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ECU Battery for other things

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ECU Battery for other things

Old 04-19-2023, 05:58 AM
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Agrav8ed
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Default ECU Battery for other things

I noticed that on Jonathan's (Canadian Man) last build he is using a three cell battery to power the whole jet, not just the ECU, using a Sbec. I was curious to know how many of us use the Ecu battery to power other things? I was thinking about using it to power my smoke pump also but have been largely hesitant to use the battery for anything other than the turbine.
Thanks,
Tone
Old 04-19-2023, 06:25 AM
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Len Todd
 
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For me it depends on the type, voltage and size of the ECU battery.

I do not like to use voltage regulators (VRs). They introduce another potential failure mechanism.

If using a 3S LiFe I do not tap into it for other devices.

If using a 4000+ mah 2 cell LiPo for the ECU, I may tap into it, if the other device is HV capable.

If I am using a small (e.g. 2000 mah, 2S, LiPo) ECU battery, I do NOT tap into it for other uses.

If using two small LiPos for the RXer, I will tap into them (e.g. one for lights and the other for gear.) But then I have battery voltage indicators on the battery circuits that can be checked before every start.

If using large (4000+ mah 2S LiPo) I will tap into them same as the smaller LiPos but I typically do not worry much about checking their voltage until late in the day.
Old 04-19-2023, 08:12 AM
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I a use 2 x rx batteries, either life 2s or liIon 2s , depends if HV system used.

Then I usually also use large 2S battery for the engine and route power for retracts and lights from it. In one case I took power for lights and retracts fron ARXL smoothflite unit which regulates V to 7.4V, and I used 5200mAh 2s LiIons then.

Old 04-19-2023, 10:06 AM
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Agrav8ed
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I normally use the the Smoothflite and 2s Lipo batteries to power the jet including the retracts, lights, etc. I then use a separate 3s lipo to power the ECU. The issue is the Swiwin smoke pump I want to get looks like it runs off of 3s. I do not want to have to have a separate 3s battery just to power the smoke pump but I have always been a bit hesitant to run anything additional off of the ECU battery. Hence the initial post to get a consensus of what others are doing. I suppose I could use a buck converter to upregulate the 2s voltage to 12 volts but not sure if that would be the right route to go.
Thanks,
Tone
Old 04-19-2023, 10:29 AM
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Auburn02
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I don't think I'd utilize a single battery for the entire airplane but have no problem tapping an ECU battery for lights or retracts.
Old 04-19-2023, 11:05 AM
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My friend uses 1 battery for everything on his Eflite 90mm Viper conversion, mainly because he has no space for another battery. Not sure how many flights he has on plane, but he has a little over 12hrs on the turbine (only been in this jet). And he has no issues with the battery. He is using a hi C battery, and he checks it every flight just to make sure. But he loves it.Straight 2S lipo for the turbine. BEC for the receiver and retracts. Not sure how he is handling the smoke system nor the Unilight system.

Last edited by wildnloose; 04-20-2023 at 01:24 AM.
Old 04-19-2023, 12:29 PM
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I tap off the 2 cell Lipo ECU battery for lights & brakes.

The (two) radio batteries are totally separate.
Old 04-19-2023, 04:22 PM
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jvaliensi
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Turbines draw a lot of energy on start up, after that, they likely draw less than a single servo.
With my FW Avanti X45 foam conversion, I use a single 4000MAH Samsung 40T 2S battery. At start up with the battery at 8V, the current draw will pull the battery down to 7V. But once the turbine is running the voltage goes back to 8V.
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Old 04-19-2023, 07:33 PM
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highhorse
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Separate. Period.

My PowerBox smoke pump recommends that. I also place the landing gear/brake controller onto a separate battery so their draws won’t vary the voltage to the ECU during their operation.

Separation is cheap insurance imo…others’ mileage will vary.
Old 04-19-2023, 10:50 PM
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Vincent
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Default Ecu batts

I typically tap the 3 cell life ecu pack to run the elec gear and brakes. I have done this for many years never a problem. Depending on the gear controller max voltage i might run a castle voltage reg too.
Old 04-20-2023, 06:57 AM
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Canadian Man
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Originally Posted by jvaliensi
Turbines draw a lot of energy on start up, after that, they likely draw less than a single servo.
With my FW Avanti X45 foam conversion, I use a single 4000MAH Samsung 40T 2S battery. At start up with the battery at 8V, the current draw will pull the battery down to 7V. But once the turbine is running the voltage goes back to 8V.
I'll chime in here as well. I don't think there is a right way or a wrong way to do it and of course you will see fairly rigid views for both sides. I have been in both categories in the past. 1. separate battery for everything and 2. one battery for all. One thing I have learned in this journey is there is nothing wrong with looking at change. If we are too rigid in our thoughts about everything, we can miss out on great tech and cool opportunities for items in the hobby.

Little off topic but I used to feel that way about telemetry, primarily when I was using a radio system that didn't support a great telemetry option. I thought I never needed, never should need it, doesn't help. Well was I wrong. Such a valuable tool for so many reasons. Many feel the same way about gyro's in aircraft and have strong views in either direction. I adopted them early and love them! I could leave it off the entire flight and just use it during the landing phase and would be satisfied.

Anyways. For the latest project in question, The U2.0 Ultimatum. The final layout is going to be a 3 Cell GensAce 4000mah 60C battery powering the turbine, control systems and gear. The lighting system is getting it's own 3Cell 2200 mah 3 Cell lipo. The lighting setup can pull some decent current.
As was mentioned in the above quote, the turbine pulls most of it's juice at startup. During the flight its a very small amount of draw. The swiwin GSU Shows the current draw on the screen. The Electron landing gear pull so little power it doesn't warrant a stand alone battery.

The U2 is not getting setup with a central power hub (ie. Jeti Central Box). Another reason for the simple setup.

I think back to many of my past builds. I would have a separate battery for everything, including the Electron Retracts. Could fly for an entire weekend and put 100-150 mah back into a 2200 mah 2 cell lipo.

Thanks!

Last edited by Canadian Man; 04-20-2023 at 06:59 AM.
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