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Intelligent Battery Power System Design

Sep 27, 2015
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Originally Posted Here
DJI Forum|Intelligent Battery Power System Design

In a previous post, I discussed how our intelligent batteries work and how they differ from traditional batteries. Dynamic power management is one key traits of intelligent batteries that makes them suitable for use with UAVs. As such, this post will talk about the basic design of intelligent battery’s power management system.
Below is a diagram detailing how power runs through an intelligent battery:


Power Outlet:
Alternating current (AC) house hold power has a voltage of 220V and a frequency of 50Hz in Shenzhen, China (where DJI HQ is located),though the exact numbers differ in different parts of the world. However, we cannot charge the battery by using 220V AC directly, so we need to adjust the power and then charge battery. So we need an…


You probably know the adapter as the “big black box”on your power adapter, as pictured above. A adapter takes the AC current from your house’s power supply and converts it to an appropriate DC current.

For example, the Inspire 1’s battery needs a 26.3V DC to charge. 26.3V DC will be output by the power adapter after the AC current runs through the copper coils of the transformer. A few other parts called the rectifier, filter and regulator make sure your signal comes out polarized and evenly.

Now that the charger outputs the correct voltage, we can charge the battery directly. But to gain intelligence, we can install a relay to control when to charge the battery and when not to charge it. Take a look at the diagram below:
Simply put, it is controls when to charge and discharge the battery.
Load Management:
Apart from the power adapter’s relay, the battery contains a number of other “load modules” that control the flow of electricity. The most basic load is the motor. In a circuit, several load devices are employed, such as resistors, inductors, capacitors, and detection sensors.
Battery Controller Chip:
The controller chip is the brain of the intelligent battery’s power management system. The controller can detect the voltage of a lithium battery and then manage the battery’s charging and discharging by controlling a relay switch. It has several basic functions:
1. It can control the battery to charge or discharge by controlling the relay.
2. It can detect the battery voltage, current, remaining power level and other parameters in real-time when the battery is powered on.
3. It can wirelessly transmit battery information to the ground system and receive the instructions from the ground system.

Some intelligent batteries have other functions, such as temperature detection protection, energy calculation, battery storage data,charging algorithms and over current circuit protection. Since battery technology is always improving, more and more control chip functions will be developed and implemented.
Wireless Data Transmission Module:
When power system information is collected by the control chip, a battery data signal will be transmitted to the aircraft and then to the RC through the wireless transmission module in the aircraft
RC will also send some instructions to the controller chip and adjust the battery discharging by controlling the relay switch, which can detect and control the aircraft in real-time.
The wireless transmission module can transmit data through the antenna. Below is a picture of the Phantom 2’s antenna:

The battery is placed in the battery socket on the aircraft. The two smaller pins on the left are used to transmit data. Two flat ports on the right are positive and negative pins used to charge the battery.

We can see two yellowish brown cables in the figure,which come from the battery’s signal port and transmit data signals to the circuit board directly

Finally, data can be transmitted to the RC by the signal antenna.

In this last section, for comparison, let’s talk about atraditional lithium battery.
The battery has multiple cells, but cables are connected to the port of each cell individually. It is not intelligent!

When the battery is charging, the charger displays the charging conditions, including voltage, amperage and charging time

Also,the voltage meter needs to be used to prevent the battery from over discharging.

Intelligent batteries have lots of powerful functionality, and I believe they will become cheaper and more powerful over time. Let’s look forward to more progress!
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Reactions: Marketal
Aug 7, 2013
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@Aeoutsider - I am curious, nearly every single one of your posts is nothing more than a link to the DJI Forum.
Why do you keep doing this?
If people wanted to see what was on that forum they can simply visit it (as a guest or member).
People come to this forum for a reason and make conscious desicision to pick this community over the DJI one (or maybe read both). If they want to read DJI content they can simply visit that site!

Occasionally a topic is worth discussing with a pertinent link elsewhere but to constantly do nothing more than copy and paste a thread and a link to the DJI site is pointless.
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Reactions: philip.delandtsheer
Mar 20, 2014
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Boston, MA
I think he may be a DJI engineer who would love to post socially but is restricted to only pre-reviewed and approved posts and info.

Just guessing tho...
Dec 18, 2015
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I think he may be a DJI engineer who would love to post socially but is restricted to only pre-reviewed and approved posts and info.

Just guessing tho...

Yep, that would be my guess.

I don't particularly mind the post either -- in fact, I found it quite interesting.

  • Like
Reactions: Phatzo

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