RPM/Trim/Timing Chart

Following an interesting post on PriusChat, https://priuschat.com/threads/e85-3-gal-e10-7-gal.121314/#post-1730070
a new chart has been added to Hybrid Reporter: you can see efficiency at various RPMs, based on Ignition Timing and Fuel Trims.
Ignition Timing points can also be painted with the BSFC value achieved.
This can be useful when using different fuel types (LGP or E85).


Fan Probe

Fan Assistant keeps your HV battery within optimal temperature range. To achieve this, it's necessary to have a good reading of the cabin air temperature.
The inhaling temperature sensor of the HV battery needs air flowing through it to have a correct reading, so, every 5 minutes, Hybrid Assistant will turn on the fan at minimum speed to update its value.
You can disable this behavior using the Fan probe switch


New charts in Hybrid Reporter

The RPM Scatter chart shows RPM values while driving at a given speed.
Note that, given our eCVT transmission, there's no fixed relationship between engine speed and vehicle speed.

The Power Map chart has been revised to give more information: beside giving the power value for each RPM of the petrol engine with a dot proportional to data accuracy, it also plots collected values range and standard deviation.
This provides a more accurate view of the collected data.

The Average Power chart plots power required to keep a given speed.
This is total power, coming from the petrol engine and HV battery.
Values are collected only when a constant speed is maintained long enough to have a consistent reading, so a trip with many different speeds may not gather enough data to plot.
Since required energy is heavily influenced by road slope, you should drive on a plain road to have a correct reading.

The Instant BSFC/Fuel Consumption Chart combines fuel efficiency with burning efficiency, giving an unprecedented insight view of engine workings.
Instant fuel consumption value is drawn using the BSFC color scale.
You can now see how efficiently you are burning the fuel needed to achieve a specific mileage.
The best desirable condition is a short cyan bar.


Phone holder reviews

Correct phone placement is essential for safety on the road.
While testing Hybrid Assistant on various cars and phones, we gained some experience on phone holders also, so we are sharing some of our impressions.
All reviews can be accessed by using the tag phone holder.

Warning: we are not affiliated in any way with the manufacturer o reseller of the product. This is just a review based on personal experience.

Phone holder review: Spigen SGP11359

Stability: the adhesive pad under the holder keeps it firmly gripped to the dashboard

Supported Orientations: only landscape

Grip: soft grip, so side buttons won't be pushed accidentally.

Portability: according to the instruction, the adhesive gel can be removed and applied again. Even though I haven't tried, the whole procedure sure won't be quick to perform.

Tested cars: Auris MY17. By sticking it a little recessed from the wheel, I was able to align the screen with the panel instrument underneath the dashboard, achieving the same focal distance for both screens.
The phone screen is also reflected on the windshield, and while this is nearly invisible in daytime, at night it could be distracting.

Warning: we are not affiliated in any way with the manufacturer o reseller of the product. This is just a review based on personal experience.

Phone holder review: Celly OlimpiaXL

Stability: the airvent retention mechanism is spring loaded and have little hooks that provides a firm and stable mount.

Supported Orientations: portrait and landscape: the holder has a rotating gear with some fixed steps to choose from. Steps may be a little loose, so the phone may off by some degrees from the intended position

Grip: lateral pads have a soft grip, so side buttons won't be pushed accidentally.

Portability: the airvent retention mechanism takes some time to unlock, so porting to other cars is possible but unconvenient.

Tested cars: Yaris MY12, Auris MY17. On both cars, the holder rests on the bottom finish of the airvent, with a furniture scratching risk. A small adhesive pad was applied to prevent that.
Airvent mounting requires some orientation of the airvent fins that may compromise air flow.

Warning: we are not affiliated in any way with the manufacturer o reseller of the product. This is just a review based on personal experience.

Phone holder review: Anker

Stability: the airvent rubber grappling hook does not guarantee a stable position: while it won't detach itself, it may vibrate and change position while driving.

Supported Orientations: portrait and landscape: you have to rotate a gear to free the support, rotate and tighten it again.

Grip: strong spring, it can push side buttons

Portability: easy to remove, but every different car may require a different orientation of the support.

Tested cars: Yaris MY12 (OK), Auris MY17 (not OK). Support should be mounted on the first fin from the bottom, or else its own weight will cause the fin to bend downward. Airvents on the Auris have only one central fin, so secure grip is not possible.

Warning: we are not affiliated in any way with the manufacturer o reseller of the product. This is just a review based on personal experience.

Phone holder review: Tsumbay

Stability: firm and stable

Supported Orientations: landscape only

Grip: soft grip but strong pressure, so side buttons may be pushed accidentally.

Portability: the holder can be inserted and removed quickly from different cars.

