Why is the brightness of the same pool light so different after 20 minutes?

Many customers have such doubts:Why is the brightness of the same pool light  so different after 20 minutes? The main reasons for the significant difference in waterproof pool lighting brightness within a short period of time are:

1. Overheat protection triggered (the most common cause)

Principle: LED or halogen swimming pool light bulbs will generate high temperatures when working for a long time. If the heat dissipation design is poor or the ambient temperature is high, the built-in temperature sensor will actively reduce the power to protect the circuit.

Troubleshooting method:

1)Turn off the lamps, let them cool down, and then turn them on again to observe if the same phenomenon recurs.

2)Check if the lamp housing is hot to the touch (pay attention to safety and avoid direct contact).

Solution:

1)Make sure that the heat dissipation holes of the pool lighting replacements are not clogged (such as covered by algae or dirt).

2)Replace with waterproof lamps with better heat dissipation performance.

2. Power supply or driver failure

Unstable voltage: Pool lights typically use 12V/24V low-voltage power supplies. If the transformer or driver ages, the output voltage may drop over time.

Capacitor failure: Damage to the filter capacitor in the power module can lead to an unstable power supply.

Troubleshooting method:

1)Measure the actual input voltage of the lamp when it is in operation with a multimeter (operated by a professional).

2)Try replacing the power driver of the same model for testing.

3. Aging or quality issues of the lamps

LED light attenuation: Inferior LED chips will rapidly decay in high-temperature and high-humidity environments, manifested as a continuous decrease in brightness.

Seal failure: Water vapor invades the interior of the lamp, causing corrosion of components (check if there is condensation or fogging on the lampshade).

Suggestion:

1)Choose lamps with an IP68 waterproof rating and specially designed for swimming pools.

2)If it has been used for more than two years, consider replacing it with a new one.

4. The automatic dimming function was activated by mistake

Smart lighting fixtures: Some high-end swimming pool lighting fixtures have timer dimming or ambient light sensing functions, which may be mistakenly set to enter energy-saving mode after 20 minutes. 

Troubleshooting method:

1)Refer to the manual and reset the lamp control program.

2)Disconnect the intelligent modules (such as Wi-Fi controllers) to test the basic functions

5. Line problem

Joint oxidation: Poor sealing of the underwater junction box can lead to an increase in contact resistance and a drop in voltage after being powered on and heating up.

Insufficient wire diameter: When transmitting over long distances, overly thin conductors can cause voltage drops (especially in low-voltage systems).

Suggestion:

1)Check whether all waterproof joints are in good condition and redo the waterproof treatment.

2)Make sure the power cord meets the power requirements (for example, for a 12V/50W lamp with a current of approximately 4.2A, a sufficiently thick wire diameter is needed).

We can also conduct a quick self-check following :

1. Cooling test: Turn off the lights and let them cool for 1 hour, then turn them on again and observe whether the brightness returns to normal.

2. Comparative test: Replace the lamp or power supply of the same model to rule out equipment issues.

3. Environmental inspection: Confirm that there are no obstructions around the pool lighting that affect heat dissipation, and the water depth does not exceed the designed maximum value.

If the problem persists, we suggest you contact professional swimming pool equipment maintenance personnel, paying special attention to safety(A mixed environment of water and electricity poses an electric shock risk).

Shenzhen Heguang Lighting Co., Ltd is a professional IP68 pool lighting manufacturer. All the lights underwater use the constant current power supply drive, ensuring the long-term stable use of the swimming pool lamps. That means when purchasing our lamps, you don’t have to worry about the pool lights having inconsistent brightness in a short period of time!

Contact us if you have more questions ~