Building an arduino uno with 5019 motor shield and hc05 to drive two motors via Bluetooth. Maybe add a sound module (with speaker) and servo later. The issue I have is that I have tried to activate the motors with the sketch to see if they work, and neither led flashes or no current/ voltage seems to be passing through either motor terminal. They are 4741 polulo motors and everything is connected, it would seem, appropriately (I can connect to bluetooth, but the rc doesn't do anything, then I tried the demo sketch, still no motor runs. Batteries are four 18650s with 2000mAh in series, and I have built two of them and applied them in parallel. The voltage in measures 15.17 volts.
This is a sketch which has the Bluetooth and servo incorporated, unlike the demo which is motor only...
I have four 18650 s in series, they are 3.7v and 20amps each, and have built two like this and attached them into the motor Shields barrels.
Total voltage is 15.4 volts with approx 40amps when fully charged. I have attached them through a switch. I am unable to upload pictures I have taken as the space of upload is too little (2MB) the motorshield is the 5019 attached directly ontop of the rev3 uno. The hc05 connected to rx tx (in reverse obviuolsy) and the ground and voltage connected up too. I have used solder on the connections to make it more secure between the shield and uno, the multimeter shows the the input barrel has 15.18 volts currently, and the 5 v and 3.3, are at the required amount (4.9 and 2.9 volts) the rx and tx, both had readings too, so it would seem the board is OK.
This pic too...
The barrel I believe is set to only take up to 16 A. So I need to wire the two battaries in series and solder them on instead of using the barrels? Total voltage 32.8 and 20amps instead of 15.4 v and 40amps (reduced to 16 currently as the barrel accepts 16Amps max...)
jremington:
Please post a hand drawn wiring diagram, a link to the motor driver and state the characteristics of your motor power supply.
Those motors have a stall current of 5.5 Amperes, so you need a heavy duty, 5-10A/channel motor driver and a 12V/12A (144 Watt) power supply, minimum.
Total going into the barells? Or for each motor, so double that? Got the 5019 motor shield that can handle that have eight batteries in series to get 30 volts and although the batteries are rated 2000mAh,they claim to have 20Amp discharge rate. Am I right in thinking they are only actually 2amps?
JP1976:
Total going into the barells? Or for each motor, so double that? Got the 5019 motor shield that can handle that have eight batteries in series to get 30 volts and although the batteries are rated 2000mAh,they claim to have 20Amp discharge rate. Am I right in thinking they are only actually 2amps?
What are these barrels that you're talking about? I can't see anything that I'd call a barrel.
And 2000mAh = 2Ah. But Ah (amp.hour) is capacity NOT current. It is not directly related to the maximum current which is measured in A (Amperes) NOT Ah. If you have a specification that says max. current is 20A then that's quite possible.
The barrels are the blue things that the vin and ground use to supply current to the driver shield. The motors are connected on either side. The batteries I purchased are 18650 2000mAh, they say the max discharge is 20 amps, which would suggest that the eight I had in series covered the requirements of 24 v and required amperage, however I feel I may be wrong and I actually had 31 volts and 2 amps, the motors require 12 volts and stall at 5.5 amps. So do I require a total of 24 volts and 11 amps for them both, they won't be at load I imagine, far from it and the manufacturer suggests 25% below 5.5, so I assume 8amps would do.
To emphasise what jremington said, the motors are effectively in parallel. So if one of them needs 12V then two of them need the same voltage 12V.
In parallel voltage stays the same, current increases. So the requirements are 12V @11A. So you should be using 3 batteries in series (11.1V nominal) or maybe 4 in series (14.8V).
Also, the 11Amps.... The batteries state 20amp discharge rate, however are 2000mAh, 2000mAh suggests it would discharge at 2amps and hour, so how do I calculate that sir? Use 3 3000mAh batteries is series, and hook four of them up in parallel? Basically using 12 batteries?
NB. If I build four 2000mAh 18650 batteries in series with two of these attached in parallel, would that double the time between recharging? With 16 volts and 4000mAh or would it be safer to build three of these batteries in series then put two of them in parallel, for these motors to be powered more efficiently?
There are enormous differences between manufacturers.
I suggest to get your project running with a decent 12V power supply, before struggling with battery packs. You may have destroyed cells by soldering to them.
That info has been appreciated. I have got the motors running, the most and easy way to explain the pain I faced was from information I didn't find elsewhere in the Internet.
The simplest way to put this (very difficult without sounding rude or out of touch) is that the information with respect to the way the current is taken from the battery is effectively irrelevant.
If its got the voltage, it will dissipate anyway. That is, if it allows such a current draw, which the 20amp drain battery does. Infact I'd like to think it would struggle to stop the current draining at any amount albeit maybe to the detriment of the cell(s) involved
