A while back I was looking at LiFePO4 batteries to solve my electrical
problems and I may still order them as my SLA batteries are getting old and
hold less of a charge.

I did, however, get behind my panel last week and changed out my master
switch for one more substantial in current capability and have experienced a
major improvement in function of my equipment. The switch that was
installed when I bought the glider was adequate for the CAI302 and the
MicroAir 760 but, after installing a Trig transponder, a Dell Steak and a
Zaon MRX, all operated from the same bus, the current capacity of the master
switch was the limiting factor. After two flights with the new master
switch installed it would appear that the problem is solved.

>After two flights with the new master
> switch installed it would appear that the problem is solved.

Dan, Just for interest what were the symptoms you were experiencing?

Dean

Dean, the radio was cutting out. Initially, other pilots would mention
scratchy and broken transmissions, later the green "Receive" light on my
radio would illuminate but no audio would be forthcoming, finally, the radio
would not function. I'd also see a large voltage drop when keying the
transmitter - sometimes over 1 volt. Switching to a fresh battery would not
solve the problem. I expect switching batteries under load caused pitting
and/or carboning of the switch, making it a high resistance junction.



"Soartech" > wrote in message
...
> >After two flights with the new master
>> switch installed it would appear that the problem is solved.
>
> Dan, Just for interest what were the symptoms you were experiencing?
>
> Dean

On Wednesday, October 16, 2013 7:26:12 AM UTC-7, Dan Marotta wrote:
> A while back I was looking at LiFePO4 batteries to solve my electrical
>
> problems and I may still order them as my SLA batteries are getting old and
>
> hold less of a charge.
>
>
>
> I did, however, get behind my panel last week and changed out my master
>
> switch for one more substantial in current capability and have experienced a
>
> major improvement in function of my equipment. The switch that was
>
> installed when I bought the glider was adequate for the CAI302 and the
>
> MicroAir 760 but, after installing a Trig transponder, a Dell Steak and a
>
> Zaon MRX, all operated from the same bus, the current capacity of the master
>
> switch was the limiting factor. After two flights with the new master
>
> switch installed it would appear that the problem is solved.

Ilec is dead set against using a master switch. The SB-7 manual has 22 cautions on the electrical installation page and the first 5 cautions are why it is a bad idea to use a master switch at all.

"MAIN SWITCHES in the electrical system can be a source of serious trouble, in particular where there are radio sets connected to them. When turning on the main switch with the radio on, heavy negative going pulses may be generated on the bus line during the typical 1-ms-bouncing periods of the main switch. They can destroy instruments, if not at once, then in the long run.. We have measured pulses of more than 10 amps".
Ilec goes on and on about what a bad idea a master switch is in a glider. What is the Master Switch really for? To shut off everything in case of an electrical problem.......can you say, smoke in the cockpit? If you do use a master switch (I don't), remember to ALWAYS turn it on FIRST and off LAST to insure these potential 10 amp pulses can't get in your delicate instruments.
Hope this helps,
JJ

On Wednesday, October 16, 2013 9:26:12 AM UTC-5, Dan Marotta wrote:
> A while back I was looking at LiFePO4 batteries to solve my electrical
>
> problems and I may still order them as my SLA batteries are getting old and
>
> hold less of a charge.
>
>
>
> I did, however, get behind my panel last week and changed out my master
>
> switch for one more substantial in current capability and have experienced a
>
> major improvement in function of my equipment. The switch that was
>
> installed when I bought the glider was adequate for the CAI302 and the
>
> MicroAir 760 but, after installing a Trig transponder, a Dell Steak and a
>
> Zaon MRX, all operated from the same bus, the current capacity of the master
>
> switch was the limiting factor. After two flights with the new master
>
> switch installed it would appear that the problem is solved.

Dan just curious, on the old switch you took out, what was the actual measured voltage drop caused by the faulty switch. Also did you happen to measure the resistance with an Ohm meter? I had a similar voltage drop when I used a riv nut to make a terminal post on a battery. Ironically it was a new LiFePo4 that didn't have the typical attachment connector. FYI I have a master switch and use the First On Last Off sequence that JJ referenced.

