How to Use Autel AP200 to Read Battery Capacity?

How-to: read vehicle battery capacity using cheap Autel MaxiAP AP200 obd2 scanner.


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One of the most important, expensive, and worrisome components of any electric vehicle is the high-voltage battery that propels the vehicle. These batteries, although designed for long life, will deteriorate over time and affect vehicle range performance. All manufacturers are required to provide a warranty for the HV batteries. For example, Honda Clarity HV battery warranty is 8 years, 100K miles in most states. It increases to 10 years, 150K miles if your vehice is registered and normally operated in some states.

In the case of the Clarity, the specifics of the HV battery warranty are based on a capacity measurement of the battery expressed in ampere-hours (Ah). This warranty is spelled out in the pre-delivery checklist (17-093) that is supposed to be provided to all new owners.

The nominal battery capacity for a new vehicle is 55 Ah, and Honda defines the eligibility for warranty replacement as being 2/3 of the nominal capacity, or 36.6 Ah.

It is not industry practice to make an electrified vehicle’s battery capacity readily available to owners and Honda followed that practice. Instead, Honda intended this readout to be available only to dealer service personnel, believing they would be better able to interpret that value. Honda equips dealer service departments with a Honda-specific system called “i-HDS,” which can extract the battery capacity value along with much other diagnostic information.

Unfortunately, some Honda dealers do not have extensive experience servicing the Honda Clarity Plug-In Hybrid and do not know about the battery capacity. In this case, presenting the service adviser with a copy of this PDI page will help them understand the Clarity PHEV’s battery capacity and how to read it.

In addition, many dealers charge a fee to read the battery capacity (unless you happen to be there for other service anyway, and you are nice to them).

However, even if your dealer is willing to provide the battery capacity of your Clarity PHEV for free, it would be much more convenient if you could read this value yourself whenever you choose to do so, and this repository will provide several means to obtain this measurement yourself.

Accessing the Battery Capacity Yourself

HV Battery Capacity is accessed through the OBDII connector which is located under the dashboard above your left leg. This is the same connector that allows access to the vehicle computer systems for diagnostic testing as well as emissions inspections. The OBDII connector contains provisions to access the vehicle’s Controller Area Network (CAN) bus.

This repository identifies 3 ways to read the HV Battery Capacity from the Honda Clarity PHEV

Option 1 – The Autel AP200, with MaxAP200 App (and pre-authorized V2.01.54 Beta version of Honda Diagnostics)
Option 2 – A Proven ‘good’ ELM327 OBDII adapter with the Car Scanner App
Option 3 – A Proven ‘good’ ELM327 OBDII adapter with a PC or Laptop, generating a formatted report

Which should I use ?

  • If you are an avid do-it-yourselfer, you my want to consider Option 1 because the Autel device provides a LOT of diagnostic information about all of the vehicle systems (not just the Electric Powertrain which contains the Battery Capacity)

    • Requires special request to Autel to authorize 2.01.54 Beta version of Honda diagnostics
    • Autel is sometimes not as responsive as we would like
  • If you are a beginner and not so technically inclined, then Option 2 is recommended, and is easy enough that almost anyone can be successful with it.

  • Once you are configured for Option 2, then you can also try Option 3 if you would like nicely formatted reports

  • Many have both the AP200 and ELM327 setups because really the costs are very low

How to Read Battery Capacity with Autel AP200?

What do you need for this approach:

1. Autel AP200 OBD2 Adapter (Cost around $60)
IMPORTANT – There are newer variants of Autel OBDII adapters. For a variety of reasons, you want the original AP200. The variants that we do NOT recommend have a letter after the name – for instance, the AP200H, AP200C, AP200M.
2. Android phone (Must be a 64-bit version of Android)
3. Internet connectivity
Autel Ap200 Opel Review 1
Necessary Firmware Authorization:
 The AP200 production diagnostic code does NOT support the Clarity Electric Powertrain functionality. In order to access the required Beta code (2.01.54) you must request access to the Beta code from Autel.
To do this, obtain your AP200 first (you will need it’s serial number), and send an email to Autel technical support. Here is a suggested template
Send to- 
Subject – Honda Beta 2.01.54 
Access Message – Please authorize my AP200 (S/N CAP2xxxxxxxx) for use with the Honda 2.01.54 Beta diagnostics. 
Vincent Liu has been their support person who worked with us from the beginning. They are supporting InsideEVs forum members as a courtesy in lieu of officially releasing this function in their released versions. Please be patient as they are busy with all their other priorities.
Procedure to use:
From the Google Play Store, install the program called Autel MaxiAP200 on your phone. When you run the application, it will require you to log in to Autel.
If you do not currently have an account, then use the “Register” function to create one (this is a free account, but you must have a login to us the AP200).
Once you are registered, then login to the account.
You will see a screen like this:
Autel Ap200 Read Battery Capacity 1
Select Diagnostics.
The Autel AP200 scanner allows you unlimited free access to one vehicle manufacturer. You will want to add Honda as your free vehicle. Use the “+” and browse to Honda and add it. If your request for the Beta code has been processed, you will see v2.01.54 as the version to download. Select ‘Download’ to install it. If you see a different version, it is because your Beta request is not active. You can proceed and download / install the production version that is shown if you want. It will give you access to many functions, but not the Electric Powertrain needed for battery capacity. When the Beta code is authorized, it will be offered as an update.
During the install, you will get a message that says:
“Secondary App is needed for normal diagnosis.
Please go to GooglePlay to download the APP:DiagAsia.”
Select OK, then Install to obtain ‘Diag-Asia’ too.
Now, back at the Diagnostics screen, you should be able to Download the Honda diagnostics. You will also see two other diagnostics entries (“Eobd”, and “Demo”).
You can download and install those too, as they give you even more free generic functionality.
When you are done, you should see something like this:
Autel Ap200 Read Battery Capacity 2
At this point, you are ready to connect the AP200 to the vehicle and obtain the Battery Capacity information from the Electric Powertrain. Connect the AP200 to the OBDII connector and “start” the vehicle (remember to depress the brake when starting)
Now, you can select “Honda” on the diagnostics screen. It will tell you to connect the “VCI” (this is the AP200). It should see your AP200 and allow you to pair with it.
Here is what the screen will look like when pairing is complete:
Autel Ap200 Read Battery Capacity 3
You will then see a screen allowing you to “Select Diagnostic Type”. Choose “System Selection”, then “USA”. It should report your vehicle information (including your VIN number). Select “YES” at the bottom of the screen. Select “Control Unit” and you will have a list of all the various vehicle subsystems. You want to select the “Electric Powertrain”. It takes a while to communicate with the vehicle, and once it is done, you can select “Live Data”. Now you should have a screen with a LOT of parameters shown. There is a lot to digest here, but at the bottom of the 1st sreen you will find the Battery Capacity. Here is an example:
Autel Ap200 Read Battery Capacity 4
The best thing to do now is to do a “Save”. It will create a comprehensive nicely formatted .pdf file with ALL of the Electric Powertrain data. If you then use the “PDF Preview” button, it will show this on the screen and you can sent it / email it to yourself.
Here is an example of the PDF preview:
Autel Ap200 Read Battery Capacity 5
Note: This is not intended to be a tutorial on how to fully utilize the Autel A200. It has a lot of capabilities that are more geared to the serious DIY user. You can explore all of the various features available on your own.