NOCO Boost GB40 Review: Is the Most Popular Jump Starter Still Worth It?
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The NOCO Boost GB40 is probably the most recognized portable jump starter in America. It is small enough to live in a glove box, yet it can start a dead battery without needing another car. For many drivers, it is the first jump starter they ever buy.
In this NOCO Boost GB40 review, we look at what 1000 amps can really start, how NOCO’s UltraSafe protection works, and whether you should buy the GB40 or step up to a bigger model.
NOCO Boost GB40
4.6 / 5 ReviewsWhiz Score- Starts gas engines up to 6.0L and diesels up to 3.0L
- Spark-proof and reverse polarity protection
- Doubles as a power bank and LED flashlight
✅ Pros
- Very compact at just 2.5 lb
- Foolproof spark-proof clamps
- Up to 20 starts per charge
- IP65 water and dust resistance
- Fast 3-hour recharge over USB-C
❌ Cons
- Not enough power for large V8s or big diesels
- Small 100-lumen flashlight
- No air compressor
- 1-year warranty is shorter than some rivals
NOCO Boost GB40 Key Specifications
| Peak current | 1000 amps |
| Engine size | Up to 6.0L gas, 3.0L diesel |
| Starts per charge | Up to 20 |
| Safety | Spark-proof, reverse polarity |
| Weight | 2.5 lb |
| Flashlight | 100 lumens, 7 modes |
| Water resistance | IP65 |
| Recharge time | About 3 hours |
Starting Power: What Can 1000 Amps Start?
NOCO rates the GB40 for gasoline engines up to 6.0 liters and diesel engines up to 3.0 liters, with up to 20 starts per charge. That covers most sedans, hatchbacks, small and midsize SUVs, motorcycles, ATVs and boats.
If you drive a full-size truck with a big V8, or any diesel above 3.0L, the GB40 is undersized. In that case, look at the NOCO GB70 or GB150.
UltraSafe Protection
The biggest reason people choose NOCO is safety. The GB40 has spark-proof technology and reverse polarity protection, so it will not send power if the clamps are connected the wrong way. That makes it a good choice for drivers who have never jump-started a car before.
Power Bank and Flashlight
The GB40 also works as an emergency power bank for your phone or tablet. It recharges in about three hours with the included USB-C cable. The built-in 100-lumen LED flashlight has seven modes, including SOS and strobe, which is handy when you break down at night.
Build Quality and What Is in the Box
The housing is rated IP65 and covered in rubber over-molding, so it can handle rain, dust and a few drops. In the box you get the GB40, heavy-duty clamps, a USB-C charging cable and a microfiber storage bag. NOCO backs it with a 1-year warranty.
Tips for Using a Jump Starter Safely
- Charge the GB40 every three to six months, even if you have not used it
- Connect red to the positive terminal first, then black to bare metal or the negative terminal
- Do not crank the engine for more than a few seconds at a time
- Store it out of direct summer sun when possible
How to Jump Start a Car With the NOCO GB40
The GB40 is built to be simple enough for first-time users, and the process takes less than a minute once you have done it once.
- Turn off the ignition, lights and accessories.
- Connect the red clamp to the positive (+) battery terminal and the black clamp to the negative (-) terminal or a bare metal ground point.
- Press the power button. The GB40 checks the connection and only sends power when the clamps are on correctly.
- Start the engine. If it does not start, wait about 30 seconds before trying again.
- Once the engine is running, turn off the GB40 and remove the black clamp first, then the red one.
If the battery is so flat that the GB40 cannot detect it, NOCO includes a Manual Override mode. It forces power to the clamps and should only be used when you are sure the clamps are connected correctly, because it bypasses the safety checks.
Which Vehicles Is the GB40 Right For?
NOCO rates the GB40 for gas engines up to 6.0 liters and diesel engines up to 3.0 liters. That covers the large majority of sedans, compact SUVs, crossovers, minivans and many V6 trucks. It is also a good match for motorcycles, ATVs, lawn tractors and boats with smaller engines.
Where the GB40 runs short is large V8 trucks, full-size SUVs with big engines and most diesel pickups. Those engines draw more current, especially in cold weather when oil is thick and the battery has lost capacity. If you drive a V8 or a diesel, or you live somewhere with hard winters, the GB70 gives you a much bigger safety margin.
GB40 vs Other Compact Jump Starters
| Model | Peak amps | Gas / diesel | Weight | Best for |
|---|---|---|---|---|
| NOCO Boost GB40 | 1000A | 6.0L / 3.0L | 2.5 lb | Most cars and small SUVs |
| NOCO Boost GB70 | 2000A | 8.0L / 6.0L | 5.0 lb | V8 trucks and diesels |
| NOCO Boost X GBX45 | 1250A | 6.5L / 4.0L | 2.4 lb | Owners who want a USB-C fast-charging upgrade |
| AstroAI S8 | 1500A | 7.0L / 5.5L | About 1.5 lb | Budget buyers |
The GB40 is not the most powerful compact jump starter, but its safety features, build quality and NOCO’s track record make it one of the most trusted choices in this size.
Storing and Maintaining Your Jump Starter
A jump starter only helps if it is charged when you need it. The GB40’s lithium battery holds its charge for months, but NOCO recommends topping it up every three to six months and after every use. The four LED charge lights show you how much power is left at a glance.
Keep the GB40 in the trunk, glove box or under a seat. It is rated to work in a wide temperature range, but long periods in extreme heat shorten the life of any lithium battery. In very hot climates, storing it in the cabin out of direct sun is better than leaving it in a closed trunk all summer.
- Recharge after each jump and every few months in storage.
- Check the clamps and cable for damage before each use.
- Use the included USB cable and a quality wall adapter for charging.
- Do not try to jump a battery that is cracked, leaking or frozen.
What Comes in the Box and Warranty
The GB40 comes with the jump starter, heavy-duty clamps permanently attached, a USB charging cable and a micro-fiber storage bag. NOCO covers it with a one-year warranty. That is shorter than some newer competitors offer, but NOCO is a well-known brand with US-based support, which matters if you ever need a replacement.
Who Should Buy the NOCO Boost GB40?
Buy it if you drive a car, crossover or small SUV and want a compact, safe jump starter for emergencies.
Skip it if you drive a large truck, a big V8 or a diesel over 3.0L. The NOCO GB70 or GB150 is the better choice.
Alternatives to Consider
- NOCO Boost GB70: 2000A for engines up to 8.0L gas and 6.0L diesel.
- NOCO Boost X GBX45: 1250A with a digital display and faster USB-C charging.
- AstroAI S8: A lower-priced 1500A option.
Final Verdict
The NOCO Boost GB40 earns its reputation. It is small, safe, easy to use and powerful enough for most everyday cars. If your engine is 6.0 liters or smaller, it is one of the easiest recommendations in car emergency gear.
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Frequently Asked Questions
What size engine can the NOCO GB40 start?
It is rated for gasoline engines up to 6.0L and diesel engines up to 3.0L.
How many jump starts does the GB40 give per charge?
NOCO rates it for up to 20 starts per charge.
How long does the NOCO GB40 take to charge?
About three hours using the included USB-C cable.
Is the NOCO GB40 safe for beginners?
Yes. It has spark-proof technology and reverse polarity protection, so it will not deliver power if the clamps are connected incorrectly.
Can the GB40 charge my phone?
Yes. It has a built-in power bank for charging phones, tablets and other USB devices.
How we evaluated: this review is based on the manufacturer’s published specifications, the product’s feature set, and how it compares with competing products in the same price range. Product details and images are provided by Amazon and may change. Prices and availability are accurate as of the time shown on Amazon and are subject to change.