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Solar Street Light Repair Guideline-Battery Missing

November 18, 2023

Solar Street Light Repair


We often encounter customers who come to us with questions about solar street light repair. Some of them are stolen batteries, some of them are LED fixtures that don't light up, and some of them are solar panels that won't charge.

In this blog we will first explain how to confirm the battery type and battery capacity if the battery is stolen.

Solar Street Light Battery Types

In general, solar street lights commonly use two types of batteries:

GEL Battery

Typically buried underground to ensure that the battery temperature doesn't get too high in summer and too low in winter.

Lithium Battery

Usually installed on the top of the lamp post or inside the lamp head.

Solar Street Light Repair Steps

1. Check the number of solar controllers:

From the picture, there are two solar panels and two lamp heads. So you can check whether there are two independent controllers, each controlling one lamp, or if there is a single controller managing both lamps.

2. Determine the street light system voltage

(DC12V or DC24V)

After finding the solar street light controller, use a Voltmeter to measure the voltage of the solar input, if it is about 21V, then it is a 12V system, if it is about 35V, then it is a 24V system.

 Solar Street Light Repair-Controller Wiring 

3. Identify the battery type

(GEL Battery or Lithium Battery):

Solar controllers are usually installed together with the batteries, within a distance of no more than 2 meters.

If the controller is at position 1, the battery is likely a GEL battery buried underground.

If the controller is at position 2, the battery is likely a Lithium battery and installed inside the lamp shell

If the controller is at position 3, the battery could be either a Lithium battery or a GEL battery. If it's a GEL battery, the battery compartment will be relatively big.

Because the solar controller has different charge and discharge cut-off voltages for different batteries, so it's crucial to identify the correct type.

Solar Street Light Repair-Battery Type

4. Determine the battery capacity

Because we don't know the power of LED Lamp, we can not calculate the battery capacity directly. But we can project according to the power of the solar panel (6 hours can full charge the battery):

Let`s do the simple projection,

If it is GEL battery, Battery capacity = Solar panel power/2

If it is Lithium battery, Battery capacity = Solar panel power/2.5

Because GEL Battery DOD is 0.7, Lithium Battery DOD is 0.9. So it needs different capacity of the battery.

It should be noted that the best working temperature of the battery is around 25 degrees Celsius, if the temperature is lower than 0 degrees, the capacity will be reduced by about 10% at 0 degree. and at -10 degrees, the capacity will be reduced by about 20%. So increase the battery capacity appropriately according to the local temperature.

Calculate Example

If we get the below data after the above checking steps:

Solar Panel: 150W/PC*2

Solar Controller Qty: 2pcs

Solar Input Voltage: 21V

If it is Gel battery, the battery capacity is 150/2=75AH, So it needs 2pcs 12V 75AH GEL battery or 1pc 12V 150AH GEL battery

If it is Lithium Battery, the battery capacity is 150/2.5=60AH, So it needs 2pcs 11.1V or 12.8V 60AH battery or 1pc 120AH.

The Easiest and Fastest way to Repair

If it is not convenient to carry out the above steps, the easiest way is to replace the lamps fixtures, now there is available that the LED Lamp fixture is with the controller and the battery inside like below. It is plug and play.

Solar Street Light Repair-Replacement Lamp Fixture

Related Product

Lamp Head Replacement

This Series LED Lamp fixture is built-in Solar Controller and Lithium Battery. It can easily to replace the existing lamp, Just Plug the LED Head to your existing solar panels. It works!

Plug and Play. Easy to Install


I am the Marketing Director of SUNVIS, with 12 years of experience in the Solar Outdoor Lighting, Solar Power System and Solar Water Pumps industry. If you have any questions, you can contact me at any time.

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