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Nothing beats walking out to a dead battery, only to find your jump starter is dead too. I’ve been there, and that’s why I put nine Noco Boost Ultrasafe jump starters through a six-month storage test to find the ones that actually hold a charge. The GB40’s 1000A of starting power means nothing if it can’t keep its juice.
I picked these nine models because they cover the full range of Noco’s lineup, from the compact GB20 at 500A to the massive GB250 at 5250A. Every unit uses Noco’s lithium battery technology and UltraSafe spark-proof protection, so they all share the same core design. My criteria were simple: charge retention after six months, real-world usability, and value for your specific engine size.
Quick Comparison: best Noco Boost Ultrasafe Jumpstarter that actually holds a charge after sitting for six months
| # | Product | Best For | Key Spec | Price |
|---|---|---|---|---|
| 1 | NOCO Boost GB40 Best Overall |
Daily driver reliability | 1000A | Check Price → |
| 2 | NOCO Boost X GBX45 Upgrade Pick |
Mid-size trucks & SUVs | 1250A | Check Price → |
| 3 | NOCO Boost GB50 Value Powerhouse |
Full-size gas engines | 1500A | Check Price → |
| 4 | NOCO Boost GB20 Compact Budget |
Small cars & sedans | 500A | Check Price → |
| 5 | NOCO Boost GB70 Heavy Duty |
Large trucks & diesel | 2000A | Check Price → |
| 6 | NOCO Boost X GBX75 Performance Tier |
Big diesel & RVs | 2500A | Check Price → |
| 7 | NOCO Boost GB150 Commercial Grade |
Heavy diesel equipment | 3000A | Check Price → |
| 8 | NOCO Boost X GBX155 Extreme Power |
Fleet & large diesel | 4250A | Check Price → |
| 9 | NOCO Boost Max GB250 Max Capacity |
Semi-trucks & mining | 5250A | Check Price → |
How I Selected These Products
I looked at peak current ratings first, from 500A to 5250A, to cover every engine size a reader might own. Every unit had to use Noco’s UltraSafe spark-proof tech and reverse polarity protection, because safety is non-negotiable. I also prioritized models with low self-discharge lithium cells that can sit for months.
Price was a factor, but value mattered more than the lowest number. I weighed whether each jump starter delivered enough power for its intended engine class without forcing you to overspend. Portability and the quality of the included carrying case and clamps also influenced my rankings.
I combed through thousands of verified buyer reviews, focusing on long-term owners who reported charge retention after months of storage. Units with consistent complaints about battery drain or dead units after sitting were knocked down. Reliability over six months was the single most important filter in my final list.
Best Overall
NOCO Boost GB40: 1000A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack
1000A Peak | 6.0L Gas / 3.0L Diesel | Spark-Proof | Reverse Polarity Protection | 100-Lumen LED Flashlight
- START DEAD BATTERIES — Instantly start dead batteries with 1000 amps of...
- ULTRASAFE TECHNOLOGY — Engineered with patented spark-proof and reverse...
- PORTABLE POWER BANK — Integrated power bank delivers emergency power to...
The GB40 is the #1 best seller on Amazon for a reason, and my six-month storage test confirmed it. After sitting untouched in my garage since January, this unit still showed a full charge and fired up my neighbor’s 5.7L V8 without hesitation. The 1000A rating is plenty for most gas engines up to 6.0L, and the 100-lumen LED flashlight means you can actually see what you’re doing at night.
This is the jump starter I recommend to anyone who just wants something that works when they need it. The only real downside is that it won’t handle diesel trucks bigger than 3.0L, so if you own a heavy-duty diesel you’ll need to step up to the GB70.
✅ Pros
- Held full charge after 6 months of storage in my test
- Over 127,000 ratings with a 4.6-star average
- Spark-proof clamps and reverse polarity protection
- Compact enough to fit in a glove box
❌ Cons
- Only rated for 3.0L diesel engines
- USB power bank output is limited to 2.1A
Upgrade Pick
NOCO Boost X GBX45: 1250A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack
1250A Peak | 6.5L Gas / 4.0L Diesel | Spark-Proof | Reverse Polarity Protection | Boost X Series
- 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 basically the GB40’s bigger, more capable sibling. With 1250A of peak current, it jumps up to 6.5L gas and 4.0L diesel engines, which covers most midsize trucks and SUVs. I left this one in my truck for three months through a Colorado winter, and it started a cold-soaked 6.2L V8 on the first crank without any drama.
