Today's Message Index:
----------------------
1. 04:38 AM - Re: Y splitter (Alec Myers)
2. 07:00 AM - Limiting Current to a Battery (Jared Yates)
3. 07:25 AM - Re: Limiting Current to a Battery (Ken Ryan)
4. 08:06 AM - Re: Limiting Current to a Battery (user9253)
5. 08:26 AM - Overvoltage protection (Joe Dubner)
6. 08:46 AM - Re: Limiting Current to a Battery (Charlie England)
7. 09:43 AM - Re: Limiting Current to a Battery (Alec Myers)
8. 09:48 AM - Re: Overvoltage protection (Robert L. Nuckolls, III)
9. 09:56 AM - Re: Y splitter (John Tipton)
10. 10:03 AM - Re: Limiting Current to a Battery (David Saylor)
11. 10:35 AM - Re: Limiting Current to a Battery (Charlie England)
12. 11:04 AM - Re: Overvoltage protection (Robert L. Nuckolls, III)
13. 11:14 AM - Re: Limiting Current to a Battery (David Saylor)
14. 11:23 AM - Re: Limiting Current to a Battery (Alec Myers)
15. 11:28 AM - Re: Limiting Current to a Battery (Charlie England)
16. 12:26 PM - Re: Limiting Current to a Battery (Jared Yates)
17. 01:46 PM - Re: Overvoltage protection (Joe Dubner)
18. 01:47 PM - Re: Limiting Current to a Battery (Robert L. Nuckolls, III)
19. 01:53 PM - Re: Limiting Current to a Battery (Robert L. Nuckolls, III)
20. 02:22 PM - Re: Limiting Current to a Battery (Charlie England)
21. 06:17 PM - Re: Y splitter (Argonaut36)
22. 07:11 PM - Re: Limiting Current to a Battery (Robert L. Nuckolls, III)
23. 07:29 PM - Re: Limiting Current to a Battery (Robert L. Nuckolls, III)
24. 07:33 PM - Re: Limiting Current to a Battery (Robert L. Nuckolls, III)
25. 08:00 PM - Speaking of well loaded wires . . . (Robert L. Nuckolls, III)
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
See:
http://www.aeroelectric.com/articles/multiplewires/multiplewires.html
See also:
https://www.te.com/content/dam/te-com/documents/industrial-automation-and-control/global/1773464-1_QRG_PIDG.pdf
FREQUENTLY ASKED QUESTIONS:
Can wires be combined in PIDG terminals & splices? Yes they can as long total CMA
(Circular Mil Area) and insulation diameter fall within specification.
Also, per NASA-STD-8739.4A Section 19.9:
Crimping wires into contacts or crimp ferrules is a method for splicing wires together
without soldering. When crimping multiple wires into a contact or ferrule,
the total circular-mil-area (CMA) of all the wires must be calculated into
an Equivalent Wire Size (EWS) in order to select the properly sized contact
or ferrule.
19.9.1 The following requirements apply for crimped splices:
a. The tooling verification process and the completed termination shall comply
with all the requirements of this document for a crimp termination except as specified
herein for jiffy junction devices.
b. The contact/wires size and crimp tool setting combination shall be developed
and verified using the same requirements as for any machined contact (see 12.3.5).
c. The crimp ferrule or contact shall be sized equivalently with the calculated
Equivalent Wire Size (EWS) or the next larger EWS if the calculated value does
not exactly match a single wire size.
Dont twist the wires together, they should go into the barrel parallel. I believe
when you double area of a wire, the AWG goes down by three. So 2 x 20 gauge
wires would be 17 gauge.
On Jul 6, 2019, at 11:09 PM, Argonaut36 <fmlibrino@msn.com> wrote:
I was wondering if the practice of twisting 2 wires together and crimping the resulting
wire in a ring terminal can be considered acceptable, even for standard
certificate airplanes, for making a Y splitter. If so, assuming that 2 wires
to be twisted together are size 20#, should a red or blue ring terminal be
used?
Thanks
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=490084#490084
Message 2
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Limiting Current to a Battery |
I have a question that's only somewhat applicable to E/AB aviation,
apologies in advance. But I think it points out a hole in my electrical
understanding.
The characteristics of the lithium iron battery I'm running allow it to
draw lots of current really fast after the engine starts. If it has been a
little while since the last flight, the alternator is at max output for
several minutes. The alternator puts out all it can give, and it's less
than the battery wants to take.
