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  #11  
Old 01-27-2019, 03:51 PM
MCA's Avatar
MCA MCA is offline
 
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Igor,

The switch layouts strike me as confusing. Perhaps I can suggest an alternate way to lay out the switches. My recommendation is 3 switches:
1. Master (not the Cessna split master)
2. ALT1/OFF/ALT2
3. Ess bus

A couple of comments:
Not sure I fully understand the reason for having both alternators on at the same time. They are not additive. The loads will use the output with the highest voltage, and the other one will be basically invisible. I recommend running on the primary alternator, then when you get a low voltage alarm on the EFIS you know it has failed. You can switch over to the backup alternator. As long as the bus voltage stays stable (not declining) you know it is supplying enough current for the loads. When running with both on, and less than 30A load, you will not know that one of them has failed.

As far as a second battery for IFR operations, most EFIS now have a backup battery capability, either built-in like the G5 or Dynon D10, or an external battery backup like the TCW product. A backup radio could be a handheld with headset and antenna adapters. In other words, IMO you don't need a whole bus backup, just key instruments to stay safe.

Just my 2 cents. Enjoy the -10!
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  #12  
Old 01-27-2019, 06:48 PM
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Carl Froehlich Carl Froehlich is online now
 
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Quote:
Originally Posted by MCA View Post
SNIP...

Not sure I fully understand the reason for having both alternators on at the same time. They are not additive. The loads will use the output with the highest voltage, and the other one will be basically invisible. I recommend running on the primary alternator, then when you get a low voltage alarm on the EFIS you know it has failed. You can switch over to the backup alternator. As long as the bus voltage stays stable (not declining) you know it is supplying enough current for the loads. When running with both on, and less than 30A load, you will not know that one of them has failed.

...SNIP
A standby alternator, like the B&C vacuum pad unit, is on all the time and only has a current output when buss voltage drops below a set level, as would be the case if the primary alternator failed. No pilot action required or desired.

You know the standby alternaor is carrying the load by buss voltage stabizing at the lower set point (typically about 13.5vdc) and if you have the B&C unit there is a yellow indicator light that you can mount on the panel.

Carl
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  #13  
Old 05-02-2020, 11:14 AM
supik supik is offline
 
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Location: Bratislava, Slovakia
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Default new layout version 22C

latest version:

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  #14  
Old 05-02-2020, 11:34 AM
supik supik is offline
 
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ESSENTIAL BUS:
Peak draw: 42.5 Amps
Typical draw: 21 Amps


I would go with an 50 Amp Klixon 5TC50-50 (85% capacity at peak draw) breaker between MAIN BUS and ESSENTIAL. This breaker is much more compact compared to the 60 Amp breaker.

The Diode between MAIN BUS and ESSENTIAL is there just in case the ESS BUS Contactor fails.

Should the MAIN BUS Contactor fail open, ALT1 could still supply everything through the Deuce Schottky Diode incl. battery charge.

This should not happen normally;
-let's assume I have a flat battery (24Ah),
-the MAIN BUS Contactor has failed open
-ALT2 is OFF
-ALT1 (60Amp) would try to feed everything on MAIN BUS and ESSENTIAL + Battery charge

-what loads shall I expect to see across the the CB from MAIN BUS to ESSENTIAL? My concern is the 50Amp circuit breaker


-opinions?
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Last edited by supik : 05-02-2020 at 04:27 PM. Reason: Contactor failed open
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  #15  
Old 05-02-2020, 05:21 PM
supik supik is offline
 
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Default v.23 with Firewall

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Last edited by supik : 05-02-2020 at 05:24 PM.
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  #16  
Old 05-03-2020, 03:22 AM
oren_rokach oren_rokach is offline
 
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Default Loadmeter

Hi Igor,
very interested in the hall effect sensors,
what load meter are you using?
Does it go to the EFIS as well?
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  #17  
Old 05-03-2020, 04:05 AM
oren_rokach oren_rokach is offline
 
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NM
found it on the GEA24
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  #18  
Old 05-03-2020, 05:16 AM
supik supik is offline
 
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Thumbs up AMPLOC

Quote:
Originally Posted by oren_rokach View Post
NM
found it on the GEA24
Hi Oren,

I have ordered the AMPLOC 100 sensors from Health Media International:
sales (at) amploc.com

http://www.aviatorshop.eu/RV-10/2020...020-inventory/
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  #19  
Old 05-03-2020, 08:03 AM
supik supik is offline
 
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Default v.24

new update with ALT2 Loadsense moved before firewall:

https://i.ibb.co/GMdtv7j/Diagram-OM-ELA-Igor-v-024.jpg
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  #20  
Old 05-03-2020, 08:43 AM
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Carl Froehlich Carl Froehlich is online now
 
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Quote:
Originally Posted by supik View Post
The Diode between MAIN BUS and ESSENTIAL is there just in case the ESS BUS Contactor fails.

Should the MAIN BUS Contactor fail open, ALT1 could still supply everything through the Deuce Schottky Diode incl. battery charge.

This should not happen normally;
-let's assume I have a flat battery (24Ah),
-the MAIN BUS Contactor has failed open
-ALT2 is OFF
-ALT1 (60Amp) would try to feed everything on MAIN BUS and ESSENTIAL + Battery charge

-what loads shall I expect to see across the the CB from MAIN BUS to ESSENTIAL? My concern is the 50Amp circuit breaker.
-opinions?
Some thoughts:
- If your battery is flat, this is a hard ?ground the airplane? issue. Use a real charger to bring it back, or better yet replace it as most AGM batteries suffer permanent capacity loss if you abuse it (e.g. leave the master on).
- I suggest you eliminate the ground power jump connection. This is a left over from vacuum driven gyros and mags. In other words, never jump start your airplane. You will be launching into the ether with no clue of battery capacity, if any. On top of that, these are massively clumkly plugs with big fat wires - both are on the list of things to minimize in our airplane.
- On loads for each alternator, you will need to carefully adjust each voltage regulator to make sure you have current flowing as you think you do (for each of your primary and back up modes). Adding diodes complicates this as voltage drop across the diode needs to be measured to achieve the load balance you want.
- Running everything off the one 60 amp alternator is not an issue. Even if you have low charge lithium batteries they will not take more current than associated with the buss voltage, and buss voltage will drop under heavy current load. So unless you are doing something weird the alternator will carry the load and buss voltage will increase with time. Note however that 60 amp alternators will put out more than 60 amps, so upsize your current limiter to 70 amps. But again if you are trying to use the alternator to breath life into a dead battery, you are violating a prime rule as discussed above.
- On my planes I do add a ?shore power? breaker to the main buss. I use this to connect my 30 amp regulated power supply using a short #14 jumper cable to run the plane on the ground. 30 amps is more than enough to run the whole panel and to keep the batteries topped off (just like the alternator does). In practice with both (charged) batteries on line and all avionics up - current draw is about 10 amps.

Carl
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