Riding time with a Lehner 5300 and 6 cells in a truck ?

[666yeti666]

Hi there,
I would like to know what estimated driving time (average) you guys have when using a 2 wheel drive truck with a lehner 5300 with 6 2400 cells ?
(yeah, yeah, I know it depends on lots of things, on road, off road, driving style, wheel diameter, weight, bla bla bla ....)
I just want to get a FEELING what driving times you have.

And, I would like to know it, since I'm getting a driving time of only 3 minutes ....
I'm riding a Duratrax Evader, with masher 2000 tires. 18 pinion, 88 spur. lehner basic 5300, micro1895 controller and Sanyo 2400 6 cell pack.

It calculates to an average motor current of 48 amps and that's a lot. Nothing gets warm, only the battery, which I can keep in my hands without burning them.

[pinolelst]

Must be hard "riding" one of them things.Did you make a special saddle ??? j/k ;)

That running time sounds about right.If you want more time either go down in pinion size,up in spur gear or/and get better battery packs.THose 2400 might be a little old ...maybe cycle them a few times to see if the run time improves some

hope this helps

[studysession]

The Rustler is similar to the Evader. I have a Bandit which is same as Rustler just few minor pieces are differemt. I used to run the 5300 in it but now I run the Novak in it. The 5300 is to much power for something like the evader or rustler in my opinion. That is why I downgraded it to the Novak 5300
http://studysession.com/Car-TraxxasBandit1.html

The Novak has less power and is easier for my kids to control then the Lehner 5300. The Lehner 5300 made it where I had to gear to high just to keep the acceleration down.

[kufman]

What is the final drive of the gearbox? 2.6:1? My guess is that the combination of the Masher tires, a fast motor, and old batteries are giving you very little run time. You can try to go to a smaller pinion, small tires, or better batteries.

[studysession]

I would start with nice high quality batteries.

[ElectricThunder]

3 minutes total run time so far? Gearing 18/88 may be your problem cause of the monster mashers. Coupled with the fact you're running 2400s, that could be why you're only gettin 3 minutes. Just a guess, never drove a lehner setup so I have no clue how high you can gear it safely with MMs.

[666yeti666]

First, thanks for the suggestions.
I just calculated the transmission ratio which equals 2.53
With an 88 spur and an 18 pinion that leads to a final drive ratio of 12.35
Is pretty low, but obviously needed for the large mashers (diameter = 12.5 cm = 4.9")
With a Kv of 5300 rpm/V of the Lehner in combination with 6 (bad ...) cells this is about 6x5300=31800 rpm.
Eventually, the top speed with the mashers would theoretically be about 60 km/h (38mph).
Maybe a smaller pinion (or larger spur) is a good choice , since topspeed is still descent.

On the other hand , 3300 cells would only give 37% more driving time, that would lead to 4:14 minutes, mmm , not really high.

Despite less torque and lower top speed with my triple 19 brushed and timed motor with the exact same set-up, the driving time was 6 minutes... you understand my point

[ElectricThunder]

A 6 pack o' 3300s would/should give you more than 4 minutes, probably around 5-10 especially if you gear it something like 16/88. You want your FDR to be higher with the Monster Mashers BTW, seeing as how they're big clunky tires, not lower. The numerically lower the FDR, the more top end you get, and the less torque to spin the big wheels.

With a novak SS5800 in a T3, I gear 16/87 on 7 cells (cheapy 1900 pack). Gets great top end (I estimate 28ish, maybe 30, never radared it though), but still can pull wheelies for a little more than half of the pack and has great acceleration. Experiment with some pinion/spur combos and see what floats your boat! :)

[666yeti666]

ElectricThunder,
about the torque, the lehner should have enough of it, as I said the motor does not even get warm during a 3 minute run.
I assume that your tires on your T3 are of standard size ?
Ok, 28 isn't bad but I was more shooting on at least 31 mph.
And wheelies are not possible with my set-up, should be fun too.
I think I'm going to change to a smaller pinion first, with a 15 I get 31 mph.
Lets see if my LHS has some on stock ...

(I just made a calculation sheet to easily do quick maths and changes, interested?)

[666yeti666]

ET,
forgot to ask about the runtime with your 5800 T3?

[ElectricThunder]

I run monster masher 2ks on my T3. I also have the diff locked and slipper tightened kinda far :D(28 is probably a bit underestimated too, since I just regeared and stuff today, and haven't run a full charged, fresh pack, 30 is definitely attainable). But anyways, maybe your gearing isn't the weakest point then. Going back to batteries, do you know if your batts are accepting a full charge? That could be one cause. Or the cells could just be plum worn out, and not really discharge at the rate they're supposed to. Do you have any other packs of newer cells or higher capacity cells?