Another thing to consider: as the switch is used, over time, the contact surface becomes pitted and corroded due to small arcing as the contact is made and broken. This will lead to less contact area, higher resistance and lower voltage across the switch. It's probably a good idea to replace every few years as a precaution, or at least check the switch for minimal resistance.

Mike

Thanks, JJ. I have always turned the master switch on first and off last
and used the individual switches on the radios and instruments. I guess
it's that switching thing midway through the flight.

A large capacitor would be one way to mitigate that but I'm thinking more of
a "make before break" setup using multiple switches, i.e., turn on the
second battery before turning off the first.

Or I could simply divide my equipment across two (or three) busses and then
rely on the load division to allow the batteries to last an entire flight.

"JJ Sinclair" > wrote in message
...
On Wednesday, October 16, 2013 7:26:12 AM UTC-7, Dan Marotta wrote:
> A while back I was looking at LiFePO4 batteries to solve my electrical
>
> problems and I may still order them as my SLA batteries are getting old
> and
>
> hold less of a charge.
>
>
>
> I did, however, get behind my panel last week and changed out my master
>
> switch for one more substantial in current capability and have experienced
> a
>
> major improvement in function of my equipment. The switch that was
>
> installed when I bought the glider was adequate for the CAI302 and the
>
> MicroAir 760 but, after installing a Trig transponder, a Dell Steak and a
>
> Zaon MRX, all operated from the same bus, the current capacity of the
> master
>
> switch was the limiting factor. After two flights with the new master
>
> switch installed it would appear that the problem is solved.

Ilec is dead set against using a master switch. The SB-7 manual has 22
cautions on the electrical installation page and the first 5 cautions are
why it is a bad idea to use a master switch at all.

"MAIN SWITCHES in the electrical system can be a source of serious trouble,
in particular where there are radio sets connected to them. When turning on
the main switch with the radio on, heavy negative going pulses may be
generated on the bus line during the typical 1-ms-bouncing periods of the
main switch. They can destroy instruments, if not at once, then in the long
run. We have measured pulses of more than 10 amps".
Ilec goes on and on about what a bad idea a master switch is in a glider.
What is the Master Switch really for? To shut off everything in case of an
electrical problem.......can you say, smoke in the cockpit? If you do use a
master switch (I don't), remember to ALWAYS turn it on FIRST and off LAST to
insure these potential 10 amp pulses can't get in your delicate instruments.
Hope this helps,
JJ

Can't say the drop across the switch since I never measured across it.
Neither did I try turning off the transponder, PCAS, and Streak.


"glidergreg" > wrote in message
...
On Wednesday, October 16, 2013 9:26:12 AM UTC-5, Dan Marotta wrote:
> A while back I was looking at LiFePO4 batteries to solve my electrical
>
> problems and I may still order them as my SLA batteries are getting old
> and
>
> hold less of a charge.
>
>
>
> I did, however, get behind my panel last week and changed out my master
>
> switch for one more substantial in current capability and have experienced
> a
>
> major improvement in function of my equipment. The switch that was
>
> installed when I bought the glider was adequate for the CAI302 and the
>
> MicroAir 760 but, after installing a Trig transponder, a Dell Steak and a
>
> Zaon MRX, all operated from the same bus, the current capacity of the
> master
>
> switch was the limiting factor. After two flights with the new master
>
> switch installed it would appear that the problem is solved.

Dan just curious, on the old switch you took out, what was the actual
measured voltage drop caused by the faulty switch. Also did you happen to
measure the resistance with an Ohm meter? I had a similar voltage drop when
I used a riv nut to make a terminal post on a battery. Ironically it was a
new LiFePo4 that didn't have the typical attachment connector. FYI I have a
master switch and use the First On Last Off sequence that JJ referenced.

On Thursday, October 17, 2013 9:10:25 AM UTC-5, Dan Marotta wrote:

> Or I could simply divide my equipment across two (or three) busses and then
>
> rely on the load division to allow the batteries to last an entire flight.

Dan, that's how I've had my LS6 setup for over 13 years and it has worked just fine so far.

2 separate busses, one for each battery, with load divided as equally and logically as possible (split varios and loggers, for example).

In addition, the master switch for each buss can also select either battery, so if one battery fails (forgot to charge it?) the essential instruments can be powered by the remaining battery.

