4+ hour runtimes

[SqueakyBum]

Couldn't see anywhere else to post this thought so feel free to move it to a a more appropriate section.



Okay, it sounds stupid doesn't it?
4+ hour runtimes from your RC car/crawler......

I had various Radio controlled kit as a kid.

One thing that always really annoyed me was the fact that the batteries only lasted for 10-20 mins. Then they have to charge for ages before you can go for it again.

Now, as a grown up, I see the same frustration in my son.
We charge up a pocketful of batteries and still return within the hour most times.

Now, despite advances in everything, the runtimes are still nearly the same as they were some 25 years ago.

I SMELL A RAT.

Now, my question is this; 4+hour runtime.

Ho do we go about getting this result for ourselves from existing tech?

All I am looking for is open minded suggestion as to how an individual may get creative and get super long runtimes.....a little banging together of heads so to speak.

No nay sayers please, believers only!!!!! hahahahaha

[skerb]

With my 5000 lipo and brushless motor I get over an hour of runtime with one battery.

Sent from my DROIDX using Tapatalk

[Duuuuuuuude]

Run times depend on a lot of things. Battery size and type most of all. If you're using a 1500mah nicd stick pack, then yeah, things have not changed.

So to answer your question more thoroughly, we need more info.

What rig?
What motor?
What battery?
How are you driving it?

[SqueakyBum]

I will get the ball rolling by suggesting something like this;


We have a HBX rockfighter, the battery is mounted centrally and low down.
There's almost enough space to fit a small form factor 4.5ah 12v lead acid in there.

What say it was possible to create a "hybrid" sort of circuit, then use a combination of series and parallel lipos to boost the capacity of it.

The LiPos handle the pressure, while the lead acid provides extra capacity.




Now, I personally can understand just about enough to know that 12V lead acid isn't the best idea and that what I'm suggesting may be utterly stupid on many levels even if it was all done using the correct theory.

Consider this for a moment though - If we were able to make our models 50-100% larger but weigh more or less the same, this would give us more room to make up a super flippin duper battery pack.



Feel free to theoreticise on this guys.
So, suggestions please, no matter how daft it is.

[SqueakyBum]

I'm using 3000Mah 25/50C 2s1p LiPos mate but I'm looking for wild and wonderful ideas about what could ACTUALLY be done.

I can imagine with both my LiPos hooked up in parallel I'd get an hour or so too. But I'm looking for BIG daddy suggestions here dude.
An hour is good, but that should have been possible in the 80s - this is the 21st century and I'm paying 50 quid for batteries that can still only manage times measurable in minutes.

Come on man, push the boat out, what could be achievable?

[Duuuuuuuude]

Consider that with that rig you are powering 2 small motors. The electronics are not the most efficient. If you are using nickle batteries, they are also not terribly efficient and they are heavy. The supplied 1500mah battery will not last long in anything. The stock power connection is also not very good. All of that results in poor run times.

Those 2 motors will work harder than larger ones. That takes more power. Inefficient electronics will use more power than better, more expensive stuff will. Heavy batteries also take more power to lug around.

If anything, get yourself some lightweight, high capacity lipos.

[SqueakyBum]

Originally Posted by Duuuuuuuude

What rig?
What motor?
What battery?
How are you driving it?

Okay, my question is meant as a complete generality....
But for the sake of being polite, lets say......

It's a 1/5 scale crawler that weighs the same as a dog turd.

The motors are stock 27T.

The battery is whatever we can dream up.

We drive it a great many ways, I ssume.


Remember dude, I'm talking about a hypothetical scenario, not my real one. I got that covered already for the time being LOL

[Duuuuuuuude]

You want the lightest, highest capacity battery as practical, a higher turn motor, good efficient electronics, and a relatively drag-free drivetrain.

[SqueakyBum]

Originally Posted by Duuuuuuuude

If anything, get yourself some lightweight, high capacity lipos.

I have two 3000Mah 25/50C Orion Rocketpack LiPos, I don't use them on the rockfighter as yet but I plan on swapping it to deans connectors and running the LiPos.

But that's not the question here. I have that on lock already.

Imagine you have a big @ss truck, that weighs next to nothing, how might you imagine you could power it's @ss for 4 hours non stop?

[Duuuuuuuude]

Originally Posted by SqueakyBum

Imagine you have a big @ss truck, that weighs next to nothing, how might you imagine you could power it's @ss for 4 hours non stop?

I already told you. Its not a deep dark mystery how to do it, and no voodoo is involved.

Make the rig so that it uses the power efficiently as possible, then strap a big ass battery to it.

If you really want to get into the semantics of it, you're going to have to crunch numbers and do the math. You'll still end up needing efficiency and a large power capacity.

[SqueakyBum]

Originally Posted by Duuuuuuuude

You want the lightest, highest capacity battery as practical, a higher turn motor, good efficient electronics, and a relatively drag-free drivetrain.

That's the spirit mate

Precisely my thoughts, if the vehicle is large, the running resistance low, the motor efficient and the battery capable then why shouldn't runtimes better than 1 hour be achievable?

The emphasis is on a large and very lightweight vehicle, that way you allow for maximum battery carrying capacity.

Utilising new battery technology we should be able to achieve this somehow, regardless of the rig.