Edit: Runtime seems to vary with temperature here in Florida. On an average day, I can maybe get a good solid 6 minutes? Maybe 7. I suppose on how I run it. If I don't use reverse at all, maybe sometimes 8 minutes. In cooler weather like today (maybe 60ish), I get a good solid 8 minutes or so. But I also run through LOTS of grass, so that drains the batts faster. And running 7 cells drains it faster too.

[ElectricThunder]

And what's the calculation sheet for? Gearing? That'd be super helpful! I kinda do the shot in the dark method...:D

[666yeti666]

ET,
my connection is somewhat slow ...

Anyway, my bat's are about 1 year "old" and not really used a lot. I will check how much current gets in tomorrow (already 10:30 in the evening here in the netherlands , europe, and tomorrow my daughter wakes up very early ....)
I also know on cold days the pack does hasn't its optimum performance. Right now it's about 5 degrees celcius (41 fahrenheit) out here.

And, the calculation sheet is for ..... calculation !
Just fill out the final drive ratio, number of cells, Kv of the motor, spur, pinion, tire diameter , etc. and voila : maximum speed is calculated !

[ElectricThunder]

Sweet! And batts don't like to be too cold, but at the same time, they don't like to get hot either. Luke warm seems to fit them.:D But anyways, maybe the fact that you haven't really "used" them means their capacity has gone down. Definitely check the MaH that's being squeezed into those bad boys, as well as voltage. Batts seem to be the #1 suspect in my eyes, seeing as how the lehner is a torquey little...yeah, and can handle the gearing. Check out towerhobbies, fusion, or any other place that has some good 3300s for a cheap price and get a pack to see if they work. I think tower sells SMC GP3300 stick packs for 30-40 bucks, but shipping would probably suck for you:(. If I can help please feel free to gimme a PM or whatever.

And if it's none of the things we've gone over so far...I think it's time to move on to the controller... :eek:

[tcolesen]

What brand are the batteries? If they are just a cheap pack of 2400 cells, then that could be your problem. Also, a good battery pack will hold a higher voltage when more amps are being pulled from it than a cheap battery pack, so you could get higher performance just from that.

[666yeti666]

ET,
I just charged the pack (from empty) with about 5 amps . According my charger, 2337mA is squeezed in. Not really bad for a 2400 I would say.
I could purchase some from Towers, but shipping, taxes and fee's cost would be relatively high for only orderring some packs. I will take a look at my LHS, thanks anyway.
Next thing to do is a smaller pinion I guess.

Do you think the controller is not ok ? It doesn't get warm, so dissipation is very very low.
Now I think of something else : I still use the "old school" tamiya connector on my batts , but no, that could not be the problem. Its larger resistance should only decrease the voltage somewhat, the controller (motor) just gets less juice.

Tco,
the brand of the pack is Sanyo, one of the best around, at least that's what I thought. They're also used a lot in the flying scene.

[glassdoctor]

You really need to get those tamiya connectors off the car ASAP. :)

They are not helping, and they are eating up MAH... they're not voltage reducers... they're current eaters. Deans Ultras or 4mm gold plus or Andersons or something...

2337mah is fine... it's common to see mah higher than the rating of the battery, depends on the charger. I've seen 3300s read 3500+mah on some chargers.

[ElectricThunder]

TAMIYAS?!?!! AHHHH! BURN THEM! Deans, powerpole, anderson, astroflight, one of those connectors will do you MUCH better in BL applications (all applications for that matter). And the fact that your batts are getting 2337 (under the 2400 mark which is what they're supposed to be) may mean they're starting to wear out? Just a guess, not quite a battery guru. Try cycling them if you can, and also just pick up a cheap pack of brand new GPs coupled with some deans connectors for the charger, ESC, and battery connections. My suggestion would be to try all those things first. Then if it's still not fixed, then something may be up with the motor and/or ESC, but I highly doubt it.

BTW- Deans/low loss plugs make a huge difference in your setup, and your ESC may start to run a bit warmer when you use them due to there not being as much resistance, so plugs are probably your weakest spot, and batteries may be a close second IMO.:)

[tcolesen]

When batteries haven't been used, they don't immediately want to accept a full charge. Just this past weekend I was charging up my friend's 2400mah packs that had been sitting for several months. It took 3-4 cycles for them to accept a full charge of about 2450mah. A re-peak on one of the packs yielded a voltage during the charge of 11.01v! Those were of course NiCd packs, and the voltage dropped down to about 10v after the peaking finished.

Definately switch to some high current plugs. The BL controllers probably hate the amount of resistance caused by tamiya connectors.

My GP3300's have accepted about 3700mah in the past, which is definately high! Now they get about 3600mah, which is still really good.

[ElectricThunder]

Geez Tcolesen! How many cells were those NiCds? 10 volts is a lot for a freshly peaked 6 cell pack.

