At ServTec UK, we specialize in diagnosing and repairing battery systems, but sometimes, a repair just isn’t viable. Recently, a customer brought in a Pylontech US2000 battery for assessment. Here’s how we determined that it had suffered irreversible damage—and why replacing it was the best option.
The Diagnosis
Upon testing, we found that even with the power switch in the off position, the battery still had 2.3V at the front terminals. This was a red flag, indicating a possible internal fault.
To investigate further, we opened the unit and disconnected the pack from the BMS. The voltage measured 2.372V, with each internal ‘brick’ sitting at 0.7V—which equates to just 0.15V per cell.
Here’s the problem: Anything below 2.5V per cell is considered irreversible damage. At this stage, the risk of dendrite growth and internal shorts is high, meaning the battery is no longer safe or reliable for use.
What Went Wrong?
Beyond the low voltage issue, we also suspected a fault with the PMU or CMU board, which likely caused the discharge FETs to stay closed. This meant the battery terminals remained connected to the cells even when the power switch was off—another indication of internal failure.
Repair vs. Replacement: Making the Right Call
While we always strive to repair batteries where possible, this case highlighted an important reality:
👉 80% of the cost of a battery is in its cells.
When the cells are compromised, repairs quickly become uneconomical. Instead of throwing money at a failing unit, the best course of action was to recommend a replacement battery.
For anyone facing a similar issue, we suggested looking at reliable suppliers:
- ITS Technologies – US2000C for £520 + VAT
- Bimble Solar – US2000C for £479 + VAT
- Trade Sparky – US2000C for £475 + VAT
Takeaways for Battery Owners
If you’re dealing with a dead or malfunctioning battery, keep these key points in mind:
✔ Check voltage levels – Anything below 2.5V per cell is a sign of irreversible damage.
✔ Look for internal faults – A battery that stays “live” when switched off may have a control board failure.
✔ Consider repair viability – If most of the cost is in the cells, replacing the unit may be the best move.
At ServTec UK, we always provide honest, professional assessments to help you make the right decision. If you’re unsure about your battery’s condition, get in touch—we’ll give you a straight answer.
Need a battery diagnosis? Contact us today!