I'm doing research on a remote control model ship. I have 11.1V LiPo batteries, but because of their weight and duration, larger batteries are considered better in this application (these batteries come were originally for RC airplanes, where lightness is key.)
My battery would go to an ESC, then to an electric motor. I have read that true, non-nominal voltages of LiPo batteries are higher, somewhere closer to 12.6V at peak. Because a 12V battery rating is also nominal, I understand it might be necessary to use a resistor or some other means of reducing voltage, but I do not really know much about how current flows, charge rating, cell count, etc.
The ESC being powered would be something like this, rated at 40A, and there would be a motor like this on the end, rated for 2s to 4s batteries. I'm assuming these ratings are just to guide people using standard material. Also, I actually have two ESCs and motors, but they are both plugged through the same receiver.
This would be the normal max power, from what I understand from this article:
power = voltage * current
480W = 11.1V battery * 40A ESC
Using this lawnmower battery for example, this would be the max power output (I think?):
420W = 12V battery * 35A battery rating
There could be something terribly wrong with this calculation, but it does look like it would work, while supplying a little less wattage, but likely allow a longer use period. Note that I used the amp rating of the battery for the second calculation, since it's lower than the ESC's max tolerance. Again, I could be mistaken. I've heard scary things about the power of 12V car batteries to solder metals together.
So I'm wondering, what arrangement would be needed to power such a system through something like a 12V lawn mower battery? Is that possible, or will this fry my ESCs, motors, and receiver?
Best Answer
The output voltage from a standard Li-Ion or Lipo battery pack with (3) cells in series (3S) ranges from about 12.6 Vdc (freshly charged) down to about 9.0 Vdc (end of life cutoff-voltage).
A standard 12V Lead-Acid battery ranges from about 14.5 Vdc (freshly charged) down to about 11.0 Vdc (end of life cutoff-voltage.
Best to check the datasheet for the device(s) that you are powering. However, my past experience says that you can safely substitute a 12V Lead-Acid in place of a 3S Li-Ion or Lipo battery pack.
[Edit] One thing to consider that Li-Ion or Lipo batteries have FAR greater energy storage as compared to a Lead-Acid battery of similar size or weight. Lead-Acid batteries are significantly less expensive than Lithium technology. That is one of the few advantages that Lead-Acid batteries have compared to Lithium-type batteries.