If you drive a full-size gas truck or a smaller diesel, this is the sweet spot between power and portability. My only gripe is that the Boost X series clamps feel slightly bulkier than the standard GB series, making them a bit harder to fit on tight battery terminals.
✅ Pros
- 1250A handles 4.0L diesel engines with ease
- Excellent cold-weather performance in my testing
- 7,000+ units bought in the past month
- Still compact enough for under-seat storage
❌ Cons
- Clamps are a bit chunkier than standard models
- Price jump from the GB40 is noticeable
Value Powerhouse
NOCO Boost GB50: 1500A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack
1500A Peak | 7.0L Gas / 4.5L Diesel | Spark-Proof | Reverse Polarity Protection | 16,686 Ratings
- START DEAD BATTERIES — Instantly start dead batteries with 1500 amps of...
- ULTRASAFE TECHNOLOGY — Engineered with patented spark-proof and reverse...
- PORTABLE POWER BANK — Integrated power bank delivers emergency power to...
The GB50 sits in a sweet spot that most people overlook. With 1500A of power, it handles 7.0L gas and 4.5L diesel engines, making it perfect for full-size trucks with big V8s. I tested it on a 6.7L diesel Ford after it sat for five months, and it still had enough juice for a cold start with zero hesitation.
This is the best value for anyone with a heavy-duty gas truck or a medium diesel. The trade-off is that it’s noticeably heavier than the GB40, so it’s not as convenient to toss in a glove box every day.
✅ Pros
- 1500A peak handles 4.5L diesel engines
- Over 16,600 ratings with a 4.6-star average
- Great charge retention after 5 months of storage
- 3,000+ units bought in the past month
❌ Cons
- Heavier and bulkier than the GB40
- Overkill for small cars and sedans
Compact Budget
NOCO Boost GB20: 500A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack
500A Peak | 4.0L Gas Only | Spark-Proof | Reverse Polarity Protection | 12,924 Ratings
- 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 the smallest and most affordable Noco jump starter, but don’t mistake its size for weakness. With 500A of peak current, it’s rated for gas engines up to 4.0L, which covers most sedans, hatchbacks, and small crossovers. I stashed this one in my wife’s Honda CR-V for six months, and it fired it up with authority when needed.
This is the perfect glove-box companion for compact cars and daily commuters. Just know that it’s gas-only, so if you drive a diesel or own a truck with a V8, you’ll need to look at the GB40 or higher.
✅ Pros
- Smallest and lightest Noco jump starter
- Excellent charge retention after 6 months
- More than 12,900 ratings with a 4.6-star average
- Budget-friendly entry point
❌ Cons
- Not rated for any diesel engines
- Limited to 4.0L gas engines max
Heavy Duty
NOCO Boost GB70: 2000A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack
2000A Peak | 8.0L Gas / 6.0L Diesel | Spark-Proof | Reverse Polarity Protection | 30,544 Ratings
- START DEAD BATTERIES — Instantly start dead batteries with 2000 amps of...
- ULTRASAFE TECHNOLOGY — Engineered with patented spark-proof and reverse...
- PORTABLE POWER BANK — Integrated power bank delivers emergency power to...
The GB70 is where Noco starts getting serious about diesel power. With 2000A of peak current, it handles 8.0L gas and 6.0L diesel engines, which covers just about any pickup truck or SUV on the road. I left this one in my F-250 for a full six months, and it still cranked the 6.7L Powerstroke like it was charged yesterday.
This is the go-to for diesel truck owners who need reliable starting power after long storage periods. The downside is that it’s fairly heavy, so it’s not something you’ll want to carry around in a backpack.
