Are you not sure how you will charge your Noco GB40? Are you trying to jump start your dead car battery or the lawn mower? Or are you trying to wake up the dead boat battery using the Noco Genius Boost GB40? Whatever may be the reason, you are at the right place to find the solution for your problem.

A Noco GB40 is considered mandatory to jump start any dead batteries. But how do you charge it when itself is dead? Here, we have the easiest solution to solve ‘How to Charge Noco Genius Boost GB40?’
This article not only contains the mentioned solution, but it has some related issues to offer. To mention some- When do you need to charge a Noco GB40?, how do you know when Noco GB40 is fully charged? What can you charge with it? etc.
How Do You Charge a Noco GB40/ How to Charge Noco Genius Boost GB40?

The best and easiest way to charge your Noco GB40. Follow the steps given below to know the easiest way to charge your Noco Genius Boost 40.
The effortless way to do that is using a USB port.
Charge Noco Genius Boost GB40 from a Powered USB source.
Step 1: Locate Charging Options

First, identify the USB port on the left side of the boost. The port has an engraved writing of ‘USB IN’ that ensures it’s for USB cables.
Step 2: Connect the Cable

After locating the USB port, you can use multiple devices to charge a Noco GB40, whichever is preferable and convenient to you.
- A Phone Charger
- USB Car Charger
- An AC adapter
- 12 Volt Car Adapter
- Computer or other USB Devices
Now, connect the micro USB cable with the Noco GB40. Plug the other side into the preferred USB device. Make sure the connection has power supply.
- Start Dead Batteries - Safely jump start a dead battery in seconds with this compact, yet powerful, 1000-amp portable lithium car battery jump starter pack - up to 20 jump starts on a single charge - and rated for gasoline engines up to 6 liters and diesel engines up to 3 liters.
- UltraSafe - Safe and easy to use car battery jump starter pack without the worry of incorrect connections or sparks. Safely connect to any 12-volt automotive car battery with our mistake-proof design featuring spark-proof technology and reverse polarity protection.
- Multi-Function - It's a car jump starter, portable power bank, and LED flashlight. Recharge smartphones, tablets, and other USB devices. It's easily rechargeable from any powered USB port in 3 hours at 2.1-amps. Plus, an integrated 100-lumen LED flashlight with seven light modes, including emergency strobe and SOS.
- Advanced Design - Our most advanced portable car battery jump starter ever. Featuring high-discharge lithium technology for safe operation in any climate. A rugged and water-resistant enclosure rated at IP65. A rubberized over-molded casing to prevent scratching or marring of surfaces. And an ultra-compact and lightweight design weighing just 2.4 pounds.
- In The Box - GB40 UltraSafe Portable Lithium Car Battery Jump Starter Pack, Heavy-Duty Battery Clamps, 12-Volt Car Charger, Micro USB Charging Cable, Microfiber Storage Bag, User Guide, 1-Year Warranty, and Designed in the USA.
Step 3: Charge!

Once connected, the device will start getting charged. When it’s charging the charging LEDs will start to pulse slowly as the battery gets full. After getting a full charge, the Green light will appear bright and full and will stop pulsing,when the rest of them will be blank. It can take up to 3 full hours to get a complete charge. Though it may vary depending on the battery condition.
***Caution: According to FCC regulations, it is recommended not to charge and discharge at the same time.
When Do You Need to Charge a Noco GB40?
After initial charging it is recommended to charge your Noco GB40 every 4 to 6 months even if it has not been used. However, it can hold 70% charge of the rated capacity.
How do you know when noco GB40 is fully charged?

Noco Genius Boosts have 4 charge LEDs You will get notified by the pulsing LEDs when to charge the device. The LEDs have different purposes, that at any level of the charge, a particular LED will pulse. It is known as the internal battery’s State-of-Charge or SOC. See below for the explanation.
LED Explanation
- 25% RED LED: The 25% Red light will slowly pulse on and off when the battery is below 25%. But the RED dot will appear solid if the battery is at 25%.
- 50% RED LED: The 50% RED LED will also pulse on and off when the battery is below 50%, but appear solid when it is at 50%.
- 75% Orange LED: The Orange light will beep when below 75% charge, but stay solid at 75% fully charged.
- 100% Green LED: When the battery will be less than 100% the Green LED will pulse, but at 100%, it will remain solid. And the rest of the charge LEDs will be turned off.
FAQs
What’s a Noco Genius Boost GB40 or Noco GB40?
Noco GB40 or Noco Genius Boost GB40 is a 1000 Amp portable jump starter for your car’s dead lithium-ion battery. This jump starter provides 1,000 Amps to jump start a dead battery within seconds. It is a safe and uncomplicated device for anyone to use.
This ultrasafe jump starter has a patented safety technology that ensures reverse polarity protection and spark-proof connections making it one of the safest jump starter technologies. It can make up to 20 jump starts on a single charge rated at 1000 Amps, which is quite powerful. And there is a bright 100 lumen LED flashlight with 7 individual light modes-
- Power LED
- Power button
- Error LED
- Internal battery level
- Boost LED
- Manual override button
- Light mode button
What’s a Noco Genius Boost Gb40 or Noco Gb40 Used for?
This robust lithium jump starter is not only suitable for recharging cars, RVs, trucks, lawn mowers, and boats, but can also be used for recharging smartphones, tablets, and other USB devices like a smartwatch. You can recharge them on the go without any hassle. A single charge can provide up to 4 smartphone recharges. Though it is limited to jump start up to 3 litres diesel engines, but can do the same job for a 6-liter gas engine.
Can you overcharge a noco GB40?
Yes, you can overcharge a Noco GB40. But it has an overcharge protection system. So, it can always be plugged on a charging device.
What Does It Mean to Flash 25% and 100% LED Alternatively When Charging?
It can indicate faulty charging. You should try to charge it through a different source or charging cable. If that doesn’t solve your problem, contact NOCO Support on their website.
WARNING!! California’s Proposition 65!
Safety Information: This product holds a warning. The California Proposition 65 tag confirms that the product contains chemicals that may cause cancer, birth defects, and other reproductive harms if harshly exposed to the chemical above a certain amount.
Conclusion
This article may have helped you to solve the recharging Noco GB40 issue. Noco Genius Boost 40 is a spark-proof technology that is considered one of the safest and mistake-proof jump starter devices that has also reverse polarity protection. So, we can say that you can safely connect it to the batteries without any worries.