High voltage or Low voltage cut off?
03-07-2005, 06:45 PM
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High voltage or Low voltage cut off?
I can program my Jeti ESC for high or low voltage cut off. Which do I want? I'm running an AXI 2814/12 motor with a Jeti 30 amp ESC and a LI-PO pack 3S2P rated at 3000MAH. The Packs are rated at 8C. The motor runs at full thottle for about 1 minute and then shuts off. The ESC is set for High voltage shut off. should I run it at low Voltage shut off or will this ruin the pack?
Thanks for any info.
Thanks for any info.
03-08-2005, 09:25 AM
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RE: High voltage or Low voltage cut off?
Do you know what the "high" and "low" cutoff levels are in Volts? Unfortunately, I'm not familiar with them, but I'd like to help.
For a 3S LiPoly pack, you would want the cutoff set at or as close to 9.0 Volts as you can get.
When you're getting premature cutout like that, the solution is generally not to lower the cutoff voltage. The problem is almost always that the motor/prop is drawing more current than the pack can handle. SOMETIMES it's because the cutoff is set too high, but that's rare. Until we know how much current you're drawing, and what the cutoff setting is, we shouldn't jump to that conclusion.
What prop are you running on the 2814/12?
For a 3S LiPoly pack, you would want the cutoff set at or as close to 9.0 Volts as you can get.
When you're getting premature cutout like that, the solution is generally not to lower the cutoff voltage. The problem is almost always that the motor/prop is drawing more current than the pack can handle. SOMETIMES it's because the cutoff is set too high, but that's rare. Until we know how much current you're drawing, and what the cutoff setting is, we shouldn't jump to that conclusion.
What prop are you running on the 2814/12?
03-09-2005, 09:44 AM
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RE: High voltage or Low voltage cut off?
Thanks for the reply. Your are right on. I found out that I should remain in high cut off (9volts) to protect the pack. My problem was solved by reducing the prop from a 10x5 to a 9x4.5. This electric is a whole new ballgame for me and I'm just starting to learn.
03-09-2005, 12:11 PM
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RE: High voltage or Low voltage cut off?
I have to question your use of full throttle at one minute. If I did that on my models, I would never see them again!
Hopefully, you were not doing this on a static ground test. On a normal ground test, use full throttle for only 5-10 seconds.
In flight, your use of full throttle should not be more than 10-15 seconds.
Hopefully, you were not doing this on a static ground test. On a normal ground test, use full throttle for only 5-10 seconds.
In flight, your use of full throttle should not be more than 10-15 seconds.
03-09-2005, 01:37 PM
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RE: High voltage or Low voltage cut off?
Your right Greg, it was while flying, I was guessing at the 1 minute time. I used full to take off and then when I was in the middle of a roll at full throttle is when the motor cut off.
03-10-2005, 09:47 AM
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RE: High voltage or Low voltage cut off?
8C on 3000mAh is 24 Amps...
The application chart for the 2814/12 at http://www.modelmotors.cz/index.php?id=en&nc=produkty_vypis&kategorie=m_neodym_ac&id_rady=axi_28&id_produktu=axi_2814_12&nazev_rady=Series%20AXI%2028&hmotnost_rady=(78%20-%20161%20g) shows it would draw close to 35 Amps on 10 NiCd cells (close to a 3S LiPoly) with a 10x6 prop.
Even dropping back to a 10x5, the Amps would still be about 5/6 of that, around 29 Amps.
You were waaaay over the limit on that LiPoly pack. That's why it was cutting out on you.
The application chart for the 2814/12 at http://www.modelmotors.cz/index.php?id=en&nc=produkty_vypis&kategorie=m_neodym_ac&id_rady=axi_28&id_produktu=axi_2814_12&nazev_rady=Series%20AXI%2028&hmotnost_rady=(78%20-%20161%20g) shows it would draw close to 35 Amps on 10 NiCd cells (close to a 3S LiPoly) with a 10x6 prop.
Even dropping back to a 10x5, the Amps would still be about 5/6 of that, around 29 Amps.
You were waaaay over the limit on that LiPoly pack. That's why it was cutting out on you.
