OBD2 in your car: fuel use and engine data, live and per ride

What you need

You need an OBD2 Bluetooth adapter in your car's diagnostic socket and the Android app. Pair the adapter in your phone's Bluetooth settings first. Then pick it in DriveBattle under Vehicles at "OBD adapter". One adapter belongs to one vehicle. The app asks for the Bluetooth permission and never scans for other devices. The feature exists for cars only, motorcycles get no OBD display.

Live in the Drive tab

In the "Drive" tab the "Car data" card shows the values while the adapter is connected. The defaults are rpm, current consumption, average consumption, range, coolant, engine load and battery. "Choose gauges" adds oil temperature, intake air, throttle and tank level. Which values you get depends on the car: when connecting, the app asks what your car reports. A missing or stale value shows a dash, never the last number. With imperial units the app shows mpg and °F.

How fuel use is worked out

If the engine control unit reports the fuel rate itself, the app takes that value. Otherwise it calculates from air mass, manifold pressure or engine load. Only the calculation from engine load is rough, and it carries the label "estimated". For this you enter fuel (petrol or diesel), tank size and engine displacement per vehicle. If fuel is set to "Unknown", the app does not guess petrol: it then measures only cars that report their fuel use directly. The consumption values have not yet been checked against real tank fill-ups.

Saved with every ride

While the adapter runs during a ride, the app saves the values about once per second next to the track and uploads them with the ride. Totals for fuel, idle time and idle fuel come with it. With the switch "Connect automatically when a drive starts" the app connects the adapter on its own. Recording runs for all users, also without Premium. A ride without an adapter looks the same as before.

Analysis per ride

In the summary of a ride with an adapter, the "Car data" card shows fuel used, cost, average consumption, maximum and average rpm, idle time, idle fuel, highest coolant temperature and highest engine load. Two curves for rpm and coolant come with it. The cost appears once you have entered a price per litre in the adapter setup, in your own currency without conversion. The comparison with your average in this car needs at least two other rides of 5 km or more, otherwise it is missing. The card also says on what percentage of the ride fuel use was measured. What was not measured is left out, a 0 never appears. This analysis is part of Premium.

Fuel map

The switch "Show consumption on the map" colours the route from frugal to thirsty. The basis is fuel flow divided by speed, in l/100 km. Below 5 km/h there is no value, and the app clips single outliers so a cold start does not wash out the scale. The colour is relative to the ride: green means frugal compared with the rest of this ride. The colour does not compare with other rides or cars. The switch appears from 10 measured values. By default the map keeps showing speed. The fuel map is part of Premium as well.

Warnings and limits

In the adapter setup the app warns about low battery voltage: below 12.0 V when standing (weak battery), below 13.0 V with the engine running (have the alternator checked). If an adapter shows signs of being a clone, a notice appears because its values may be unreliable. Vehicles with CAN-FD (roughly from 2019, many electric cars from 2023) cannot be read with ELM327 adapters. Some adapters draw current with the ignition off. If the car stands for more than 2 to 3 weeks, unplug the adapter.

Which adapter

The app talks to Bluetooth OBD2 adapters that speak the ELM327 protocol, over Bluetooth Low Energy and, if needed, classic Bluetooth. There is no list of tested brands. The connection has so far been tested against a simulated adapter, tests on a range of real adapters and cars are still open. The app rates a paired adapter as recommended, compatible or not recommended for permanent use. That rating rests on manufacturer data, not on our own measurements. If the connection fails, the app names the reason: Bluetooth off, permission missing, adapter not found, ignition off, or a device that does not answer like an OBD adapter.

Visible only to you

Only your account sees the OBD data of a ride. Crew, other users, GPX export, share cards and live sharing do not contain it, even if you share the route. It feeds neither XP nor leaderboards. You delete the vehicle data of a single ride, the ride and its route stay. The data export contains it.

In the car with Android Auto

The speedometer in Android Auto shows up to four of the values you chose on the phone. Warnings about coolant and battery move to the front, even if you did not choose that value. Without fresh data the speedometer goes back to the ride values. Android Auto is part of Premium.

What it costs

On the phone, the live display, recording, upload, deleting and data export are not Premium features. Premium is the analysis per ride: the "Car data" card, the curves and the fuel map. Without Premium you see a locked preview with sample figures on a ride with an adapter. Your data is saved all the same and is ready after an upgrade. The server checks this as well. Android Auto is part of Premium as a whole. During the beta everything is unlocked. After that Premium is paid, the purchase runs through Google Play and Google Play shows the price. This page describes the Android app.

Frequently asked questions

Does DriveBattle show my car's fuel use via OBD2?

Yes, with a Bluetooth OBD2 adapter in the diagnostic socket. The app shows current and average consumption live and saves fuel use with every ride. The feature exists for cars only.

Which OBD2 adapter works with DriveBattle?

You need a Bluetooth adapter that speaks the ELM327 protocol. There is no list of tested brands: the connection has so far been tested against a simulated adapter, tests on real adapters are still open.

Which values does the app show live?

Rpm, current and average consumption, range, coolant, engine load and battery, optionally also oil temperature, intake air, throttle and tank level. What appears depends on the car.

Is there a fuel map for my ride?

Yes. In the summary of a ride a switch colours the route from frugal to thirsty, relative to that ride. The fuel map is part of Premium.

Who sees my OBD data?

Only you. Crew, other users, GPX export, share cards and live sharing do not contain it. You can delete it per ride.

Is the OBD data part of Premium?

Recording and the live display on the phone are not. The analysis per ride with fuel, cost, curves and fuel map is part of Premium, and so is Android Auto as a whole.