Why does my Land Rover Defender keep saying "low battery"?

Short answer: Lock the Defender whenever you walk away so it can go to sleep, and limit door openings when you're camping. Owners say each opening wakes up dozens of modules. Use a battery maintainer if it sits for a week. If the warning keeps coming back after normal driving, have the dealer test the battery, install updates and check whether your VIN has the DC-DC converter recalls. One owner got a battery under warranty this way.

Symptom: 'Low battery' or 'Low battery, start engine' messages after camping, after the car sits, or even after a long drive. Sometimes it blocks a software update.

What to check first

1. Lock the car every time you leave it.
2. On a camping trip, keep the doors shut as much as you can and turn interior lights off.
3. Use a maintainer if it sits more than a few days.
4. Have the battery load-tested and ask the dealer for software updates.
5. Run your VIN at nhtsa.gov/recalls for 26V248000 and 26V599000.

Likely causes

1. Modules waking up when doors open. An owner explained that opening a door wakes up dozens of control modules, which draw a lot of current for a few minutes. Do that all weekend at a campsite and the battery runs down.
2. Car not going to sleep. If the car isn't locked, it can stay partly awake and keep drawing power.
3. Software or mild-hybrid starter-generator issue. The P400 uses a belt-driven starter-generator (BISG). Owners say an update at the dealer fixed some warnings.
4. DC-DC converter failure (recall). On mild hybrids, the DC-DC converter turns high voltage into 12 volts to keep the regular battery charged. Land Rover recalled some because they can fail.

What it usually costs

One owner's battery was replaced under warranty along with the update. Recall work is free.

Is it safe to keep driving?

A low battery warning by itself isn't dangerous, but the recall says a failed DC-DC converter can stop 12-volt charging and lead to a loss of drive power and exterior lights. If you get charging warnings while driving, get it checked right away.

DIY or shop?

Locking habits, maintainers and battery testing are DIY. Updates and recall work are dealer jobs.

Recalls, bulletins and complaints in plain words

• Related recalls: NHTSA lists 26V248000 and 26V599000 for certain 2020-2024 Defender mild-hybrid models: the DC-DC converter can fail from an electrical overload (and in 26V599000, a software error at start-up), which stops 12-volt charging and can lead to a complete loss of drive power and exterior lights. Check your VIN at nhtsa.gov/recalls. If your car is part of a recall, the dealer fixes it for free.
• Plain words: The complaint count below shows how often owners reported problems that mention these words to NHTSA. A count is not proof of a defect.
• NHTSA complaints: 44 keyword-matched complaints for Land Rover Defender 2020–2024 (of 292 unique complaints queried, NHTSA complaints API by model year, queried 2026-10-31; keywords: battery, drain, dead, 12 v, won t start, low battery) (NHTSA returned no data for 36 model-year queries). This counts complaints that mention these words. It is not a defect finding.

What owners report

• In New Defender L663 – Low battery warning after 30 hours of camping… dealer’s “solution” = generator on Reddit r/NewDefender, an owner of a 2024 Defender got a low battery warning after about 24-30 hours of camping while opening and closing the doors. The dealer called it normal and suggested a generator. Others said Land Rovers draw a lot of power when parked and to use a battery tender if it sits, and one explained each door opening wakes up 30-plus modules for a few minutes.
• In Is anyone getting a “low battery start engine” light on Defender 2021? on Reddit r/Defender, a 2021 Defender owner kept getting 'low battery, start engine' even after a two-hour highway drive, and the warning blocked a software update. Another owner said to lock the car every time so it can sleep. One said P400s had starter-generator issues fixed by a dealer update. The owner later had the dealer install the update and replace the battery under warranty.

Quick tip

Get a small jump pack for the camping box and lock it every time. And check those two recall numbers. A converter failure is a lot worse than a nagging message.

Vehicle focus: Land Rover Defender (L663), 2020-2024.

Safety / mechanic note

Charging-system failures can cause a loss of power. Verify with a mechanic.