Probably WAY over-engineered, but it was fun to wire up and has worked as designed so far (ugly to look at, though - bit of a spaghetti factory behind that small LS6 panel that I want to clean up some day...).

Kirk
66

How about this, diagram below.
Each battery should have its own fuse.
Switches are drawn as -o\-
Vertical line is the Master bus.
Optional PV charge controller charges the active battery, whether avionics are on or off.
I'd suggest locking switches like Alcoswitch MTL106D available from Mouser for $12.60.
Jim

Bat 1 -----o\-----|
Bat 2 -----o\-----|
Bat 3 -----o\-----|
|-----o\----- Avionics
PV Charger -------|

Sorry, the line looked vertical before shipping.
Jim

On Wednesday, October 23, 2013 2:34:15 PM UTC-4, JS wrote:
> Sorry, the line looked vertical before shipping.
>
> Jim

I would put a fuse downstream of the PV charger. If it develops a short, your whole system dies.

Thanks Kirk,

The panel on my LAK is incredibly small and I'm pulling out my hair trying
to figure out where to cram terminal strips.

"kirk.stant" > wrote in message
...
> On Thursday, October 17, 2013 9:10:25 AM UTC-5, Dan Marotta wrote:
>
>> Or I could simply divide my equipment across two (or three) busses and
>> then
>>
>> rely on the load division to allow the batteries to last an entire
>> flight.
>
> Dan, that's how I've had my LS6 setup for over 13 years and it has worked
> just fine so far.
>
> 2 separate busses, one for each battery, with load divided as equally and
> logically as possible (split varios and loggers, for example).
>
> In addition, the master switch for each buss can also select either
> battery, so if one battery fails (forgot to charge it?) the essential
> instruments can be powered by the remaining battery.
>
> Probably WAY over-engineered, but it was fun to wire up and has worked as
> designed so far (ugly to look at, though - bit of a spaghetti factory
> behind that small LS6 panel that I want to clean up some day...).
>
> Kirk
> 66

Those switches look like what I used as my new master switch, except mine is
DPDT. I could use one to power two separate busses from two separate
batteries.


"JS" > wrote in message
...
> How about this, diagram below.
> Each battery should have its own fuse.
> Switches are drawn as -o\-
> Vertical line is the Master bus.
> Optional PV charge controller charges the active battery, whether avionics
> are on or off.
> I'd suggest locking switches like Alcoswitch MTL106D available from Mouser
> for $12.60.
> Jim
>
> Bat 1 -----o\-----|
> Bat 2 -----o\-----|
> Bat 3 -----o\-----|
> |-----o\----- Avionics
> PV Charger -------|

Right you are, Flub.
As well as the individual loads.
Jim

On Wednesday, October 23, 2013 5:10:37 PM UTC-7, son_of_flubber wrote:

> I would put a fuse downstream of the PV charger. If it develops a short, your whole system dies.

In article > JS > writes:
>How about this, diagram below.
>Each battery should have its own fuse.
>Switches are drawn as -o\-
>Vertical line is the Master bus.
>Optional PV charge controller charges the active battery, whether avionics are on or off.
>I'd suggest locking switches like Alcoswitch MTL106D available from Mouser for $12.60.
>Jim
>
>Bat 1 -----o\-----|
>Bat 2 -----o\-----|
>Bat 3 -----o\-----|
> |-----o\----- Avionics
>PV Charger -------|

I would seriously recommend against this.

If you only turn on the avionic load switch, with no batteries in
the circuit, the avionics will see the full open circuit output of
the solar panel.

Many "12 volt" panels deliver in the vicinity of 21.6 volts open
circuit -- even if not that high, they can easily be enough to damage
electronics.

Charge should be applied through a charge controller, so the panel
doesn't overcharge and cook the battery, and should be applied in
such a way that it cannot be applied directly to the load alone.

Alan

If anyone is interested my panel wiring can be found here:

www.boffins.co.uk/downloads/j1mwiring.pdf

Jim

Very nice, Jim. I'm going to save a copy of that!


