# How can I connect many brushless motors to a big battery pack instead of using a separate small pack for each motor?

Usually brushless motors comes with indications on how many batteries you can connect to them, it is common to to see 2x3 battery packs where each battery provides 3.6 Volts or so to power a single brushless motor. However I fear things are not that simple when putting much more stuff in parallel.

Let's assume I have a battery with

• 9000 mah
• 210 grams weight
• rated 10C
• 3.7 Volts working
• 2.8 Volts discharge cutoff

If I want to operate a brusheless motor at 7.4 volts I have to put 2 batteries in series, then if the operating current for the motor is 10A, with a 15 A ESC connected to it, then the motor will run for about 54 minutes) in theory (in reality it would be less due to infinite factors).

However if I setup 10 brushless motors, each one with 2 batteries, every motor will run at most 54 minutes, but due to motors each running at slightly different powers, some motors will ends power sooner than others, and they will turn soon into extra useless weight for the drone.

If I want to share all the power across all motors to avoid some stuff turning suddendly into dead weight, I have to setup an array of batteries with 2 rows in series, and 10 in parallel (20 total batteries).. Is there any extra precaution to use compared to a regular parallel light bulbs?

The theory behind my question is that if I put motors in parallel and batteries in parallel, I can view motors as resistances, in ideal world each motor would absorb same amount of current, but motors do not have constant resitance, which makes me fear that under some conditions I could actually burn my motors or my batteries by providing much more more power putting so many batteries in parallel.

As long as I burn a single battery or a single motor it is fine, but If doing this is wrong I could actually burn a lot more motors and batteries: lot more money gone. That's why I'm asking to experts.

I have no degree so far in any electric-related stuff, I'm learning everything from internet so I'm sorry If I'm not asking the question in the best possible way.

• The question in your title is much different than the questions at the end of your text. What is it you are really asking? – Elliot Alderson Mar 10 at 13:09
• "Usually brushless motors comes with indications on how many batteries you can connect to them", um, no, that's not something I've seen on any motor description page / datasheet. Are you specifically talking about model engine motors, maybe? – Marcus Müller Mar 10 at 13:10
• When looking at some motors sale page they come with "suggested number of batteries". Like this motor shows a description with some different setups: (sorry for link if it is wrong just remove it) goo.gl/ZcRzaR – GameDeveloper Mar 10 at 13:14
• ah, ok, Aliexpress... really not the place I'd be shopping for electronics. Low prices, but no datasheets, and you're lucky when you get what you've ordered. So, anyways, I guess this is for a model plane project or something? – Marcus Müller Mar 10 at 13:25
• Battery packs should generally not be paralleled. The measures necessary to do so without an unacceptable increase in danger are far beyond the level of understanding shown in this post. You need to gain some experience with a normal drone used in a normal way before you try to do something unusual. – Chris Stratton Mar 10 at 15:28