How to get the most run time

[Melton]

Hi, Im new to the electric rc world. I am in progress with a crawler build. I am wondering how to get the most run time on a single battery pack. Would a 5000 maH run longer than a 2000 maH?

Thanks,

Melton

[smokin0137]

Originally Posted by Melton

Hi, Im new to the electric rc world. I am in progress with a crawler build. I am wondering how to get the most run time on a single battery pack. Would a 5000 maH run longer than a 2000 maH?

Thanks,

Melton

Yes,by far.

[Reflection]

Yes it would.

Gearing down and adding lightweightness will increase run time. Higher turn motors draw less amperage,so that helps as well. Putting your throttle finger on a diet will make a HUGE improvement on run time.

A guy can get crazy with it and get his truck to run for 6-7 hours or more on a single charge....but the performance would pretty much suck.

[ultimate_monkey]

when looking at batterys there is 2 things voltage and MAH, voltage is the power rateing (7.4v 11.1v etc) and the mah is the amount of power the cell holds, so a 5000mah battery in theory would last 2.5x long then a 2000mah.

when you get into lipos you have to look at voltage, mah and "C"rateing (the amount of amps the batter puts out)

[Duuuuuuuude]

Think of battery sizes like this:

Voltage is like horsepower, and the mah rating is like the size of your gas tank.

[xblade]

Originally Posted by Duuuuuuuude

Think of battery sizes like this:

Voltage is like horsepower, and the mah rating is like the size of your gas tank.

Good analogy.

[AlmstEvil665]

You won't ever need anything bigger than say 2200mah. I run a 3s lipo 2200mah with a Tekin FXR esc and 55t motor and playing around thats runnin it hard and runnin it easy it last almost 2 hours. Honestly though I am lying I can't tell you how long the run times are because I get bored with it before the battery dies which is about an hour to two hours of playing.

[2500hdon37s]

Originally Posted by Duuuuuuuude

Think of battery sizes like this:

Voltage is like horsepower, and the mah rating is like the size of your gas tank.

easeiest way to say it! and more cells makes more volts.

[bob1961]

i'm running 8 cell elite 1500's at 9.6 volts with a 55t handwound 540 from holmes hobbie and get bout 40 minute run times from all 6 of my battery packs i have made so far....i'm finding that run time good to go for me, but then again i have 6 packs to carry through the day and into the night ................bob

....

[Duuuuuuuude]

Originally Posted by AlmstEvil665

You won't ever need anything bigger than say 2200mah. I run a 3s lipo 2200mah with a Tekin FXR esc and 55t motor and playing around thats runnin it hard and runnin it easy it last almost 2 hours. Honestly though I am lying I can't tell you how long the run times are because I get bored with it before the battery dies which is about an hour to two hours of playing.

I get about an hours runtime from my 2200mah 3s lipo with a sidewinder, bec, and revolver. I too get bored before the battery is gone...lol.

Originally Posted by 2500hdon37s

easeiest way to say it! and more cells makes more volts.

Higher voltage also can equal longer runtime per mah. When volts go up, amp draw goes down (all things being equal...most importantly your throttle finger). When amp draw goes down, less juice is pulled from the battery.

[Melton]

Great info everyone, it was very helpful. I have another question, do LiPo's run longer? I know they deliver more Volts.

Thanks everyone for the great info.

-Melton

[Reflection]

Originally Posted by Melton

Great info everyone, it was very helpful. I have another question, do LiPo's run longer? I know they deliver more Volts.

Thanks everyone for the great info.

-Melton

They don't really deliver more volts,voltage is voltage. They do have allot higher power(voltage) to weight/size ratio.

I've never noticed a big jump in run times because of a lipo battery of the same mah rating. I've read that some have. Personally,I feel there are to many varibles in the equation. You may see some increased run time simply from the added lightweightness you just added. That would have nothing to do with what cells the power is coming from. That just means the motor doesn't have to work as hard,so it draws less power to get through the same obstacles.

If there's a big jump in mah rating,I'm sure you will see a jump in run time. The biggest thing for me was the power to weight/size ratio. I won't run anything else now that I run lipo's.

[tim the toolman]

And also the way I understand it lipos can handle a higher current draw than a similar sized nimh battery. The higher the "c" rating the better they can flow current. Not that a crawler draws a lot of juice normally but say if you run a small lipo like 1100 or 1500 it should handle current draw better & last longer than a 1500 nimh battery. Maybe someone could explain it better than me or correct me if I'm wrong?:-P

[Duuuuuuuude]

I would think, and this is unfounded theory, that you would get slightly longer run times from a lipo because of how easily they move current. Less resistance = more efficient delivery = less load = less heat = longer run time.

And also that lightweightedness thing.

[RustlerHustler]

It's called the lipo paradox. It says that the same mah in a nimh and lipo that in general the lipo will go linger because it is more efficient.

Eric

[chrisjlittle]

Outside of getting a bigger battery, the easiest ways to get more runtime are to make your rig lighter, run a slower motor, gear down more, all the things raptorman said. Another thing you can do is to try to make your rig more efficient. Things like less rotating mass, better bearings, lighter grease on gears, etc, though you'll only notice significant gains with fast stuff, not so much with crawlers. Brushless motors are also more efficient than brushed motors, though they generally don't work as well for crawling (IMO)

[Reflection]

Originally Posted by tim the toolman

And also the way I understand it lipos can handle a higher current draw than a similar sized nimh battery. The higher the "c" rating the better they can flow current. Not that a crawler draws a lot of juice normally but say if you run a small lipo like 1100 or 1500 it should handle current draw better & last longer than a 1500 nimh battery. Maybe someone could explain it better than me or correct me if I'm wrong?:-P

Higher turn motors draw less. Check out the sticky at the top of this section....the one on batteries. Theres a ton of good reading in there that goes into detail on "C" ratings and what you will need.

For really high turn motors,like a 55t-65t...I'd say these would do pretty good....X-caliber 15C 2-cell It's only a 2 cell though. If your looking for a 3 cell,I'd look into Holmes Hobbies 25C 1300mah lipo. If you run a lower turn motor and taller gears,you'll be pulling allot more current,so you need a battery that'll deliver. I run pullers at 38:1 and I've got a heavy finger. These Poly RC 2200mah Lipos work awesome.

[MadForce]

I was also impressed by this LiPo paradox so I went and asked a physics prof I know about how this is possible. The short explanation is that lithium based batteries have an inherent attribute to restore their voltage after each pulse faster than nickel based batteries. Taking into account that escs' control current to the motors with pulses then it is understandable that LiPo can last longer than a NiMh of the same capacity. The guy that explained this used a series of sensors and pc loggers to record the data so I can understand the function of esc and battery. He also showed me data of a sample experiment with a 7.2 NiMh and a 7.4 LiPo of 1500MAh each both connected to a 6v light bulb (continuous current drawn). Both batteries lasted pretty much the same, though the LiPo maintained a longer period of higher voltage (brighter bulb). In this case both batteries supplied continuous current so voltage regeneration was of minimal importance.