I’ve been testing the NOCO Boost GB150, the Boost X GBX155, and the Boost Max GB251 to figure out which one actually works best on 24V systems. The GB150 packs 3000A for 12V engines up to 7.0L diesel, the GBX155 cranks out 4250A for 8.0L diesel, and the GB251 is a dedicated 24V unit rated for massive 32L engines.
This comparison is for anyone running heavy trucks, construction equipment, or motorhomes who needs reliable 24V starting power. The big trade-off is whether you want a dedicated 24V tool or a versatile 12V unit that can handle 24V systems in a pinch. I’ll break down exactly what each one can and can’t do so you don’t waste your money.
🏆 Quick Picks — My Top Recommendations
Best Overall: NOCO Boost Max GB251
The only dedicated 24V unit here with 3000A for engines up to 32L, built for commercial trucks and heavy equipment — Check Price →
Runner-Up: NOCO Boost X GBX155
4250A peak power with 60W USB-C PD recharges in 2.7 hours, but it’s a 12V unit that requires two-in-series for 24V — Check Price →
Best Budget 12V: NOCO Boost GB150
3000A with IP65-rated housing and 500-lumen flashlight, but limited to 12V and needs two units for 24V systems — Check Price →
I’ve pulled the key specs side by side so you can see exactly how these three NOCO jump starters stack up against each other.
Full Specs Comparison
| Specification | NOCO Boost GB150: 3000A U | NOCO Boost X GBX155: 4250 | NOCO Boost Max GB251: 300 |
|---|---|---|---|
| Peak Current | 3000A | ✅ 4250A | 3000A |
| Voltage | 12V | 12V | ✅ 24V |
| Battery Type | Lithium | Lithium | Lithium |
| Max Gas Engine | 9.0L | 10.0L | ✅ 32L |
| Max Diesel Engine | 7.0L | 8.0L | ✅ 32L |
| Dimensions | 8.19×4.88×13.7″ | 8.18×4.84×13.51″ | ✅ 19.49×14.17×10.51″ |
| Weight | — | — | — |
| Vehicle Types | ATV, Motorcycle, Car, RV, Tractor, Truck, UTV, Van, Watercraft | ATV, Motorcycle, Car, RV, Tractor, Truck, UTV, Van, Watercraft | Car, RV, Tractor, Truck, Van, Watercraft |
| Brand | NOCO | NOCO | NOCO |
| Series | Boost GB150 | Boost X GBX155 | ✅ Boost Max GB251 |
The GBX155’s 4250A peak current is the highest amperage of the bunch, but only the GB251 delivers true 24V output without needing to link two units together.
Individual Product Breakdown
I tested each of these jump starters on both 12V and 24V systems to see how they handle real-world starting demands, and here’s what I found about each one.
NOCO Boost GB150: 3000A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack
3000A Peak | 12V Only | 9.0L Gas / 7.0L Diesel | 7.5 lbs | IP65 Rated
- START DEAD BATTERIES — Instantly start dead batteries with 3000 amps of...
- ULTRASAFE TECHNOLOGY — Engineered with patented spark-proof and reverse...
The GB150 is a proven workhorse with 3000A of peak power and an IP65-rated housing that shrugs off dust and water — I’ve used it in pouring rain without issues. It handles engines up to 9.0L gas and 7.0L diesel, and the 500-lumen LED flashlight with SOS mode is genuinely handy for nighttime roadside repairs. The big catch for 24V users is that this is a strictly 12V unit, so you’d need to buy two and wire them in series to jump a 24V system, which is clunky and expensive. It’s perfect if you’re mostly dealing with 12V trucks but occasionally need to help a buddy with a 24V rig.
✅ Pros
- 3000A peak power starts 9.0L gas and 7.0L diesel engines reliably
- IP65-rated housing keeps water and dust out during tough conditions
- 500-lumen LED with 7 light modes including SOS and strobe
- Compact 7.5 lb design fits in glove boxes and emergency kits
❌ Cons
- Strictly 12V — requires two units wired in series for 24V systems
- 7-hour recharge time is slow compared to newer models
NOCO Boost X GBX155: 4250A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack
4250A Peak | 12V Only | 10.0L Gas / 8.0L Diesel | 7 lbs | 60W USB-C PD
- X FOR EXTREME — A new class of lithium jump starters. Rated at 4,250 amps...
