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  1. #1
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    Lvd at 3.8v why?????

    Mine shuts down at 3.8v and the battery is under 10 bucks. All my other models with $200+ batteries are set at 3.2 or 3.4 with no problems and still going strong 3+ years later. 3.8v is playing it way way to safe, especially for a under 10 dollar battery. Would like to be able to set myself for more flight time. 3.8 cutoff is way to high. Maybe we will get a programmer in future for it I hope. As this is my only complaint about the alias. Will this be adjustable in the future?

  2. #2
    Traxxas Employee Propsmoke's Avatar
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    Quote Originally Posted by Russ916 View Post
    Mine shuts down at 3.8v and the battery is under 10 bucks. All my other models with $200+ batteries are set at 3.2 or 3.4 with no problems and still going strong 3+ years later. 3.8v is playing it way way to safe, especially for a under 10 dollar battery. Would like to be able to set myself for more flight time. 3.8 cutoff is way to high. Maybe we will get a programmer in future for it I hope. As this is my only complaint about the alias. Will this be adjustable in the future?
    The cutoff is not set at 3.8V. You are measuring the battery voltage after your flight has ended and there is no longer a load on the battery. If you could measure the battery voltage in flight at the time the cutoff actually activates it would be significantly lower, probably in the 3.2V - 3.4V range you indicated in your post. I did not design the electronics so I can't tell you for sure exactly where the cutoff is set but I did do a little test after I read your post. I took my battery off of my Alias after flying it until it went into low voltage cutoff. By the time I checked the battery voltage with a voltmeter it was indeed around 3.8V. I then placed that same battery on my EZ_Peak Plus Lipo Charger and set it for a 2.0 amp discharge. Within 15 seconds the battery voltage dipped below 3.4V and the charger automatically stopped discharging it because even with that modest load it would have dipped dangerously low within another few seconds. I can also tell you that if you do the math, it is obvious that the Alias will put more than a 2 amp load on that battery. Here is an easy way to “reason” it out. A 650Mah battery can provide 650 milliamps of current for 1 hour, 650 milliamps = 0.65 amps. Flight times will vary but just to make it simple lets say you typically get a 10 minute flight time. 10 minutes is 1/6 of an hour. Therefore; for the Alias to drain the 650Mah battery in ten minutes, it must be drawing an average of 6 x 0.65 amps which equals 3.9 amps. Now remember, that is an average over the entire flight which means at wide open throttle the Alias must draw significantly more than 3.9 amps and as I explained earlier, if you put that much load on the battery, the voltage will drop significantly. Therefore we can deduce that the battery voltage must have been closer to the 3.2 – 3.4V range you mentioned in your post at the time the low voltage protection kicked in. Hope this helps.

  3. #3
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    Didn't realize it drew that much power being so small. So I take it that the detection is under load like 3.4 then? That makes sense. Guess I should think a little more into it. I was just measuring my batteries after flight and they are always at 3.8-3.82v.again didnt realize it drew so much power. Still would like to have the option to change it. Maybe I'm just a controle freak when it comes to my models. Thanks for the info

  4. #4
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    Ok. Thought alittle more and brings up another question. The alias pulls more than 2 amps? From a battery that is only a .65 amp? Won't that alone be bad on battery? Always Ben told to have a battery that is equal to or more than the amps the esc and motor can pull. Maybe I or someone else will put a amp/watt meter between the alias and battery and find out exactically what it draws. When I charge my batteries it only puts around 340 + or - back into battery from alias lvd. The batteries are new so this will change. I once used a smaller amp rating batt. Than my esc and motor can put out, and it puffed. So is this battery to small if alias is drawing 2+ amps. Does traxxas battery have a high C rating to compensate the low mah? Idk, I'm confused now lol. Too many variables I guess. Just buy 10 batteries an have fun it is a great quad. And traxxas employee's are great at helping figure things out and get you up and going if you have problems. Thanks
    Last edited by Russ916; 12-10-2013 at 12:42 PM.

  5. #5
    RC Turnbuckle Jr. Dadx2mj's Avatar
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    To figure the amps a battery is capable of delivering you multiply the mah x C rating so you would need to know how many C the battery is rated to figure out how many amps it can deliver.
    BlindMan Racing
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  6. #6
    Traxxas Employee Propsmoke's Avatar
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    Quote Originally Posted by Russ916 View Post
    Ok. Thought alittle more and brings up another question. The alias pulls more than 2 amps? From a battery that is only a .65 amp? Won't that alone be bad on battery? Always Ben told to have a battery that is equal to or more than the amps the esc and motor can pull. Maybe I or someone else will put a amp/watt meter between the alias and battery and find out exactically what it draws. When I charge my batteries it only puts around 340 + or - back into battery from alias lvd. The batteries are new so this will change. I once used a smaller amp rating batt. Than my esc and motor can put out, and it puffed. So is this battery to small if alias is drawing 2+ amps. Does traxxas battery have a high C rating to compensate the low mah? Idk, I'm confused now lol. Too many variables I guess. Just buy 10 batteries an have fun it is a great quad. And traxxas employee's are great at helping figure things out and get you up and going if you have problems. Thanks
    I did not say you could only draw 0.65 amps from it. I said it is a 650mAh battery and then I converted that to amps to make my calculations. 650mAh stands for 650 milliamp hours. It is a standard used in the industry to measure the capacity of a battery. It means you could draw 650 milliamps (or 0.65 amps, same thing) from the battery continuously for 1 hour before the battery would be depleted of its charge. That does not mean you can't draw more power from the battery, but if you do it will obviously deplete it more quickly. How much power can be drawn from a battery continuously without damaging it is know as the battery's "C" rating. If you look on the back of the Alias battery it says the continuous discharge rating is 20C, which means you can draw 20 times more than the stated mAh of the battery. In this case, that would be 13000 milliamps (650 x 20 = 13000). A milliamp is 1/1000th of an amp so to convert 13000 milliamps to amps you simply divide by 1000 (13000 divided by 1000 = 13). So, you could draw 13 amps from that little battery, which is probably way more than the Alias could ever possibly draw from it, but that's a good thing. You would much rather have the battery be over-designed for the application rather than under designed. I just wanted you to understand the basics. You should do an Internet search for "lipo battery basics" or "everything you ever wanted to know about lipo batteries". All of this info is readily available from various sources.

