Battery Trouble
 

Hi! I'm getting ready for my first race at Adrenaline Raceway in Tampa, so i bought a new Venom 2 cell 7.4V 20C 5000 mAh LiPo,an Onyx 230, and an equinox LiPo Balancer and i have not been able to charge it right. This is my first LiPo battery. It charges to about 3200 mAh each time and i don't think i am getting the maximum performance out of it.
Any help will be apreciated, including info about racing, not just the battery.
Thanks
Dan

Brand new, lipos are delieverd with some charge already, so charging before using when new, this is not surprising.

Are you running with a low voltage cutoff? 3200mah may be all thats being discharged down to the lvc. What is it set at, sounds like it may be too high based on the mah you're putting back in. What esc??

This may not be a charging problem, but a discharge prob. You can't put in too much more than you take out (discharge).

i have lipo cut off programmed, but i don't have a discharger. i'm sorry can you go a little slower i'm new to the LiPo lingo lol. Are you saying i should run down my battery untill the lipo cut off on my esc shuts my car off? i didn't think that would be good for the battery or car.

That is what the cut-off is for, to shut down your car before damage happens, but after most of the energy is spent.

Make sure the Onyx lipo profile you selected is set to charge to 5000 mAh. I know there are the default profiles in there but it sounds like you need to customize it. CHeck the directions for how to check and change the profiles.

Hope that does the trick for you.

I was using the the custom setting already because the pre-set ones didn't have a 5000 mAh one. I already know how to program it too, because i had a onyx 220 before the 230, and you program it the same way. I was asking what do i need to program it for i guess. And i need to run it until the LiPo cutoff shuts it off? i just didn't think that was good for the car.
Thanks
Dan

You are correct, it's not good to run lipos down to or past cutoff. Unlike NiMH cells you should never deep-cycle them, so the pack rating is really nominal. I think it's accurate that you're getting 3500Mah into your 5000 pack, since cutoff occurs between 20 and 30% of capcity.

So 3500 is all i'm going to get out of it? And this is the best speed i'll get out of this battery? I was expecting to see a big increase in speed. I'm running a Novak Havok 13.5, but with these two upgrades, and some new gears, I have not seen that much differnence in the top speed, though my acceleration is awesome, Adrenaline also has a large strait away that i get killed on, though i do really well in the turns. Am i just going to have to live with this speed?

Gearing determines speed, there is not that much diff in voltage between fully charged 6cell pac and a 2S lipo, so I'm not surprised you're not seeing a top speed increase.

Consider re-gearing, gear it up (larger pinion or smaller spur) - this will increase top speed, it will reduce the accel a little, but it sounds like you have it to spare.

I have geared it up quite a few times, now i have a 30t pinion in, which is really big and causes a lot of friction on the spur, so it slows down really fast when i'm off the gas. I'm afraid if if i gear up any more it won't even fit. I've already gone over the recomended pinion limit of 27 teeth since i got a fan from MuchMore racing that i installed on my motor to keep tempetures down. Should I try a different pitch? if so should i go higher in pitch or lower? Any tips, in any area, would be greatly apreciated for my first race :p
Thanks
Dan

Hi TC4Racer123,

you didn't post what your spur was, but I'm going ot guess it's the stock 72 tooth one. If that's the case, then your gearing for that motor is going to be way too high (too slow). I couldn't find a recommended Final Drive Ratio (FDR) for your Novak motor, but I run a Losi 13.5 and they recommend an FDR of 4.6 for the 13.5 motor.

Your FDR is the following :

Spur divided by pinion multiplied by your internal drive ratio
in your case that would be
72(spur) / 30(pinion) = 2.4 (gear ratio) * 2.5 (internal drive ratio of a TC4) = 6.0

Don't be afraid to ask other drivers at your track what their final drive ratio is and you can work backward from there! You may have to make modifications to your chassis to acomodate the larger pinions, and you may have to switch to 64 pitch gears. I would guess that a 64 tooth spur with a 34-35 tooth pinion should put you in the ballpark for that motor/car. Tiger72 is running a TC4 using 64 pitch gears and squeezed a 53 tooth pinion in there with a little dremel work :)

do you have a suggestion on what gear to use? I don't know how (i could probably find out if i need to) to put a new spur in, and were can you buy spurs for a TC4? Do all spurs fit the same? How hot/fast does you car run, Tiger?
Thanks
Dan

I have the same battery and i don't like it very much i don't like venom period.:tire:

gear suggestion ^^^

I think most spurs should fit. Take your car with you to your hobby shop and ask them to help you get the right part!