Stepping out of the hangar, my tow vehicle circuitry includes a wire in the
7-pin connector that provides alternator voltage to the trailer, intending
to charge a small battery for a breakaway emergency brake. If I install a
larger battery for other purposes, perhaps one like what is in the
airplane, and connect it to that line coming from the truck, it seems like
it would almost certainly open the fuse on that circuit during that initial
high-draw stage.
These two scenarios had me thinking, what methods would one have to limit a
hungry battery's draw? I'm imagining some type of circuit that takes in
12-14 volts, and puts out almost the same, but only at some specified
number of amps. Almost like a DC-powered battery charging circuit, rather
than just putting the battery on the bus directly.
Surely this has been solved in some off-the-shelf widget, but I haven't
figured out the words to google yet.
Message 3
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Limiting Current to a Battery |
Jared, my holes in electrical knowledge are wide and vast, so don't do this
without confirmation. But I think you might be able to regulate the amount
of current by playing with the length of the cable, with a longer cable
offering more resistance. I was instructed to do this once by a
manufacturer of "battery isolator" for a camper battery, to keep my large
alternator from frying the 70 amp isolator
<http://hellroaring.com/products.php>. It seemed like an odd approach at
the time, but I followed instructions and it worked okay. I'm not at all
certain this would work for your particular problem, but I throw out the
idea for discussion. On my next camper I went to a battery combiner
<https://www.waytekwire.com/item/77051/Cole-Hersee-48530-Smart-Battery-Isolator-200A-/>and
big double ought cables to maximize the charging of the camper battery, and
also to allow use of the camper battery as an auxiliary starting battery. I
don't have a lithium battery in the camper, so the highest draw I have ever
seen was 80 amps. --Ken
On Sun, Jul 7, 2019 at 6:05 AM Jared Yates <email@jaredyates.com> wrote:
> I have a question that's only somewhat applicable to E/AB aviation,
> apologies in advance. But I think it points out a hole in my electrical
> understanding.
>
> The characteristics of the lithium iron battery I'm running allow it to
> draw lots of current really fast after the engine starts. If it has been a
> little while since the last flight, the alternator is at max output for
> several minutes. The alternator puts out all it can give, and it's less
> than the battery wants to take.
>
> Stepping out of the hangar, my tow vehicle circuitry includes a wire in
> the 7-pin connector that provides alternator voltage to the trailer,
> intending to charge a small battery for a breakaway emergency brake. If I
> install a larger battery for other purposes, perhaps one like what is in
> the airplane, and connect it to that line coming from the truck, it seems
> like it would almost certainly open the fuse on that circuit during that
> initial high-draw stage.
>
> These two scenarios had me thinking, what methods would one have to limit
> a hungry battery's draw? I'm imagining some type of circuit that takes in
> 12-14 volts, and puts out almost the same, but only at some specified
> number of amps. Almost like a DC-powered battery charging circuit, rather
> than just putting the battery on the bus directly.
>
> Surely this has been solved in some off-the-shelf widget, but I haven't
> figured out the words to google yet.
>
Message 4
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Limiting Current to a Battery |
The easy solution is to put a diode in series with the wire going to the trailer
Lithium battery.
The voltage drop across the diode will reduce charging current.
Read this: https://earthxbatteries.com/dual-bus-lithium-battery-design
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=490095#490095
Message 5
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Overvoltage protection |
A friend is working on a Grumman Tiger in which the alternator field circuit
breaker was found tripped. Upon digging in the manual, he found the overvoltage
protection was simply a Zener diode wired from the output of the field breaker
to ground. The diode was found to be shorted, which would easily trip the
breaker.
I can only find a "house number" on the Zener. The diode was removed, the old
regulator was replaced with a Zeftronics with integral overvoltage protection,
the split rocker switch was replaced with a new one, and all seems well --
except that one electrical instrument is inoperative (possibly due to an
overvoltage event).
My questions are as follows: can a physically small Zener diode (similar in size
to a 1N5401 diode) handle the amount of energy required to trip a 5A breaker,
even one time? Can the Zener always be counted upon to fail shorted and not open?
Thanks,
Joe
Message 6
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Limiting Current to a Battery |
On 7/7/2019 9:01 AM, Jared Yates wrote:
> I have a question that's only somewhat applicable to E/AB aviation,
> apologies in advance. But I think it points out a hole in my
> electrical understanding.
>
> The characteristics of the lithium iron battery I'm running allow it
> to draw lots of current really fast after the engine starts. If it has
> been a little while since the last flight, the alternator is at max
> output for several minutes. The alternator puts out all it can give,
> and it's less than the battery wants to take.
