How to Identify and Fix a Below-Minimum HV Battery on a 500e

[Chuchara_0604]

If you’ve bought a non-working Fiat 500e or your car’s been sitting idle and now won’t charge, you might be dealing with a High Voltage (HV) battery that’s dropped below its minimum charge level. Here are the key symptoms:

• No contractor sound: Normally, you’d hear a “clunk” when opening the door—if not, something’s off.
• 38% charge reading: The car shows exactly 38%, regardless of its actual charge.
• “Service Charging System” error: When plugged in, this message pops up.
• BPCM stops responding: After trying to read important details like cell voltages, the Battery Pack Control Module (BPCM) may stop responding, forcing a restart.

Likely Causes:
HV battery voltage is too low: To fix this, you may need to open the HV pack. Don’t worry—most cars recover fine after this.
Something caused the issue: It could be neglect or a 12V battery failure. You won’t know for sure until the HV pack is recovered.

 

[f.r.a.n.k.]

Got it! That’s super helpful info for anyone tackling a Fiat 500e. Huge thanks for dropping that knowledge!

 

[ChuckJ07]

Thanks a bunch for this @Chuchara_0604!

Have you run into any of these symptoms before with your Fiat?

 

[Scotty]

I’ve encountered this issue with my 500e too. The HV battery can drain too low if left idle, causing the symptoms you mentioned. I found that after recharging the HV battery, the car came back to life.

 

[ChargingSpray90]

If you’ve bought a non-working Fiat 500e or your car’s been sitting idle and now won’t charge, you might be dealing with a High Voltage (HV) battery that’s dropped below its minimum charge level. Here are the key symptoms:

• No contractor sound: Normally, you’d hear a “clunk” when opening the door—if not, something’s off.
• 38% charge reading: The car shows exactly 38%, regardless of its actual charge.
• “Service Charging System” error: When plugged in, this message pops up.
• BPCM stops responding: After trying to read important details like cell voltages, the Battery Pack Control Module (BPCM) may stop responding, forcing a restart.

Likely Causes:
HV battery voltage is too low: To fix this, you may need to open the HV pack. Don’t worry—most cars recover fine after this.
Something caused the issue: It could be neglect or a 12V battery failure. You won’t know for sure until the HV pack is recovered.

How do you know all of these? Have you gone through the big issue?

 

[Fox500]

That sounds like some solid expert advice. This info is incredibly helpful, and much appreciated! It clears up a lot of confusion

 

[ZeroGas500]

That's really interesting about opening the HV pack to recover the battery. I've been wondering about the accessibility of these components for DIY repair. While it's good to know it's possible, I'd definitely caution anyone without proper experience to proceed with extreme care. High voltage systems are no joke! I've learned that safety should always be the top priority with EV repairs