Got a 2002 from our son a year ago, we've driven 4000 miles. Red triangle twice, six months ago cleared it by charging the 12v battery. This time that didn't clear it. I got an OBD2 scanner and downloaded DrPrius. Found block 14 bad, and high Delta SOC. I read, then cleared two codes, then disconnected the 12v ground for five minutes. Now driving ok, no warning, but battery monitor still clearly shows bad block 14. Wife likes the car. What to do? I was a mechanic in a former life, have tools and courage but no Prius experience.
It really is not as difficult to learn and understand the workings of a Gen1 Prius,especially if to have an automotive mechanical background, and if you heed all warnings and safety practices of working with high voltage hybrid systems. Servicing and repairing the battery assembly is not at all difficult once you clear access to the battery. The process of replacing the bad cells/modules is easy to figure out. There are many instructions available online and on youtube. My experience with my 2003 Gen1 has pretty much proven to me how easy it is to maintain these cars. So many people resort to expensive hv battery replacement when these assemblies are so maintainable and restorable. When my HV battery went bad I diagnosed 3 bad cells and discovered 2 other marginal cells. I replaced the 5 cells and found a bad sensor wire that I replaced. I practiced some care and patience in doing the reconditioning and balancing process. For less than $300 I had a strong battery assembly. After two years now the assembly's lifetime reading is at 92%. No codes, going strong and reliable.
Watching "battery monitor," it's always clear block 14 is bad. Occasionally blocks 1, 5 and 19 seem out of the norm, but that is transient. I'll need to learn how to discern which modules to plan to replace ... or, with a 22 yr-old battery (I know both previous owners and can be sure this is the original), when is it smarter to get the $1250 replacement for the whole HV battery? From all the tutorials, I'm comfortable doing the work myself. I'm getting red exclamation triangle every 15 miles, with over 50% Delta SOC on the monitor (in red) most of the time.
Is there a simple way to know whether I should now replace the whole battery, or just a few modules? 2002, 200,000 miles ...
Agreed. I think the "conventional wisdom" is that it's a good idea to replace the entire battery when modules start failing due to age, since there's an expectation that the modules that are good now will probably go bad soon too, and you can end up doing a lot of futzing with the battery if you keep chasing down bad modules.
Couple of threads for removing battery Gen 1 - HV Traction Battery removal the easy way. | PriusChat How to Change the HV Battery CELL / Module/s on Gen 1 Prius | PriusChat You could replace the battery with a refurbished Gen 1 pack https://2ndlifebattery.com/product/2001-2003-toyota-prius-hybrid-refurbished-battery/ Best option is to replace with a ProjectLithium pack, new inventory expected early April. Some PriusChat members have been using the Lithium packs for a number of years. @PriusCamper will be along to answer any questions. https://projectlithium.com/?ref=9qLPw https://projectlithium.com/products/prius-gen1-lithium-upgrade-pack-19-blocks
It makes sense to me that at 22 yrs, better to replace the whole thing rather than start playing whack-a-mole. When I first started looking, I found a $1250 battery from bestbuyhybrids. I see the superiority of the lithium replacement, but I'm not sure I want to invest twice as much in an "around-town" car. I'm glad to listen to advice ... I don't have to decide this week, my patient wife is ok driving my '99 Corolla for now. Thanks for sending the link to "walking it out through the trunk."
Sorry, that was "besthybridbatteries" from near Chicago ... a few hours' drive for me. Anyone have experience with them?
After market remanufactured packs for gen1 are hit and miss, and from my experience are only as good as their warranty. Best long term solution is a new battery pack from Toyota, which are getting harder to find, but you may still be able to find one by calling around to nearby Toyota service centers. (Note, parts from original pack, like ECM and main relay, need to be swapped over from the original battery assembly before returning it as a core.)