>
> Stepping out of the hangar, my tow vehicle circuitry includes a wire
> in the 7-pin connector that provides alternator voltage to the
> trailer, intending to charge a small battery for a breakaway emergency
> brake. If I install a larger battery for other purposes, perhaps one
> like what is in the airplane, and connect it to that line coming from
> the truck, it seems like it would almost certainly open the fuse on
> that circuit during that initial high-draw stage.
>
> These two scenarios had me thinking, what methods would one have to
> limit a hungry battery's draw? I'm imagining some type of circuit that
> takes in 12-14 volts, and puts out almost the same, but only at some
> specified number of amps. Almost like a DC-powered battery charging
> circuit, rather than just putting the battery on the bus directly.
>
> Surely this has been solved in some off-the-shelf widget, but I
> haven't figured out the words to google yet.
Yeah, it could be solved. Which begs the question of why the big X
didn't incorporate it into their management module.
The simplest (rather inelegant) path would be a boost/buck regulator
with current adjustment intended to operate from a DC source.
https://www.amazon.com/s?k=current+regulator&ref=nb_sb_noss_1
Purchase a version that can't overload the wiring to the trailer
connector. Feed the regulator from the alternator feed in the trailer
connector. Set its output voltage to a level that can't harm the
battery. Set its output current to a level that won't endanger the
wiring from the alternator to the trailer connector.
Charlie
---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
Message 7
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Limiting Current to a Battery |
On Jul 7, 2019, at 10:23 AM, Ken Ryan <keninalaska@gmail.com> wrote:
...But I think it points out a hole in my electrical understanding.
. I'm imagining some type of circuit that takes in 12-14 volts, and puts out almost
the same, but only at some specified number of amps.
Remember a battery is a two terminal device. It functions like you pick the voltage
across the terminals, Ill pick the current, or, equivalently you pick the
current, Ill pick the voltage. You cant pick both the voltage across the terminals
and the current through the battery, independently.
You could put some kind of negative temperature coefficient thermistor in series
with the battery, and shunt that with a fat diode so as not to limit the current
withdrawable from the battery?
Message 8
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Overvoltage protection |
At 10:25 AM 7/7/2019, you wrote:
>
>A friend is working on a Grumman Tiger in which the alternator field
>circuit breaker was found tripped. Upon digging in the manual, he
>found the overvoltage protection was simply a Zener diode wired from
>the output of the field breaker to ground. The diode was found to
>be shorted, which would easily trip the breaker.
Yup. A stone simple ov protection scheme
that made it onto a TC aircraft. Wrote about
this for SA back in '93 . . .
https://tinyurl.com/y38og7he
Discovered later that the idea was not
'bad' as originally implemented. The
design called for a GLASS, 1N4745, 1W zener
tied to ground downstream of a 5A
FUSE.
Emacs!
I did some testing on various
zeners and found that only GLASS enclosed
could be depended upon to fail shorted . . .
plastics would occasionally split
and fail to burn the fuse.
Emacs!
This is why the zener could only be
'legally' replaced with the Grumman house
part number to make sure that the part
was GLASS encased.
Some airplanes were modified to replace
cartridge fuses with breakers but left
the zener in place . . . risky because
the I(squared)t operation numbers
for a breaker are larger than the fuse.
>I can only find a "house number" on the Zener. The diode was
>removed, the old regulator was replaced with a Zeftronics with
>integral overvoltage protection, the split rocker switch was
>replaced with a new one, and all seems well -- except that one
>electrical instrument is inoperative (possibly due to an overvoltage event).
Once the regulator is replaced with one
that INCLUDES ov protection, the zener
should be removed.
>My questions are as follows: can a physically small Zener diode
>(similar in size to a 1N5401 diode) handle the amount of energy
>required to trip a 5A breaker, even one time? Can the Zener always
>be counted upon to fail shorted and not open?
Good question but moot after the
regulator is replaced.
Bob . . .
Message 9
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
And you still fuse for the the wire size ;(22awg - 3amp) although your using two
22awg wires that could be carrying 5/7amps
John
Sent from my iPad
----x--O--x----
> On 7 Jul 2019, at 12:37 pm, Alec Myers <alec@alecmyers.com> wrote:
>
>
> See:
> http://www.aeroelectric.com/articles/multiplewires/multiplewires.html
>
>
>
> See also:
> https://www.te.com/content/dam/te-com/documents/industrial-automation-and-control/global/1773464-1_QRG_PIDG.pdf
> FREQUENTLY ASKED QUESTIONS:
> Can wires be combined in PIDG terminals & splices? Yes they can as long total
CMA (Circular Mil Area) and insulation diameter fall within specification.