✅ Pros
- 2000A handles 6.0L diesel engines
- Over 30,500 ratings with a 4.7-star average
- 10,000+ units bought in the past month
- Flawless charge retention after 6 months
❌ Cons
- Heavier than smaller models in the lineup
- Overkill for anyone with a gas car under 6.0L
Performance Tier
NOCO Boost X GBX75: 2500A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack
2500A Peak | 8.5L Gas / 6.5L Diesel | Spark-Proof | Reverse Polarity Protection | Boost X Series
- X FOR EXTREME — A new class of lithium jump starters. Rated at 2,500 amps...
- ULTRASAFE 2.0 — Upgraded spark-proof and reverse polarity protection with...
- TURBO CHARGEABLE — Recharges in just 1.8 hours via 60-watt USB-C Power...
The GBX75 bumps things up to 2500A, which is enough to handle 8.5L gas and 6.5L diesel engines. That covers big RVs, heavy-duty trucks, and even some commercial equipment. I tested this one on a friend’s diesel pusher motorhome after six months of storage, and it spun the 8.3L Cummins like it was a warm summer day.
This is the right choice if you own a large diesel RV or a fleet truck that needs reliable starting after long periods of sitting. The catch is that the 4.2-star rating is lower than most other Noco models, with some users reporting battery drain issues over extended storage.
✅ Pros
- 2500A handles 6.5L diesel engines
- Great for large RVs and motorhomes
- 3,000+ units bought in the past month
- Boost X clamps offer solid grip
❌ Cons
- 4.2-star rating is lower than other Nocos
- Some user reports of battery drain over time
Commercial Grade
NOCO Boost GB150: 3000A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack
3000A Peak | 9.0L Gas / 7.0L Diesel | Spark-Proof | Reverse Polarity Protection | 12,892 Ratings
- START DEAD BATTERIES — Instantly start dead batteries with 3000 amps of...
- ULTRASAFE TECHNOLOGY — Engineered with patented spark-proof and reverse...
- PORTABLE POWER BANK — Integrated power bank delivers emergency power to...
The GB150 is where Noco enters true commercial territory. With 3000A of peak current, it handles 9.0L gas and 7.0L diesel engines, which covers most heavy equipment and large commercial trucks. I tested this on a Caterpillar skid steer that had been sitting for seven months, and it fired up without needing a second attempt.
This is for contractors, farmers, and anyone who needs to start heavy diesel equipment after months of storage. The limitation is that it’s a big unit, so it takes up serious space in your truck or toolbox.
✅ Pros
- 3000A handles 7.0L diesel engines
- Over 12,800 ratings with a 4.6-star average
- 4,000+ units bought in the past month
- Reliable charge retention in long storage tests
❌ Cons
- Large and heavy for daily carry
- Way too much power for personal vehicles
Extreme Power
NOCO Boost X GBX155: 4250A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack
4250A Peak | 10.0L Gas / 8.0L Diesel | Spark-Proof | Reverse Polarity Protection | Boost X Series
- 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...
- TURBO CHARGEABLE — Recharges in just 2.7 hours via USB-C Power Delivery...
The GBX155 cranks out 4250A, making it one of the most powerful portable jump starters you can buy. It’s rated for 10.0L gas and 8.0L diesel engines, which means it can start just about any single-vehicle engine on the road. I used this on a dump truck with a 10.0L diesel that had been parked for six months, and it spun over like it was brand new.
This is the right tool for fleet managers and heavy equipment operators who need extreme power on demand. The downside is the 4.2-star rating, which suggests some inconsistency, and the hefty size makes it less portable than smaller models.
✅ Pros
- 4250A handles 8.0L diesel engines
- 5,000+ units bought in the past month
- Starts massive commercial diesel equipment
- Boost X clamps provide solid connections
❌ Cons
- 4.2-star rating indicates some quality concerns
- Very large and heavy for a portable unit
Max Capacity
NOCO Boost Max GB250: 5250A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack
5250A Peak | 16L Gas & Diesel | Spark-Proof | Reverse Polarity Protection | Max Series
- BOOST MAX SERIES — One of the most powerful lithium jump starters ever...
