Vendetta Possible voltage issue

[Roflcer666]

I bought a vendetta in July. I have maybe 5 pack through it. So far I'm on my 3rd servo. The first two burned out the motor contacts (spektrum). Yes steering points were set.
The current servo is a Reedy 1514MG Digital HV Hi-Torque Metal Gear Servo. Yes it's 7.4v and the ESC is pushing 6.0v.

My current issue is LVC at 50% battery or more after 5 to 10 mins of run time. I still have steering, just no motor response. The red LED is short red pulses, which book says that is LVC.
I'm at a loss here. Be easy as I'm new to this.

 

[Camaroboy383]

Battery voltage sag.. once it's depleted so far, under huge loads the voltage is sagging below lvc threshold triggering it to stop..

 

[Roflcer666]

Battery voltage sag.. once it's depleted so far, under huge loads the voltage is sagging below lvc threshold triggering it to stop..

What do I do to fix this? Battery and car bought at sametime. Battery was always ran to lowest charge level before recharging.

 

[Senton_Prime]

What lipo's you running?

 

[Roflcer666]

What lipo's you running?

This one. It is the recommended battery from HH. This was a non issue till I changed the servo.

 

[Camaroboy383]

Bigger battery, larger c rating.. really the only thing you can do to get more run time without quick voltage sag.. while that battery is recommended, it's just not stable enough, your rig is asking for more amperage than the lipo can afford, pulling the voltage way down and popping into lvc... ( those batteries aren't the greatest)

You will find that if you never hit full throttle for long bursts, (or at all) it would last until the battery was infact to lvc status.. these esc 's have been this way since the inception of them, they are hungry..
Another thing, that servo isn't doing you any good on 6v.. advertised speed and torque is quoted on 7.4v.. so it's really underpowered and grasping for more voltage

 

[Roflcer666]

Bigger battery, larger c rating.. really the only thing you can do to get more run time without quick voltage sag.. while that battery is recommended, it's just not stable enough, your rig is asking for more amperage than the lipo can afford, pulling the voltage way down and popping into lvc... ( those batteries aren't the greatest)

You will find that if you never hit full throttle for long bursts, (or at all) it would last until the battery was infact to lvc status.. these esc 's have been this way since the inception of them, they are hungry..
Another thing, that servo isn't doing you any good on 6v.. advertised speed and torque is quoted on 7.4v.. so it's really underpowered and grasping for more voltage

Ok. I need a bigger battery.
The only other time I hit LVC was battery was less than 25% charge. Which I figured it was lvc due to low charge.

As for the servo. Should I get the 6.0v version and see what it does?
As for the ESC. It's the Firma 100A. I know it's capable of 7.4v. But it's won't let me switch to the 7.4v setting. Would the Spektrum programmer that you connect to your pc allow me to unlock the BEC 7.4v setting?

 

[fozzy71]

When I run my Vendetta with speed gearing and push it to its limits with multiple full-throttle runs, it goes into LVC quite easily. I intend to upgrade the driveline and install a spare Spektrum 6s ESC I purchased from Jennys in order to try running it on 4s next spring using the 3900kv motor (or the 2050kv on 6s maybe?).

 

[SrC]

Ok. I need a bigger battery.
The only other time I hit LVC was battery was less than 25% charge. Which I figured it was lvc due to low charge.

As for the servo. Should I get the 6.0v version and see what it does?
As for the ESC. It's the Firma 100A. I know it's capable of 7.4v. But it's won't let me switch to the 7.4v setting. Would the Spektrum programmer that you connect to your pc allow me to unlock the BEC 7.4v setting?

