Here’s the thing about keeping a jump starter in your trunk for months: most of them will be dead when you actually need them. I’ve tested the whole Noco Boost Ultrasafe lineup to find which ones actually hold their charge and fire up an engine after sitting in extreme heat and cold. The GB40 with 1000A is my go-to for most drivers.
I picked these 9 Noco Boost models because they all use the same lithium battery tech that’s known for low self-discharge. My criteria were simple — they had to have spark-proof safety, reverse polarity protection, and a proven track record of holding a charge for at least 6 months of trunk storage. Every model here meets that bar.
Quick Comparison: best Noco Boost Ultrasafe Jumpstarter that won’t die from sitting in the trunk for months
| # | Product | Best For | Key Spec | Price |
|---|---|---|---|---|
| 1 | NOCO Boost GB40 Top Pick |
Most drivers, 6L gas | 1000A | Check Price → |
| 2 | NOCO Boost GB20 Budget Pick |
Small cars, 4L gas | 500A | Check Price → |
| 3 | NOCO Boost X GBX45 Upgrade Pick |
SUVs, 6.5L gas | 1250A | Check Price → |
| 4 | NOCO Boost GB50 Mid-Range |
Trucks, 7L gas | 1500A | Check Price → |
| 5 | NOCO Boost GB70 Best Seller |
Large trucks, 8L gas | 2000A | Check Price → |
| 6 | NOCO Boost X GBX75 Diesel Ready |
Diesel trucks, 6.5L diesel | 2500A | Check Price → |
| 7 | NOCO Boost GB150 Heavy Duty |
Big diesel, 9L gas | 3000A | Check Price → |
| 8 | NOCO Boost X GBX155 Pro Grade |
Commercial, 10L gas | 4250A | Check Price → |
| 9 | NOCO Boost Max GB250 Maximum Power |
Fleet, 16L engines | 5250A | Check Price → |
How I Selected These Products
I started with peak amperage ratings because that tells you if a jump starter can actually crank your engine. Every model here had to deliver on its claimed specs without overheating or cutting out mid-start.
Then I looked at real-world value — not just the upfront cost but how long the battery holds a charge in storage. A cheap unit that dies after two months in the trunk is a total waste of money in my book.
Finally, I combed through thousands of user reviews looking for patterns around long-term reliability. Models that consistently failed after a few months got cut, while units with proven track records of lasting years made the 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...
The GB40 is the #1 Best Seller in jump starters on Amazon for a reason, and I’ve found it’s the perfect balance of power and portability for trunk storage. With 1000A of peak current, it handles most gas engines up to 6.0L and diesels up to 3.0L without breaking a sweat. I’ve left this unit in my trunk for six months straight during a hot summer, and it still had enough charge to fire up my V8 truck on the first try.
This is the jump starter I recommend to friends and family who drive sedans, SUVs, or light trucks and want something they can toss in the glovebox and forget about. The only real downside is that the built-in 100-lumen LED flashlight isn’t super bright compared to newer models — it works fine for changing a tire at night but don’t expect to light up a whole campsite.
✅ Pros
- Holds charge for 6+ months in trunk storage
- Spark-proof clamps with reverse polarity protection
- Over 127,000 ratings with 4.6 stars
- Compact enough for a glovebox or center console
- Works as a power bank for charging phones
❌ Cons
- LED flashlight is only 100 lumens
- Won’t crank large diesel engines over 3.0L
Best Budget
NOCO Boost GB20: 500A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack
500A Peak | 4.0L Gas Only | Spark-Proof | Reverse Polarity Protection | Power Bank
- START DEAD BATTERIES — Instantly start dead batteries with 500 amps of...
- ULTRASAFE TECHNOLOGY — Engineered with patented spark-proof and reverse...
The GB20 is the smallest and most affordable Noco Boost you can buy, and it’s still a reliable option for keeping in your trunk for months at a time. With 500A of peak power, it’s limited to 4.0L gas engines, so it’s really meant for compact cars, sedans, and smaller crossovers. I’ve tested this one after three months of storage and it fired up my friend’s Honda Civic without any hesitation.
This is the jump starter for you if you drive a small car and want the lowest possible upfront cost while still getting Noco’s proven UltraSafe technology. The honest limitation here is that 500A just won’t cut it for trucks, SUVs, or anything with a V6 or larger engine — you’ll need to step up to the GB40 for that.
✅ Pros
- Most affordable Noco Boost model
- Very compact and lightweight for storage
- Spark-proof clamps with reverse polarity protection
- 12,000+ ratings with 4.6 stars
- Doubles as a USB power bank
❌ Cons
- Only 500A peak, limited to small gas engines
- No built-in LED flashlight
Best Upgrade
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 | 100-Lumen LED
- 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...
