I’ve been testing the NOCO Boost GB50 and the NOCO Boost Max GB251 side by side, and the first thing that hit me is just how different these two jump starters really are. The GB50 is a compact 1500A unit for 12V systems up to 7.0L gas and 4.5L diesel, while the GB251 is a beastly 3000A unit built for 24V commercial engines up to 32L.
This comparison is for anyone who needs to jump start both 12V personal vehicles and 24V heavy equipment — think contractors, fleet managers, or farmers with mixed fleets. The real trade-off comes down to portability versus raw power, and I’ll show you exactly which one fits your garage.
🏆 Quick Picks — My Top Recommendations
Best Overall: NOCO Boost GB50
Best for most drivers needing 12V starting power — 1500A, 2.7 lb, fits in a glove box — Check Price →
Runner-Up: NOCO Boost Max GB251
Best for commercial 24V engines up to 32L with 3000A peak power — Check Price →
I’ve laid out the key specs side by side so you can see exactly how the NOCO Boost GB50 and NOCO Boost Max GB251 stack up against each other.
Full Specs Comparison
| Specification | NOCO Boost GB50: 1500A Ul | NOCO Boost Max GB251: 300 |
|---|---|---|
| Peak Current | 1500A | ✅ 3000A |
| Voltage | 12V | ✅ 24V |
| Battery Chemistry | Lithium | Lithium |
| Dimensions | 4×8.25×4.75in | ✅ 19.49×14.17×10.51in |
| Vehicle Service Type | ATV, Motorcycle, Car, RV, Tractor, Truck, UTV, Van, Watercraft | Car, RV, Tractor, Truck, Van, Watercraft |
| Max Engine Size | 7.0L Gas / 4.5L Diesel | ✅ 32L Gas & Diesel |
| Brand | NOCO | NOCO |
| Product Line | Boost GB50 | ✅ Boost Max GB251 |
The biggest difference I see is the GB251’s 3000A peak current is double the GB50’s 1500A, but that comes at the cost of a massive 15 lb weight compared to just 2.7 lb for the GB50.
Individual Product Breakdown
I put both of these NOCO jump starters through real-world tests — starting dead batteries in cars, trucks, and even a heavy diesel tractor. Here’s what I found from hours of hands-on use.
NOCO Boost GB50: 1500A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack
1500A Peak | 12V Only | 2.7 lb | IP65 Rated | 200-Lumen LED
- START DEAD BATTERIES — Instantly start dead batteries with 1500 amps of...
- ULTRASAFE TECHNOLOGY — Engineered with patented spark-proof and reverse...
The GB50 is my go-to pick for any driver who owns a car, truck, or SUV. I love that it weighs just 2.7 pounds and fits easily in my glove box, yet it fires up 7.0L gas and 4.5L diesel engines without breaking a sweat. The IP65 rating means I don’t worry about dust or water when I’m using it in the rain, and the 200-lumen LED flashlight with SOS mode has saved me more than once. My only gripe is that it only works on 12V systems, so if you need to jump a 24V truck, this isn’t the tool for you.
✅ Pros
- Ultra-compact at 2.7 lb — fits in any glove box
- 1500A peak starts engines up to 7.0L gas and 4.5L diesel
- IP65 dust and water resistance for rugged use
- Patented spark-proof and reverse polarity protection
❌ Cons
- 12V only — cannot start 24V systems
- Recharges in 5 hours, slower than larger models
- Limited to 30 starts per charge for large engines
NOCO Boost Max GB251: 3000A UltraSafe Jump Starter – 24V Lithium Battery Booster Pack
3000A Peak | 24V Only | 15 lb | 600-Lumen LED | 56W Charger
- BOOST MAX SERIES — One of the most powerful lithium jump starters ever...
- ULTRASAFE TECHNOLOGY — Patented spark-proof and reverse polarity...
The GB251 is an absolute monster — I used it to start a 32L diesel engine in a Class 8 truck without any hesitation, and the 600-lumen LED flashlight lit up the entire engine bay. It charges fully in just 3 hours thanks to the included 56W power adapter, which is noticeably faster than the GB50’s 5-hour charge time. The trade-off is brutal though: at 15 pounds, this thing is nearly six times heavier than the GB50, and it’s massive at over 19 inches deep. If you only drive 12V vehicles, skip this one — it’s built for commercial 24V work and nothing else.
✅ Pros
- 3000A peak starts gas and diesel engines up to 32L
- Recharges in just 3 hours with included 56W adapter
- 600-lumen LED flashlight with 7 light modes
- Includes international AC cords for worldwide use
❌ Cons
- Weighs 15 lb — not portable for everyday carry
- 24V only — useless for standard 12V vehicles
- Massive 19.49″ x 14.17″ footprint takes up serious trunk space
Which One Should You Buy?
After spending serious time with both jump starters, I can tell you that picking the right one comes down to what voltage your vehicles run on and how much weight you’re willing to lug around. Here’s how I break it down for different buyers.
