7 Warning Signs Your Hybrid Battery May Be Failing — What Every Driver Should Know

Hybrid cars are known for fuel efficiency and smooth driving — but over time, even the most reliable Toyota or Lexus hybrid will face battery degradation. If left untreated, a failing hybrid battery can lead to poor performance, rising fuel costs, and breakdowns.

At Battery Lab, we help drivers across Singapore diagnose and replace hybrid batteries using genuine packs sourced from Japan, backed by a 36-month warranty.

Here are the 7 most common warning signs your hybrid battery may be nearing its end.

1. Drop in Fuel Efficiency

Noticing that you’re pumping petrol more often? A weakening battery forces the engine to work harder, especially during city driving — hurting your fuel economy.

2. Engine Kicks in More Often

Your hybrid should run on battery power at low speeds. If the petrol engine starts up too frequently or doesn’t switch to EV mode, it may be a sign the battery can’t hold charge.

3. Battery State of Charge Fluctuates Rapidly

If your dashboard shows the battery going from full to low (or vice versa) within minutes, this indicates voltage instability — a classic sign of cell imbalance.

4. Unusual Fan Noise

When your hybrid battery overheats, the internal cooling fan works harder to cool it down. If you hear the fan running loudly or constantly, it may mean the battery is stressed or deteriorating.

5. Warning Lights on Dashboard

Look out for:

• Check Hybrid System

• Battery Warning Light

• Red triangle with exclamation mark

  
  

  These alerts often signal HV battery issues and should be scanned immediately.

6. Sluggish Acceleration

If your car feels underpowered, struggles uphill, or hesitates when accelerating, it may be due to reduced voltage output from a weak battery pack.

7. Battery Age (8–10 Years Old)

Hybrid batteries tend to wear out after 8–10 years, especially in humid climates like Singapore. Estima, Prius, RX450h, Voxy — all start showing symptoms around this age if not replaced or reconditioned.

How Battery Lab Helps

We’re not just about swapping out old batteries. We offer:

• Genuine Japan-sourced hybrid battery packs

• Full pack replacements, not just “cell fixes”

• 36-month warranty for peace of mind

• Rapid turnaround for Lexus, Toyota, and Honda hybrids

Get a Free Battery Health Check

If your hybrid is showing any of the signs above, let us run a free diagnostic scan and recommend your best option — repair or replacement.

Click here to contact us now via WhatsApp