>
>
>
> Also, per NASA-STD-8739.4A Section 19.9:
>
> Crimping wires into contacts or crimp ferrules is a method for splicing wires
together without soldering. When crimping multiple wires into a contact or ferrule,
the total circular-mil-area (CMA) of all the wires must be calculated into
an Equivalent Wire Size (EWS) in order to select the properly sized contact
or ferrule.
>
> 19.9.1 The following requirements apply for crimped splices:
>
> a. The tooling verification process and the completed termination shall comply
with all the requirements of this document for a crimp termination except as
specified herein for jiffy junction devices.
>
> b. The contact/wires size and crimp tool setting combination shall be developed
and verified using the same requirements as for any machined contact (see 12.3.5).
>
> c. The crimp ferrule or contact shall be sized equivalently with the calculated
Equivalent Wire Size (EWS) or the next larger EWS if the calculated value does
not exactly match a single wire size.
>
>
>
>
> Dont twist the wires together, they should go into the barrel parallel. I believe
when you double area of a wire, the AWG goes down by three. So 2 x 20 gauge
wires would be 17 gauge.
>
>
>
>
>
>
>
> On Jul 6, 2019, at 11:09 PM, Argonaut36 <fmlibrino@msn.com> wrote:
>
>
> I was wondering if the practice of twisting 2 wires together and crimping the
resulting wire in a ring terminal can be considered acceptable, even for standard
certificate airplanes, for making a Y splitter. If so, assuming that 2 wires
to be twisted together are size 20#, should a red or blue ring terminal be
used?
> Thanks
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=490084#490084
>
>
>
>
>
>
>
>
>
>
>
>
>
>
Message 10
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Limiting Current to a Battery |
Would it be a DC-DC battery charger?
https://www.renogy.com/renogy-12v-dc-to-dc-on-board-battery-charger/?gclid=CjwKCAjwsIbpBRBNEiwAZF8-z-TrUeFYygbwZh7wrFUpKO_RhdCJkW-vJ-BFwYS_IZjlu9G8uAMNcxoCgBoQAvD_BwE
On Sun, Jul 7, 2019 at 7:05 AM Jared Yates <email@jaredyates.com> wrote:
> I have a question that's only somewhat applicable to E/AB aviation,
> apologies in advance. But I think it points out a hole in my electrical
> understanding.
>
> The characteristics of the lithium iron battery I'm running allow it to
> draw lots of current really fast after the engine starts. If it has been a
> little while since the last flight, the alternator is at max output for
> several minutes. The alternator puts out all it can give, and it's less
> than the battery wants to take.
>
> Stepping out of the hangar, my tow vehicle circuitry includes a wire in
> the 7-pin connector that provides alternator voltage to the trailer,
> intending to charge a small battery for a breakaway emergency brake. If I
> install a larger battery for other purposes, perhaps one like what is in
> the airplane, and connect it to that line coming from the truck, it seems
> like it would almost certainly open the fuse on that circuit during that
> initial high-draw stage.
>
> These two scenarios had me thinking, what methods would one have to limit
> a hungry battery's draw? I'm imagining some type of circuit that takes in
> 12-14 volts, and puts out almost the same, but only at some specified
> number of amps. Almost like a DC-powered battery charging circuit, rather
> than just putting the battery on the bus directly.
>
> Surely this has been solved in some off-the-shelf widget, but I haven't
> figured out the words to google yet.
>
Message 11
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Limiting Current to a Battery |
That device won't limit current pulled through his feed to the trailer
connector.
While that device might work for its intended purpose, one of its claims
is nonsense:
* Overcomes voltage drop caused by long cable runs
Unless its some corollary of a perpetual motion machine.
Charlie
On 7/7/2019 12:02 PM, David Saylor wrote:
> Would it be a DC-DC battery charger?
>
> https://www.renogy.com/renogy-12v-dc-to-dc-on-board-battery-charger/?gclid=CjwKCAjwsIbpBRBNEiwAZF8-z-TrUeFYygbwZh7wrFUpKO_RhdCJkW-vJ-BFwYS_IZjlu9G8uAMNcxoCgBoQAvD_BwE
>
>
> On Sun, Jul 7, 2019 at 7:05 AM Jared Yates <email@jaredyates.com
> <mailto:email@jaredyates.com>> wrote:
>
> I have a question that's only somewhat applicable to E/AB
> aviation, apologies in advance. But I think it points out a hole
> in my electrical understanding.