Tested cars: Yaris MY12 (not OK), Auris MY17 (OK). Yaris dashboard is too thick and the holder can't be properly installed. Auris dashboard is within holder limits by a few millimeters.
Phone is close the steering wheel, thus making tapping easy, but putting the screen on a different eye focus plane that the other dashboard instruments. This can put a strain on the eyes while focusing on different car panels.

Warning: we are not affiliated in any way with the manufacturer o reseller of the product. This is just a review based on personal experience.


Fan Assistant

Introducing the new Fan Assistant

The Fan icon is now a 3-state toggle; every tap will rotate between:
OFF - fan controlled by the car
MANUAL - forced ventilation
AUTO - Hybrid Assistant will turn on or off according to temperature

The Fan Assistant can help you keep your HV battery in an optimal temperature range.
If the battery is too hot, the fan will spin to cool it down.
If the battery is cold, and the cabin temperature is hotter, the fan will spin to heat up the battery.
This feature is primarily meant to be used in really cold climate areas, where a pre-ignition heater is installed in the car.

Warning: the fan control feature is not approved or validated by Toyota. Hybrid Assistant and its development team can't be held responsible for any inconvenience that may related to its usage or misusage. Use it only with high quality OBD adapters and at your own risk.

High Precision Fuel Chart

The High Precision Fuel Chart has undergone a major restyling.

The new High Precision Fuel Chart combines fuel efficiency with burning efficiency, giving an unprecedented insight view of engine workings.

As always, the left vertical bar depicts L/100km instant value, but it's color is drawn using the BSFC color scale.
You can now see how efficiently you are burning the fuel needed to achieve a specific mileage.
The best desirable condition is a short cyan bar.


Brake Specific Fuel Consumption

"Brake specific fuel consumption (BSFC) is a measure of the fuel efficiency of any prime mover that burns fuel and produces rotational, or shaft, power. It is typically used for comparing the efficiency of internal combustion engines with a shaft output.
Commonly BSFC is expressed in units of grams per kilowatt-hour (g/(kW·h))."- Wikipedia

Hybrid Assistant shows BSFC in the Engine Power Meter using a color scale reflecting efficiency:
Cyan - Best efficiency range (220 g/kWh)
Yellow - High efficiency range (230 g/kWh)
Orange - Medium efficiency range (240 g/kWh)
Red - Low efficiency range (> 240 g/kWh)

Actual thresholds vary with engine type, according to official Toyota documents

Example chart from a Toyota Yaris


Engine Temperature Management

During the winter season, a classic trick is covering up the radiator grid, but this can be risky if you don't properly monitor the engine temperature.

You can use Hybrid Assistant, while driving, to check that the engine temperature stays within operating limits.
While this is usually not an issue in a urban environment, driving on the highway is not always considered safe.
Using Hybrid Reporter, you can check the engine behavior: here is a test of 20 kms at 130 km/h indicated speed.
The engine coolant temperature settles on a safe value of 90°C.
We can see that the electric engine temperature was raising, but its operating temperature is way higher that the petrol one, beeing able to work until about 160°C.
A higher trip may show if the trend will slow down and settle on a stable temperature.

Aggregated Trip Reports

It's now possible to aggregate trips is a single report in Hybrid Reporter.
Trips must be contiguous.
If you want to aggregate 3 trips, select the first trip in the trips list and press Generate Report

Then select "3" as number of aggregated trips

Not all charts are available in aggregation mode, but those based on aggregate data will have a greater precision


Engine Stage Assistant

If you are driving a 3rd generation HSD car, like Auris, Yaris, or Prius 3, you can take advantage of the Engine Stage Assistant.
On screen indicators will help you perform a better S1 and to correctly switch to S4

Enable subtitles on the following videos to read instructions.




Introducing the Engine Stage Assistant

The new release of Hybrid Assistant, for selected car models (Yaris, Auris, Prius3), will advise you about the engine stages. 
At car power-on, a "Play" icon will appear on the engine icon if the engine needs to be warmed up and will start in a few moments. 
You can prevent it by switching to N or selecting EV mode. 

When the right conditions for an idle check are met, a "Pause" icon will show up. 
If you begin to coast, the engine will perform the idle check and will switch to stage S4.


"HA Tips" - a video serie for HA users

With the help of an appassionate user, Robikinkela, from Hybrid Synergy Forum, the team is developing a serie of short videos with the goal to help the new user of HA to learn the application features.
The videos will be periodically published on the YouTube channel of Hybrid Assistant. A new video shall be broadcasted once per week.

