Helijive Bavarian Demon question

[firemedic295]

I have helijive 120 /4525 ult in a 600 size heli.I am using Bavrian demon and have to run minimum of 5.5v.I am also using futaba 157 servos.my question is.can I run 6v from the jive bec without buffer pack?and would the bec sustain 6v or drop at any point?

[taosgraveyard]

I run helijive and HC on a lot of helicopters.

Depending on your flying style, certainly it's possible for the helijive BEC to drop below 6. To test this on the bench, test the setup for brown outs by taking both sticks to the cornes of travel, and let them both snap back to center, do this a bunch of times,

But even if you cant force a borwnout, remember that Kontronic always recommends using a buffer pack with the helijive,

And I always do.

You don't need much of a pack... I use a 200 mah Gens Ace LIFE pack when I run the BEC at 6V.

At 5 bucks and 15 grams, its very cheap and not very heavy insurance.

And when running satellite on HC, a pilot will want some insurance, IMO.

[firemedic295]

Using 18MZ.did not want to add a buffer pack or external bec. but may have to.

[Vinger]

Never ran any buffer pack on PJ or HJ, using high quality BLS servos is the answer. Futaba BLS servos seems to have very little back EMF and I have been using them with 6V BEC setting no problem. The BEC will only shut down if detected volts go above 7.2V or if a prolonged current draw of 15A or more is detected. JLog has indicated peaks of 15A draw on some of my flights, but obviously only a peak, voltage would then drop to 5.2V, but it has never caused any shutdown of my JR DMSS system or VBar.

But as always, experiment for yourself and fit what works for you..

[Chris.C]

I have been running HJ with 4525ULT in my TDR with BLS157HV + BLS251 and CGY750 without buffer pack. I did not touch the internal setting of my HJ and my 14SG tells me that the rx voltage is at 5.6V.

[taosgraveyard]

Originally Posted by firemedic295

Using 18MZ.did not want to add a buffer pack or external bec. but may have to.

Then you don't have to worry about the 5.5 volt limit. As.I Understand it, that lower limit only applies when using spectrum or JR satellites, because when used with HC or BD units ( and perhaps other FBL units?) , they brown out at 5.5 volts. some folks get lucky and won't have brown outs until 5.2 volts, but the company recommends 5.5 minimum when using spectrum or Jr satellites.

[GimpyGolden]

Originally Posted by taosgraveyard

Then you don't have to worry about the 5.5 volt limit. As.I Understand it, that lower limit only applies when using spectrum or JR satellites, because when used with HC or BD units ( and perhaps other FBL units?) , they brown out at 5.5 volts. some folks get lucky and won't have brown outs until 5.2 volts, but the company recommends 5.5 minimum when using spectrum or Jr satellites.

Yup it's the step down reg used on the Sat power bus that needs ~5.5 in to keeps your Sat's awake and happy.
Anything other than Spek/JR Sat's you have nothing to worry about.

[Vinger]

Originally Posted by taosgraveyard

Then you don't have to worry about the 5.5 volt limit. As.I Understand it, that lower limit only applies when using spectrum or JR satellites, because when used with HC or BD units ( and perhaps other FBL units?) , they brown out at 5.5 volts. some folks get lucky and won't have brown outs until 5.2 volts, but the company recommends 5.5 minimum when using spectrum or Jr satellites.

It os not a problem with the JR/Spek sats, rather specific to Bavarian FBL. VBar and others have no problem with volts as low as 4.5V, no brownouts at all.

[dl7uae]

SPEKTRUM sats work nominally with 3.3 volts. Most SPEKTRUM sats work down to at least 2.9V.

[taosgraveyard]

But not when connected to a Bavarian demon FBL unit... Brown outs are well documented at 5 volts.

[taosgraveyard]

Originally Posted by Vinger

It os not a problem with the JR/Spek sats, rather specific to Bavarian FBL. VBar and others have no problem with volts as low as 4.5V, no brownouts at all.

