32
Generation II Toyota Prius
311,000 miles
Is there really anything wrong
with it?
Predictive Maintenance
What is Predictive Maintenance?
It is the measurement of the high voltage propulsion system
allowing you to do long term tracking (Trending) and state of health
(SOH) to statistically measure and document the performance of
the high voltage system. PM can also provide short term SOH
analysis or analyses/diagnosis.
Predictive Maintenance
What is Trending?
Trending is a method by which data is acquired from high voltage
system components on a Annual/Biannual or Triennial intervals to
determine the SOH by comparing the test results to previous test
data.
Predictive Maintenance
Trending high voltage components is similar analyzing the state of health (SOH)
of an internal combustion engine (ICE) by:
• Performing a compression test, cylinder leak down, engine vacuum tests,
ignition test, and fuel system tests.
• Trending an engine and sub-systems can determine the overall mechanical
health of the vehicle being tested.
• This identifies any system or subsystem deterioration or rate of
deterioration.
Predictive Maintenance
Short Term State of Health
• Predictive Maintenance can be utilized for determining the high
voltage system state of health to benchmark the system
components and or component performance.
• Predictive maintenance can (and should) be used in conjunction
with OEM diagnostics before replacing a high cost component
What Components are Tested?
• Electric Machines (MG1/MG2)
• Drive Motor
• Generator
• Electric A/C Compressor
• Power invertor and control system
• Energy Storage System (HV Battery)
• DC-DC Convertor
• High Voltage Cables
Who can use Predictive Maintenance?
• “Out of Warranty” Owners
• “ In Warranty” Owners
• Fleet Customers
• Used Car Dealers
• Sub-Contracting from OEM dealers
• Salvage industry
• Collision Repair /Insurance industry
Battery Limiting and Energy Capacity Pack Power Drive Test (Five Cycles)
Battery Pack Power Limiting and energy Capacity Test (on-car)
Compare your results with these percentages SOC%:
Less than 5%outstanding
Less than 10% could be serviced (talk about this)
Less than 15% evaluate – service
Less than 20% evaluate – service
Always compare pre-SOC ______to post SOC ________
Compare V-Block high _____to V-Block low _______
Battery SOC should never fall below 13 volts
SOC% - State of Charge percentage
Always make sure that the Disconnect is removed !
Always use the proper protective equipment!
Check voltages with a CAT III DVOM.
Before jumping straight to
the battery, always spend
the extra moments to do an
inverter test!
Here we are using a Pico
Tool and Fluke clamps!
After removing the interior
pieces, we discover the
Main Battery Pack
Gloves required beyond
this point!
Make sure to use caution while
removing the cooling duct work
as these are vital components to
pack cooling.
Finally we have made it to the
electrical components!
Removing the series of
protective covers
With the connecting
bars and sensors
removed the cells are
exposed!
No Gloves required while
connecting the test leads!
Take care to make sure
no leads are crossed
First off - the Power Test!!! Well-this doesn’t look good!!!
On to the Energy Test!!!
Test leads connected.
This is a 6.5 Amp Hour pack
– all modules are drawing
down to 12 volts
Time to start cooking, but first
we must discharge the cells!!
It is vital to keep a close eye
on the battery temps through
out these processes as to
not cause a thermal incident!!
Three phase charging:
2.5 amps for 2 hours
1.5 amps for 1 hour
1 amp for 1 hour
Cooling is essential during this time.
Max temp should never exceed 50 degrees
Celsius.
After the cycling of the pack it
is wise to redo the Power and
Energy test!!
That looks much
better, all modules
are balanced!!
Now that all the cells are balanced
and everything checks out well its time
to reinstall the battery and get ready to
take it for a spin!!!
Putting things back
together!!!
Time for the
horrible gloves
again!!
Getting everything bolted
back down!!
Don’t forget all the electronic
plugs, before reinstalling the
interior panels!!
This car was in great shape for the miles
but after the Refresh we increased the
mileage by 10+ miles per gallon!!!
Before: 36mpg
After: 47mpg
• Thank you for joining me today - Ken Mays ([email protected])
• Special thanks to COCC Students Braddon Harrison and Pete Olson for the
photos and PowerPoint help.