The first video, an introduction to Hybrid Assistant, is ready for You on YouTube: "Using the App"

Subscribe to the Hybrid Assistant YouTube channel and stay tuned for new "HA Tips"


A new member joins our Team

The Hybrid Assistant team is growing: Davide Vitali is joining our team.
Davide is an experienced Android developer, with a long list of released apps.
Check his page at @Appsbydavidev.dev or at http://dev.appsbydavidev.it/
The new version of Hybrid Assistant already features his contributions:
- crash dump reporting: if an error occours, HA will ask for permission to send a dump to the developers
- new settings menu
- new settings page
- multilanguage translation (English, Italian, French, German, Spanish)
Other minor enhancements include:
- accelerator position is now displayed
- accelerator color is based on CHG/ECO/POWER meter
- fix for false readings on Prius Prime
- support for Toyota Highlander
- better detection of ICE spinning


LGP tweaking

A creative user from Hybrid Synergy Forum has found a way to use Hybrid Assistant for checking an LGP modified engine that was behaving erratically.
Using the fuel trim chart he helped the tech support to correct settings of the engine LGP control unit.

Full story is available here:

By his suggestion, the new version of Hybrid Reporter now charts fuel trim corrections for each RPM range of the engine.

Here is the map of the misbehaving engine, with very high trims at high RPMs

After tweaking, the trims are back to lower values


LGP fuel quality evaluation

Joshue Martín de Blas, a long time friend of Hybrid Assistant, has put to good use the Fuel Trim charts of Hybrid Reporter.
In his own words:

These 2 Fuel trims graphics are of the same trip, but with different LPG brand. It's clear that in one case the effective Fuel Trim is bigger (and the fuel consumption higher also), because the ECU needs to make much more corrections tho the injection time.

some more information on fuel trims may be found here:
and here:


HV Battery Capacity Estimate

During an HV Check, an estimate of the battery capacity is also shown on screen.
All models (except Prius Plus and Prius Plugin) have a nominal 6.5 Ah battery capacity.
To evaluate capacity follow these guidelines:
1) be sure to have at least 60% SOC, engine and battery at operating temperatures (i.e. not too low or too high)
2) park the car
3) start A/C at the lowest temperature, to put some load on the battery
4) be sure the petrol engine is not running and have completed S1 phase
4) start HV Check
5) keep the check running until actual SOC is at least 10% less than the starting SOC

The Estimated Capacity will change color when enough data will be collected.

The same information is present on the report from Hybrid Reporter

New Release

  • Capacity estimate in HV Check
  • Fix for trip data missing during HV Check
  • Changed SOC red color at 42% 

  • Fuel chart with km breakdown
  • Battery capacity estimate
  • Fix for empty fuel chart 

Fuel usage over distance

The Fuel usage over distance chart plots consumption on a distance scale.
The green line shows overall fuel usage starting from the beginning of the trip, while the red histogram depicts local fuel consumptionin every single kilometer of the trip


New Release

  • HV battery temperatore now shows when fuel chart is displayed
  • Fix for inverter and MG temperatures for Prius 2 and RX400h 

  • Increased line thickness in several charts
  • Fixed filled polyline baseline
  • Lowered sample count for plotting average kw/speed 


New Release

New release for Hybrid Assistant and Hybrid Reporter

  • The HV Check screen now shows more info about the ongoing test
  • The EV stats panel now shows EV % while moving or total
  • Brake evaluation for Lexus IS300h is now more accurate
  • Fix for inverter temperature lower bound
  • SOC chart
  • HV Temperature chart
  • HV Delta chart
  • Fix for empty fuel charts
  • EV in motion
  • Option for full VIN display
  • Average speed over total trip
  • Average EV speed
  • BSFC color scale


Voltage Delta Chart

The Voltage Delta chart plots voltage differences between blocks.
The bottom area plots delta value between maximum and minimum values.
Min, Max and average values are also plotted.
If the average value is not roughly halfway between min and max, we may have a block balancing issue.

HV Battery Temperature Chart

The HV Battery Temperature chart plots temperature sensors values during an HV Check.
Common thresholds (fan and EV disable) are also shown, along with current.

Block Values Chart

The Block values chart plots individual battery block voltage values.
SOC % level is also shown


New Release

New versions for Hybrid Assistant and Hybrid Reporter


  • HA can now use miles, gallons and farheneit temperature
  • Accelerator pedal readings for Prius 4 and C-HR
  • Display of time while moving or total trip time
  • Added option for complete reset in settings screen
  • Status bar is now black
  • Fix for size of AVG/INST labels


  • HR can now display miles, gallons and farheneit temperature
  • Odometer
  • Time in motion
  • CCL and DCL chart
  • Fix for HV fitness min/max error


Time in motion

The EV summary panel can now display trip time as total time or just time spent while the car is actually moving.
You can tap the panel to switch between the two information.


You can reset all options back to default with the "Reset All" button.
Note that this will also delete all trips data from the database used by Hybrid Reporter.
Settings will be reset as soon as you restart Hybrid Assistant.

Overseas rejoice

Overseas rejoice! Hybrid Assistant now can display miles and gallons: you can set them in the settings screen