Model Boat Mayhem

Technical, Techniques, Hints, and Tips => The "Black Arts!" ( Electrics & Electronics ) => Topic started by: guitar man on February 13, 2013, 10:17:16 pm

Title: Two motors one battery
Post by: guitar man on February 13, 2013, 10:17:16 pm
Hi all
Looking for some advice
I have just fitted a couple of drive motors into my new project ,each motor works fine individually on 6v but when they were connected up in series one motor is fine while the other is barely turning .Now the info which came with the motors say they can be wired in series or parallel. Now the motors are rated 6 to 12v,when using a 12v battery both seem fine this was just a quick test to run the motors together so no esc is fitted just a direct wiring to battery.Would I be better off
1.  wiring in parallel
2. having an independent battery for each motor (which I was hoping to avoid)
3. Why did the one motor go so slow

Kind Regards as always Tony
Title: Re: Two motors one battery
Post by: Vidion on February 13, 2013, 10:48:17 pm
im no electrician, but i can imagine that the first engine will draw most of the 6v away leaving to little for the second, hence the working on 12 v as both will draw 6 v then.
my guess would be thats its better to hook em up parralel
 
 
vidion
Title: Re: Two motors one battery
Post by: NFMike on February 14, 2013, 12:19:24 am
Connected in series each motor should in theory get half the supply voltage, which means if you series them on 6V they are only getting 3V each. This is well below their rating so they will be slow and in practice there will be differences between the two, even though they appear identical, which means one will run faster. The amount you describe does suggest there is a significant difference, but you don't say what sort of motors they are or if they are connected to physical loads.

If you want them to run at 6V then you will need them in parallel for a 6V battery and in series for 12V. But I don't recommend series connection, partly because you can get some odd effects as the motors affect one another, but more for the simple reason that if one fails to an open circuit the other will stop too, so you have an unnecessary single point of failure.
Title: Re: Two motors one battery
Post by: Spook on February 14, 2013, 02:03:35 am
^^^ What he said.


Run them in parrallel. Works for me on several models.
Title: Re: Two motors one battery
Post by: guitar man on February 14, 2013, 06:30:14 am
Hi all

Cheers guys :-)) a very interesting point about a motor fail, Oci  had not considered that, parallel it is then.

Thanks to all

Regards Tony