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Berg axles 2 motors and yes you need a bigger battery than what you normally use!!!

When you say a small pack, what is a small pack ?

I thought mah= run time, the bigger mah the longer run time you will get.
The C and burst rate is what I though a person should be looking at?


Yes mAh = runtime but in general the more capacity in a pack the higher the amp draw is that the pack can handle then you add in a higher c rating and that same pack can handle more amps.


Jason
 
Guys for any of you that do this enough I would highly suggest you invest in a Data logger. It's a great tool when it comes to doing motor set-ups and gearing changes. The Eagle Tree Micro Data logger costs about 70 bucks and with a computer you have one of the best tools out there to help with setting your rigs power system up.

Jason
 
You guys have this. Did not see on the site, just wondering if i've overlooked it:?:


Guys for any of you that do this enough I would highly suggest you invest in a Data logger. It's a great tool when it comes to doing motor set-ups and gearing changes. The Eagle Tree Micro Data logger costs about 70 bucks and with a computer you have one of the best tools out there to help with setting your rigs power system up.

Jason
 
Guys with the bergs the days of small packs mounted on the front axles is over they simply in most cases will require larger packs for the power consumption they have.

Jason

I have ran anywhere from a 2s 20c 700 Mah to a 3s 1100 in my clods and have never once had any problem with 45t motors. I only use 100-200mah per course and can usually run get around 1hr runtime(if not more). But as JRH stated, it has alot to do with terrain and driver.
 
When you say a small pack, what is a small pack ?

I thought mah= run time, the bigger mah the longer run time you will get.
The C and burst rate is what I though a person should be looking at?
MAH= How much current can be drawn for 1 hour. ie a 4500 mah battery can sustain 4.5 amps for 1 hour. this is assuming the formula is in theory or in real world conditions. I know that i can run on the rocks in my back yard for several hours w/two 4500's and two 65t motors. As far as C and burst rate,I am ignorant. I still refuse to shell out the obscene amount of money reqiured for lipo.
 
MAH= How much current can be drawn for 1 hour. ie a 4500 mah battery can sustain 4.5 amps for 1 hour. this is assuming the formula is in theory or in real world conditions. I know that i can run on the rocks in my back yard for several hours w/two 4500's and two 65t motors. As far as C and burst rate,I am ignorant. I still refuse to shell out the obscene amount of money reqiured for lipo.

Kinda apples to oranges don't you think?

We are using batts that fit in limited spaces. You on the other hand are running 2 fullsize packs. There is no way any of us could fit 1, much less 2 fullsize packs on our Bergs.

If you wanted to have a comp worthy crawler, you would have to ditch those fullsize packs. You are also running your run of the mill lathe motors where we are running 35-45 turn handwounds. Plus you are trying to run for hours, we are trying to get through a 5 min course w/o grenading a battery.

Basically, what you run on your basher has no bearing whatsoever on what we are trying to accomplish.
 
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Wouldn't "Clod Stall" be a factor in this equation?

Great point, I wonder the effect of clod stall on amps needed.

How could one test amps being pulled? I'm not about to sped $50-$100 for a data logger to tell me amp draw. There must be another method.
 
Data logger is the way to go.


What would the test be, two motor shafty vs clod? I have logged my Berg many times, what do you want to know?
 
45t I haven't tried, I generally run either 35t, 55t, or cobalt pullers. Guessing from experience 45s on 3s lipo won't need over 50 amps in a Berg. Just one 45t motor will generally burst around 30 amps on 3s lipo, but it really depends on the driver and terrain. If you wedge a tire and keep giving it throttle there really is no limit to the amp draw, I have watched a piddly 55t integy draw over 500 amps on a good sub C pack before smoking. That was a locked rotor with battery plugged straight into the motor and it took about 2 seconds to reach critical temp.

Really there is no clear cut answer, only best estimates with rough driving in mind and some data logs to back it up. Data loggers are most useful for finding dud packs and cheap lipos really. Voltage under load is what really matters, and a cell that isn't up for the task at hand will fall in voltage. It doesn't matter if it is undersized or overrated from the factory- voltage under load tells all.
 
Just up the Voltage, higher voltage=lower amps. So a 4s pack of 1500 mah would work better than a 2s pack of 1500mah. Correct?
 
Yes- On a fast buggy or plane, when you reduce gearing to keep prop speed or wheelspeed constant.


In a crawler when you increase the voltage you increase the amperage upon stall. The higher the voltage, the higher the stall amps and power you get.
 
Kinda apples to oranges don't you think?

We are using batts that fit in limited spaces. You on the other hand are running 2 fullsize packs. There is no way any of us could fit 1, much less 2 fullsize packs on our Bergs.

If you wanted to have a comp worthy crawler, you would have to ditch those fullsize packs. You are also running your run of the mill lathe motors where we are running 35-45 turn handwounds. Plus you are trying to run for hours, we are trying to get through a 5 min course w/o grenading a battery.

Basically, what you run on your basher has no bearing whatsoever on what we are trying to accomplish.
Is there a useful or valid point to yer quote? Mine was to clarify that MAH does not translate DIRECTLY to run time due to many factors in the equation. My "run of the mill motors" are hand wound and my rig is not COMP WORTHY due to the fact that in my part of the world, everyone is running 2.2. I made the mistake of building a super before researching what was neeeded to compete in my area. So, now I must build a 2.2"thumbsup". Star or no star, the input of your reply is useless...
 
Thanks for this thread. I too was thinking about running a small li-po. I see no need now to mess around with a li-po that might not be up to the task. You literally don't want to get burned here. Why would you spend a grand or more and then chance it going up in smoke to save 30.00$ on a battery? Weight savings and size are an answer, but not good enough to chance fire or injury to yourself or someone else. I just picked up a TP 2200 3cell with 25c cont./50c burst ratings. Even if it is a little overrated I should be fine. Happiness is an empty chassis, I don't know if I will ever see happiness...but I don't wanna burn.
 
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