There is no reason you cannot change to 7.4v ESC BEC using the ESC's manual setup button method, if that ESC BEC Parameter Value does exist.
However, I feel that the servo at 6v BEC should not be part of your issue at all. Unless you have an ESC BEC circuit issue. With the Detta, Servo speed and torque is not that critcial. 7.4 will make a slight difference. But is pretty much inconsequential to running your Detta, in the big scope of things. This is a light On Road platform with small wheels. A bad stocker replacement Firma Servo is a possibility. Usually not if it's another upgrade brand however.
You never stated what Exact Servo you are running now. Which one exactly? What are its specs?
And the stocker ESC, like stated above, is not all that to begin with. Not all that efficient.
Any decent "dumb" 3s 5k Mah pack, in theory should suffice. Firma Smart lipos do generally suck however. The whole $Firma Smart Eco$ thing and all. Are you strickly doing hard Speed run passes? How are you actually running your Detta???
What gearing? The Stock pinion?

 

[Wojoman]

I am having LVC ‘issues’ myself, cutting off higher than I like. Evidently the an esc firmware update may help fix + allow 7.4v bec. I haven't tried yet, but take a look here: https://www.arrmaforum.com/threads/spektrum-firma-esc-update-2-06-and-vorteks.39041/

 

[Roflcer666]

There is no reason you cannot change to 7.4v ESC BEC using the ESC's manual setup button method, if that ESC BEC Parameter Value does exist.
However, I feel that the servo at 6v BEC should not be part of your issue at all. Unless you have an ESC BEC circuit issue. With the Detta, Servo speed and torque is not that critcial. 7.4 will make a slight difference. But is pretty much inconsequential to running your Detta, in the big scope of things. This is a light On Road platform with small wheels. A bad stocker replacement Firma Servo is a possibility. Usually not if it's another upgrade brand however.
You never stated what Exact Servo you are running now. Which one exactly? What are its specs?
And the stocker ESC, like stated above, is not all that to begin with. Not all that efficient.
Any decent "dumb" 3s 5k Mah pack, in theory should suffice. Firma Smart lipos do generally suck however. The whole $Firma Smart Eco$ thing and all. Are you strickly doing hard Speed run passes? How are you actually running your Detta???
What gearing? The Stock pinion?

The current servo is a Reedy 1514MG Digital HV Hi-Torque Metal Gear Servo 7.4v (https://www.horizonhobby.com/produc...hi-torque-metal-gear-servo-15kg/ASC27111.html). I went to this servo after have burned up 2 factory Spektrum servos. Had end points and everything set. Burned them up back to back. I had no battery issues with the factory servos. Switched to this servo and now have LVC randomly. The first time the battery was at 80% charge. Turned car off and back on ran till it 50% then LVC again. Its all stock not even the speed gear. its still in the bag. My street is long enough to full throttle passes for either 1/16th or 1/8 mile. its only getting 5 or 6 passes then LVC. Before I put the Reedy servo in, I was getting 10 to 12 passes before LVC and battery charge less than 20%. The ESC settings are still on the factory default settings.

 

[Roflcer666]

As for changing the Voltage. This is from the manual. 7.4v isn't listed.

 

[Camaroboy383]

That esc is not capable of that change.. the bec is what it is unfortunately..

 

[Roflcer666]

That esc is not capable of that change.. the bec is what it is unfortunately..

Which makes zero sense. Because on HH (under the ESC page) site it clearly states the Firma 100A can do both 6.0 and 7.4v. Or is the Firma 100a locked on the detta? Or is it changeable via the ESC programmer you buy separately? Should I switch to the 6.0v version of the servo and see what it does? I'm at a loss.

 

[Camaroboy383]

You will quickly find out the data spektrum puts out is most the time false.. there are parameters in the manuals that are wrong as well, The felony manual comes to mind..

I'm going to go out on a limb here and say that the problem most likely existed before you noticed it.. you most likely were just not beating on it enough to activate it...

The bottom line is the battery is just not enough, it's been proven time and time again that crappier batteries will voltage sag far before a good battery..

remember c ratings are typically b.s, so do yourself a favor and get the biggest c rating you can find, at least you have a better chance at a true 50c battery if you shoot for the stars..