  7. #7
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    I did a little test with my 2 Latrax Alias batteries with Voltage Meter. When the Alias shuts down completely, the battery voltage reads 3.59v on both batteries.

  8. #8
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    Mine always read 3.82 or slightly more

  9. #9
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    Quote Originally Posted by Russ916 View Post
    Mine always read 3.82 or slightly more
    Interesting Russ. I did test them couple of more times and every time it reads 3.59v...

  10. #10
    Marshal ksb51rl's Avatar
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    Quote Originally Posted by Russ916 View Post
    Mine always read 3.82 or slightly more
    That is about what my land-based LiPo batteries come in at. Of course, that's resting voltage and the level has rebounded from the 3.4 to 3.5 volts per cell at which the LVC is set.

    Where do you guys fly: indoors or outdoors?
    Alt-248 on the number pad =

  11. #11
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    Quote Originally Posted by ksb51rl View Post
    That is about what my land-based LiPo batteries come in at. Of course, that's resting voltage and the level has rebounded from the 3.4 to 3.5 volts per cell at which the LVC is set.

    Where do you guys fly: indoors or outdoors?
    I personally fly outdoors. Love to see her go crazy in a air =)

    We should have LaTrax Alias Party one day...
    Last edited by Dadx2mj; 12-15-2013 at 06:16 PM. Reason: Merged

  12. #12
    Marshal ksb51rl's Avatar
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    Quote Originally Posted by Gevtron View Post
    I personally fly outdoors. Love to see her go crazy in a air =)

    We should have LaTrax Alias Party one day...
    I would have guessed yours to be indoors. When (exactly) are you measuring the voltage?
    Alt-248 on the number pad =

  13. #13
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    Quote Originally Posted by ksb51rl View Post
    I would have guessed yours to be indoors. When (exactly) are you measuring the voltage?
    As soon as it starts beeping I bring it back. By the second beep it's already in my hand. It starts rapid beeping while I'm unplugging the battery. I unplug it and plug in voltage meter. Always solid 3.59v

  14. #14
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    Got mine stuck on the tree...yes I'm very mad


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  15. #15
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    Mine was indoors as -20 outside checked voltage after it hit lvd and won't fly no more. Imeadiatly check battery an always at 3.8-3.82 never lower. I understand this is just resting voltage. It's really no big deal as I bought 8 batteries. It is alittle wierd of the varrying voltages people are getting after cut off. Wish weather would warm up so I can take it out side. But still need my replacement motors to show up. Pluss have a watt meter coming so I can check draw at full power and get true running lvd cutoff.

  16. #16
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    Quote Originally Posted by Russ916 View Post
    Mine was indoors as -20 outside checked voltage after it hit lvd and won't fly no more. Imeadiatly check battery an always at 3.8-3.82 never lower. I understand this is just resting voltage. It's really no big deal as I bought 8 batteries. It is alittle wierd of the varrying voltages people are getting after cut off. Wish weather would warm up so I can take it out side. But still need my replacement motors to show up. Pluss have a watt meter coming so I can check draw at full power and get true running lvd cutoff.
    Does Traxxas replace it for you or you purchase them?


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  17. #17
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    Well they said they would send them to me, but got tired of waiting so bought some from ebay. As this seems to be a common fail point on these alias's for some people, so good Idia to have extras on hand anyway.

  18. #18
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    Quote Originally Posted by Russ916 View Post
    Mine was indoors as -20 outside checked voltage after it hit lvd and won't fly no more. Imeadiatly check battery an always at 3.8-3.82 never lower. I understand this is just resting voltage. It's really no big deal as I bought 8 batteries. It is alittle wierd of the varrying voltages people are getting after cut off. Wish weather would warm up so I can take it out side. But still need my replacement motors to show up. Pluss have a watt meter coming so I can check draw at full power and get true running lvd cutoff.
    Hey Russ916, sorry for the reply to a very old post. Did you ever get the watt meter connected to the Alias to see what the draw at full power was and work out what value the LVC was set at? Also, what flight times were you getting when you check the resting voltage and it came back at 3.8V?

  19. #19
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    Quote Originally Posted by speedojames View Post
    Hey Russ916, sorry for the reply to a very old post. Did you ever get the watt meter connected to the Alias to see what the draw at full power was and work out what value the LVC was set at? Also, what flight times were you getting when you check the resting voltage and it came back at 3.8V?
    Doubt he will respond. This thread died five years ago and Russ has not logged in for over four and a half: Last Activity 06-19-2014 11:57 AM
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