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Electron Retract battery source - potentially really dumb idea/question

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Old 01-16-2018, 07:06 AM
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Default Electron Retract battery source - potentially really dumb idea/question

Hello fellas,

Anyone running their Electron retracts off of their ECU battery source? The manual suggests you do not share the source with the RX for obvious reasons. I ran a separate battery for the gear in my Rebel all last season and noticed the retracts barely consume any power in a full day of flying. Having said that, a separate battery definitely provides the benefit of a discrete power system from the RX or ECU. So, I ran the gear for a season to get familiar with it, as suggested by Electron. I noticed they react to binding real well (just stops at the point of binding) and do not appear to cause any adverse draw or drain from the battery. I even looked at their chart(s) which illustrate amp (p/wheel) draw when brakes are fully applied, etc... That plus taking into consideration that the max draw from the ECU takes place at startup, you would presume the two systems do not really contend with each other very much. Unlike a bunch of servos fighting for current at the same time. There will be 2 gear cycles which take place per flight (1 up/1 down) while the turbine is running. But the ECU draw from the battery would mostly be pump at this time. I won't bore the thread with the math, but if you look at the potential max draw figures from the starter, pump and gear, putting this max load on a 11.1v 50C/5K mAh Lipo should"technically" not be a problem. It should be able to handle the load pretty easily w/out breaking a sweat. So the real concern would be what if scenarios.

A little more about the setup. Jet Central Cheetah SE, ran it all last season on 9.9v LiFe, which I would switch to 11.1v LiPo. Specifically because both JC and Electron support 3s LiPo. So it would be pretty sweet if I could simply connect both devices to 1 battery using a parallel cable/extension like the one from DMP, link below.

Ok, so why am I doing this? I'm trying to limit the number of batteries I need to manage. I typically go to the field with 2 sets for every system. On this jet that means eight batteries. 2 x RX, 1 x Gear & 1 x ECU, plus 1 spare for each = 8 batteries. I can drop this down to 3 production and 3 spares, or 6 batteries. The caring of the batteries is becoming tedious when you have multiple jets in flight ready mode.

Thoughts?
Suggestions?
Lashing for such a silly idea?

Link to cable @ DMP: Dreamworks Model Products LLC

thanks in advance for your help, and sorry for the long post.

sc





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Old 01-16-2018, 07:20 AM
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Dave Wilshere
 
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I use a separate 2s (7.4v) 1000mAh battery on the Mephisto, I have not charged it yet...8 flights over 3 weeks, plus testing.
There are so many what if's using a shared supply. Almost certainly OK...but the effort is almost nothing and the loss of an airframe because something did shut down, not worth the risk imo.
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Old 01-16-2018, 07:53 AM
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I donít recommend to use the ECU battery because the voltage may drop a bit when gear is operating, and the ECU will have to adjust for that new voltage, best case is an rpm oscillation during gear operation and worst case a flame out

Sorry for my English

Regards
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Old 01-16-2018, 08:16 AM
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i installed a 1/4 scale ia63 pampa with electron retracts and motors run 9,9v from turbine battery pack,not a single issue!!! go for it...
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Old 01-16-2018, 09:36 AM
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Quote:
Originally Posted by jetmon View Post
I donít recommend to use the ECU battery because the voltage may drop a bit when gear is operating, and the ECU will have to adjust for that new voltage, best case is an rpm oscillation during gear operation and worst case a flame out

Sorry for my English

Regards
That was my concern when making this same decision on my Natrix. I think the chance of an issue is small but since gear retraction normally occurs at a critical point (i.e. shortrly after takeoff), it's the worse time for an engine hick-up or flame out. For that reason I came to the same conclusion Juan is recommending. Just stick with a separate battery for the retracts. As you mentioned, one charge lasts a long time.

Craig
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Old 01-16-2018, 10:06 AM
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Guys,

Thank you for taking the time to read my post and for commenting. My gut is telling me to heed to common knowledge and be practical about this and simply keep using the separate battery. But the techie in me is telling me to take this at least one step further. I'm going to perform some (ground) testing, I think I will perform a series of gear up/downs at idle, mid-range and full throttle. I will monitor closely the battery volts, battery amps, & turbine rpm, turbine pump volts/amps. To see if I notice any notable ill effects. I would like to include a binding test scenario as well, to be thorough. But I just don't feel comfortable intentionally binding my retracts. I have accidentally done it before with an obstruction, but I would feel bad doing it intentionally to my gear.

