Why does my Aiways U5 show every warning light at once and then not start?

Almost always low voltage, not a dead car. The Aiways U5 runs its low-voltage system from a 12 V lead-acid battery that is charged by a DC-DC converter whenever the high-voltage system is live. When that battery falls far enough, several control units brown out together and the car lights up the whole dashboard at once. Owners report the threshold at roughly 11.8 V measured at rest — below that the car behaves like a total failure while the only real fault is undervoltage.

My U5 battery only goes flat in rain or damp weather. Does that mean anything?

Yes, and it is the single most useful clue. Several owners report the drain correlates with rain or condensation rather than with cold. That points to moisture in a connector or at a ground point, not to an old battery — a battery that is simply worn out goes flat in any weather, not only when it is wet. If your drain follows the weather, say so when a workshop looks at the car; it changes where they look first.

Does the Aiways U5 recharge its own 12 V battery?

It has a system for it, but it can give up. The car monitors the 12 V battery through an intelligent battery sensor on the negative terminal. Below about 80% state of charge the sensor wakes the body control module, which asks the vehicle control unit to bring up the high-voltage system so the DC-DC converter can recharge the 12 V battery — the converter runs at about 14.5 V. If that sequence is blocked, the car retries once after roughly 30 minutes; on the second failure it stops trying for that ignition cycle and reports it through the telematics unit, which can surface as an app or message warning that intelligent charging has failed.

Should I just replace the 12 V battery?

Not first. Replacing the battery is the last step, not the first, because a parasitic drain will flatten a brand-new battery exactly like an old one. Check the ground point and look for a module that keeps waking up before you spend money on a battery. Only replace it once the rest of the circuit is known good.

Aiways U5: 12V battery keeps draining

The car is dead, every warning light on the dashboard is lit, and nothing responds. On an Aiways U5 that picture is usually low voltage, not a dead car — and the order you check things in decides whether you find the fault or just buy another battery. This page sets out what the warning storm means, what the car does on its own, and the wet-weather pattern owners have found that most workshops never think to ask about.

1. First: the warning storm is one fault, not twenty

The U5 runs its low-voltage system from a 12 V lead-acid battery — 45 Ah — mounted in the front compartment. While the car is powered up, that battery and a DC-DC converter supply the low-voltage loads together; in normal running the converter is held at about 14.5 V.

When the battery falls far enough, several control units brown out at the same time and each one independently announces a fault. The result looks catastrophic and is not: it is one undervoltage condition presenting itself many times over. Owners report that the car becomes unmanageable below roughly 11.8 V measured at rest. That figure comes from owner measurement rather than from the workshop manual, so treat it as a field reference, not a specification — but it matches what the car does.

Practical consequence: measure the battery at rest before you conclude anything. A car that looks destroyed and a car with a flat battery look identical on the dashboard.

2. The wet-weather pattern

The most useful thing an owner has contributed to this problem: on several cars the drain only happens in rain or high humidity, not in cold and not all year round.

That detail matters because it rules things out. A battery that has simply reached the end of its life goes flat in any weather. A drain that tracks the weather points at moisture in a connector or at a ground point. If your car behaves this way, tell the workshop before they start — it changes which end of the car they look at first.

3. Check in this order

Do not skip to step 4. The sequence is the point.

Measure the 12 V battery at rest. Let the car sit with everything off, then measure. If you are far below the mid-11 V range the whole dashboard is explained and nothing else needs diagnosing yet.
Check the ground point in the engine bay, passenger side, low down. Owners report this one works loose. A poor ground produces exactly the intermittent, weather-linked behaviour described above.
Look for a module that keeps waking up. A car that is parked is not silent — it is supposed to settle down to a very small standby current over the first day or two. If it never settles, something is waking the network. After Aiways wound down its connected services, the telematics unit repeatedly retrying is a known suspect.
Only then judge the battery. Replacing the battery is the last step, because a parasitic drain flattens a new battery just as fast as an old one.

4. What the car does on its own

The U5 is not passive about this, and knowing what it attempts helps you read the evidence. An intelligent battery sensor (IBS) sits on the negative terminal and reports through a LIN connection to the body control module — current, voltage, state of charge and temperature. Its supply comes from a 5 A fuse (EB23) in the front compartment fuse box.

