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Old Jun 10, 2010, 03:16 AM
The truth will prevail
skyrock's Avatar
Westbury, NY
Joined Nov 2009
682 Posts
Quote:
Originally Posted by gregq View Post
LOL..sorry, tried to include all info and left the important bit out

Mustang was powered by a 2 cell LiPo through an 8 amp regulator. This regulator has 2 inputs and 2 outputs. Only using 1 input but I had both outputs being used. 1 into the SPC and the other in the battery port for the servos.

I hope someone has an answer, engine in the 'Stang is a Saito FG14 petrol jobbie, and it cost more than the radio. It survived, but really wary about risking it again in my soon to be completed Zero

Also, if it was a brown out, then it should have reconnected once the voltage level bounced back, but I had no control till after the rx and tx were both restarted. (I did confirm, it is in normal mode not scan)

Greg
That is definitively not the right setup!

The lipo should be connected directly to the SPC port!

In the meantime several crashes with the PowerBox systems have occurred, because pilots were using their power supply instead of connecting their batteries directly to the SPC port.

RTFM !

The correct configuration is shown on page 21!

Juergen
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Old Jun 10, 2010, 04:54 AM
Registered User
Port Augusta, Sth Australia
Joined Aug 2006
16 Posts
Quote:
Originally Posted by skyrock View Post
That is definitively not the right setup!

The lipo should be connected directly to the SPC port!

In the meantime several crashes with the PowerBox systems have occurred, because pilots were using their power supply instead of connecting their batteries directly to the SPC port.

RTFM !

The correct configuration is shown on page 21!

Juergen
It does not say that! It suggests that it can be done that way yes, but voltages are allowed up to 35 volts. What is the difference between a second battery of 6 volts connected to the SPC or a regulator set to put out 6 volts?? Last time I checked, not a great deal.

I posted here for suggestions, not to listen to self righteous twits like you... Climb down off your high horse for a moment!

I accept that may be the regulator failed. but that is no different that a pack failing. My concern is not the loss of signal, but the fact that it did not reconnect until after the tx and rx were powered off than back on, even though the radio is in Normal not Scan mode.

Greg
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Old Jun 10, 2010, 06:24 AM
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Dallas, TX
Joined Jan 2005
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Quote:
Originally Posted by gregq View Post
It does not say that! It suggests that it can be done that way yes, but voltages are allowed up to 35 volts. What is the difference between a second battery of 6 volts connected to the SPC or a regulator set to put out 6 volts?? Last time I checked, not a great deal.

I posted here for suggestions, not to listen to self righteous twits like you... Climb down off your high horse for a moment!

I accept that may be the regulator failed. but that is no different that a pack failing. My concern is not the loss of signal, but the fact that it did not reconnect until after the tx and rx were powered off than back on, even though the radio is in Normal not Scan mode.

Greg
Greg,
If the regulator is the same one being used to power the servos then if a servo stalls and causes the voltage to drop then the voltage to the rx through the SPC port will drop also. The best way is to remove as many points of failure as possible. So I would still suggest A123s for the battery pack straight into the servos without a regulator. The voltage of a 2s A123 is roughly the same as a 5 cell NiMh or NiCad pack.

Alan
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Old Jun 10, 2010, 06:43 AM
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Deutschland, Nordrhein-Westfalen, Geilenkirchen
Joined Aug 2007
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Quote:
Originally Posted by jh2rc97 View Post
Greg,
So I would still suggest A123s for the battery pack straight into the servos without a regulator. The voltage of a 2s A123 is roughly the same as a 5 cell NiMh or NiCad pack.

Alan
No, it's not the same at all, it's more voltage, for some servos maybe too much, at least, the durability of your servos might go down on the long run. A fully charged 5 cell NiMh-pack looses his maximum voltage after charging very quick, the 2S-123 pack will keep it's power!