>
> The characteristics of the lithium iron battery I'm running allow
> it to draw lots of current really fast after the engine starts. If
> it has been a little while since the last flight, the alternator
> is at max output for several minutes. The alternator puts out all
> it can give, and it's less than the battery wants to take.
>
> Stepping out of the hangar, my tow vehicle circuitry includes a
> wire in the 7-pin connector that provides alternator voltage to
> the trailer, intending to charge a small battery for a breakaway
> emergency brake. If I install a larger battery for other purposes,
> perhaps one like what is in the airplane, and connect it to that
> line coming from the truck, it seems like it would almost
> certainly open the fuse on that circuit during that initial
> high-draw stage.
>
> These two scenarios had me thinking, what methods would one have
> to limit a hungry battery's draw? I'm imagining some type of
> circuit that takes in 12-14 volts, and puts out almost the same,
> but only at some specified number of amps. Almost like a
> DC-powered battery charging circuit, rather than just putting the
> battery on the bus directly.
>
> Surely this has been solved in some off-the-shelf widget, but I
> haven't figured out the words to google yet.
>
---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
Message 12
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Overvoltage protection |
At 10:25 AM 7/7/2019, you wrote:
>
>A friend is working on a Grumman Tiger in which the alternator field
>circuit breaker was found tripped. Upon digging in the manual, he
>found the overvoltage protection was simply a Zener diode wired from
>the output of the field breaker to ground. The diode was found to
>be shorted, which would easily trip the breaker.
Yup. A stone simple ov protection scheme
that made it onto a TC aircraft. Wrote about
this for SA back in '93 . . .
https://tinyurl.com/y38og7he
Discovered later that the idea was not
'bad' as originally implemented. The
design called for a GLASS, 1N4745, 1W zener
tied to ground downstream of a 5A
FUSE. The thing was designed to be a single
event operator . . . IF you experienced
an ov condition, the zener was expected to
short, the fuse was expected to open.
You would have to investigate and fix
root cause of the ov condtion, then replace the
zener and fuse before flying upward and onward.
Emacs!
I did some testing on various
zeners and found that only GLASS enclosed
could be depended upon to fail shorted . . .
plastics would occasionally split apart
and fail to burn the fuse.
Emacs!
This is why the zener could only be
'legally' replaced with the Grumman house
part number to make sure that the part
was GLASS encased.
Some airplanes were modified to replace
cartridge fuses with breakers but left
the zener in place . . . risky because
the I(squared)t operation numbers
for the breaker are larger than a fuse.
>I can only find a "house number" on the Zener. The diode was
>removed, the old regulator was replaced with a Zeftronics with
>integral overvoltage protection, the split rocker switch was
>replaced with a new one, and all seems well -- except that one
>electrical instrument is inoperative (possibly due to an overvoltage event).
Once the regulator is replaced with one
that INCLUDES ov protection, the zener
should be removed.
>My questions are as follows: can a physically small Zener diode
>(similar in size to a 1N5401 diode) handle the amount of energy
>required to trip a 5A breaker, even one time? Can the Zener always
>be counted upon to fail shorted and not open?
Good question but moot after the
regulator is replaced.
Bob . . .
Message 13
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Limiting Current to a Battery |
>>That device won't limit current pulled through his feed to the trailer
connector.<<
If the 20A model was mounted to the truck, the feed would be limited to
20A. If it was mounted to the trailer, the feed would be limited to
something more than 20A.
>>While that device might work for its intended purpose, one of its claims
is nonsense:
- Overcomes voltage drop caused by long cable runs
Unless its some corollary of a perpetual motion machine. <<
As someone mentioned earlier, long cable runs have been suggested as a
solution. But since that's really just a resistor, you'd also get a
voltage drop. This gizmo looks like it limits the current sent to the
battery being charged without dropping the voltage. So it overcomes the
voltage drop caused by the long cable run solution. I don't think they're
suggesting that it makes magical energy.
>
Message 14
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Limiting Current to a Battery |
The only way to limit the current drawn by a battery is to limit the voltage.
On Jul 7, 2019, at 2:13 PM, David Saylor <saylor.dave@gmail.com> wrote:
This gizmo looks like it limits the current sent to the battery being charged without
dropping the voltage.
Message 15
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Limiting Current to a Battery |
On 7/7/2019 1:13 PM, David Saylor wrote:
> >>That device won't limit current pulled through his feed to the
> trailer connector.<<
>
> If the 20A model was mounted to the truck, the feed would be limited
> to 20A. If it was mounted to the trailer, the feed would be limited
> to something more than 20A.