If anyone else has any additional feedback, please feel free to comment.

sc

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Old 01-16-2018, 10:06 AM
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I use a dual battery regulator for my receivers in my jets - usually a Smartfly one, with two 2S LiPos. The regulator draws power for the receiver from whichever battery has the higher voltage. I run my Electron retracts off of one of those batteries. I have telemetry to read the voltage of both batteries. When the retracts are in motion or the brakes are on, you can see the voltage of the one battery go down a few tenths, but as soon as the draw from the retracts/batteries stops, the voltage recovers. If the retracts/brakes ever over-draw the battery, the other one will take over and power the RX until I get back on the ground...

Bob

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Old 01-16-2018, 10:08 AM
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Aren't we all using 2 separate RX packs for redudancy? I have been using one of my receiver batteries to power the electric gear in all of my planes. The power consumption is negligible, so they both deplete about the same. I also wouldn't use my turbine battery for obvious reasons, but why add a 4th battery that needs to be charged?

Thomas
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Old 01-16-2018, 10:18 AM
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Quote:
Originally Posted by bluelevel View Post
Aren't we all using 2 separate RX packs for redudancy? I have been using one of my receiver batteries to power the electric gear in all of my planes. The power consumption is negligible, so they both deplete about the same. I also wouldn't use my turbine battery for obvious reasons, but why add a 4th battery that needs to be charged?

Thomas
I would consider using one of my RX packs, but they're both directly connected to a PowerBox SRS. I would either have to peel off one prior to the PB or use a spare servo port off of the PB just for power. If I use one of these ports I would have to step down the wire gauge as they are jr connectors rather than mpx. I would prefer to use the larger gauge wire to power the gear.
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Old 01-16-2018, 10:23 AM
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Quote:
Originally Posted by skunkwurk View Post
I would consider using one of my RX packs, but they're both directly connected to a PowerBox SRS. I would either have to peel off one prior to the PB or use a spare servo port off of the PB just for power. If I use one of these ports I would have to step down the wire gauge as they are jr connectors rather than mpx. I would prefer to use the larger gauge wire to power the gear.
I am also using Powerbox products in all of my planes and never had a single issue with this setup for hundreds of flights. My batteries are mounted in the nose, so I need extensions anyway to connect the batteries to the PB. When I solder the extensions, I simply "Y" one branch with an MPX plug at the end. Works perfectly and as explained by Bob, the PB is smart enough to always use the battery with the higher voltage. This way they drain about the same, although one of them also powers the e-gear.

Thomas
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Old 01-16-2018, 10:28 AM
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I run 2 Jeti Li Ion 5200mAh packs in my Ultra Flash with Electron gear.

Both Li Ion packs go to the CB200 to power the radio/ servos. One of the Li Ion packs also feeds the Electron gear, while the other Li Ion battery also runs the engine/ ECU.

I have over 100 flights on the UF with no issues. I can get at least 5-6 flights before a recharge, and that is only limited by the voltage drop on engine start. The other battery (Rx/ Gear) is always less depleted than the Rx/ ECU battery. Normally I keep flying until I get a failed start.

if the engine can start, I have plenty of battery power for everything else. It is self-limiting.

Paul
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Old 01-16-2018, 10:30 AM
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Quote:
Originally Posted by bluelevel View Post
I am also using Powerbox products in all of my planes and never had a single issue with this setup for hundreds of flights. My batteries are mounted in the nose, so I need extensions anyway to connect the batteries to the PB. When I solder the extensions, I simply "Y" one branch with an MPX plug at the end. Works perfectly and as explained by Bob, the PB is smart enough to always use the battery with the higher voltage. This way they drain about the same, although one of them also powers the e-gear.

Thomas
I like it, I am going to see how I can cleanly do this. I have my two RX batteries mounted on small boards near my PB, so they're directly connected and visible. Adding a splice to one would be practical, but less elegant. Man... you know you've lost it when vanity gets in the way of being practical...

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Old 01-16-2018, 10:34 AM
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I use PowerBox with dual 2000mah Rxer packs, a Xicoy gear controller & separate LiPo ECU supply.

For the gear controller, I just tap into one of the RXer packs before the PB. Never had a problem with stray RF or any other issue. The gear uses so little power it has relatively no impact.
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Old 01-16-2018, 10:39 AM
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Quote:
Originally Posted by JSF-TC View Post
I run 2 Jeti Li Ion 5200mAh packs in my Ultra Flash with Electron gear.