Of course, I was speaking about the OPs configuration... He is using BD.

[dl7uae]

But not when connected to a Bavarian demon FBL unit... Brown outs are well documented at 5 volts.

Thats strange..

That would mean that the internal voltage regulator of the BD is not only no LDO than one with a tremendous high drop out voltage, - 2 volts?!

Cannot imagine overload condition by the 50..60mA of two sats..

Or is there a series resistor, a PTC behind the voltage output for sats?

Somebody should measure at the voltage input of a sat if BD's raw voltage is 5 volts.

So let's ask Joachim from Captron..

[BKF]

Originally Posted by dl7uae

Thats strange..

That would mean that the internal voltage regulator of the BD is not only no LDO than one with a tremendous high drop out voltage, - 2 volts?!

Cannot imagine overload condition by the 50..60mA of two sats..

Or is there a series resistor, a PTC behind the voltage output for sats?

Somebody should measure at the voltage input of a sat if BD's raw voltage is 5 volts.

So let's ask Joachim from Captron..

That would be nice to find out. People have wondered why the electrical specs are so "needy" for satellites when other FBL units that use directly connected satellites don't seem to have the same issue. Maybe it's just a vocal minority here on the forums, and not a big deal in general? Otherwise you'd think they'd fix it somehow, instead of offloading the responsibility on the user to make sure they have a good BEC.

I had this same delimma when I was putting together my Rush 750. I ultimately decided on the Kosmik and an HV setup, figuring it would take quite a bit to get to 5V if you're starting at 8V. I still chickened out and attached a full rx, which lets the attached satellite (connected to an AR8000) not experience any brownouts until it gets near 3v. I've also got a 2s Lipo connected. Guess I'm paranoid.

[Primal]

I ran a BD3SX with dual sats on my 550X with a western robotics Hercules super bec at 6V. Zero issues. I believe as long as you're using a quality bec you should be ok.

That said, on my 7HV I decided to use a receiver and I satellite, powered by a Kosmik bec. No issues either.

Using a receiver is probably the better option, unless you don't have the space.

[GimpyGolden]

Or use Futaba and skip all this drama Spek stuff always seems to have.
Tom nailed it, it's the reg. Requires 5+Volt in to get 3+Volt out.

I'll see if I can dig up the thread Danny (F1Rocket) posted to on the subject.

[dl7uae]

Nobody knows. Will call Joe tomorrow.

"Tomorrow"... GM, 3:24. GN.

[mkovalcson]

Originally Posted by GimpyGolden

Or use Futaba and skip all this drama Spek stuff always seems to have.
Tom nailed it, it's the reg. Requires 5+Volt in to get 3+Volt out.

I'll see if I can dig up the thread Danny (F1Rocket) posted to on the subject.

And if you work use telemetry Jeti has a lot less drama than Futaba does

[GimpyGolden]

Yup,and you'll pay for it too.
I have no need or interest in telemetry.

[taosgraveyard]

Originally Posted by GimpyGolden

Yup,and you'll pay for it too.
I have no need or interest in telemetry.

Using jeti and having the milliamp hours used reported while i am flying sold me... So much better than a timer. I always land with 75 percent in the battery,

That and never having to tach a headspeed again. And knowing how hot the ESC is.

And knowing what's going on to with the individual cells In a battery...


And the logging... Visible as graphs right on the transmitter ... Being able to easily view PWM graphs, what a great way to get the gearing spot on...

And

I am sold on telemetry

Yes, is an expensive radio. It's an expensive hobby....

[GimpyGolden]

Meh, my Kosmik has the cap warning which I use and like.
Does logging too which I use to set gearing as well as my JLog on my Jive's.
Head Speed I don't care as much about a figure as I do about the feel. Good to know you aren't going over recommended but that is usually pretty obvious.

As to temp if it isn't shutting down I'm happy.
Maybe I am becoming more utilitarian in my age. My ole 10CG is still doing all I ask, mAh alarm on all my machines would be nice.