"Jim White" > wrote in message
...
> If anyone is interested my panel wiring can be found here:
>
> www.boffins.co.uk/downloads/j1mwiring.pdf
>
> Jim
>

I have just rewired my Lak19T and have shared your frustration with the
small panel. I have Butterfly vario, Butterfly dispaly for powerflarm,
ClearNav vario and display (remotely mounted, Oudie (remotely mounted) ASI,
T/S, Radio and Altimeter all packed in running off two extra batteries
mounted 'in' the wheelbox. The standard batteries and mountings supply the
engine management.
For the instruments two terminal strips are mounted at the side of my knees
in the sloping part of the panel and the common earth sits on the floor of
the panel behing the ASI.
There are two way switches and fuses for each instrument. A master switch
each for engine and instrument circuits.
Have fun i did. i am sending a photo of the panel but photo of the rear of
the panel or a circuit diagram will take a little longer.
Oh i forgot there is panel space for a transponder display but sadly not a
main unit but i think this might be able to go on the cockpit floor behind
the panel unit if i eventually fit one.
Strzeb

At 01:01 24 October 2013, Dan Marotta wrote:
>Thanks Kirk,
>
>The panel on my LAK is incredibly small and I'm pulling out my hair trying

>to figure out where to cram terminal strips.
>
>"kirk.stant" wrote in message
...
>> On Thursday, October 17, 2013 9:10:25 AM UTC-5, Dan Marotta wrote:
>>
>>> Or I could simply divide my equipment across two (or three) busses and

>>> then
>>>
>>> rely on the load division to allow the batteries to last an entire
>>> flight.
>>
>> Dan, that's how I've had my LS6 setup for over 13 years and it has
>worked
>> just fine so far.
>>
>> 2 separate busses, one for each battery, with load divided as equally
and
>
>> logically as possible (split varios and loggers, for example).
>>
>> In addition, the master switch for each buss can also select either
>> battery, so if one battery fails (forgot to charge it?) the essential
>> instruments can be powered by the remaining battery.
>>
>> Probably WAY over-engineered, but it was fun to wire up and has worked
as
>
>> designed so far (ugly to look at, though - bit of a spaghetti factory
>> behind that small LS6 panel that I want to clean up some day...).
>>
>> Kirk
>> 66
>
>

Sorry to confuse.
There's a Strobl OS2H charge controller on the glider installations:
"Optional PV Charge Controller" Abbreviated like the fuses and connectors are in the text-only drawing.
Jim

On Wednesday, October 23, 2013 10:55:06 PM UTC-7, Alan wrote:
> In article > JS > writes:
>
> >How about this, diagram below.
>
> >Each battery should have its own fuse.
>
> >Switches are drawn as -o\-
>
> >Vertical line is the Master bus.
>
> >Optional PV charge controller charges the active battery, whether avionics are on or off.
>
> >I'd suggest locking switches like Alcoswitch MTL106D available from Mouser for $12.60.
>
> >Jim
>
> >
>
> >Bat 1 -----o\-----|
>
> >Bat 2 -----o\-----|
>
> >Bat 3 -----o\-----|
>
> > |-----o\----- Avionics
>
> >PV Charger -------|
>
>
>
> I would seriously recommend against this.
>
>
>
> If you only turn on the avionic load switch, with no batteries in
>
> the circuit, the avionics will see the full open circuit output of
>
> the solar panel.
>
>
>
> Many "12 volt" panels deliver in the vicinity of 21.6 volts open
>
> circuit -- even if not that high, they can easily be enough to damage
>
> electronics.
>
>
>
> Charge should be applied through a charge controller, so the panel
>
> doesn't overcharge and cook the battery, and should be applied in
>
> such a way that it cannot be applied directly to the load alone.
>
>
>
> Alan

I'm just re-wiring my panel for a Silent2 Targa self-launcher. I wanted to
simplify the switching and I did not trust the two miniature switches that
were used and which were connected (without any fuse - I will now add one)
to a very powerful engine battery! I have selected a larger high quality
OTTO switch for the master, and I have used latching switches (anti-fumble)
for the Power Flarm brick and for AUX power for a PDA etc. A relay will
automatically connect the solar panel controller when the Flarm is switched
on, so that it will not latch on provided that you switch the Flarm off
before the master. Note that the Vario and radio will be switched off
internally when power is lost. If I see a voltage on the voltmeter then I
will know that the solar panel is still connected to the panel, but of
course it would not stay latched on when the glider is in the trailer.

Schematic here if anyone is interested:
http://ubuntuone.com/162WfU0vGsXXzw2YpKGGif