Both Li Ion packs go to the CB200 to power the radio/ servos. One of the Li Ion packs also feeds the Electron gear, while the other Li Ion battery also runs the engine/ ECU.

I have over 100 flights on the UF with no issues. I can get at least 5-6 flights before a recharge, and that is only limited by the voltage drop on engine start. The other battery (Rx/ Gear) is always less depleted than the Rx/ ECU battery. Normally I keep flying until I get a failed start.

if the engine can start, I have plenty of battery power for everything else. It is self-limiting.

Paul
I like your setup for small airframes when weight is a concern. I also use LiIon batteries a lot, but their C-rating isn't high enough to deliver the high amps that are required to reliably start a big block engine. Bigger jets need weight in the nose anyways, so adding a third battery should not come with a penalty. I just don't like charging and maintaining that many battery packs if I don't have to.

Thomas
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Old 01-16-2018, 11:18 AM
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Quote:
Originally Posted by skunkwurk View Post
Guys,

I'm going to perform some (ground) testing, I think I will perform a series of gear up/downs at idle, mid-range and full throttle. I will monitor closely the battery volts, battery amps, & turbine rpm, turbine pump volts/amps. To see if I notice any notable ill effects. I would like to include a binding test scenario as well, to be thorough. But I just don't feel comfortable intentionally binding my retracts. I have accidentally done it before with an obstruction, but I would feel bad doing it intentionally to my gear.

sc
A binding test shouldn't be a big deal. I've never had Electron retracts but the others I've owned all have an "amp out" feature that cuts off the current if the amps start to spike. I think that's even how Down and Locked retracts normally stop at the end points. If you're going to test, you should probably do it under "worst case scenario" conditions. I would be interested in hearing your results.
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Old 01-16-2018, 11:31 AM
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Quote:
Originally Posted by CraigG View Post
A binding test shouldn't be a big deal. I've never had Electron retracts but the others I've owned all have an "amp out" feature that cuts off the current if the amps start to spike. I think that's even how Down and Locked retracts normally stop at the end points. If you're going to test, you should probably do it under "worst case scenario" conditions. I would be interested in hearing your results.
The Electron retracts have this feature - at least if you are using the Xicoy version of the controller.. In fact, if you are using the Xicoy version of the controller, you can set the Amp cutoff value to suit the motor you are using.

The Electron retracts don't have limit switches and they actually use this max. Amp cutoff to stop the motor at each limit of their travel. Once the retracts reach their limit, there is also an adjustable "timeout" value where the motor is run in reverse momentarily to take the load off of the motor and gear system and make sure its properly taken up by the mechanical locking mechanism.

Thus, "stopping" the gear manually in the middle of the travel doesn't necessarily put more strain on them than normal operation.

Bob
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Old 01-16-2018, 01:49 PM
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Guys,

I think I figured out an other option. On this jet I'm using all PB PowerBUS. I fortunately have a PowerBUS adapter close to the Electron controller for the gear is in the fuse. I am going to run a PB SBUS jumper from the OUT of the adapter to the gear controller. I checked polarity and it looks like it follows the standard MPX pin-out for power. The exception being the signal lead, which is the end pin on the positive side trio. I am going to make my own wire or just snip it on a PB jumper and I should be good to go.

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Old 01-16-2018, 03:57 PM
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Quote:
Originally Posted by skunkwurk View Post
Guys,

I think I figured out an other option. On this jet I'm using all PB PowerBUS. I fortunately have a PowerBUS adapter close to the Electron controller for the gear is in the fuse. I am going to run a PB SBUS jumper from the OUT of the adapter to the gear controller. I checked polarity and it looks like it follows the standard MPX pin-out for power. The exception being the signal lead, which is the end pin on the positive side trio. I am going to make my own wire or just snip it on a PB jumper and I should be good to go.
Sorry to say this so drastically, but I think it's THE WORST idea to tap into the entire servo system, just because you don't like to see an additional connector or wire splice. In case of a power spike caused by a faulty gear controller, you will most likely loose control over the entire plane. If you have it conneced to one receiver battery, you still have the 2nd pack to power the servos.

Just my 2cents of course but vanity should never get in the way of safety concerns.