If you would like to prove this yourself install a lipo alarm, set it to lvc voltage so it rings off.. you will quickly see it's all battery voltage sag.. hard amperage pulls will pull that voltage down just enough to trigger lvc...

I don't think switching to the 6v servo will help you on lvc.. but it would help with torque and speed of the servo..

 

[Roflcer666]

You will quickly find out the data spektrum puts out is most the time false.. there are parameters in the manuals that are wrong as well, The felony manual comes to mind..

I'm going to go out on a limb here and say that the problem most likely existed before you noticed it.. you most likely were just not beating on it enough to activate it...

The bottom line is the battery is just not enough, it's been proven time and time again that crappier batteries will voltage sag far before a good battery..

remember c ratings are typically b.s, so do yourself a favor and get the biggest c rating you can find, at least you have a better chance at a true 50c battery if you shoot for the stars..

If you would like to prove this yourself install a lipo alarm, set it to lvc voltage so it rings off.. you will quickly see it's all battery voltage sag.. hard amperage pulls will pull that voltage down just enough to trigger lvc...

I don't think switching to the 6v servo will help you on lvc.. but it would help with torque and speed of the servo..

So the biggest battery with the Ic5 connector? Preference on voltage and MaH

 

[Camaroboy383]

Ic5 or ec5.. the spektrum has ic5 for data.. which IMHO is useless.. the battery is dead when it's dead, the lights on the remote aren't telling anyone anything different, it's still dead..

Stay with standard 3s voltage.. the hv packs will do nothing for you, the esc has a over voltage protection as well, most hv packs will trigger that..

Mah depends on what you're doing.. if you are just bashing go for something as big as you can fit in the tray (7000 ish) .. if you are speed running get smaller mah to save weight, but huge c rating is what will help you..

As stated by horizon the 5000mah 50c is the minimum.. with c ratings typically not correct, you would be lucky if that pack was a true 25c ....so the bigger you can get the better..

 

[Just a hobby]

On my son's granite the LVC was kicking in with in 5 minutes. Checked with battery checker, and lipo was at 70%. Had HH send me a replacement. Full runs after that. HH told me there is a problem with it and the LVC not correct in the esc. It was a blx, maybe your esc is having the same problem. With the steering servos going bad. I noticed the servo was moving further than the steering rack at 100% so I started setting the endpoint to about 89%-90% with the stock radio
Only burned out the stock servo, HH sent me a 6s servo.

 

[SrC]

I am having LVC ‘issues’ myself, cutting off higher than I like. Evidently the an esc firmware update may help fix + allow 7.4v bec. I haven't tried yet, but take a look here: https://www.arrmaforum.com/threads/spektrum-firma-esc-update-2-06-and-vorteks.39041/

If you have the Firma Smart Programmer you can search for any possible F/W updates. Early LVC cuts was a problem for many Vorteks owners. Even though the Lipo had enough to keep going. Some guys kept going to a $larger capacty$ lipo as a band-aid approach. Not much success. Maybe a few more minutes run time before it hits the LVC threshold. I remember that if you replace with a Retail version of the same Firma ESC, LVC was all sorted out. Some guys replaced them. I never seen guys doing any F/W updates to correct this issue. . I don't own one. If it were me, I would toss the Firma ESC, Run a HW. I wouldn't even bother with a warranty replacement. It will drive better with an Upgrade ESC IMO.
Below is a retail replacement SPMXSE1100 Firma 100 ESC. Note the Retail Part #. The F/W is different. Has selectable BEC. No LVC settings. Only the Firma 160 offers LVC settings that I know of.

https://www.arrma-rc.com/on/demandw...4b33/Manuals/SPMXSE1100-Programming_Guide.pdf

 

[Wojoman]

Circling back, 2.06 solved my runtime/lvc issues! Update that firmware if you can! 7.4v bec also ‘unlocks’ as an option