1.  HEVs are nothing more than a traditional automobile with advanced technologies that deliver the same end result as a traditional automobile, but with unique service hazards  Safety is of utmost importance when approaching a HEV  Isolation of HV systems for routine system service may be a necessity  ALWAYS refer to the manufacturer’s recommended isolation techniques when servicing an HEV

2.  When approaching an HEV, it is important to recognize the potentially high voltage you may be working around  Manufacturers have developed a way of identifying high voltage systems with brightly colored markings 2009 Prius A/C compressor with ORANGE sheathing surrounding HV supply to compressor

3.  Sheathing has been categorized into colors that indicate voltage levels present  Black – 12-42V  Yellow or Blue – ~42V  Orange – 144-650V Information courtesy of Jim Halderman

4. Information/images courtesy of Jim Halderman

5.  While hybrids may look and feel similar to traditional vehicles, the introduction of HV to the vehicle creates unique work risks  For example, the THS-II system on the 2004+ Toyota Prius can exhibit 500V under operation  Identifying the location of HV components on any HEV is key to working safely

6.  Gloves  Must be routinely inspected (as in EACH use!)  Must have a Class 0 rating (safe up to 1000V)  Should have protective capabilities beyond insulation, i.e., puncture resistance  This is why traditional HEV service gloves have a leather our glove and an insulating Class 0 rated primary glove  DISCARD if damaged!  Recommended replacement every 6 months  Do NOT gamble when dealing with high voltage!

9.  Testing gloves  Blow air into glove and roll it to inspect for fractures that may allow HV to penetrate  MUST be free from water, sweat, oil and other potentially conductive and combustible/flammable chemicals  Glove Dust may be used to reduce sweating in gloves

11.  Tools  Insulated tools, which commonly have been tested at 10kV, are recommended  Typically have a safe working voltage of 1000V  Are relatively inexpensive ($500-$1000 per set)  Should be routinely inspected  Should be used as recommended by the manufacturer

13.  Clothing  Sleeved shirts  Short sleeve vs. long sleeve  Jewelry should be removed as it is conductive  Should be free from water, sweat, oil and other potentially conductive and combustible/flammable chemicals

14.  Digital Multimeters  CAT III rating recommended  According to D. Marinucci (MOTOR, 2008), automotive manufacturers have not endorsed a particular rating  CAT III-CAT IV recommended by leading industry experts with extensive HEV service research experience  Rating will be indicated on the face of the meter  Gloves MUST be worn when testing HV circuitry

15.  Multimeters  A meter with insulation testing capabilities is also recommend to test HV insulation properties  Do NOT insulation test yourself as the meter supplies HIGH VOLTAGE and low current to check conductivity (Fluke 1587 outputs 1017VDC @ 1.60mA)  Leads must also be CAT rated appropriately for the systems you are evaluating  Test Voltage should be selectable  Fluke 1587 ranges are: 50V, 100V, 250V, 500V, 1000V

16. Measured Resistance DMM Voltage Output HV Output Warning In Progress

18.  On HEVs, it is important to note that some may start with the key in the proximity of the vehicle  Toyotas use a READY light to indicate the engine may start  MEA Article by Dave Scaler MEA Article by Dave Scaler

20.  In the event the auxiliary battery dies, you can remove the lock cylinder key to enter the vehicle Chrome Toyota symbol identifies this key as a Smart Key

21.  Brake pedal must be depressed to start Prius  Note READY light on dash

23.  Known good (tested and inspected gloves) must be used to isolate HV circuit  Refer to manufacturer’s information to locate the HV disconnect plug

27.  Even though the plug may be removed mechanically, HV is still available at the battery terminals  NEVER service the HV system without first verifying HV is no longer present (with a properly rated DMM)

28. HV Disconnect

29. 1. Pull Up 2. Rotate

30. Wait 10 minutes, test for HV and proceed if no HV is present before servicing vehicle 3. Remove

31.  It is possible to charge a HV battery, but not very common  Typically, the 12V (auxiliary battery) will fail and cause a no start condition  Jump starting the 12V battery varies from mfr. to mfr.