Thomas
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Old 01-16-2018, 03:58 PM
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... double post

Last edited by bluelevel; 01-16-2018 at 08:25 PM.
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Old 01-16-2018, 04:30 PM
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I currently have been using the ECU battery for both and doing it two years with absolutely no issues in a BVM MK Bandit. These are not Electron but the BVM Purple gear with the Xicoy controller . The battery for the ECU that came with the turbine was a 2200mah at 25C 2 cell, so in order to ensure no issues the battery that I installed was a 5000mha at 30C 2 cell. And yes these gear have seen max amps to there the gear have over amped and stopped half way through a gear rotation even when this happened (more than once on nose gear) the turbine operated just fine. Also you all know the Bandit has gear doors which operate though the same controller, and I have them set so in the closed position they are not off but always holding position, had to do it this way because they would get sucked open it the power to the servo was set to off in the closed position.

Robert
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Old 01-16-2018, 04:35 PM
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I also have been splicing into one of my batteries. I would just do it and never look back.
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Old 01-16-2018, 05:36 PM
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Quote:
Originally Posted by bluelevel View Post
Sorry to say this so drastically, but I think it's THE WORST idea to tap into the entire servo system, just because you don't like to see an additional connector or wire splice. In case of a power spike caused by a faulty gear controller, you will most likely loose control over the entire plane. If you have it connected to one receiver battery, you still have the 2nd pack to power the servos.

Just my 2cents of course but cosmetical issues should never outweigh safety.

Thomas
I need to confirm to be 100% sure with Richard, but there is a servo short/overload function built into the adapter to protect against this. It shuts down the output port and maintains a live signal. I am testing on the output of the last adapter in the segment. If this does work properly, it may actually be the most reliable, as it should eliminate the potential of the battery to overload. Below is a snip from the Royal SRS manual.

Snip from the Royal SRS Manual - Section 10: PBUS
However, until now there has always been one drawback: if a short-circuit occurs in one servo, this blocks the bus lead, and all the servos connected to it stop working. Here at PowerBox-Systems we have now completely eliminated this former disadvantage: The servo distributors which we have developed are protected against short-circuits in the power supply wires and the signal wire! This means that if one output is shorted out at a servo distributor, that output is switched off within a few micro-seconds, and the bus lead remains active. This supplementary feature is very important to flight safety, since a servo bus without it is not suitable for use in valuable model aircraft!
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Old 01-16-2018, 08:29 PM
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Quote:
Originally Posted by skunkwurk View Post
I need to confirm to be 100% sure with Richard, but there is a servo short/overload function built into the adapter to protect against this. It shuts down the output port and maintains a live signal. I am testing on the output of the last adapter in the segment. If this does work properly, it may actually be the most reliable, as it should eliminate the potential of the battery to overload. Below is a snip from the Royal SRS manual.

Snip from the Royal SRS Manual - Section 10: PBUS
However, until now there has always been one drawback: if a short-circuit occurs in one servo, this blocks the bus lead, and all the servos connected to it stop working. Here at PowerBox-Systems we have now completely eliminated this former disadvantage: The servo distributors which we have developed are protected against short-circuits in the power supply wires and the signal wire! This means that if one output is shorted out at a servo distributor, that output is switched off within a few micro-seconds, and the bus lead remains active. This supplementary feature is very important to flight safety, since a servo bus without it is not suitable for use in valuable model aircraft!
Sorry, but regardless what PB says I don't get it. You are potentially risking your plane just because you think that splicing into one battery lead doesn't look pretty enough!

Thomas
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Old 01-16-2018, 08:47 PM
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Quote:
Originally Posted by bluelevel View Post
Sorry, but regardless what PB says I don't get it. You are potentially risking your plane just because you think that splicing into one battery lead doesn't look pretty enough!

Thomas
I haven't determined how I'll proceed, but if this works as advertised by PB, I think it would definitely be my preferred approach. As has been quite obvious from all of the responses today, there are many ways to accomplish this. Even Electron stated they've seen many users share either the RX or ECU battery w/out issues. They don't recommend either as it could lead to a liability. Anyway, thank you for your suggestion, noted.

sc
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Old 01-16-2018, 09:27 PM
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I have been flying my Ultra Flash with a JetsMunt M140xbl for the past 3 years with Bihotec C40 Elecrtic Retracts and brakes. I'm using a shared battery 2s LiPo with the ECU without a single problem. Hundreds of flights. I also have had the retracts "overamped" since at times I have had too high of a speed after takeoff and the gear got stuck in halfway retracted position. Cycling the gear retracts them without issues after slowing down a bit. I just did not want to use another battery. I also thought of adding a schottky diode between the retract controller and battery but did not want any lower voltage since I'm already using a 2s LiPo (3s is recommended).
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