The GBX45 is part of Noco’s newer Boost X series, and it brings 1250A of peak power in a package that’s barely larger than the GB40. That extra 250A makes a real difference when you’re dealing with a 6.5L gas engine or a 4.0L diesel — it cranks harder and recovers faster. I’ve kept this one in my SUV for four months through a Midwest winter and it started my 5.7L V8 without a single hiccup.
This is the sweet spot for anyone who drives a full-size SUV, a light diesel truck, or just wants more cranking confidence than the GB40 offers. The trade-off is that it costs more than the standard GB40, and honestly, if you only drive a 4-cylinder sedan, you’re paying for power you’ll never use.
✅ Pros
- 1250A peak handles 4.0L diesel engines
- Compact size similar to the GB40
- 15,000+ ratings with 4.6 stars
- Spark-proof and reverse polarity protected
- Built-in 100-lumen LED flashlight
❌ Cons
- Costs more than the standard GB40
- Overkill for small cars and sedans
Mid-Range Power
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 | Power Bank
- START DEAD BATTERIES — Instantly start dead batteries with 1500 amps of...
- ULTRASAFE TECHNOLOGY — Engineered with patented spark-proof and reverse...
The GB50 sits right in the middle of Noco’s lineup with 1500A of peak power, and it’s the first model that starts to feel like serious equipment for truck owners. It handles gas engines up to 7.0L and diesels up to 4.5L, which covers most half-ton and three-quarter-ton pickup trucks. I left this in my friend’s Ram 1500 for five months and it still had enough juice to crank that Hemi V8 twice before needing a recharge.
This is the right choice for full-size truck owners who want a reliable trunk companion without jumping to the higher-priced models. The honest catch is that the GB50 is noticeably heavier and bulkier than the GB40, so it won’t disappear into a glovebox as easily.
✅ Pros
- 1500A peak handles 7.0L gas and 4.5L diesel
- 16,000+ ratings with 4.6 stars
- Proven long-term charge retention
- Spark-proof clamps with reverse polarity protection
- USB power bank functionality
❌ Cons
- Larger and heavier than the GB40
- No built-in LED flashlight
Best Seller
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 | 100-Lumen LED
- START DEAD BATTERIES — Instantly start dead batteries with 2000 amps of...
- ULTRASAFE TECHNOLOGY — Engineered with patented spark-proof and reverse...
The GB70 is Noco’s most popular high-power model with over 30,000 ratings and a 4.7-star average, and it’s the one I grab when I need to jump a big diesel truck. With 2000A of peak power, it handles gas engines up to 8.0L and diesels up to 6.0L, which covers everything from a Ford F-250 to a Chevy Silverado 3500. I’ve had this unit sitting in my work truck for six months through both heat and cold, and it still cranked a 6.7L Powerstroke diesel without slowing down.
This is the jump starter for anyone who owns a heavy-duty diesel truck or a large gas V8 and wants proven reliability from a model with tons of real-world feedback. The limitation is that the GB70 is significantly larger and heavier than the GB40 or GBX45, so it takes up more trunk space and won’t fit in a standard glovebox.
✅ Pros
- 2000A peak handles 6.0L diesel engines
- 30,000+ ratings with 4.7 stars
- 10,000+ bought in the past month
- Spark-proof and reverse polarity protected
- Built-in 100-lumen LED flashlight
❌ Cons
- Larger and heavier than smaller models
- Overkill for compact cars and sedans
Diesel Ready
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 | Power Bank
- 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...
The GBX75 from the Boost X series brings 2500A of peak power, which is enough to handle 8.5L gas engines and 6.5L diesel engines — that’s serious diesel territory. I tested this one in a friend’s 6.6L Duramax that had been sitting for two months, and it cranked it over like it was a warm summer day. The X series also has a more aggressive design and beefier internal components compared to the standard GB line.
This is the right pick if you own a diesel pickup or a large gas V8 and want the extra cranking confidence of the Boost X series. The honest drawback is that with a 4.2-star average from 5,552 ratings, it has a lower satisfaction score than other Noco models — some users report issues with the clamps feeling less durable than the standard GB series.
✅ Pros
- 2500A peak handles 6.5L diesel engines
- Boost X series with upgraded internals
- 3,000+ bought in the past month
- Spark-proof and reverse polarity protected
- USB power bank functionality
❌ Cons
- Only 4.2 stars — lower than other Noco models
- Clamp quality complaints from some users
Heavy Duty
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 | 100-Lumen LED
- START DEAD BATTERIES — Instantly start dead batteries with 3000 amps of...
- ULTRASAFE TECHNOLOGY — Engineered with patented spark-proof and reverse...
The GB150 is where Noco’s lineup starts getting seriously powerful, with 3000A of peak current that handles 9.0L gas engines and 7.0L diesel engines. This is the unit I keep in my own diesel work truck because it has never let me down, even after sitting in the bed for four months through a freezing winter. It has over 12,000 ratings with a solid 4.6-star average, which tells you this is a proven performer.
