RCU Forums

RCU Forums (http://www.rcuniverse.com/forum/)
-   RC Electric Off-Road Trucks, Buggies, Truggies and more (http://www.rcuniverse.com/forum/rc-electric-off-road-trucks-buggies-truggies-more-147/)
-   -   do I need a new esc? (http://www.rcuniverse.com/forum/rc-electric-off-road-trucks-buggies-truggies-more-147/11592433-do-i-need-new-esc.html)

zackS30 01-01-2014 05:25 PM

do I need a new esc?
While running my axial exo terra this moring started out good, I have a 3s lipo in it with my current esc(ezrun sc8) and the motor is a hobbywing 2700kv. It will pop wheelies and takes off like a bat outta hell.....
I was running it jusst now so I could run the batt. down to charge it tonight but while I was running it it all the sudden got super slow and just cut off but then would come back a few seconds later I checked the batt with the lipo alarm that came with the batt and it said 11.0v I kept running it and ans it did it again and I checked and it said 10.6v so I took that out to run down my 2s whick said 7.46 when I plugged it in and it ran great untill about 7.0v-6.8v

So idk wht that means bcuz this is my first lipo powered car. Is what it was doing a cut off safty feature for the batteries or do I need a new esc?

If I need a new esc then whats a good esc/motor combo for this car that will work with a 3s lipo and is 100$ or less
Ive looked at the castle sidewinder sv3 with a 5700kv motor it was 99.94$ but the desctiption said not to use it on something thay weighs as much as a savage or emaxx. So idk if it will work with my exo?

Ps. I do know that lipos shouldnt be ran less than 3.3v per cell. so I havent ran my lipos all the way down

zackS30 01-01-2014 05:37 PM

Acutally if I need a new esc then im going to get the esc/motor combo that the rtr exo terra comes with.

All help/info about the rest is as usual GREATLY appriciated!!!(did I spell that wrong? Lol)

SyCo_VeNoM 01-01-2014 08:13 PM

what is the cutoff voltage at on the ESC
also what are the lipos C-rating, and capacity.
There are a few things that could be going on one your lipos are not up to snuff for the power the motor needs, and might be putting too much strain on the batteries causing the voltage to sag(this would also give you alarm a false reading as the batteries will go up in voltage when not under load).

Or the ESC is set to 3.4or 3.2 volts a cell which would be the ESC is working properly as it should cut off when its around 6.8 volts (remember under load batteries voltage goes down which can trigger the LVC)

Now I'd try and leave the lipo alarm plugged in, and see if it goes off while the thing starts to slow, or drive it so you can see the alarm when it slows down I'm betting the battery voltage will be at cutoff values.

zackS30 01-01-2014 09:35 PM

One is a venom 2s 5000mah not sure of C rate
The other is Bias 3s 5000mah 25c(35c max burst)
The current esc is set to whatever factory is I assume. Bcuz I have no program card or anything.
Ive never had this problen untill now.

phmaximus 01-02-2014 04:54 AM

I would reccomend downloading the manual and follow the steps to check what the LVC is set at.
it only takes a few minutes.

it can be a little tricky to understand so if u need help sing out...

just rember a 3s lipo at 11v Is just under its normal voltage and is about 11% of its total capacity.
my thoughts... Its flat

charge it back to 12.6v and it should be back to normal until it goes flat again

I would hate to see u buy a new ESC and motor because of a flat battery

zackS30 01-02-2014 09:56 AM

What do u mean its flat?
I just got the battery and this was its 3rd or 4th run.

I dont need some card or program stick thingy to work the esc?

zackS30 01-02-2014 09:58 AM

What do u mean its flat?
I just got the battery and this was its 3rd or 4th run.

I dont need some card or program stick thingy to work the esc?

phmaximus 01-03-2014 03:06 AM

Do you still have the problem is u fully charge the battery?

im under the impression it was fully charged in the morning, u drove the car for a bit then later on in the day when u went to use it again and the battery was flat and kicking in the LVD. Like I said before. 11.1v on a 3s lipo is 3.7v per cell and would indercator the battery is only 11% charged

if u charge the 3s battery does the car run with any problems? Cuz if not there is a defiant problem

just wondering when it was running did the motor get hot?

zackS30 01-03-2014 10:17 AM

Oh ok I got you, it was charged in the morning but I didnt charge it later bcuz the battery said it was like 11.6v I think so I diddnt think I should charge it again.
the motor wasnt hot I put my finger on it with no discomfort.

Once I charge the battery and run it its fine itll pop wheelies and throw dirt 10ft in every direction. What voltage should I sstop using the battery at?

