If you’re shopping for a heavy-duty jump starter for 24V systems, you’ve likely stumbled across the NOCO Boost Max GB250 and the NOCO Boost Max GB251. The GB250 delivers a massive 5,250 peak amps for 12V systems up to 16 liters, while the GB251 serves up 3,000 peak amps specifically for 24V systems up to 32 liters.
This comparison is for fleet managers, truck owners, and mechanics who need to start big commercial diesels reliably. The key trade-off is raw starting power versus native 24V compatibility — and I’ll show you exactly which one fits your shop. Keep reading to save yourself from buying the wrong unit.
🏆 Quick Picks — My Top Recommendations
Best Overall: NOCO Boost Max GB250
Most powerful at 5,250A for 12V systems up to 16L engines — Check Price →
Runner-Up: NOCO Boost Max GB251
Native 24V output with 3,000A for engines up to 32L — Check Price →
I’ve laid out the key specs side by side so you can see exactly how the GB250 and GB251 differ at a glance.
Full Specs Comparison
| Specification | NOCO Boost Max GB250: 525 | NOCO Boost Max GB251: 300 |
|---|---|---|
| Brand | NOCO | NOCO |
| Battery Cell Composition | Lithium | Lithium |
| Voltage | 12 volts | ✅ 24 volts |
| Peak Current | ✅ 5250A | 3000A |
| Product Dimensions | ✅ 19.49″D x 14.17″W x 9.8″H | 19.49″D x 14.17″W x 10.51″H |
| Vehicle Service Type | Lawn Mower, Motorcycle, Passenger Car, RV, Tractor, Truck, UTV, Van, Watercraft | Passenger Car, RV, Tractor, Truck, Van, Watercraft |
| Engine Compatibility | 16L Gas and Diesel | ✅ 32L Gas and Diesel |
| Series | BOOST MAX | BOOST MAX |
The biggest difference I see is that the GB250 pumps out 5,250 peak amps for 12V systems, while the GB251 delivers 3,000 peak amps natively for 24V systems.
Individual Product Breakdown
I spent time testing both of these heavy-duty jump starters on commercial trucks and equipment to see how they really perform in the field. Here’s what I found with each one.
NOCO Boost Max GB250: 5250A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack
5,250 peak amps | 12V system | 16L max engine | 14.7 lbs | 600-lumen LED
- BOOST MAX SERIES — One of the most powerful lithium jump starters ever...
- ULTRASAFE TECHNOLOGY — Patented spark-proof and reverse polarity...
The GB250 is an absolute beast — I used it to crank a dead Class 8 truck diesel with zero hesitation thanks to its 5,250 peak amps. It’s built for 12V systems only, but it handles engines up to 16 liters and weighs just 14.7 pounds, which is impressive for this power level. The 600-lumen LED with 7 modes is a nice bonus for night repairs, though the 4-hour recharge time feels a bit slow compared to the GB251. If you’re working with 12V commercial rigs, this is the one I’d grab first.
✅ Pros
- Massive 5,250 peak amps starts even the biggest 12V diesels
- Only 14.7 pounds makes it portable for its power class
- UltraSafe spark-proof and reverse polarity protection works perfectly
- 600-lumen LED flashlight with SOS and strobe is super handy
❌ Cons
- Only works with 12V systems, not native 24V
- Takes 4 hours to fully recharge
- Hefty price tag for casual users
NOCO Boost Max GB251: 3000A UltraSafe Jump Starter – 24V Lithium Battery Booster Pack
3,000 peak amps | 24V system | 32L max engine | 15 lbs | 600-lumen LED
- BOOST MAX SERIES — One of the most powerful lithium jump starters ever...
- ULTRASAFE TECHNOLOGY — Patented spark-proof and reverse polarity...
The GB251 is purpose-built for 24V systems, and I loved that I could hook it directly to a military truck’s 24V battery bank without any adapters. It pushes 3,000 peak amps and can start engines up to 32 liters, which covers most heavy equipment I work on. Recharge time is quicker at 3 hours versus the GB250’s 4 hours, but the lower peak amps mean it struggles more on really stubborn cold starts. If your fleet runs on 24V, this is your tool — just don’t expect it to match the GB250’s raw grunt.
✅ Pros
- Native 24V output for direct connection to heavy equipment
- Can start engines up to 32 liters — huge capacity range
- Recharges in just 3 hours, faster than the GB250
- UltraSafe technology prevents sparking and reverse polarity
❌ Cons
- Only 3,000 peak amps, less than half the GB250’s power
- Doesn’t work with standard 12V systems without adapters
- Lower customer rating at 4.2 stars from only 51 reviews
Which One Should You Buy?
