Lets talk about batteries

[psycho]

Hi!
I am fairly new to the hobby. I got some nitro cars but what got me hooked to the electrics is my Mamba 8000 18T. It kicks a lot of nitro cars.
I understand that voltage is a measure of power(charge gradient), and amperage is a measure of current(quantity of energy flow).
I do notice that when I run the 3300 batteries on my Ezilla it surely run quicker and faster(also longer time) compared with the 2000 batteries. Now that I plan to run it brushles and lipo(I expect it will not hold for long), I got a question.
A 5s 4000mah would be also quicker and faster than a 5s 2000mah lipo in the same way as the Nimh? Or only the run time will be longer? What lipo set up would be better?
A single 5s 4000mah or 2 5s 2000 in parallel?
Thanks:devil

[squeeforever]

well i would think a single 5s but i think you would run into problems mounting it so 2 in parallel would be better but remember that would be a pretty big pack and would be hard to mount either way. i would go with a 2s and 3s or 2 3s or 2 2s. just make sure that the C rating (capable amp draw) is high enough.

[MetalMan]

Originally posted by psycho

I do notice that when I run the 3300 batteries on my Ezilla it surely run quicker and faster(also longer time) compared with the 2000 batteries. Now that I plan to run it brushles and lipo(I expect it will not hold for long), I got a question.
A 5s 4000mah would be also quicker and faster than a 5s 2000mah lipo in the same way as the Nimh? Or only the run time will be longer? What lipo set up would be better?
A single 5s 4000mah or 2 5s 2000 in parallel?
Thanks:devil

The difference in capacity does relate to run time, but it also does relate to the voltage. A 4000mah battery that is rated at 40amps will be able to put out twice the current as a 2000mah 20amp rated battery. The 4000mah pack will be able to put out twice the power as the 2000mah pack.

Voltage comes into play here also. When a battery has a larger load on it, its voltage will drop more. Let's say a battery drops 0.01v with a 10amp load. At a 30amp load, it would drop 0.05v (for example). So, the 2000mah pack would have twice the voltage drop of the 4000mah pack on the same load. With Lipos, you want a pack that can handle your motor setup, since each Lipo cell should not drop below 3volts (they are 3.7v nominal). For a vehicle like an E-Maxx, the 5s 4000mah pack would be better. For a 1/10 stadium truck with a slow motor (to account for the high voltage), a 5s 3000mah would be better.

These things are rather complicated. You can't just take the capacity and say that it will work (I only did as an example). A battery will be able to handle a certain number of amps for a certain period of time (or until it hits its cutoff voltage). If you know the number of amps that the battery can handle, then you can take that number and divide the capacity by it. For example, if a 3000mah battery can handle 40 amps continuously (unti it hits its cutoff voltage), then 40amps / 3Ah (capacity) = 13.3C. This "C" stands for capacity in amp hours, and is multiplied by the packs capacity to find out the amp draw.

How's this for battery talk? :)

[makana59]

more information then my brain can handle... lol excellent info though.

[psycho]

As stated before, I am fairly new to the hobby and even newer to the electric part. Will do a search for better understanding of the electricity, batteries and motor principles.
Thanks:devil