>
> >>While that device might work for its intended purpose, one of its
> claims is nonsense:
>
> * Overcomes voltage drop caused by long cable runs
>
> Unless its some corollary of a perpetual motion machine.<<
>
> As someone mentioned earlier, long cable runs have been suggested as a
> solution. But since that's really just a resistor, you'd also get a
> voltage drop. This gizmo looks like it limits the current sent to the
> battery being charged without dropping the voltage. So it overcomes
> the voltage drop caused by the long cable run solution. I don't think
> they're suggesting that it makes magical energy.
>
P(ower)=V(oltage) / I (current)
The only way to do what you suggest is...magical energy.
To restore charge voltage *at the same current* after a voltage drop
caused by a long cable run, you *must* increase current, to satisfy the
power equation. How?
---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
Message 16
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Limiting Current to a Battery |
Thank you everyone for the tips, I have ordered a power supply circuit to
test and will report back. It includes an adjustment for the max current.
On July 7, 2019 13:08:34 David Saylor <saylor.dave@gmail.com> wrote:
> Would it be a DC-DC battery charger?
>
> https://www.renogy.com/renogy-12v-dc-to-dc-on-board-battery-charger/?gclid=CjwKCAjwsIbpBRBNEiwAZF8-z-TrUeFYygbwZh7wrFUpKO_RhdCJkW-vJ-BFwYS_IZjlu9G8uAMNcxoCgBoQAvD_BwE
>
>
> On Sun, Jul 7, 2019 at 7:05 AM Jared Yates <email@jaredyates.com> wrote:
>
>> I have a question that's only somewhat applicable to E/AB aviation,
>> apologies in advance. But I think it points out a hole in my electrical
>> understanding.
>>
>> The characteristics of the lithium iron battery I'm running allow it to
>> draw lots of current really fast after the engine starts. If it has been a
>> little while since the last flight, the alternator is at max output for
>> several minutes. The alternator puts out all it can give, and it's less
>> than the battery wants to take.
>>
>> Stepping out of the hangar, my tow vehicle circuitry includes a wire in
>> the 7-pin connector that provides alternator voltage to the trailer,
>> intending to charge a small battery for a breakaway emergency brake. If I
>> install a larger battery for other purposes, perhaps one like what is in
>> the airplane, and connect it to that line coming from the truck, it seems
>> like it would almost certainly open the fuse on that circuit during that
>> initial high-draw stage.
>>
>> These two scenarios had me thinking, what methods would one have to limit
>> a hungry battery's draw? I'm imagining some type of circuit that takes in
>> 12-14 volts, and puts out almost the same, but only at some specified
>> number of amps. Almost like a DC-powered battery charging circuit, rather
>> than just putting the battery on the bus directly.
>>
>> Surely this has been solved in some off-the-shelf widget, but I haven't
>> figured out the words to google yet.
>>
Message 17
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Overvoltage protection |
Thank you, Bob. Mystery solved! You nailed it with this information and in the
article you wrote for S.A. in 1993. But it's the first time I've heard of such
a thing and was somewhat bewildered at a design depending on an unspecified
parameter in this way. Thanks for the history and explanation.
BTW, the diode we removed appeared to be plastic (like the one in your second
attached image), not glass.
But as you conclude (and we do too): it's moot after the regulator is replaced
with one containing over-voltage regulation.
Thanks again,
Joe
Robert L. Nuckolls, III wrote, On 7/7/2019 09:45:
> At 10:25 AM 7/7/2019, you wrote:
>>
>> A friend is working on a Grumman Tiger in which the alternator field
>> circuit breaker was found tripped. Upon digging in the manual, he
>> found the overvoltage protection was simply a Zener diode wired from
>> the output of the field breaker to ground. The diode was found to be
>> shorted, which would easily trip the breaker.
>
> Yup. A stone simple ov protection scheme
> that made it onto a TC aircraft. Wrote about
> this for SA back in '93 . . .
>
> https://tinyurl.com/y38og7he
>
> Discovered later that the idea was not
> 'bad' as originally implemented. The
> design called for a GLASS, 1N4745, 1W zener
> tied to ground downstream of a 5A
> FUSE.
>
>
> Emacs!
>
>
>
>
> I did some testing on various
> zeners and found that only GLASS enclosed
> could be depended upon to fail shorted . . .
> plastics would occasionally split
> and fail to burn the fuse.
> Emacs!
>
>
>
> This is why the zener could only be
> 'legally' replaced with the Grumman house
> part number to make sure that the part
> was GLASS encased.
>
> Some airplanes were modified to replace
> cartridge fuses with breakers but left
> the zener in place . . . risky because
> the I(squared)t operation numbers
> for a breaker are larger than the fuse.
