NiMH
Toyota Prius 2nd Generation (NHW20) Hybrid Battery
The Toyota Prius 2nd Generation (NHW20) Hybrid Battery is the high voltage battery in the Toyota Prius (2004-2009).
Specifications
| Chemistry | NiMH |
|---|---|
| Cell format | prismatic |
| Nominal voltage | 201.6 V |
| Modules | 28 |
| Module voltage | 7.2 V |
| Cooling | forced air (battery blower; blower relay listed in Toyota dismantling manual) |
| Location | Luggage area, mounted to floor pan cross member behind rear seat, concealed by fabric liner |
| Weight | 39 kg |
Cars That Use It
- Toyota Prius 2004-2009 NHW20 liftback, all US trims Run the checklist
What Goes Wrong
Reported failures, each from a source listed below, as of October 7, 2026.
- Owner complaints NHTSA lists under the Hybrid Propulsion System component for the Toyota Prius, by model year: 2005: 3 · 2006: 1 · 2007: 2 · 2008: 3. These are all hybrid system complaints, owner reported and unverified, not only battery faults, as of 2026-10-07.
Symptoms
- Toyota service bulletin T-SB-0074-20 (Aug 2020) describes the check engine light (MIL) coming on with DTC P0A80 and/or P0A7F stored because dust or debris has built up in the HV battery cooling fan or intake filter; the procedure cleans the fan and cleans or replaces the intake filter. It lists 2003-2020 Prius, covering all 2004-2009 model years. (static.nhtsa.gov: MC-10179698-9999.pdf, 2026-10-07)
- Toyota bulletin T-SB-0153-13 (2004-2009 Prius, now superseded by T-SB-0074-20) described MIL ON with DTC P0A80 or P0A7F due to dust or debris in the HV battery cooling fan. (static.nhtsa.gov: MC-10169322-9999.pdf, 2026-10-07)
Same Electrical Spec
These packs share this one's chemistry, voltage and module count. That is a spec match only. It does not mean the parts fit each other, so check with a technician.
Warranty
Toyota's 2005 and 2006 Prius Warranty and Maintenance Guides list the hybrid battery under Toyota's hybrid system warranty for 8 years or 100,000 miles, and the California Emission Control Warranty section lists the hybrid battery at 10 years or 150,000 miles for vehicles covered by that warranty; 2004 and 2007-2009 guides were not found. (techinfo.toyota.com: T-MMS-06Prius.pdf, 2026-10-07)
Get This Pack Tested
Do not open it yourself. The pack can hurt you with the car switched off.
Sources
- toyota.co.nz: prius_nhw20-min.pdf
- osti.gov: 890029
- engr.uvic.ca: 890029.pdf
- techinfo.toyota.com: T-DM-001-D.pdf
- techinfo.toyota.com: T-ERG-005-D.pdf
- techinfo.toyota.com: T-MMS-05Prius.pdf
- techinfo.toyota.com: T-MMS-06Prius.pdf
- static.nhtsa.gov: MC-10179698-9999.pdf
- static.nhtsa.gov: MC-10169322-9999.pdf
- NHTSA complaints, 2005 Toyota Prius
- NHTSA complaints, 2006 Toyota Prius
- NHTSA complaints, 2007 Toyota Prius
- NHTSA complaints, 2008 Toyota Prius
Last updated October 7, 2026. Failure and recall notes are as of that date. Spotted a mistake, or speaking for a maker? Report an error.
Hybrid Battery Test is independent. It is not affiliated with, sponsored by or endorsed by Toyota. Names and part numbers are used only to identify the vehicle and the part.