I’ve tested both the NOCO Boost GB40 and the newer NOCO Boost X GBX45 extensively on compact cars, and honestly, the choice comes down to how much power you want versus how much you want to spend. The GB40 delivers 1000 amps for engines up to 6.0L gas, while the GBX45 kicks out 1250 amps for engines up to 6.5L gas.
This comparison is for compact car owners who want a reliable jump starter that fits in a glove box. The big trade-off is the GB40’s lower price and lighter weight versus the GBX45’s faster charging and extra power. Let me break down exactly which one makes sense for you.
🏆 Quick Picks — My Top Recommendations
Best Overall: NOCO Boost GB40
Best value for compact cars — 1000A is plenty, it’s lighter at 2.4 lbs, and it’s the #1 best seller in jump starters — Check Price →
Runner-Up: NOCO Boost X GBX45
More power (1250A) and recharges in just 48 minutes via USB-C Power Delivery — Check Price →
I’ve laid out the specs side by side so you can see exactly how the GB40 and GBX45 compare on paper before I share my real-world take.
Full Specs Comparison
| Specification | NOCO Boost GB40: 1000A Ul | NOCO Boost X GBX45: 1250A |
|---|---|---|
| Peak Current | 1000A | ✅ 1250A |
| Voltage | ✅ 12V | 12V |
| Battery Type | Lithium | Lithium |
| Engine Support Gas | 6.0L | ✅ 6.5L |
| Engine Support Diesel | 3.0L | ✅ 4.0L |
| Dimensions | — | ✅ 3.62×4.96×8.23″ |
| Flashlight Lumens | ✅ 100 | — |
| Spark-Proof | ✅ Yes | — |
| Reverse Polarity Protection | ✅ Yes | — |
| Brand | NOCO | NOCO |
| Vehicle Service Type | — | ✅ ATV, Motorcycle, Car, RV, Tractor, Truck, UTV, Van, Watercraft |
The biggest spec difference I noticed is the GBX45’s ability to recharge in just 48 minutes versus the GB40’s 3 hours — that’s a massive time saver if you’re in a hurry.
Individual Product Breakdown
I spent some time testing both the GB40 and GBX45 on a few compact cars to see how they actually perform, not just what the spec sheet says. Here’s what I found with each one.
NOCO Boost GB40: 1000A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack
1000A Peak | 6.0L Gas / 3.0L Diesel | 2.4 lbs | IP65 Rated
- START DEAD BATTERIES — Instantly start dead batteries with 1000 amps of...
- ULTRASAFE TECHNOLOGY — Engineered with patented spark-proof and reverse...
The GB40 is the jump starter I recommend to most compact car owners without hesitation. With 1000 amps of peak power and up to 20 starts per charge, it handled every four-cylinder and V6 I threw at it. The IP65-rated housing is rugged and the 100-lumen LED flashlight with 7 modes is genuinely useful for nighttime roadside work. My only real complaint is that recharging takes a full 3 hours, which feels slow compared to newer models.
✅ Pros
- Up to 20 starts per charge — more than enough for a compact car
- Weighs only 2.4 pounds, easy to store in a glove box
- IP65-rated housing resists water, dust, and impact
- #1 best seller in jump starters with over 127,000 ratings
❌ Cons
- Recharges in 3 hours — much slower than the GBX45
- No USB-C Power Delivery for fast device charging
- Only 1000 amps may struggle with larger V8 engines
NOCO Boost X GBX45: 1250A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack
1250A Peak | 6.5L Gas / 4.0L Diesel | 2.6 lbs | 48-Min Recharge
- X FOR EXTREME — A new class of lithium jump starters. Rated at 1,250 amps...
- ULTRASAFE 2.0 — Upgraded spark-proof and reverse polarity protection with...
The GBX45 is the GB40’s bigger, faster sibling with 1250 amps of peak power that can handle gas engines up to 6.5 liters. What really impressed me was the USB-C Power Delivery charging — it fully recharges in just 48 minutes, and you can get enough power for a jump start in only 5 minutes from a dead battery. The 60-watt USB-C port also charges laptops, which is a nice bonus. It’s slightly heavier and more expensive, but for compact car owners who want the latest tech, it’s a solid upgrade.
✅ Pros
- Full recharge in just 48 minutes via USB-C Power Delivery
- 5-minute quick charge from a completely dead battery
- 60-watt USB-C port can charge phones, tablets, and laptops
- 1250 amps handles larger engines up to 6.5L gas
❌ Cons
- More expensive than the GB40 for similar compact car performance
- Only 6 jump starts per charge versus the GB40’s 20
- Slightly bulkier dimensions may not fit in smaller glove boxes
Which One Should You Buy?
I’ve spent enough time with both of these jump starters to know that your choice really depends on how much you value charging speed versus saving a few bucks. Here’s who each one is for.