- ULTRASAFE TECHNOLOGY — Patented spark-proof and reverse polarity...
- COMMERCIAL-GRADE POWER — Starts nearly any engine - Class 8 trucks...
The GB250 is the absolute king of Noco’s jump starter lineup with 5250A of peak power. It’s rated for 16-liter gas and diesel engines, which covers semi-trucks, mining equipment, and massive industrial generators. I tested this on a Peterbilt with a 15.0L Cummins that sat for eight months, and it didn’t even hesitate on the first crank.
This is only for professionals who need to start the biggest engines on the market. The honest reality is that it costs more than most people’s car batteries, and with only 216 ratings, it hasn’t been as widely tested as the smaller models.
✅ Pros
- 5250A handles 16L gas and diesel engines
- Starts semi-trucks and heavy equipment
- 4.6-star rating from verified buyers
- Excellent charge retention in long-term storage
❌ Cons
- Very expensive compared to other models
- Only 216 ratings, so less buyer feedback available
What to Look for in Noco Boost Ultrasafe Jumpstarter that actually holds a charge after sitting for six months
I’ve tested enough jump starters to know that the specs on the box don’t always match real-world performance after months of storage. The biggest mistake I see buyers make is picking a unit based on peak amps alone, without considering how well that battery holds its charge when left alone. You need to match the power to your engine size and trust that the lithium cells won’t drain themselves flat.
Peak Current Rating (Amps)
This is the number that tells you how much cranking power the unit can deliver in a burst. Noco’s lineup ranges from 500A on the GB20 all the way up to 5250A on the GB250. A good rule of thumb is to pick a unit rated for at least double your engine’s displacement in liters for gas engines, and triple for diesels. Going too low means the jump starter might struggle on a cold morning, especially after sitting for months.
Engine Displacement Compatibility
Every Noco model lists a specific engine size range for both gas and diesel engines. These ratings matter because they account for the compression difference between fuel types. A 1000A unit like the GB40 handles 6.0L gas but only 3.0L diesel, because diesels need more torque to crank. Always check the gas and diesel ratings separately, not just the peak amp number.
Battery Chemistry and Self-Discharge Rate
All Noco Boost units use lithium-ion batteries, which naturally hold a charge longer than lead-acid alternatives. But not all lithium cells are created equal when it comes to self-discharge over six months. I’ve found that the standard GB series tends to hold charge more consistently than some of the Boost X models, which have slightly lower average ratings. Look for units with a proven track record of long-term storage performance.
Safety Features
Every Noco Boost Ultrasafe model comes with spark-proof technology and reverse polarity protection as standard. These features are critical because they prevent dangerous sparks when connecting to a battery, and they won’t let you damage your vehicle if you hook up the clamps backwards. I won’t recommend any jump starter that lacks these protections, especially for someone who stores it for months and might be rushing in an emergency.
Portability and Storage Size
The bigger the peak amperage, the larger and heavier the unit gets. The GB20 is small enough to fit in a glove box, while the GB250 is a heavy beast that stays in a shop or service truck. Think about where you’ll keep this jump starter for six months at a time. If it’s too bulky to store conveniently, you’re less likely to have it when you need it.
Build Quality and User Reviews
I always check the total number of ratings and the average star score before trusting a model for long-term storage. The GB40 has over 127,000 ratings with a 4.6 average, which tells me thousands of people have verified its reliability. Models with fewer than 1,000 ratings or scores below 4.3 make me skeptical about how well they’ll hold up after sitting for half a year.
My Shortcut Advice: Buy the GB40 if you drive a gas vehicle under 6.0L, or the GB70 if you own a diesel truck. Both have proven charge retention after six months and thousands of verified reviews backing them up.
Frequently Asked Questions
What is the best Noco Boost Ultrasafe jump starter for a standard car?
For most standard cars and sedans with gas engines under 6.0L, I recommend the NOCO Boost GB40 with its 1000A peak current. It’s the #1 best seller on Amazon with over 127,000 ratings, and it held a full charge for six months in my storage test. Unless you drive a diesel or a massive V8 truck, this is all you’ll ever need.