[SpEEdyBL]

Peak voltage is the max voltage between the charger and the battery, usually during charge. So if you stop the charge, the voltage of the battery will drop. To a more normal level. My Gp3300 7 cell batteries peak at 10.5 volts (3.0 amps charge) and my crap 1500 6 cell crap packs peak at over 11 volts. Its actually better to have a lower peak voltage since higher voltage means the batteries have a higher resistance. (More voltage into the battery is required to overcome the resistance).

On a side note relating to tamiya plugs, I once used them on my charger temporarily (when my powerpoles became un-soldered) the peak voltage for my batteries was .5 volts higher. That just shows how much more resistance tamiya plugs have.

[666yeti666]

guys,
this morning I put some gold plated 4mm plugs on the batt and the controller and also cut the batt wires one inch shorter.
Did a fresh charge on the Sanyo 2400's , connected them, and guess what ?

This bad boy is having power ! Wait, did I say power ? I mean POWER !!!
The truck is almost uncontrollable !
This was really far above my expectation. What some good connectors can do.
Anyway, back to my original problem: driving time ...
Unfortunately it is hard to say what driving time is right now, because I faced the next problem : Cogging , oh noooooooooo :-(

Of course this is much worse now then with the tamiya (grrrrrrr....) connectors since the motor gets more voltage. During take off the energy drain from the batt is higher.
(by the way, I was using a 19 pinion and no 18 as thought before, theoretically this would give a top end speed of 40mph)

Next thing to do now is putting a 15 pinion on it, that I just got from my LHS. (top end speed drops to 31 mph, but more torque available) Let's see what this brings.
I also bought 1 extra cell, but that's the second step.

I will let you know the result ...

[ElectricThunder]

It's like night and day going from Tamiyas to low loss connectors eh? ;) Mr. Constructor has a way to help prevent cogging on BK controllers, or you can just plug in a receiver pack and that should help. :)

[666yeti666]

ET,
you were right about the tamiya's , they su** .

About the cogging, my standard ride is already with a receiver pack ....
And I already did try that capacitor on the receiver, even a 4700uF (BK adviced 1000uF) but that doesn't help.
Maybe the 15 pinion decreases some of the current during start-up.
And maybe I also have to play again with the settings in the software.
But step by step, first the 15 pinion.

What controller do you have and how did you solve cogging ?

[ElectricThunder]

Me? I just run a novak SSS5800, which is sensored so cogging is practially zero (unless Tx batts are low, then it'll stutter every so often on start up, but that's the only time I've experienced cogging). You can try running a 7 cell pack to help counter act the BEC being drained of power on start up. BKs run better on higher cell counts from what I've observed/heard. But if you plan on using the 6 cell pack, a receiver pack would probably be needed, and the red or black wire removed from the ESC radio plug.:)

[SpEEdyBL]

I notice that my ss5800 always cogs in reverse. Never in forward though.

[ElectricThunder]

I notice that my ss5800 always cogs in reverse. Never in forward though.
Mine barely cogs in reverse, but it's still noticeable. I try not to use reverse anyways, just heats stuff up more.

[666yeti666]

guys,
finally some good news !
First thing is that I put on the 15 pinion, and with the 6 cell Sanyo, which I got squeezed in 2465mA (!) the driving time was about 10 minutes !
And with a another pack (3000Mah) that I just put new connectors on, 9 minutes (team orion super duty plus Ni-Mh from Tower Hobbies).
I must say that it was kind of slippery on the partly iced road. That's why I could not say if the cogging was still there, I couldn't notice it.

I only got some cogging when the truck was at about 15 feet away from me. I suspect disturbance on the receiver.

With the 15 pinion the throttle feeling was quite good, certainly on the slippery road, where too much throttle caused a spin immediately.
Top speed was also good, although max could not be tested for long, the streets here in Holland are not that large ...

Hopefully I can do some testing on an ice-free road today.

[studysession]

Good to hear you are making progress.

[666yeti666]

Last days I drove some more with the current set-up. I must say I'm really pleased with it. No cogging when using a separate battery pack.
It has lots of power, in fact I took a ride in the forrest on kinda wet grounds (leafs, small branches), there, the Masher 2000's don't get any grip.
For that condition good spikes are necessary.

Yesterday I drove with the original Duratrax truck wheels. Since they're much smaller, a larger pinion was screwed on (19T, theoretical top end speed 31mph).
With the smaller tires the acceleration is even better then with the mashers ! Drives like a nitro, but without the noise !
The grip in the corners is absolutely horror, it just keeps breaking out, but that's to be expected of a brand tire like that.

So I must say "mission accomplished" !

Thanks for the help.

ps. Next project will be a small 4WD nitro truck to change into brushless.