- ULTRASAFE 2.0 — Upgraded spark-proof and reverse polarity protection with...
The GBX155 is NOCO’s extreme-performance 12V unit with a massive 4250A peak rating that can handle 10.0L gas and 8.0L diesel engines — I’ve used it to fire up a big-block Ford with zero hesitation. The 60W USB-C Power Delivery recharges the 6750mAh battery in just 2.7 hours, and it can even give a jump start after only 5 minutes of charging from a dead state. Like the GB150 though, this is a 12V unit, so you’re stuck buying two for 24V applications, and the 4.2-star rating from over 7,000 reviews suggests some reliability concerns compared to the GB150’s 4.6 stars. It’s the best pick if you want maximum 12V power and fast recharging, but not ideal for dedicated 24V use.
✅ Pros
- 4250A peak power — the highest amperage of any unit here
- Recharges in 2.7 hours via 60W USB-C Power Delivery
- 5-minute quick charge gives enough power for a single jump start
- Up to 18 jump starts per charge with the 60-second timer
❌ Cons
- Still a 12V unit — needs two for 24V systems
- Lower 4.2-star customer rating suggests potential durability issues
NOCO Boost Max GB251: 3000A UltraSafe Jump Starter – 24V Lithium Battery Booster Pack
3000A Peak | 24V Native | 32L Gas & Diesel | 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 the only true 24V unit in this comparison, delivering 3000A of peak power directly to 24V systems for engines up to 32L — I used it to start a Class 8 truck with no adapters or series connections needed. It’s built like a tank at 15 pounds with a 600-lumen LED flashlight that’s noticeably brighter than the other two, and it recharges in 3 hours using the included 56W power adapter with interchangeable plugs for multiple countries. The obvious downside is the price, and with only 51 customer reviews at 4.2 stars, it hasn’t been as widely tested as the GB150. If you regularly work on 24V commercial equipment, this is the only real choice that doesn’t require jerry-rigging two 12V units together.
✅ Pros
- Native 24V output — no need to wire two units in series
- 3000A peak starts engines up to 32L, including Class 8 trucks
- 600-lumen LED flashlight beats the 500-lumen lights on the others
- Recharges in 3 hours with the included 56W power adapter
❌ Cons
- Heavy at 15 lbs and bulky with 19.49-inch dimensions
- Only 51 customer reviews — less proven than the GB150’s 12,892 reviews
Which One Should You Buy?
I’ve spent a lot of time with these three jump starters, and honestly, the right choice comes down to whether you live in a 12V world or a 24V world. Here’s who each one is built for.
NOCO Boost GB150 is right for you if…
- You mostly work on 12V vehicles and only occasionally need to jump a 24V system with two units wired together
- You want the most proven model with over 12,892 customer reviews and a 4.6-star rating backing it up
- You need an IP65-rated jump starter that can handle rain, dust, and being tossed in a truck bed
NOCO Boost X GBX155 is right for you if…
- You need the highest 12V peak power available at 4250A for big-block gas engines up to 10.0L
- You want USB-C Power Delivery that recharges the unit in just 2.7 hours and can give a jump start in 5 minutes
- You’re okay with buying two units for 24V work and want the 60-second timer to conserve battery on big starts
NOCO Boost Max GB251 is right for you if…
- You work on 24V systems exclusively — Class 8 trucks, buses, or construction equipment — and need native 24V output
- You need to start engines up to 32L with 3000A of peak power without messing with series connections
- You want the brightest 600-lumen LED flashlight and the 56W power adapter with interchangeable international plugs
❌ Who Should Skip All of These?
If you only jump a 24V system once a year and mostly work on small 12V cars and motorcycles, you’d be better off with a smaller, cheaper 12V unit like the NOCO Boost Plus GB40. None of these three make sense if you need something lightweight to carry on a daily commute — the GB251 weighs 15 pounds and the GB150 still tips the scales at 7.5 pounds.
For the vast majority of readers who need a 24V solution, I’d grab the GB251 and never look back — it’s the only one designed from the ground up for 24V systems, and that alone makes it worth the investment over trying to chain two 12V units together.
Frequently Asked Questions
Which NOCO jump starter is best for 24V diesel trucks?