Quote:
If the regulator is the same one being used to power the servos then if a servo stalls and causes the voltage to drop then the voltage to the rx through the SPC port will drop also. The best way is to remove as many points of failure as possible.
I can confirm this statement.

Instead of using one 2S-pack of 123 LiFePo, just connect the SPC-port directly with your LiPo-cells, not through the regulator, bacause:

- first of all those SPC-port can handle voltage up to 35 Volt's! It's designed for that "high voltage", why not use it?

- second: if your regulator will be overloaded, doesn't matter why, it will go down on both of his exit's, that can't help you because the microprocessor inside of the rx doesn't like at all, if the voltage wil drop below a certain level, I think that is in the case of the Optima's 3,5 Volt. It doesn't like this "low-volt" even for one or two milliseconds, that is really a very short time!

What happened to you was, that your rx was out of power, due to this dropping of voltage, but normally it should reboot really quick. Maybe your rx is faulty?

Udo
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Old Jun 10, 2010, 06:46 AM
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Ipoh, Perak Malaysia
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Greg,

If the servos has pulled down the regulator (maybe due to stalling servos or SOMETHING), switching off the tx won't relieve the regulator from being pulled down. However, once you switch off the rx, then the servos are no longer stalled and this may have relieved the situation and the rx can reboot.

Anyway, all this is just conjectures at this point. The main point is to power your rx directly from a lipo/A123 or a separate small Ni pack apart from the servos/regulator. This way, your tx will display the actual voltage of the pack and you can see if the pack is being run-down. However, it won't help your servos if one is shorted or stalled and is draining your regulator.

Nowadays I use 1100mAH 2S A123 packs with servos that can take 6V. This way, if the servos manages to draw enough to go below 3.5V, that means one of two things:

1. You forgot to charge your packs and you are running on empty

or

2. Your plane is about to burst in flames since your servo has shorted out and you are drawing way more than 30A.

chewy
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Old Jun 10, 2010, 06:52 AM
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Port Augusta, Sth Australia
Joined Aug 2006
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Yep, I intend to do just that. My new "test" plane will be using a different regulator this time and I will be hooking a LiPo direct to the SPC port, as I said in post #6926. I am aware that if the regulator had overloaded I would have lost everything. Again mentioned my working this out for my very own self in that same post. I really don't have an issue about the "brownout" itself.
I am more concerned that the rx was powered, but I had no servo control until I had powered down, then back up. Almost like it was in Scan mode, and browned out but it was in Normal (I checked).

Greg
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Old Jun 10, 2010, 06:52 AM
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Ipoh, Perak Malaysia
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Quote:
Originally Posted by udogigahertz View Post
No, it's not the same at all, it's more voltage, for some servos maybe too much, at least, the durability of your servos might go down on the long run. A fully charged 5 cell NiMh-pack looses his maximum voltage after charging very quick, the 2S-123 pack will keep it's power!

Udo
If you have doubts that your servos can take 6.6V in the long run, just put in a pair (for redundancy) of high amp (20A) or so schottky diodes for the servo supply. This way, you will normally get 40A total when both works and 20A should one fail.

This will also drop the voltage by about .4V to .7V which will bring the pack supply voltage to around 5.9V to 6.2V which should be safe enough for 6V rated servos.

I have been using these 2S A123 in all my nitro/gas planes for more than a year now. I have not have a servo fail on me yet due to this voltage problem. Failure from crashes is another matter.

chewy
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Old Jun 10, 2010, 06:55 AM
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jackosmeister's Avatar
Auckland NZ
Joined Aug 2007
7,177 Posts
I run my hotliner rx and servos directly off an 1100 2S A123 pack, the voltage drops to 6.5V very quickly and sits there. The eneloop 5S NimH pack in on of my slope soarers holds exactly the same voltage. The difference is that the A123's stay at 6.5V for much longer than the nimh pack. Its been working directly off the A123's, with 6x 6V rated servos, for about 30+ flights now without an issue. If anything it works better than running regulated 6V, as the digital servos have more torque around centre than they use to.
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Old Jun 10, 2010, 06:59 AM
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Port Augusta, Sth Australia
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Quote:
Originally Posted by chewytm View Post
Greg,

If the servos has pulled down the regulator (maybe due to stalling servos or SOMETHING), switching off the tx won't relieve the regulator from being pulled down. However, once you switch off the rx, then the servos are no longer stalled and may this may have relieved the situation and the rx can reboot.