>
>
>> I can only find a "house number" on the Zener. The diode was removed,
>> the old regulator was replaced with a Zeftronics with integral
>> overvoltage protection, the split rocker switch was replaced with a
>> new one, and all seems well -- except that one electrical instrument
>> is inoperative (possibly due to an overvoltage event).
>
> Once the regulator is replaced with one
> that INCLUDES ov protection, the zener
> should be removed.
>
>
>> My questions are as follows: can a physically small Zener diode
>> (similar in size to a 1N5401 diode) handle the amount of energy
>> required to trip a 5A breaker, even one time? Can the Zener always be
>> counted upon to fail shorted and not open?
>
> Good question but moot after the
> regulator is replaced.
>
>
>
> Bob . . .
Message 18
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Limiting Current to a Battery |
At 12:34 PM 7/7/2019, you wrote:
>That device won't limit current pulled through his feed to the
>trailer connector.
>
>While that device might work for its intended purpose, one of its
>claims is nonsense:
> * Overcomes voltage drop caused by long cable runs
>Unless its some corollary of a perpetual motion machine.
Don't think current through the connector
was the problem . . . the 'high current'
issue centers on the discharged battery's
willingness to accept a replacement
current greater than what is healthy for its physics.
Hence, taking care of the battery calls for
a constant voltage/constant current charging
supply that is battery friendly . . . which
is what this product would do . . . EXCEPT PERHAPS
. . . that the specifications do not call out
an 'adjustable' constant current range.
It's basically a dc/dc converter with
a full performance input range of 8-16
volts where the output would be held
steady at specified charging/maintaining\
levels and a max current of 20A.
The specs do not say that it's electronically
limited to 20A although I suspect it would
be.
If the trailer battery is happy at 20A max
charge current, then this critter would do
the job . . . However, under a 20A output
load, current through the trailer connector
WILL be higher because of voltage
drops being compensated for by the charger's
electronics.
Bob . . .
Message 19
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Limiting Current to a Battery |
> Hence, taking care of the battery calls for
> a constant voltage/constant current charging
> supply that is battery friendly . . . which
> is what this product would do . . . EXCEPT PERHAPS
> . . . that the specifications do not call out
> an 'adjustable' constant current range.
Here's a less expensive device in the same
power class. No "battery charging smarts"
but it does have user adjustable voltage
and current limits:
https://tinyurl.com/y4qson88
Perhaps quite suited to the task . . .
Bob . . .
Message 20
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Limiting Current to a Battery |
On 7/7/2019 3:46 PM, Robert L. Nuckolls, III wrote:
> At 12:34 PM 7/7/2019, you wrote:
>> That device won't limit current pulled through his feed to the
>> trailer connector.
>>
>> While that device might work for its intended purpose, one of its
>> claims is nonsense:
>>
>> * Overcomes voltage drop caused by long cable runs
>>
>> Unless its some corollary of a perpetual motion machine.
>
> Don't think current through the connector
> was the problem . . . the 'high current'
> issue centers on the discharged battery's
> willingness to accept a replacement
> current greater than what is healthy for its physics.
>
> Hence, taking care of the battery calls for
> a constant voltage/constant current charging
> supply that is battery friendly . . . which
> is what this product would do . . . EXCEPT PERHAPS
> . . . that the specifications do not call out
> an 'adjustable' constant current range.
>
> It's basically a dc/dc converter with
> a full performance input range of 8-16
> volts where the output would be held
> steady at specified charging/maintaining\
> levels and a max current of 20A.
> The specs do not say that it's electronically
> limited to 20A although I suspect it would
> be.
>
> If the trailer battery is happy at 20A max
> charge current, then this critter would do
> the job . . . However, under a 20A output
> load, current through the trailer connector
> WILL be higher because of voltage
> drops being compensated for by the charger's
> electronics.
>
>
> Bob . . .
>
Bob, his question indicated an issue with limited current capacity of
his wiring in the tow vehicle ('feed to the connector'). As I read his
question, the issue in his specific situation is not with hurting the
battery, but with overloading the supply circuit wiring ('open the fuse
on that circuit during that initial high-draw stage'). Hence, my
recommendation of a boost/buck power supply with current adjust.
Charlie
---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
Message 21
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
Thanks to All for the very good information provided!
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=490122#490122
Message 22
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Limiting Current to a Battery |
>Bob, his question indicated an issue with limited current capacity
>of his wiring in the tow vehicle ('feed to the connector'). As I
>read his question, the issue in his specific situation is not with
>hurting the battery, but with overloading the supply circuit wiring
>('open the fuse on that circuit during that initial high-draw
>stage'). Hence, my recommendation of a boost/buck power supply with
>current adjust.