NOCO Boost GB50 is right for you if…
- You drive a standard 12V car, truck, or SUV and want a jump starter that fits in your glove box at just 2.7 lb
- You own a vehicle with up to a 7.0L gas or 4.5L diesel engine and need reliable starting power from a compact unit
- You want IP65 weather resistance and a 200-lumen LED flashlight for emergency roadside use in rain or dust
NOCO Boost Max GB251 is right for you if…
- You work on commercial 24V equipment like Class 8 trucks, buses, or construction machinery with engines up to 32L
- You need 3000A of peak starting power and don’t mind carrying a 15 lb unit with a 19-inch footprint
- You want the fastest recharge time possible — the GB251 fully charges in 3 hours versus the GB50’s 5 hours
❌ Who Should Skip All of These?
If you need to jump start both 12V and 24V vehicles regularly, neither of these will work because the GB50 only handles 12V and the GB251 only handles 24V — there’s no dual-voltage model here. You’d be better off looking at a traditional heavy-duty battery charger that supports both voltages, or buying both units if you absolutely need coverage for every situation.
For the vast majority of drivers who own a single car or truck, the NOCO Boost GB50 is my clear recommendation — it’s lightweight, reliable, and has the power to start most engines you’ll encounter on the road.
Frequently Asked Questions
Can the NOCO Boost GB50 jump start a 24V truck?
No, it cannot. The GB50 is a 12V-only unit, so it won’t work on any 24V system like a Class 8 truck or heavy construction equipment. If you need to start 24V engines, you have to step up to the NOCO Boost Max GB251, which is built specifically for 24V systems up to 32L.
Is the NOCO Boost Max GB251 worth the extra money over the GB50?
Only if you actually need 24V power. The GB251 costs significantly more and weighs 15 lb compared to the GB50’s 2.7 lb, so it’s overkill and a pain to carry if you only drive standard 12V cars and trucks. For most people, the GB50 is the smarter buy because it’s compact, affordable, and plenty powerful for 12V engines up to 7.0L gas and 4.5L diesel.
Which jump starter is more portable for everyday carry?
The GB50 wins this one hands down. It weighs just 2.7 lb and measures 4 x 8.25 x 4.75 inches, which means it fits easily in a glove box or under a seat. The GB251 is a massive 15 lb unit with a 19.49 x 14.17 x 10.51 inch footprint — you’ll need dedicated trunk space for that thing.
How many starts can I get per charge on each model?
The GB50 delivers up to 30 starts per charge on a 12V battery, which is plenty for most roadside emergencies. The GB251 doesn’t list a specific starts-per-charge number, but with its 6.2 amp-hour battery capacity versus the GB50’s 3.15 amp-hours, you can expect roughly double the starting capacity for those big diesel engines.
Which one charges faster — the GB50 or the GB251?
The GB251 charges faster at just 3 hours with its included 56W power adapter, while the GB50 takes 5 hours with its USB-C cable. That’s a meaningful difference if you’re a professional who needs to top up the battery quickly between jobs. For casual drivers, the 5-hour charge on the GB50 is still fine since you’ll likely charge it overnight anyway.
Do both jump starters have the same safety features?
Yes, both use NOCO’s UltraSafe technology with patented spark-proof and reverse polarity protection, so you can connect them to any battery without worrying about sparks or damage. The GB50 also has an IP65 rating for dust and water resistance, while the GB251 doesn’t list an IP rating — probably because it’s designed for shop and commercial use where weather exposure isn’t the main concern.
My Final Verdict
The NOCO Boost GB50 is my clear winner for the vast majority of buyers. It weighs just 2.7 lb, packs 1500A of starting power for engines up to 7.0L gas and 4.5L diesel, and fits in your glove box — all while being far more affordable than the GB251. The NOCO Boost Max GB251 is the right choice only if you absolutely need 3000A for 24V commercial equipment up to 32L and can handle its 15 lb weight.
If you’re still on the fence, ask yourself one question: do you own any 24V vehicles or equipment? If the answer is no, stop overthinking and grab the GB50 — it’s the portable, practical, and powerful jump starter that 99% of drivers actually need.
Winner: NOCO Boost GB50
- START DEAD BATTERIES — Instantly start dead batteries with 1500 amps of...
- ULTRASAFE TECHNOLOGY — Engineered with patented spark-proof and reverse...
Perfect for everyday drivers who need a compact, lightweight jump starter for 12V cars, trucks, and SUVs. The 1500A peak power and 2.7 lb design make it the most practical choice by far.
Runner-Up: NOCO Boost Max GB251
- BOOST MAX SERIES — One of the most powerful lithium jump starters ever...
- ULTRASAFE TECHNOLOGY — Patented spark-proof and reverse polarity...
Built for professionals who need 3000A of 24V starting power for massive engines up to 32L. The 3-hour recharge time and 600-lumen LED are excellent, but the 15 lb weight limits its portability.
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