Stage	What the car does
Parked, first day	Standby current settles in stages — on the order of 50 mA through the first 24 hours, about 25 mA into the second day, then roughly 4 mA once fully asleep. A 45 Ah battery also self-discharges at about 0.1% per day.
State of charge below about 80%	The sensor wakes the body control module, which asks the vehicle control unit to bring up the high-voltage system so the DC-DC converter can top the 12 V battery up.
If charging is refused	The car retries once after roughly 30 minutes. After a second failure it stops for that ignition cycle and reports through the telematics unit.
Reported to the owner	A message along the lines of intelligent charging failed, the battery is at risk of draining, have it checked — usually by app or message rather than on the dashboard.
State of charge reaches about 95%	The body control module reports overcharge and the high-voltage system is shut down again.

Why this matters: if the car has logged that it abandoned intelligent charging, the battery is being left to run down on purpose, and the fault is in the charging path rather than in the battery. That is a diagnostic clue, and it is stored in the car — an Aiways-aware workshop can read it.

5. If you are charging it manually

The manual is specific about one thing that is easy to get wrong: connect the charger's negative lead to the IBS post on the negative side, away from the battery itself. That keeps the sensor in the circuit — charge around the sensor and the car never learns the battery was charged, which leaves the state-of-charge estimate wrong afterwards.

Switch off all electrical loads first. The positive lead goes to the battery positive or to the jump-start stud in the engine bay.

6. Are these the parts you need?

The 12 V battery itself is a common lead-acid size and is best bought locally — shipping a battery across Europe costs more than the battery, and a local motor factor is the practical place to get one. What we do supply for this area of the car is the surrounding hardware: battery covers and carrier panels, terminal and ground harnesses, and the DC-DC cabling.

If you cannot find the right battery locally, send us the model or part number and we will help you check what fits — the size has to be exact, and we would rather you got the right one than guessed.

See the Aiways U5 / U6 parts we supply — or, if the car is reporting a code, start from the Aiways U5 fault code index.

One honest note on numbers. Those internal document numbers are not orderable references, and the orderable reference for your car is confirmed from the VIN. If you need a specific part, send us the VIN and we will confirm the actual reference and the version for your car.

7. Short answers

Can I keep driving while it does this?: A car that will not start is not a car you can drive. If it starts but throws warnings, treat it as a warning that the next cold or damp night may leave you stranded.
Will a new battery fix it?: Only if the battery is genuinely the fault. If the drain comes from moisture or a module that keeps waking up, the new battery will drain the same way. That is why the battery is step four and not step one.
Is this specific to the U5?: The architecture — 12 V battery maintained by a DC-DC converter, monitored by a sensor on the negative terminal — is common to the U5 and U6. The problem is not exotic; the difficulty in Europe is that there is no manufacturer network left to read the car.
What should I send you?: The VIN, and a description of when it happens. Whether it follows wet weather is genuinely useful information, not small talk.

Where this comes from. The behaviour described above is drawn from the Aiways U5 workshop manual — the battery monitoring system documentation and the associated system control, component location and harness documents — combined with patterns reported by owners of these cars in the European owner community. Where a figure is an owner measurement rather than a manufacturer specification, we say so. Wording is our own; we do not reproduce manual pages.

Important — please read before you act on anything here

This page is general information only. It is not a repair instruction, not a diagnosis of your particular vehicle, and not a substitute for professional advice. Have any work carried out by a qualified workshop or an authorised service centre. Do not attempt a repair yourself unless you are trained and equipped to do it.

High-voltage safety. This is an electric vehicle. Its high-voltage system can cause fatal injury. Never open, disconnect, cut or work on high-voltage components, cables or connectors unless you are qualified to do so, and always follow the manufacturer's own safety procedure.

Vehicles differ. Equipment, hardware versions and part numbers change between model years, markets and individual VINs. Confirm what applies to your vehicle before ordering or repairing anything. The manufacturer's documentation is the authoritative source for your car — where anything here differs from it, follow the manufacturer.

Consumables and specifications change without notice. Torque figures, fluids and procedures given here are for orientation only.

No liability. This information is published in good faith and to the best of our knowledge, but we accept no liability for any loss, damage or injury arising from reliance on it. Use it at your own risk, and verify anything safety-critical before you rely on it.

Who we are. GNSGO is an independent supplier of parts. We are not affiliated with, endorsed by, sponsored by or acting as an authorised agent of any vehicle manufacturer. References to a vehicle or model describe compatibility only.

8. Related

Need a part for this? Send the VIN and we will confirm the version that fits — get in touch.