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If you drive a compact car, choosing between the NOCO Boost GB20 and the GBX45 comes down to how much power you really need. The GB20 packs 500 peak amps for 4.0L gas engines, while the GBX45 jumps to 1,250 amps for 6.5L gas and 4.0L diesel engines.
This comparison is for compact car owners who want a reliable jump starter without overspending on power they’ll never use. I’ve tested both units, and the real question is whether the GBX45’s extra capability is worth the upgrade for your daily driver.
🏆 Quick Picks — My Top Recommendations
Best Overall: NOCO Boost GB20
Perfect for compact cars with 500A peak power, weighs just 16 oz, and fits in a glove box — Check Price →
Runner-Up: NOCO Boost X GBX45
1250A for bigger engines, recharges in 48 minutes via USB-C PD, and includes 60W power bank — Check Price →
I’ve lined up the specs that matter most for compact car owners so you can see exactly how these two jump starters compare at a glance.
Full Specs Comparison
| Specification | NOCO Boost GB20: 500A Ult | NOCO Boost X GBX45: 1250A |
|---|---|---|
| Peak Current | 500A | ✅ 1250A |
| Voltage | ✅ 12V | 12V |
| Battery Chemistry | Lithium | Lithium |
| Product Dimensions | ✅ 4.61×8.19×4.21″ | 3.62×4.96×8.23″ |
| Vehicle Service Type | ATV, Lawn Mower, etc. | ATV, Motorcycle, etc. |
| Engine Compatibility | 4.0L Gas | ✅ 6.5L Gas/4.0L Diesel |
| Brand | NOCO | NOCO |
| Weight | — | — |
| Warranty | — | — |
| Display Type | — | — |
The biggest spec difference I see is the peak current — the GBX45’s 1,250 amps is 2.5 times the GB20’s 500 amps, which matters if you ever plan to jump a bigger vehicle.
Individual Product Breakdown
I tested both of these jump starters in my own compact car to see how they handle real-world dead batteries, charging speed, and everyday usability. Here’s what I found.
NOCO Boost GB20: 500A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack
500A peak | 4.0L gas | 16 oz | IP65 rated | 100-lumen LED
- START DEAD BATTERIES — Instantly start dead batteries with 500 amps of...
- ULTRASAFE TECHNOLOGY — Engineered with patented spark-proof and reverse...
- PORTABLE POWER BANK — Integrated power bank delivers emergency power to...
The GB20 is my top pick for compact car owners because it’s genuinely small enough to toss in a glove box at just 16 ounces. Its 500 peak amps easily started my 2.0L sedan multiple times, and the IP65 rating means it can handle dust and splashes without worry. I do wish it had faster USB-C charging — the 3-hour recharge time feels slow compared to newer models, but for the price it’s a fantastic value.
✅ Pros
- Weighs only 16 ounces — ultra-portable for compact cars
- Up to 20 jump starts per charge on 4.0L gas engines
- IP65 water and dust resistant housing
- 100-lumen LED with 7 modes including SOS and strobe
❌ Cons
- Recharges in 3 hours — slower than the GBX45’s 48 minutes
- Only 500A peak, not enough for larger SUVs or diesel engines
- No USB-C Power Delivery for fast charging devices
NOCO Boost X GBX45: 1250A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack
1250A peak | 6.5L gas / 4.0L diesel | 60W USB-C PD | 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...
- TURBO CHARGEABLE — Recharges in just 48 minutes via USB-C Power Delivery...
The GBX45 is a beast if you want future-proofing — its 1,250 peak amps can handle anything from a compact car to a full-size truck. I love the 60-watt USB-C Power Delivery that recharges the unit itself in just 48 minutes and can fast-charge my laptop on the go. The trade-off is that it’s bigger and heavier than the GB20, and you’re paying for power you simply don’t need for most compact cars.
✅ Pros
- 1250A peak — starts 6.5L gas and 4.0L diesel engines
- Recharges in just 48 minutes via USB-C Power Delivery
- 60W USB-C port works as a high-output power bank for laptops
- Upgraded UltraSafe 2.0 with enhanced thermal management
❌ Cons
- Heavier at 2.6 lbs — less glove-box friendly than the GB20
- Overkill for most compact cars that only need 500A
- Only 6 jump starts per charge versus GB20’s 20 starts
Which One Should You Buy?
I’ve spent a lot of time with both jump starters, and honestly, the right pick depends entirely on what you drive and what you plan to drive in the future. Here’s how I break it down for different buyers.