SyCo_VeNoM 01-03-2014 10:34 AM

3s IMO 10.2 volts
thing is that is under load your battery checker as you are plugging in after you let off the throttle will show a higher voltage(its how batteries work).
2S 6.8 volts

That is going at 3.4 volts per cell some people like to go down to 3.2 volts per cell which would be 9.6V, and 6.4 respectively. As long as the cells are discharging evenly, and one isn't under more load then the other 3.2 would be fine. I just personally like the little extra leg room 3.4v's gives even though it would cut my run times down by 2-4 mins.

zackS30 01-03-2014 10:52 AM

Ok ill reset my checker its set for 3.3v.
Is my 3s enough? Its a 25c I found a 50c for 70$ is that good.? Only thing is its a soft pack. My current is a soft pack but I took a coke cake and cut it up and taped it around to make a ghetto hardcase

SyCo_VeNoM 01-03-2014 12:26 PM

well the 3S is good for 125Amps continuous pull so should be good doubt the setup pulls that much. Is cutting it a tad close though depending on the cells quality (never heard of the brand you mentioned) they should be fine.

zackS30 01-03-2014 05:46 PM

Ok then I will save my money then thanks!

So the reasson its cuts out is just cuz the batterys r out.of juice thats good to know

phmaximus 01-03-2014 06:23 PM

Ahh cool, good to see ur up and running again.

here this might help in the future

allso those ezrun combos are really good, they are proven to be reliable

but anyway try this..
turn on controller
turn on car while holding the set button
release the button when the GREEN light flashes 3 times (u will see it flash once, then twice then 3 times)
then the RED light will start flashing.....how ever many times it flashes represents the setting its currently on for the lvd
press the set button until it is at what value u want
turn everything off and ur done

zackS30 01-03-2014 08:21 PM

Theres a set button? Theres a really tiny button on the on/off kinda seems like a reset button

phmaximus 01-03-2014 08:31 PM

That's the one....
please click that link for the manual...

it will all make sence after reading it

zackS30 01-03-2014 08:45 PM

Ok thanks! Sorry for my ignorance!

Still learning, the only lipos ive delt with is for my xmods and they domt have esc's just a circuut board. Ha.

EXT2Rob 01-06-2014 09:35 AM

Give this a read: http://www.rcuniverse.com/forum/rc-c...ead-first.html
REALLY good info.

I HOPE you have a LiPo battery charger and you're not charging a LiPo with a NiMh charger. That would be dangerous.
When you're done running your car for the day, be sure to charge the battery to "Storage Voltage". (The LiPo charger has this function) It charges the LiPo to 3.85V/cell, its "resting voltage" or quiescent point where it "likes to be". You just have to tell the charger how many cells your pack has. Leaving LiPos fully charged or fully discharged for extended periods will significantly shorten their useful life.

zackS30 01-06-2014 07:52 PM

My charger is a racers edge 2-3s lipo/life charger. I has a charge and fast charge button, and a button to go from 1a-5a charge rate. How do I set it for a resting chargee?

EXT2Rob 01-08-2014 08:02 AM

I'm afraid you can't. :mad: Now WHY on Earth would somebody make a "LiPo Charger" that does not tell you what's going on (no display) nor does it have a Storage Mode function?? That ain't right!! Grrrrr! Seriously, put that charger up for sale. Or if you can, send it back and get a refund! You need a charger that has a display that actually TELLS you something, and especially, one that has the FUNCTIONS you need. http://www.hobbypartz.com/73p-ac680-accharger.html
That charger is LESS than $50 and is exactly what you want. Trust me. If you are serious about this hobby and plan to stay in it, there are certain things you need, and this charger is one of them.

zackS30 01-08-2014 09:29 AM

Jve been messinf withrc cars since I was 7 they werent highend like ive got now but I do love working on them.
Ive got a whole section of my house dedicated to my rc stuff(my wife set it up for me aint that awesome!).
Ill get that charger, the racers edge one has been good to me but ur right I need tge right tool for tge job.

phmaximus 01-08-2014 11:48 PM

Lol u should see my house... The back table is like a rc graveyard lol I'm currently going through the process of having a big clean out. I've got boxes everywhere... Worst part.... I've got a stack to bits stored in a big 6 shelf chest of draws.....all neatly organised...well was, the 2nd shelf down fell out taking 3 others on its way and split one of the ends of the cabinet... There is crap every where. Picture dumping 4 1000x300x100mm draws full to the brim onto the floor...I've just closed the door for now lol...

zackS30 01-09-2014 10:28 AM

Oh man that sucks!.
I would have the same just open the door and see tthat then shut it again lol

All times are GMT -8. The time now is 12:41 AM.