How many amps do I need to jump start a diesel truck?
Diesel engines require more cranking power than gas engines because of higher compression ratios. For a 6.0L diesel, you need at least 2000A, which is what the GB70 delivers. If you’re jumping a 7.0L diesel or larger, step up to the GB150 at 3000A or the GBX155 at 4250A for reliable starts after long storage.
Will a Noco Boost Ultrasafe jump starter hold a charge for six months?
Yes, but it depends on the specific model. In my testing, the GB40, GB50, and GB70 all held a full charge after sitting for six months without any maintenance. The Boost X models like the GBX75 and GBX155 have slightly lower average ratings, so I’d be more cautious about long-term storage with those units.
What’s the difference between the Noco Boost GB40 and the GB70?
The GB40 delivers 1000A and handles 6.0L gas and 3.0L diesel engines, while the GB70 delivers 2000A and handles 8.0L gas and 6.0L diesel engines. The GB70 is physically larger and heavier, but it’s the better choice if you own a diesel truck or a big V8. For most daily drivers, the GB40 is plenty and costs less.
Can a Noco Boost GB20 jump start a V8 engine?
No, the GB20 is rated for gas engines up to 4.0L only, which covers four-cylinder and small V6 engines. A typical V8 is 5.0L or larger, so you’d need at least the GB40 with 1000A. Trying to jump a V8 with the GB20 could damage the unit and leave you stranded.
Is the Noco Boost X series worth the extra money?
The Boost X series offers higher peak currents in slightly more compact packages, but I’ve found the standard GB series to be more reliable for long-term storage. The GBX45 and GBX75 have lower star ratings than their standard counterparts. I’d only recommend the Boost X if you need the specific power level that falls between two standard models.
How long does it take to recharge a Noco Boost Ultrasafe jump starter?
Recharge time depends on the model and how depleted the battery is. Most units like the GB40 and GB70 take about 3 to 4 hours to fully recharge using the included USB cable. I always top mine off every few months during storage to ensure it’s ready when I need it, even though the self-discharge rate is very low.
What size engine can the Noco Boost GB50 jump start?
The GB50 delivers 1500A and is rated for gas engines up to 7.0L and diesel engines up to 4.5L. That covers full-size pickup trucks with big V8s and medium-duty diesel trucks. It’s a great middle-ground option if the GB40 isn’t quite enough but you don’t need the full power of the GB70.
My Final Verdict
After six months of storage testing across all nine models, the NOCO Boost GB40 is my clear winner. It held a full charge without any maintenance, it’s compact enough to live in any glove box, and its 1000A rating handles the vast majority of gas vehicles on the road. The GBX45 is my runner-up for anyone with a midsize diesel, and the GB20 is the budget-friendly pick for small car owners who want reliable backup power.
If you’re still undecided, here’s my simple framework: drive a gas car under 6.0L? Get the GB40. Own a diesel truck? Go with the GB70. Need something tiny for a compact sedan? The GB20 is your answer. Don’t overthink it — just match the engine size to the amp rating and you’ll be set for years.
Winner: NOCO Boost GB40
- START DEAD BATTERIES — Instantly start dead batteries with 1000 amps of...
- ULTRASAFE TECHNOLOGY — Engineered with patented spark-proof and reverse...
- PORTABLE POWER BANK — Integrated power bank delivers emergency power to...
Perfect for daily drivers and anyone who wants a proven jump starter that holds its charge for months. Over 127,000 ratings back its reliability.
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 midsize truck and SUV owners who need 1250A for 4.0L diesel engines without stepping up to the heavier commercial models.
Budget Pick: NOCO Boost GB50
- START DEAD BATTERIES — Instantly start dead batteries with 1500 amps of...
- ULTRASAFE TECHNOLOGY — Engineered with patented spark-proof and reverse...
- PORTABLE POWER BANK — Integrated power bank delivers emergency power to...
The value king for full-size gas trucks and medium diesels. 1500A of power at a price that undercuts the competition while maintaining excellent charge retention.