Can I make my solar garden light brighter by adding additional LEDs ?

Thread Starter


Joined Nov 22, 2022
I have a solar garden light using a 1.5V battery charged by the Solar panel. The outer case near the solar panel is cracked. I am not sure if the solar panel still works. The light works when I use a regular 1.5V battery. The circuit board is covered with rubber putty. I scrapped off some rubber and I can see two S8050 transistors and some resistors on the board. In order to map out the circuits, I have to dig deeper into the rubber and risk breaking the working circuit. What I want is to make a LED light out of it using the circuit. I can remove the solar panel and just use a 1.5V battery. But I want it brighter (up to 4 or 5 times). I was wondering if I can just add additional LEDs (up to 4 or 5 in total). If I can, should I add the LEDs in parallel to the existing one or in series? Will the existing circuit handle the additional load?


Joined Jan 15, 2015
Will the existing circuit handle the additional load?
I am going to venture a guess of no. In most of these garden light circuits they are designed around supporting the load they have and no more. During daylight, assuming bright daylight they charge their battery. During darkness they discharge their battery. Most I have seen generally don't make it through the hours of darkness.


Thread Starter


Joined Nov 22, 2022
I believe the two S8050 transistors are part of the voltage booster circuitry to bring the voltage up from 1.5v to at least 2 to 3 volts required by the LED to light up. As I mentioned in my post, the light is on using a regular 1.5V battery. We can take the solar panel out of the picture. I don't mind powering the light with just a regular battery. If there is enough voltage to turn on one LED. It should be able to turn on additional LEDs connected in parallel (from the voltage perspective). I am just not clear how the current requirements will be impacted and if the existing circuitry can handle it.


Joined Jun 5, 2013
Voltage is only part of the story. It may not be able to provide the current for more than one LED. You don’t need a boost circuit to run LEDs. A 28650 Lithium cell will do fine and all you need in addition is a resistor for each LED.

Audioguru again

Joined Oct 21, 2019
The solar garden cells I bought 18 years ago used two transistors. All newer ones (I have many) use an IC to switch between charging the battery and lighting the LED with the voltage boost circuit in the IC. The inductance of the boost inductor determines the LED current (brightness). Some of my solar garden lights have added LEDs (total of four) and others use a bright colors-changing LED.

Modern solar garden lights use a 2V solar panel with a glass cover but old ones used a solar panel with a plastic cover that soon gets sunburned. Lately they come with cheap low capacity rusting Ni-MH batteries but I changed them all to high capacity Energizer Ni-MH ones. Of course if there is more than one LED and they are bright then the charge on a battery will not last all night long.

I have a cheap flashlight that uses 60 white LEDs powered from 3 AAA battery cells. High quality alkaline battery cells allow it to produce very bright light. All LEDs are in parallel and it has no resistors.



Joined Sep 24, 2015
Powering a single LED from a battery (not considering the necessary voltage or current regulation) THAT LED will be lit by that battery for X period of time. Double the LED's powered from that battery will result in 0.5X (half the lighting time). FOUR LED's will run one quarter of the time. You WILL have more light, but the amount of light is not linear. While having four LED's you won't have four times the light. Well, that is "Perceived" light.

You can also light an LED for 1/30th of a second at a very bright level and then have it off for 29/30th's of a second and not notice any flicker. Battery life will be greatly extended because the LED is only lit for a very short period of time. Once I attended a lecture. The speaker used a xenon flash tube that was lit for 1/10,000 of a second - thirty times every second. None of us knew the light was off most of the time. It appeared as a continuous light. At the end of the lecture he told us about the timing of the light and we were amazed. We started thinking about energy savings. But the thing about that circuit was that it drew a lot more current just to charge the circuit to light that flash tube. In reality though the light was off most of the time the amount of current drawn was a little higher than a regular light.

LED's can do the same thing without all the charging time. Since you want to get away from solar and just use batteries I'd suggest starting from scratch and not attempt to modify a Mazda into a 767 jet air liner. Way too much work and a poor place to start from. Better off just getting the light module you wish and the necessary battery(ies) to light it. That's all I really wanted to say. Build from scratch. Or buy what you need already built.

What is the purpose of your project?