hey all!
i have project that include this component:
arduino uno
HC 05
L293D shield (not chip, shied for 4 motors)
water pump 12V 4.8W
i need help with choosing of battery for arduinmo
thanks!
How long does it have to run for?
its model. it need to work total maximum 3-4 hours
Duty cycle?
no, only on off
So you want to run a roughly 5.5W load for four hours?
4hrs gives 4x5.5 = 22watthours .
As it’s 12v that gives 22/12~ = 2amphours.
So a 12v 2Ah battery will do it , but I’d go for something bigger to give a bit of reserve , say 3Ah.
I'd suggest a 15-16V battery to actually be able to get 12V to the motor considering the losses of the L293D chip (which no doubt is present on your shield); a 4S LiPo would do, 14.8V nominal.
Add a buck converter with 5forV output for the Arduino in the mix.
12V 4.8W motor is 400 mA; add another 100 mA for everything else, that'd be 2,000 mAh. So a pack of four 2,600 mAh 18650 batteries would do.
You can save yourself a good amount of money by not using that ancient L293D but go for a more modern driver like the TB6621FNG - in that case just three LiPo cells will work just as well. Basically all the energy of the fourth cell is wasted by the L293D in the from of heat...