What Is the Smallest NOCO Jump Starter? (The Complete Answer)
The smallest NOCO jump starter is the NOCO Boost Sport GB20. It delivers 500 amps of peak power, weighs about 2.1 pounds, and measures just 7.72 x 3.16 x 1.71 inches. It fits easily in a glove box and handles gasoline engines up to 4.0 liters. It’s NOCO’s entry-level model — small, affordable, and built for compact vehicles.
Your battery dies on a cold morning. You’re alone. No jumper cables, no second car. Sound familiar? That’s exactly why a portable jump starter belongs in every vehicle.
I’m Alex Rahman, and I’ve tested and reviewed car accessories for years. One question I get constantly is: which NOCO jump starter is the smallest? The answer is simple — but choosing the right one for your vehicle takes a little more thought.
Let’s break this down so you can make the right call fast.
- The NOCO GB20 is the smallest NOCO jump starter at just 2.1 pounds.
- It puts out 500 amps — enough for gas engines up to 4.0 liters.
- It’s not rated for diesel engines.
- The GB40 is the next step up at 1000 amps and handles most cars and SUVs.
- All NOCO Boost models include UltraSafe spark-proof technology and an IP65 rating.
What Makes the NOCO GB20 the Smallest NOCO Jump Starter?
The GB20 is NOCO’s entry-level lithium jump starter. It measures 7.72 inches long, 3.16 inches tall, and 1.71 inches deep. It weighs just 2.1 pounds — lighter than most water bottles when full.
Compare that to the GB40, which is noticeably larger at around 2.4 pounds. The difference feels minor on paper, but in your glove box, the GB20 wins easily.
NOCO designed the GB20 for everyday drivers with smaller vehicles. It’s not a heavy-duty tool. It’s a reliable backup for when your battery lets you down at the worst possible time.
The GB20 fits in the palm of your hand. Toss it in your glove box, center console, or backpack — it takes up almost no space.
NOCO GB20 Specs: What You’re Actually Getting
Here’s every key specification for the GB20 in one place.
| Spec | GB20 Value |
|---|---|
| Peak Amps | 500A |
| Gas Engine Rating | Up to 4.0L |
| Diesel Engine Rating | Not recommended |
| Jump Starts Per Charge | Up to 20 |
| Internal Battery | 24 Watt-Hour Lithium-Ion |
| Dimensions | 7.72″ x 3.16″ x 1.71″ |
| Weight | 2.1 lbs (0.95 kg) |
| LED Flashlight | 100 Lumens, 7 Modes |
| IP Rating | IP65 (dust and water resistant) |
| USB Input | USB-C: 5V / 2.1A |
| Recharge Time | Approx. 3 hours |
The GB20 also doubles as a USB power bank. It can recharge smartphones, tablets, and other USB devices. That 100-lumen flashlight has seven modes, including SOS and emergency strobe — genuinely useful during a roadside emergency at night.
Is 500 Amps Enough to Jump Start a Car?
Here’s the honest answer: yes, for most small to mid-size cars it is.
A typical four-cylinder car engine needs around 100 to 150 amps to crank over during a start. The GB20’s 500 peak amps gives you a solid safety margin for engines up to 4.0 liters.
That covers most compact cars, hatchbacks, sedans, motorcycles, ATVs, and lawn mowers. It won’t handle diesel engines, and NOCO doesn’t recommend it for them.
The GB20 is not rated for diesel engines at all. If you drive a diesel vehicle, go with the GB40 minimum — it handles diesel engines up to 3.0 liters. For larger diesel trucks, look at the GB70 or above.
NOCO GB20 vs GB40: Which One Is Right for You?
Most people end up choosing between these two models. Here’s how they compare side by side.
| Feature | GB20 | GB40 |
|---|---|---|
| Peak Amps | 500A | 1000A |
| Gas Engine | Up to 4.0L | Up to 6.0L |
| Diesel Engine | Not recommended | Up to 3.0L |
| Weight | 2.1 lbs | ~2.4 lbs |
| Size | 7.72″ x 3.16″ x 1.71″ | ~7.2″ x 3.1″ x 1.7″ |
| Best For | Compact cars, bikes, ATVs | Most cars, SUVs, small trucks |
| Price Range | Lower | Slightly higher |
The GB20 wins on size and price. The GB40 wins on power and versatility. If you drive a small car or a motorcycle, the GB20 is all you need. If you drive an SUV or a V6 sedan, go with the GB40.