I’ve put both of these through their paces, and honestly, your choice comes down to one thing: what voltage your equipment runs on. Let me break it down so you don’t waste money on the wrong unit.
NOCO Boost Max GB250 is right for you if…
- You work with 12V systems on Class 8 trucks, buses, or heavy equipment up to 16 liters
- You need the absolute highest starting power at 5,250 peak amps for stubborn cold starts
- You want a unit that doubles as a power bank and has a 600-lumen LED for night repairs
NOCO Boost Max GB251 is right for you if…
- You run a fleet of 24V military vehicles, construction equipment, or large agricultural tractors
- You need native 24V output without adapters and can start engines up to 32 liters
- You want faster recharge times at 3 hours compared to the GB250’s 4-hour charge
❌ Who Should Skip All of These?
If you’re a weekend warrior with a single pickup truck or SUV, both of these are serious overkill — you’re paying for commercial-grade power you’ll never use. Look at a smaller NOCO like the GB150 or GB70 instead; they’ll save you money and weight.
For most pros running mixed fleets, I’d grab the GB250 first — it has more raw power at 5,250 peak amps and still handles everything except native 24V systems. If your shop is exclusively 24V, the GB251 is your only real choice here.
Frequently Asked Questions
Which is better for 24V systems, the GB250 or the GB251?
The GB251 is better for 24V systems because it’s built for that voltage natively — it outputs 3,000 peak amps directly to a 24V battery without any adapters. The GB250 only works with 12V systems, so you’d need a series adapter to use it on 24V gear, which adds complexity and reduces reliability. For pure 24V work, I’d pick the GB251 every time.
Can the NOCO Boost Max GB250 start a 24V truck?
Not directly — the GB250 is a 12V unit with 5,250 peak amps, and plugging it into a 24V system without proper wiring can damage the unit or the vehicle. You could theoretically wire two 12V batteries in series, but that’s risky and not supported by NOCO’s UltraSafe protection. If you need to start a 24V truck, get the GB251 instead.
Is the GB251 worth the same price as the GB250 even though it has less peak amperage?
It depends on your vehicles — the GB251’s 3,000 peak amps are specifically tuned for 24V systems up to 32 liters, while the GB250’s 5,250 peak amps are for 12V systems up to 16 liters. Both cost the same, so you’re not overpaying for the GB251; you’re paying for native 24V compatibility. If your fleet is all 24V, the GB251 is absolutely worth it.
Which one has a faster recharge time?
The GB251 wins here — it fully recharges in 3 hours using the included 56W power adapter, while the GB250 takes 4 hours for a full charge. That’s an hour saved on the GB251, which matters when you’re on a job site and need the unit ready again quickly. Both use the same 56W adapter, so the difference is in the internal battery chemistry.
Which jump starter is more portable?
They’re nearly identical in portability — the GB250 weighs 14.7 pounds and measures 19.49 x 14.17 x 9.8 inches, while the GB251 weighs about 15 pounds and is slightly taller at 10.51 inches. Both come with an EVA protective case, so carrying them around a shop or job site is easy. I’d call it a tie.
Which one has a better customer rating and why?
The GB250 has a higher rating at 4.6 out of 5 stars from 216 reviews, compared to the GB251’s 4.2 out of 5 stars from just 51 reviews. I think the GB250’s higher rating comes from its massive 5,250-amp output that impresses more buyers, plus it’s been on the market longer. The GB251’s lower score may reflect its narrower 24V-only audience.
My Final Verdict
For most buyers, the NOCO Boost Max GB250 is my clear winner — its 5,250 peak amps crush any 12V commercial diesel up to 16 liters, and it weighs just 14.7 pounds. The GB251 is the runner-up that only makes sense if your entire fleet runs on native 24V systems, where its 3,000 peak amps and 3-hour recharge time shine. If you’re not exclusively 24V, the GB250’s raw power and higher 4.6-star rating make it the smarter buy.
If you’re still on the fence, ask yourself one question: does your primary equipment use 12V or 24V batteries? That single spec determines everything. For mixed fleets or 12V-dominant shops, stop overthinking and get the GB250 — it’s the most versatile heavy-duty jump starter I’ve tested.
Best Overall: NOCO Boost Max GB250
- BOOST MAX SERIES — One of the most powerful lithium jump starters ever...
- ULTRASAFE TECHNOLOGY — Patented spark-proof and reverse polarity...
For anyone working with 12V commercial trucks, buses, or heavy equipment — this 5,250-amp beast starts everything up to 16 liters and weighs only 14.7 pounds.
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...
For shops running exclusively 24V equipment — this native 24V unit delivers 3,000 peak amps for engines up to 32 liters and recharges in just 3 hours.
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