For the Hyundai IONIQ 9
Know your battery, cell by cell.
NineWatt reads your IONIQ 9's high-voltage battery through an OBDLink MX+ adapter and shows what the car doesn't: state of health, every cell's voltage, temperatures, charging power and more, live on your iPhone or Android phone.
In beta now. Have an IONIQ 9 and an OBDLink MX+? Ask to join the beta.
Free to use. NineWatt Pro adds history and analytics for $9.99 a year.
Illustration
What it shows
Everything the battery management system knows.
The car shows a percentage and a range. The battery management system knows much more, and NineWatt reads it out for you.
Live dashboard
State of charge (as displayed and as the BMS sees it), energy left, live power with a 10-minute trace, voltage and current, charging time left, temperatures, the 12 V battery, the BMS power limits and the odometer.
Every cell
Each cell's voltage as a heatmap, a bar chart or a histogram, the spread between the highest and lowest cell, and the 16 temperature sensors spread through the pack.
Battery health
State of health, estimated usable capacity, equivalent full cycles, lifetime BMS counters, and plain-language checks of balance, temperature spread, the 12 V system and insulation resistance.
History Pro
Trends from six hours to all time, every charging session (AC or DC, kWh, peak and average kW) and every drive (distance, energy, regeneration, efficiency).
How it works
Plug in, pair, and look inside.
Plug in the adapter
NineWatt works with the OBDLink MX+ Bluetooth adapter, plugged into the car's OBD-II port.
Pair your phone
Pair the MX+ in your phone's Bluetooth settings: an iPhone or an Android phone both work.
Open NineWatt
Pick the adapter in the app. With the car on, live battery data appears within seconds.
Read-only. NineWatt only asks the car questions. Nothing it sends writes to or reconfigures the car. When the high-voltage system has been off for a few minutes, it goes quiet so the car can sleep and the 12 V battery isn't drained.
NineWatt Pro
Your battery's story, not just today.
The live dashboard, cells and health checks are free. NineWatt Pro keeps the history and turns it into something you can read, and gives you a say in what NineWatt does next.
Billed through the App Store or Google Play. Renews every year until you cancel in your App Store or Google Play subscription settings. Prices may differ by country.
Yearly subscription
$9.99 / year
- Trends of charge, power, temperatures, cell spread and the 12 V battery, from six hours to all time
- Charging sessions and drives: energy, peak and average power, regeneration, efficiency
- Long-term views: cells that run consistently low or high, and how state of health changes
- Export: your recorded history as a spreadsheet (CSV)
- Votes on feature requests: three to start, then one a month
Privacy
Your battery data stays on your phone.
There's no account to make, no advertising and no analytics. Readings and history are kept on the phone. Our server only keeps the feature requests and bug reports people send, an anonymous id for each installation, and the store's confirmation of Pro subscriptions. Read the privacy policy.
Questions
Good to know
Which adapter do I need?
The OBDLink MX+ from OBD Solutions. It connects over Bluetooth Classic, which NineWatt uses on both iPhone and Android. Other adapters aren't supported.
Does it work with other cars?
NineWatt is built for the Hyundai IONIQ 9. Its battery map comes from the E-GMP platform the IONIQ 9 shares with other Hyundai, Kia and Genesis models, but other cars are not supported and may show wrong values.
Can I leave the adapter plugged in?
NineWatt stops asking the car for data a few minutes after the high-voltage system turns off and then only checks the 12 V battery now and then, so the car can sleep. The adapter itself still draws a little power; see OBD Solutions' advice for leaving it plugged in.
Is it a diagnostic tool?
No. NineWatt shows what the car reports, decoded from community research, for your information. It can't diagnose faults or tell you a battery is safe. For anything that worries you, ask your Hyundai dealer.
How do I cancel NineWatt Pro?
In your App Store subscriptions (iPhone: Settings → your name → Subscriptions) or in Google Play (Profile → Payments & subscriptions → Subscriptions). Pro stays on until the end of the year you paid for. More help.