limited by chemistry and temperature, and that may be as much as 10-12 amps or more. In fact people who have poor batteries and turn on all the lights right after starting, load the alternator. With this high electrical demand and demand from a weak battery they pop their alternators output (B-lead) circuit breaker, which is pumping out its max capacity. The combo of normal electrical load with the added load of charging a weak battery caused the overload. Of course the simple process of reducing load and resetting of the CB would solve the problem, but why cause the problem in the first place.
>
Not sure why all that is relevant as it's all speculation. Not 12 amps
or more initially. Maybe during the 'middle' of the charge cycle.
>Look at your alternators load or amp meter after starting, before turning on any electrical load, you see the amp meter showing many amps being drawn from the alternator, that is the battery being charged. The current goes down as the battery charges and reaches it full charge state. To say a discharged or low voltage battery does NOT draw more current form the alternator shows a lack of system knowledge.
>
Well, you'll have to show me more fact than fiction.
>WHY?
>Again to repeat, if your battery has been discharged you should charge it before flying, but that is just me. Your comment:
>
>"However, that Piper plug does something your trickle charger won't do .... start the engine from an external source.....Lucky will be long gone while those with a trickle charger cable wait impatiently on the ramp."
>
> Who cares, wait. If you are dumb enough to leave the master on or fly with a known weak battery you deserve to have to wait. I don' t care how remote an airport is or how bad you have to get home, flying decisions should be based on safety (airworthiness) not personal need, but that is just me. In conclusion I find little use for a jump jack, because I see no need or would ever use it to jump a dead battery.
>
Well, since this IS a free country, you're entitled to your opinion. I
have a suggestion: Take a chill pill, don't install a ground power
jack, and enjoy your flights. I hope you never have a need for one.
>If you are flying a plane with an electrically dependent engine (dual electronic ignition or electronic fuel injection used in auto conversions) you are foolish to fly with a jumped dead battery to "get-er-done". Sure it was done back in te day but we know better now. Regardless of whether your engine is electrically depended or not, flying with known maintenance issues and a weak battery is asking for trouble.
>
>Lucky, figure the weight, it is several pounds to add this feature; Lynn is doing it, but than he likes to fly with dead batteries.
>
Hmmm, I don't think I said that. What else are you making up???
> If you want it, put it on, but consider the uses.
>
Well, I find that terribly magnanimous of you!!!
> In fact the last story I heard about jumping a GA plane was at a FBO, who jumped the plane with 24 volts and blew several expensive items in the electrical system.
>
Well, they weren't perfect either!
Linn
>Cheers George
>vansairforce@yahoogroups.com wrote:
>From: "jmtipton"
>2. Re: Re: AeroElectric-List: recharge/jump start receptacle
>
>________________________________________________________________________
>________________________________________________________________________
>
>Message: 2
>Date: Tue, 23 Aug 2005 09:41:29 -0400
>From: linn walters
>Subject: Re: Re: AeroElectric-List: recharge/jump start receptacle
>
>gmcjetpilot wrote:
>>Lucky: how much are you going to need a JUMP?
>When you need it, it only takes once!
>>If the battery is dead (presumably from leaving the master on) you
>>need to charge it first. Jumping a dead battery and going flying in
>>an airplane is not a great idea. It also loads the alternator, which
>>can put a strain on it.
>Whoa. If you jump the battery an just start it, there isn't enough
>'charge' in the battery to get the alternator to generate voltage.
>Charging an almost dead battery won't place any more strain on the
>alternator than an almost fully charged one. Actually, the almost dead
>battery will be less strain because of it's higher internal resistance.
>>I suggest if you drain the battery you use a small plug (cigarette
>>lighter) and wait an hour or so to get a charge on it. You don't need
>>thick wire to charge. I understand the need to charge, but you don't
>>need a high amp exterior jack to do that.
>We're back to how long you want to wait on the ramp while you trickle
>charge the battery with a cigarette lighter cord. In order for this to
>work, the cigarette lighter needs to be hard-wired to the battery (which
>most aren't). Having any 'loads' connected upstream of the main
>contactor invite that dead battery.
>>As was pointed out, cost, weight, and build time TO benefit favors
>>not installing a high amp jump plug in my opinion. There are some
>>ways to access the battery (under cowl or behind baggage compartment)
>>for charging.
>However, that Piper plug does something your trickle charger won't do
>.... start the engine from an external source. You can get the engine
>started and wait until the alternator kicks in before unplugging. And
>it's a standard connection. You have to carry an adapter, and Lucky
>carries his installed plug (albeit maybe with less weight.) Lucky will
>be long gone while those with a trickle charger cable wait impatiently
>on the ramp.
>>So how many times have you really NEEDED to jump an airplane. Having
>>to wait to charge the battery for a short bit is a fair punishment
>>for leaving the master on.
>I can't speak to Lucky, but in my case I was on a cross country .... on
>my way home ...... when I overnighted. The plane was a little hard to
>start, but the elder battery chose this opportunity to tell me it needed
>replacement. We pulled the top cowl (Grumman AA-1B) and jumped it with
>battery cables from a car ..... it's Sunday morning and the place was
>deserted except for this fellow and his dog that stopped to help. We
>got the engine started and ran it for a while, shut down and put the
>cowl back on. Started the engine, but couldn't get the alternator back
>online. It was an uncontrolled field, and so was my destination. I bit
>the bullet and flew home. The only thing I really missed was my radio
>because I couldn't give and receive position reports in the uncontrolled
>patterns. I musta looked like an owl as I scanned for traffic.
>
>Bottom line, for just a little weight penalty, Lucky has received some
>piece of mind and ability to quickly extract himself from a poor
>situation rapidly. As you can guess, my -10 will have an external
>ground start capability ..... and it'll probably be the Piper part.
>Linn
>>George
>__________________________________________________
>Do You Yahoo!?
>Tired of spam? Yahoo! Mail has the best spam protection around
>http://mail.yahoo.com
>
>[Non-text portions of this message have been removed]
>Online help on this group at:
>http://help.yahoo.com/help/groups/
>
>Yahoo! Groups Links
----------
No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.338 / Virus Database: 267.10.13/78 - Release Date: 8/19/05
[Non-text portions of this message have been removed]
------------------------ Yahoo! Groups Sponsor --------------------~-->
Get fast access to your favorite Yahoo! Groups. Make Yahoo! your home page
http://us.click.yahoo.com/dpRU5A/wUILAA/yQLSAA/1yWplB/TM
--------------------------------------------------------------------~->
Online help on this group at:
http://help.yahoo.com/help/groups/
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/vansairforce/
<*> To unsubscribe from this group, send an email to:
vansairforce-unsubscribe@yahoogroups.com
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/