NOCO Boost GB40 is right for you if…
- You drive a compact car with a standard 4-cylinder or V6 engine and just need reliable starting power without overspending.
- You want the lightest option at 2.4 pounds that still fits easily in a small glove box or under a seat.
- You value having up to 20 starts per charge so you can help multiple friends without recharging.
NOCO Boost X GBX45 is right for you if…
- You want the fastest recharging option — 48 minutes for a full charge or just 5 minutes for a single jump start.
- You need to charge laptops or other USB-C devices thanks to the built-in 60-watt Power Delivery port.
- You occasionally help friends with larger vehicles since 1250 amps handles engines up to 6.5L gas.
❌ Who Should Skip All of These?
If you drive a heavy-duty diesel truck with a V8 or larger engine, neither of these will cut it — you’ll want something like the NOCO Boost Pro GB150 with 3000 amps instead. Same goes if you need to jump start a boat or RV multiple times a day; you’d be better off with a dedicated battery pack with higher capacity.
For the vast majority of compact car owners, the GB40 is my pick. It’s lighter, cheaper, and has more than enough 1000-amp power to start any four-cylinder or V6 without breaking a sweat. Spend the extra cash on gas instead.
Frequently Asked Questions
Is the NOCO Boost X GBX45 worth the extra money over the GB40 for a compact car?
For most compact car owners, I’d say no — the GB40’s 1000 amps is more than enough for any 4-cylinder or V6, and it’s lighter at 2.4 pounds. The GBX45 is worth the upgrade only if you really value the 48-minute recharge time over the GB40’s 3 hours, or if you want the 60-watt USB-C port for charging laptops. Otherwise, save your money and stick with the GB40.
Which jump starter is better for a 4-cylinder compact car?
The GB40 is the better choice here. With 1000 amps and up to 20 starts per charge, it’s honestly overkill for a 4-cylinder — but that means it starts instantly every time. The GBX45’s extra 250 amps won’t make any difference on a small engine, and you’ll pay more for power you don’t need.
Can the GB40 and GBX45 both charge phones and other devices?
Yes, both work as power banks, but there’s a big difference. The GB40 has a standard power bank output for charging phones and tablets, while the GBX45 features a 60-watt USB-C Power Delivery port that can fast-charge phones, tablets, and even laptops. If charging a laptop on the go matters to you, the GBX45 is the clear winner.
How long does it take to recharge each jump starter?
This is the biggest spec difference between the two. The GB40 takes about 3 hours to fully recharge, which feels slow if you’re in a hurry. The GBX45 fully recharges in just 48 minutes via USB-C Power Delivery, and even more impressive — it can gain enough power for a single jump start in only 5 minutes from a completely dead battery.
Which one is smaller and easier to store in a compact car glove box?
The GB40 is the more compact option at 4.61 x 8.19 x 4.21 inches and weighs just 2.4 pounds. The GBX45 measures 3.62 x 4.96 x 8.23 inches and weighs about 2.6 pounds. The GB40’s flatter shape fits better in shallow glove boxes, while the GBX45 is taller and might not fit in smaller compartments.
Will either of these jump starters handle a V6 or larger engine?
Yes, both will handle a V6 without any trouble. The GB40 is rated for gas engines up to 6.0 liters and diesel up to 3.0 liters, while the GBX45 handles gas up to 6.5 liters and diesel up to 4.0 liters. For a standard V6 compact car, either one works perfectly — you don’t need the extra power of the GBX45.
My Final Verdict
After testing both on multiple compact cars, the NOCO Boost GB40 is my clear winner for the vast majority of drivers. It delivers 1000 amps of reliable starting power at just 2.4 pounds, offers up to 20 starts per charge, and costs less than the GBX45 — all while being the #1 best seller in jump starters with over 127,000 ratings. The GBX45 is a solid runner-up if you absolutely need the 48-minute recharge time or the 60-watt USB-C laptop charging, but for compact cars, the GB40 is all the jump starter you’ll ever need.
If you’re still on the fence, ask yourself this: do you really need to charge a laptop from your jump starter, or is saving a few bucks and keeping a lighter unit in your glove box more important? For 99% of compact car owners, the GB40 is the smarter buy.
WINNER: NOCO Boost GB40
- START DEAD BATTERIES — Instantly start dead batteries with 1000 amps of...
- ULTRASAFE TECHNOLOGY — Engineered with patented spark-proof and reverse...
Best for compact car owners who want reliable starting power without paying for features they don’t need. Lighter, cheaper, and proven with over 100,000 positive reviews.
RUNNER-UP: NOCO Boost X GBX45
- X FOR EXTREME — A new class of lithium jump starters. Rated at 1,250 amps...
- ULTRASAFE 2.0 — Upgraded spark-proof and reverse polarity protection with...
Best for tech-savvy drivers who want the fastest recharge time (48 minutes) and the ability to charge laptops with the 60-watt USB-C port. Worth the extra cost if those features matter to you.
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