The GB40 has been NOCO’s best-selling jump starter for over a decade. It’s the sweet spot between compact size and real power. The GB20 is better when maximum portability matters more than maximum amps.
What Vehicles Can the NOCO GB20 Jump Start?
The GB20 works with any 12-volt lead-acid battery. That includes flooded, AGM, EFB, and gel battery types.
Here’s a quick list of compatible vehicles:
- Compact and subcompact cars (4-cylinder engines)
- Motorcycles and scooters
- ATVs and UTVs
- Lawn mowers and riding mowers
- Personal watercraft and small boats
- Small RVs with 12V batteries
It’s not the right choice for V8 trucks, large SUVs, or diesel vehicles. For those, NOCO offers the GB40 (1000A), GB50 (1500A), GB70 (2000A), and larger models.
How Does NOCO UltraSafe Technology Work?
Every NOCO Boost jump starter — including the GB20 — uses NOCO’s patented UltraSafe Technology. This is what makes these devices safe for everyday drivers, not just mechanics.
Here’s what it does in practice:
- Spark-proof connections: The clamps won’t spark when you attach them. This removes the risk of igniting battery gases.
- Reverse polarity protection: Connect the clamps backwards by mistake? The device won’t activate until you fix the connection.
- Mistake-proof design: The unit detects if it’s not properly connected before sending power.
This technology is why NOCO is trusted by mechanics, fleet managers, and everyday drivers alike. You don’t need experience to use one safely.
If the GB20 won’t activate after connecting the clamps, check the polarity first. The red clamp goes on the positive terminal, black on negative. The unit won’t fire until it detects a proper, safe connection.
How to Use the NOCO GB20 Step by Step
- Make sure the GB20 is charged before you need it.
- Connect the red clamp to the positive (+) battery terminal.
- Connect the black clamp to the negative (–) battery terminal.
- Power on the GB20 — wait for the green indicator light.
- Start your vehicle as normal.
- Once running, disconnect the black clamp first, then the red.
- Recharge the GB20 fully after use via the USB-C port.
The whole process takes under two minutes. Keep the GB20 charged — store it at full charge and top it off every few months when not in use.
How Often Should You Recharge the GB20?
NOCO recommends keeping the GB20 charged and topping it off every three months if you’re storing it. Lithium-ion batteries do lose small amounts of charge over time, even sitting unused.
The GB20 takes about three hours to fully recharge via its USB-C port. That’s the fastest recharge time in NOCO’s Boost lineup, which is another advantage of choosing the smallest model.
After you use it to jump start a vehicle, recharge it to 100% right away. Don’t leave it at a low charge state — that degrades the battery faster over time.
Does the GB20 Work in Cold Weather?
Cold temperatures are the enemy of both car batteries and lithium-ion devices. The GB20 handles cold better than you might expect. Its high-discharge lithium technology is designed for safe operation across a wide temperature range.
That said, extreme cold (below -20°C / -4°F) will reduce its effective output. If you live somewhere with severe winters, warm the GB20 inside your jacket for a few minutes before using it. That small step can make a real difference in performance.
Drivers in cold climates may also want to consider the GB40, which offers more amp headroom for cold-weather cranking.
The GB20 is NOCO’s smallest and lightest jump starter. It weighs 2.1 pounds, fits in a glove box, and delivers 500 amps for gas engines up to 4.0L. It’s ideal for compact cars, motorcycles, and ATVs. Not suitable for diesel engines. Recharges in about 3 hours via USB-C.
NOCO Boost Model Lineup: From Smallest to Largest
Here’s the full NOCO Boost consumer lineup in 2025, sorted from smallest to largest by power output.
| Model | Peak Amps | Max Gas Engine | Max Diesel Engine | Best For |
|---|---|---|---|---|
| GB20 | 500A | 4.0L | Not rated | Compact cars, bikes |
| GB40 | 1000A | 6.0L | 3.0L | Most cars and SUVs |
| GB50 | 1500A | 7.0L | 4.5L | Large SUVs, trucks |
| GB70 | 2000A | 8.0L | 6.0L | Heavy trucks, HD vehicles |
| GB150 | 3000A | 9.0L | 7.0L | Commercial, fleet use |
NOCO also offers the newer Boost X series (GBX45, GBX55, GBX75, GBX155) with USB-C fast charging and updated PX Lithium Technology. These are newer designs but fall in the same power range as the classic models above.