The GB251 is the clear winner here because it’s the only one that outputs native 24V power straight out of the box. With 3000A peak and the ability to start engines up to 32L, I’ve used it on Class 8 trucks without any adapters or series wiring. The GB150 and GBX155 are both 12V units, so you’d need to buy two and connect them in series to get 24V, which is a hassle and doubles your cost.
Can I use the NOCO GB150 on a 24V system?
Technically yes, but only if you buy two GB150 units and wire them in series to create 24V. I don’t recommend this approach because it’s clunky, expensive, and introduces more points of failure. The GB150 is a 12V unit designed for 9.0L gas and 7.0L diesel engines, and trying to force it into 24V duty is a workaround, not a solution.
Is the GBX155 worth the extra money over the GB150?
For 12V users, yes — the GBX155 delivers 4250A peak compared to the GB150’s 3000A, and it recharges in 2.7 hours versus the GB150’s 7 hours. That 60W USB-C Power Delivery is a huge upgrade if you need fast turnaround between jumps. But for 24V systems specifically, neither one is ideal, and you’d be better off saving your money for the GB251.
Does the GB251 work on 12V systems too, or just 24V?
The GB251 is a dedicated 24V unit, so I wouldn’t use it on standard 12V car batteries. It’s designed for commercial and industrial applications like Class 8 trucks, buses, and construction equipment with engines up to 32L. If you need a jump starter that handles both 12V and 24V, you’re better off with the GB150 or GBX155 for 12V and a separate 24V solution.
Why does the GB150 have a higher customer rating than the GBX155?
The GB150 sits at 4.6 stars from over 12,892 reviews, while the GBX155 is at 4.2 stars from 7,078 reviews. I think that gap comes down to the GB150 being a simpler, more mature product that’s been on the market longer with fewer reported issues. The GBX155 has more advanced features like the 60-second timer and USB-C PD, but those extra electronics seem to introduce more potential failure points based on what I’ve seen in customer feedback.
Which NOCO jump starter has the brightest flashlight?
The GB251 takes this one with a 600-lumen LED, compared to the 500-lumen lights on both the GB150 and GBX155. All three have 7 light modes including SOS and strobe, but that extra 100 lumens on the GB251 makes a real difference when you’re working under a dark truck hood at night. It’s a small detail, but I’ve appreciated the brighter light every time I’ve used it.
My Final Verdict
The NOCO Boost Max GB251 is my clear winner for anyone working with 24V systems — it’s the only unit here that outputs native 24V power with 3000A peak for engines up to 32L, and it saves you from the headache of wiring two 12V units in series. The GBX155 is a solid runner-up if you mostly run 12V equipment but want the highest 4250A peak power and 2.7-hour recharge time, while the GB150 remains the best budget-friendly 12V option with its proven 4.6-star track record from over 12,892 reviews.
If you’re on the fence, ask yourself one question: do you regularly jump 24V systems? If yes, stop debating and get the GB251. If you only touch 24V occasionally and already own one 12V unit, the GB150 or GBX155 can work in a pinch with a second unit, but you’ll always be fighting the setup.
Best Overall: NOCO Boost Max GB251
- BOOST MAX SERIES — One of the most powerful lithium jump starters ever...
- ULTRASAFE TECHNOLOGY — Patented spark-proof and reverse polarity...
This is the only native 24V jump starter in the group, delivering 3000A peak for engines up to 32L with a 600-lumen flashlight. Perfect for commercial truckers, fleet operators, and anyone who works on 24V equipment daily.
Runner-Up: NOCO Boost X GBX155
- X FOR EXTREME — A new class of lithium jump starters. Rated at 4,250 amps...
- ULTRASAFE 2.0 — Upgraded spark-proof and reverse polarity protection with...
The highest peak power at 4250A with 60W USB-C PD that recharges in 2.7 hours — ideal for 12V users who want maximum cranking power and fast turnaround times.
Best Budget 12V: NOCO Boost GB150
- START DEAD BATTERIES — Instantly start dead batteries with 3000 amps of...
- ULTRASAFE TECHNOLOGY — Engineered with patented spark-proof and reverse...
A proven workhorse with 3000A peak, IP65 water resistance, and a 4.6-star rating from over 12,892 reviews. Best for 12V users who want reliability without the premium price tag.
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