>
>Charlie
Well fooey . . . got mentally snarled up
in another discussion from years past . . .
but I think I had this same discussion with
a builder back in the Compuserve AvSig days.
Not yet Dr. Dee and I were still running
the airport . . .
We fiddled with some current limiting
schemes involving lengths of 10AWG wire
(0.001 ohm/foot), a small contactor
and a comparator to sense when drop
across the resistor fell below a
user adjustable level. The idea was
to have additional resistance in the
line to the discharged trailer battery
that would be bypassed at some adjustable
preset.
That proved pretty messy. He decided to
up-size his trailer connector to handle 6AWG
battery feeders. I think it was
this one:
https://tinyurl.com/y48u7znv
The mated pair of connectors was really
cheaper than the bill of materials to
do the fancy hat-dance with an
electronically modulated current
limiter.
Since there was a battery on both ends
of the feeder, I think he put an ANL35
on both ends.
Thanks for the heads-up Charlie . . .
Bob . . .
Message 23
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Limiting Current to a Battery |
>Bob, his question indicated an issue with limited current capacity
>of his wiring in the tow vehicle ('feed to the connector'). As I
>read his question, the issue in his specific situation is not with
>hurting the battery, but with overloading the supply circuit wiring
>('open the fuse on that circuit during that initial high-draw
>stage'). Hence, my recommendation of a boost/buck power supply with
>current adjust.
>
>Charlie
Well fooey . . . got mentally snarled up
in another discussion from years past . . .
but I think I had this same discussion with
a builder back in the Compuserve AvSig days.
Not yet Dr. Dee and I were still running
the airport . . .
We fiddled with some current limiting
schemes involving lengths of 10AWG wire
(0.001 ohm/foot), a small contactor
and a comparator to sense when drop
across the resistor fell below a
user adjustable level. The idea was
to have additional resistance in the
line to the discharged trailer battery
that would be bypassed at some adjustable
preset.
That proved pretty messy. He decided to
up-size his trailer connector to handle 6AWG
battery feeders. I think it was
this one:
https://tinyurl.com/y48u7znv
The mated pair of connectors was really
cheaper than the bill of materials to
do the fancy hat-dance with an
electronically modulated current
limiter.
Since there was a battery on both ends
of the feeder, I think he put an ANL35
on both ends.
Thanks for the heads-up Charlie . . .
Bob . . .
Message 24
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Limiting Current to a Battery |
> The mated pair of connectors was really
> cheaper than the bill of materials to
> do the fancy hat-dance with an
> electronically modulated current
> limiter.
The link I offered for the connectors
was to Waytek Wire who has a really
comprehensive catalog of wiring products.
Interested Listers are invited to download
a copy of their catalog here:
http://www.aeroelectric.com/Mfgr_Data/Misc/Waytek/waytek_catalog231.pdf
Back in the days when we were selling
a lot of materials, tools and supplies,
we ordered quite a bit of stuff from
Waytek.
Bob . . .
Message 25
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Speaking of well loaded wires . . . |
The a/c quit on the Barber Co homestead
a couple days ago. Pulled of the covers
and found a wire burned off the dual
motor run capacitor.
Emacs!
The failure started in the Fast-On crimp
and pretty well toasted the wire and it's
mating capacitor tab before parting.
I didn't think to save the carcass . . .
While working the replacement, the wire fell
out of the terminal on the FAN side of
the capacitor!
The terminal on the capacitor COMMON lead
carries nearly the same current (~20A) as the
COMPRESSOR side, but it was in good shape.
HOWEVER . . . the other end of the capacitor
COMMON wire attaching to the run contactor
was starting to show stress . . . not in
the crimp but on the Fast-On grips.
Emacs!
In the case cited above, the terminals were
under-crimped. I'd replaced that same
capacitor in years past but didn't see
a problem with the terminals. But these
were in service for over 10 years
in a pretty unfriendly environment.
This time, ALL the PIDG devices in the
condenser wiring got replaced with a fine,
ratchet-handled mash-tool.
Even tho the catalogs offer a yellow PIDG
for up to 10AWG wire, I think it prudent
NOT to push this technology that hard
in aircraft.
7A or so continuous in blue PIDG Fast-Ons
have a track record of good performance.
If you must push into yellow terminal
territory, make sure they're 'real'
TE Connectivity PIDG and use the
ratchet-handled tool.
Bob . . .
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|