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Old Nov 03, 2005, 01:22 PM
Registered User
El Cajon, CA, USA
Joined Feb 2001
801 Posts
new feature for Phoenix speed controllers?

you guys ever thought about a special ESC which had 2 different LVC's? The thing would be changeable via a spare channel or a small switch.

this way you could run your older generation batteries to the lower volt LVC (say 9-9.5 volts) and your new batteries to the 10-10.5 needed in order not to overdischarge them.

Just an idea.

Daniel
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Old Nov 03, 2005, 11:37 PM
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G.P.'s Avatar
Joined May 2005
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All of the phoenix esc's have a programmable lvc. It can be set to preprogrammed settings with your tx or set to any value that you want with the castle link.
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Old Nov 04, 2005, 02:31 PM
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El Cajon, CA, USA
Joined Feb 2001
801 Posts
I realize this. What I'm looking for is a super quick and easy to change the voltage between two preprogramed points.

Basically, when I fly my new packs the LVC is set high enough that I don't overdischarge the battery right? but when I put on an older battery with the same cutoff the LVC is cutting in from beginning of the flight.

The battery is not being damaged because it is not being overdischarged. It's just that old packs drop voltage under loads much much more than new ones.
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Old Nov 04, 2005, 06:01 PM
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United States, CA, Bear Valley Springs
Joined Feb 2000
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I fail to see your point, Munch.
3 volts per cell under load is the LVC regardless of the condition or age of the pack.

mw
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Old Nov 04, 2005, 07:56 PM
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Joe Ford's Avatar
Olathe, KS
Joined Aug 2003
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Mark...I think what Munch is trying to say is that the Gen 1 lipos used to recommend 7.2v cutoff for a 3 cell due to their inability to sustain voltage under load the way Gen 2/3 do today...he'd like a way to switch between Gen 2/3 lipo LVC and Gen 1. I'll pass the recommendation on to the engineers.
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Old Nov 05, 2005, 04:14 AM
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High Ridge, Mo USA
Joined May 2002
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Joe,

I have a request for twin applications.

I have an A-10 w/ twin razors on 4S w/ CC25's (and a UBEC). The problem I have is that one ESC will see LVC before the other and reduce throttle. The other ESC never sees the LVC because the other ESC/engine is compensating by reducing throttle. As the pack discharges the yaw caused by one motor spinning full RPM and the other reducing throttle to compensate for LVC becomes quite pronounced.

Would it be possible for one ESC to control LVC and signal the other ESC through the Y connector to synchronize throttle to maintain voltage near LVC?
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Old Nov 05, 2005, 07:02 AM
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Andy W's Avatar
Marietta, GA
Joined Jun 1999
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Your solution is to disable both LVC's, learn to recognize when the power is dropping, and land.
..a
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Old Nov 05, 2005, 05:13 PM
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High Ridge, Mo USA
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Quote:
Originally Posted by Andy W
Your solution is to disable both LVC's, learn to recognize when the power is dropping, and land.
..a
IMHO, thats a bad solution. I'd rather lose the airframe then a $180 lipo pack!
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Old Nov 05, 2005, 05:17 PM
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El Cajon, CA, USA
Joined Feb 2001
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Power never drops on my new prolite 2000 pack. Probablly because I'm only pulling burst of 7C with it but if I set the LVC to 9 volts the pack will be way overdischarged and damaged.

You're on the right track Joe, Its actually the difference between Gen 2 and 3 packs that's causing me the problem. The voltage drop is so small compared to my Gen2 II 2100 pack that I'm having to go back to timed flights again.

I guess I"m the only person with this issue.

Thanks for listening guys.

Daniel
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Old Nov 05, 2005, 05:38 PM
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Chicago
Joined Feb 2003
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Fiasco - you could manually adjust LVC of both ESC's so that they both cut at the same time. Also make sure all other settings are the same, use fixed throttle too.

Munch - I hear you on your issue, its not only our issue, actually standard 3V LVC is getting to be a bad standard as lipos get better. I use 3.2-3.4 LVC per cell for TP prolites depending on load. Best way is to custom set it for each aircraft, I try to use same type of cells for given aircraft, so solution is to use only prolite or gen 2 or whatever without switching back and forth.

Timed flights are actually a good approach, as lipos don't like to be discharged low, use timed flights and leave some juice in the packs, they will thank you with longer life, better power and less problems.
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Old Nov 06, 2005, 01:06 AM
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How can I manually adjust each LVC?
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Old Nov 06, 2005, 01:34 AM
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Using Castle Link and "custom LVC" setting.
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Old Nov 10, 2005, 02:43 PM
Registered User
El Cajon, CA, USA
Joined Feb 2001
801 Posts
Hovertime,

That's what I was afraid of.

Tell you what. Lipolys are an expensive pain in the butt.

That said.....I would't trade them for anything

the thought of 3 oz nimh packs on my 5 oz shokie make me sick.

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Old Nov 10, 2005, 03:15 PM
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Chandler, AZ
Joined Apr 2003
12 Posts
I agree with Munch.

I would like to have the ability to switch LVC without having to enter the programming mode. I realize this is might be a temporary problem while guys switch to the newer packs but, considering how fast the technology is changing, this issue might be around for a while. There might even be some hidden value to having a speed controller which could take advantage of another channel for in-flight programming like gyros do. Another example might be to use this switch to change the governed RPM for helis. Just a thought.
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