Anyway, all this is just conjectures at this point. The main point is to power your rx directly from a lipo/A123 or a separate small Ni pack apart from the servos/regulator. This way, your tx will display the actual voltage of the pack and you can see if the pack is being run-down. However, it won't help your servos if one is shorted or stalled and is draining your regulator.

Nowadays I use 1100mAH 2S A123 packs with servos that can take 6V. This way, if the servos manages to draw enough to go below 3.5V, that means one of two things:

1. You forgot to charge your packs and you are running on empty

or

2. Your plane is about to burst in flames since your servo has shorted out and you are drawing way more than 30A.

chewy

Makes Sense.

However, when we got to the remains, the wing had separated from the fuse. So stalled retract or Ailerons are not the problem. Firewall was about 10 feet from the rest so throttle is also out. Leaves Elevator and Rudder, both these were disconnected from the flight surfaces due to its back being broken. So it could only have been the Elevator or Rudder servo itself, not control surfaces and if that had happened then my testing back at the pits afterwards would have recreated it but didn't...... did i explain that right, or did I confuse you like I just did myself

Greg
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Old Jun 10, 2010, 07:10 AM
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Ipoh, Perak Malaysia
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Greg,

I am not confused and understand what you are saying. Yes, Hitec should check if a big brown-out will cause the rx to hang and not come back to life even after being relieved from the brown-out. If they find that it comes back ok from the brown out, then I have no idea what caused your rx to hang.

chewy
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Old Jun 10, 2010, 07:11 AM
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However, I would still say to get away from regulators whenever possible. On my 80" w.s. zero, I use dual 2300mAH 2S packs with 2 switches for redundancy. If that fails, then nothing will help. If that fails, you are talking about drawing down a 120A supply!

Unless both switches fails at the same time, which is not very likely. I test the switches by alternating the order of turning on the 2 switches each time. If you get no response when you turn on the 1st switch, then you know that switch is no longer reliable. It's not 100%, but nothing is.

chewy
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Old Jun 10, 2010, 07:17 AM
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Port Augusta, Sth Australia
Joined Aug 2006
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Yeah I read every post in this thread since it happened, result.... I sorta figured out that there are better ways of connecting power to the rx.
he he he and the the bunch of replies stating the same thing rams it home nicely!

So I will be doing it better next time.... Sunday with luck

Greg
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Old Jun 10, 2010, 08:38 AM
AMA # L576
vhoward1122's Avatar
United States, OR, North Bend
Joined Sep 2006
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I also would not use the rx that was in the crash until it has been checked out at the service center.
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Old Jun 10, 2010, 09:06 AM
LAN
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Sweden, Östergötland, Valdemarsvik
Joined Oct 2003
456 Posts
This is just a theory, but I guess it could be possible that if Greg's regulator had a power dip for just a few milliseconds, this very short power dip could cause the RX to hang. I am just comparing to other types of electronics. If you power cycle your PC extremely fast, chances are it's gonna hang as parts of the circuitry will loose power while others will not and everything will be in an inconsistent state.

Either way, using the SPC will take care of the issue.

/Leif
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Old Jun 10, 2010, 09:06 AM
good listener
Haltom City TX
Joined May 2008
88 Posts
Wonder if when you cycle the power to the rx it recycles/resets the regulator. As was mentioned before, the red light remains on in the rx but this does not prove there is power on the servo bus.
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