If I was pulling a trailer of batteries (lightweight LiFe or LiPo) - surely I could get 4 hours that way also?

I'll be back later but for now I ask you to give it some thought, nobody is happy with their runtimes, unless they get more than an hour every tiome, even then they want more, why wouldn't they?

[Propane]

I tried nitro about 10 years ago because of the battery run times back then. But with all the high capacity batteries on the market when I restarted into the hobby a couple years ago I went back to electric.

I now run 2s 4000mah lipos on a Goat2s 18.5t brushless scaler. It's a heavy rig weighing in at 8.5 pounds. Overdrive/underdrive gears and 1.9 pitbulls and running full LED lights. On a G6 day I ran just over an hour before changing my battery. That's driving and winching. I don't mind changing out my battery once an hour, it's the perfect time to check your temps.

In the end, are you building your rig to drive and have fun? Or to be efficient for long drive times. You can't have it all so it's going to be give and take.

[Duuuuuuuude]

Originally Posted by SqueakyBum

I'll be back later but for now I ask you to give it some thought, nobody is happy with their runtimes, unless they get more than an hour every tiome, even then they want more, why wouldn't they?

I wouldn't say that at all. I'm plenty happy with my run times. I get 20 minutes with my comp crawler, which is more than fine because it really isn't meant to run that long anyway, and an hour or better out of my scale rigs (depending on how I drive them).

Chances are you'll break something or get bored before you hit the 4 hour mark anyway.

Not everyone wants to run a massive battery. They either take up too much space or detract from the look of the vehicle. Comp rigs use very small ones to keep weight down, and they really only run 5-8 minutes at a time anyway. For the most part, scale guys use the biggest battery that they can hide.

I've got a couple of 5000mah lipos I could use and get tremendous run time, but I don't. Like I said earlier, long run times are not a mystery nor are they out of reach. Its just that not too many people worry about it.

[Charlie-III]

As mentioned, you can get some huge mah LiPO's, but you pay for them as well.

Keep in mind, if you toast one of these expensive packs, you WILL be pissed!

Better to get a few smaller packs so you can change them out as needed, replacement cost is lower, size & weight is down, charge times are more reasonable.

As to mixing battery chemistries, I would spend a LOT of time reviewing discharge curves before buying anything. The different chemistries will discharge at different rates, thus making it hard to not over-discharge one or more packs.

As a suggestion, why not run 2 5000mah LiPO packs with a switch between them & the ESC?? When one hits the LVC, flip a switch and run the other one down.

[Duuuuuuuude]

Originally Posted by Charlie-III

As mentioned, you can get some huge mah LiPO's, but you pay for them as well.

Keep in mind, if you toast one of these expensive packs, you WILL be pissed!

Not really. I've had a pair of these for a year now. They perform just as well as they did when I got them.

GForce 40C 5000mAh 2S Car LiPO Pack (Hard Case)

Originally Posted by Charlie-III

As a suggestion, why not run 2 5000mah LiPO packs with a switch between them & the ESC?? When one hits the LVC, flip a switch and run the other one down.

Why not run them together and not worry about switching them?

[Meatwad]

Everything is a trade off. You can't just say you want obese runtimes and not think its going to affect other aspects of a 1/10 crawler, even with newer motor/battery capacity technology.

First off, that thing has 380 motors. Its like having a v6 in a full size truck, not great gas mileage because its constantly working too hard.

Make a list of small goals to accomplish your largest goal. Ask questions as you need, but just expecting one trick to work just won't with a stock crawler. If you wanna throw money at it quick and be done with it.. buy about 8-10 1800-2200mah 2s packs and a couple 4x chargers and switch em out as needed.

[Charlie-III]

Originally Posted by Duuuuuuuude

Why not run them together and not worry about switching them?

You could, but what if one pack discharges faster than the other? You may go too low on one pack and kill it.
While it is not likely, I start to get leery about doing parallel packs. Likely from years in facilities/maintenance.

[Duuuuuuuude]

Originally Posted by Charlie-III

You could, but what if one pack discharges faster than the other? You may go too low on one pack and kill it.
While it is not likely, I start to get leery about doing parallel packs. Likely from years in facilities/maintenance.

Its no different than a series pack. There is always the potential for one to go down before the others.

[AsILayDying]

I have no issue with run times at all. Nice trail day and I might change out once only if needed after a good mud session.
I run either 2x 2 cell 5000mah LiPos in either parallel for really long run times where I never change the battery. Paralleled it gives me a 10,000mah 2s LiPo. Or if I'm wanting to run 4s, I'll throw on the series connector and still get a good run time.
My other rig I run 2x 3s 2200mah LiPos with the parallel connector and get a 3s with 4400mah.
I get my batteries off HobbyPartz.com and it's well worth it. You can make a 2s 10,000mah LiPo for under 40 bucks of you shop.

[AdverseCity]

One thing that kills run times on scalers is the full throttle driving from one spot to the next. That's another reason I love my SCX with a summit 2 speed transmission. I can go the same speed at 25% throttle as a stock one goes at full throttle. This doesn't work as well for actual trailing as the torque just isn't there. I compare it to a really high overdrive gear on a truck, great on the highway but useless offroad. Just a little something to consider....