Why Choose NOCO Over Other Jump Starter Brands?
NOCO (the NOCO Company) has been making battery products since 1914. That’s over a century of electrical engineering experience. Their Boost lineup introduced lithium jump starters to the mainstream market.
Competing brands like Gooloo, HULKMAN, and DeWalt also make capable jump starters. But NOCO’s UltraSafe Technology, IP65 weatherproofing, and compact form factor keep them at the top of most tested comparisons.
The Car and Driver jump starter testing guide consistently includes NOCO models among their top picks due to build quality and safety features.
For what it is, the GB20 offers reliable performance and a genuinely useful set of features — flashlight, power bank, and safety tech — all in a glove-box-friendly package.
What Are the Limits of the NOCO GB20?
The GB20 is great — but it has real limits worth knowing before you buy.
- Not for diesel: NOCO explicitly rates it as not recommended for diesel engines.
- No fast charging: Its USB-C input only does 5V / 2.1A. Recharging takes about 3 hours. Faster charging requires higher-end NOCO models.
- Short cables: Like the GB40, the GB20’s clamp cables are around 6 inches long. That can be tight in some engine bays with deep-set batteries.
- 24Wh battery capacity: After heavy use, you may need a recharge after just two jump starts in rapid succession.
None of these are dealbreakers for the GB20’s target user. If any of these limits matter to you, the GB40 or Boost X series is the smarter choice.
If your battery is completely dead and deeply discharged, connect the clamps and wait 60 seconds before attempting to start. This lets the GB20 partially recover the battery first, improving your success rate.
Is the NOCO GB20 Worth Buying in 2025?
Yes — if you own a small car, motorcycle, ATV, or lawn mower. It’s the most affordable and most portable entry point into the NOCO Boost lineup.
For drivers with larger vehicles, it’s not the right tool. A V6 SUV or a diesel truck needs more power than the GB20 provides.
But for urban commuters, motorcycle riders, and anyone who wants a no-fuss emergency backup in their glove box, the GB20 delivers exactly what it promises. Check the official NOCO GB20 specifications page for the most current technical details.
NOCO Boost GB20: 500A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack, Portable Jump Box, Power Bank & Jumper Cables – for 4.0L Gas Engines
The smallest NOCO jump starter you can buy — compact enough for a glove box, powerful enough to start most compact cars and motorcycles in seconds.
Conclusion
The NOCO GB20 is the smallest jump starter NOCO makes. At 2.1 pounds and 500 amps, it handles compact cars, motorcycles, and ATVs without taking up any meaningful space in your vehicle.
If you drive something larger — an SUV, truck, or diesel vehicle — step up to the GB40 or higher. The extra size is worth it for the added power and diesel capability.
Pick the model that matches your engine size, keep it charged, and you’ll never be stranded with a dead battery again. As someone who has tested jump starters for years, I can tell you — having even the smallest NOCO in your glove box is a decision you’ll never regret. — Alex Rahman
Frequently Asked Questions
What is the smallest NOCO jump starter available?
The NOCO Boost Sport GB20 is the smallest model NOCO makes. It weighs 2.1 pounds, measures 7.72 x 3.16 x 1.71 inches, and delivers 500 amps. It fits easily in a glove box and is designed for gas engines up to 4.0 liters.
Can the NOCO GB20 jump start a diesel car?
No — NOCO does not recommend the GB20 for diesel engines. If you drive a diesel vehicle, you need at least the GB40, which handles diesel engines up to 3.0 liters. Larger diesel trucks require the GB70 or higher.
How long does the NOCO GB20 hold its charge?
The GB20 holds its charge well during storage, but NOCO recommends topping it off every three months. Lithium-ion batteries drain slowly even when unused. A full recharge takes about three hours via the USB-C port.
What is the difference between the NOCO GB20 and GB40?
The GB20 delivers 500 amps and works on gas engines up to 4.0 liters. The GB40 delivers 1000 amps and handles gas engines up to 6.0 liters plus small diesel engines. The GB40 is slightly larger and heavier but covers far more vehicle types.
Is the NOCO GB20 safe for someone with no experience to use?
Yes. The GB20 uses NOCO’s UltraSafe Technology with spark-proof connections and reverse polarity protection. It won’t activate if you connect the clamps incorrectly. It’s designed to be mistake-proof and safe for first-time users.