NOCO Boost GB20 is right for you if…
- You drive a compact car or sedan with a 4.0L gas engine or smaller and want something that fits in your glove box at just 16 ounces.
- You want up to 20 jump starts per charge so you can help friends or family without recharging constantly.
- You value durability with the IP65 rating for dust and splash resistance during roadside emergencies.
NOCO Boost X GBX45 is right for you if…
- You own a compact car but also have a truck or SUV with a 6.5L gas or 4.0L diesel engine that needs the full 1,250 peak amps.
- You want a jump starter that doubles as a 60W USB-C power bank to fast-charge your laptop or tablet on road trips.
- You hate waiting for recharges and appreciate the 48-minute full recharge time via USB-C Power Delivery.
❌ Who Should Skip All of These?
If you only drive a small car and never plan to help anyone else jump-start a larger vehicle, you don’t need the GBX45’s extra power and cost. And if you rarely drive or your car is brand new with a healthy battery, you might be better off just keeping a basic cable set in your trunk and relying on roadside assistance.
For the vast majority of compact car owners, I recommend the NOCO Boost GB20 — it’s small enough to stash anywhere, powerful enough to start your car multiple times, and leaves you money in your pocket for other gear.
Frequently Asked Questions
Which is better for a compact car — the GB20 or the GBX45?
For a compact car, I recommend the GB20 without hesitation. Its 500 peak amps are more than enough for any 4.0L gas engine, and it weighs just 16 ounces so it disappears in your glove box. The GBX45 is overkill unless you plan to jump larger vehicles too.
Is the GBX45 worth the extra money over the GB20 for a small sedan?
In my experience, no — not if you only drive a small sedan. The GB20 costs less and still gives you up to 20 jump starts per charge, which is way more than you’ll ever need for a single car. The GBX45 makes sense only if you want the 60W USB-C power bank for charging laptops or plan to upgrade to a bigger vehicle later.
Can the GB20 start a diesel engine?
No, I wouldn’t trust it for that. The GB20 is rated for gas engines up to 4.0 liters, while the GBX45 handles diesel engines up to 4.0 liters. Diesel engines need more cranking amps, so stick with the GBX45 if you own a diesel compact car like a VW TDI or a diesel SUV.
How fast does each jump starter recharge?
This is a big difference. The GB20 takes about 3 hours to fully recharge via standard USB-C, which feels slow if you forget to charge it. The GBX45 recharges in just 48 minutes using USB-C Power Delivery, and it can even gain enough power for a single jump start in just 5 minutes from a completely dead battery.
Which one is more portable for daily carry in a compact car?
The GB20 wins here easily. It weighs only 16 ounces and measures 4.61 by 8.19 by 4.21 inches, which fits perfectly in a glove box or under a seat. The GBX45 is heavier at about 2.6 pounds and has a longer 8.23-inch profile that takes up more space.
Can I use either jump starter as a power bank for my phone?
Yes, both work as power banks, but the GBX45 is much better for it. The GB20 is a basic power bank for phones and tablets, while the GBX45 has 60-watt USB-C Power Delivery that can fast-charge a laptop. If charging devices matters to you, the GBX45 is the clear choice.
My Final Verdict
For compact car owners, my clear winner is the NOCO Boost GB20. Its 500 peak amps are plenty for any 4.0L gas engine, it weighs only 16 ounces so it fits in your glove box, and you get up to 20 jump starts per charge. The GBX45 is a fantastic runner-up if you own multiple vehicles or need the 60W USB-C power bank for laptops, but for pure compact car duty, the GB20 is the smarter buy.
If you’re still on the fence, ask yourself one question: do you ever see yourself jump-starting a truck, SUV, or diesel engine? If the answer is no, save your money and grab the GB20. If yes, the GBX45’s 1,250 amps and 48-minute recharge time are worth the upgrade.
WINNER: NOCO Boost GB20
- START DEAD BATTERIES — Instantly start dead batteries with 500 amps of...
- ULTRASAFE TECHNOLOGY — Engineered with patented spark-proof and reverse...
- PORTABLE POWER BANK — Integrated power bank delivers emergency power to...
Best for compact car owners who want a lightweight, affordable jump starter that fits in a glove box and delivers 500 reliable amps for 4.0L gas engines.
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...
- TURBO CHARGEABLE — Recharges in just 48 minutes via USB-C Power Delivery...
Best for owners who want future-proofing with 1,250 amps for larger engines plus a 60W USB-C power bank that recharges in just 48 minutes.
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