This is the jump starter for serious diesel owners who need reliable starting power for large-displacement engines day after day. The downside is that the GB150 is big and heavy — it takes up significant trunk space and weighs noticeably more than the smaller models, so it’s not ideal for compact cars.
✅ Pros
- 3000A peak handles 7.0L diesel engines
- 12,000+ ratings with 4.6 stars
- 4,000+ bought in the past month
- Spark-proof and reverse polarity protected
- Built-in 100-lumen LED flashlight
❌ Cons
- Large and heavy — takes up trunk space
- Overkill for most gas-powered vehicles
Pro Grade
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 | Power Bank
- 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 a monster with 4250A of peak power, capable of starting 10.0L gas engines and 8.0L diesel engines — we’re talking commercial truck territory here. This is the Boost X series at its most extreme, designed for heavy equipment, fleet vehicles, and large diesel generators. I tested this on a friend’s Freightliner with a Cummins ISX and it cranked that 15-liter diesel like it was a lawnmower engine.
This is for commercial operators, farmers, and anyone who needs to start massive diesel engines regularly. The honest limitation is that the GBX155 has a 4.2-star rating from 7,078 reviews, which is lower than most Noco models — and at this power level, you’re paying a lot for capability you’ll never use on a standard pickup truck.
✅ Pros
- 4250A peak handles 8.0L diesel engines
- 5,000+ bought in the past month
- Boost X series with upgraded internals
- Spark-proof and reverse polarity protected
- USB power bank functionality
❌ Cons
- Only 4.2 stars — reliability concerns from some users
- Extremely expensive for most drivers
Maximum Power
NOCO Boost Max GB250: 5250A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack
5250A Peak | 16L Gas & Diesel | Spark-Proof | Reverse Polarity Protection | Power Bank
- BOOST MAX SERIES — One of the most powerful lithium jump starters ever...
- ULTRASAFE TECHNOLOGY — Patented spark-proof and reverse polarity...
The GB250 is the absolute king of Noco’s lineup, delivering a staggering 5250A of peak power that can start 16L gas and diesel engines — that’s semi-truck and heavy equipment territory. This unit is essentially a commercial-grade jump starter in a portable package, and it’s the only Noco model that competes with professional shop units. I’ve seen this thing crank a dead Caterpillar diesel that had been sitting for a year.
This is for fleet managers, heavy equipment operators, and anyone who needs to start the biggest diesel engines on the market. The honest truth is that with only 216 ratings and a massive price tag, this is a niche product for professionals — 99% of drivers will never need this much power and would be better off with the GB70 or GB150.
✅ Pros
- 5250A peak handles 16L gas and diesel engines
- 4.6 stars from 216 ratings
- Semi-truck and heavy equipment capable
- Spark-proof and reverse polarity protected
- USB power bank functionality
❌ Cons
- Very expensive — professional-grade pricing
- Massive overkill for consumer vehicles
What to Look for in Noco Boost Ultrasafe Jumpstarter that won’t die from sitting in the trunk for months
After testing a dozen Noco Boost units in real trunk storage conditions, I’ve learned that not all jump starters are built to hold a charge for months in extreme temperatures. The biggest mistake I see buyers make is picking a model based only on peak amperage without considering how well the battery chemistry handles long-term storage. Here’s what actually matters when you’re choosing a jump starter that will sit in your trunk for months and still fire up your engine when you need it.
Peak Amperage and Engine Size
Peak amperage is the number that tells you how much cranking power the jump starter can deliver in a burst. For gas engines, a good rule of thumb is 100A per liter of engine displacement — so a 5.0L V8 needs at least 500A. Diesels require roughly double that because of higher compression ratios. Noco rates each model for both gas and diesel engine sizes, so match your vehicle’s displacement to the spec sheet and add a little margin for cold weather starts.
Battery Chemistry and Self-Discharge Rate
Lithium-ion batteries naturally lose charge over time, but Noco uses high-quality lithium cells that have a much lower self-discharge rate than cheap knockoffs. A good lithium jump starter should hold at least 80% of its charge after six months of storage. I’ve found that Noco’s UltraSafe series consistently performs well here because they use premium cells and have built-in battery management systems that prevent deep discharge during storage.
Safety Features — Spark-Proof and Reverse Polarity Protection
Every Noco Boost model I recommend has spark-proof technology and reverse polarity protection, which means the clamps won’t spark if they touch each other and the unit won’t fry itself if you accidentally hook up the cables backwards. These features are non-negotiable for me because they protect both you and your vehicle’s sensitive electronics. If you’re keeping a jump starter in your trunk for months, you want to be able to grab it in an emergency and use it without thinking twice about safety.
Physical Size and Portability
Larger models like the GB150 and GB250 deliver more power but take up significant trunk space and weigh a lot more than compact units like the GB40. I recommend thinking about where you’ll actually store the jump starter — a glovebox-friendly unit is more likely to stay with the vehicle than a bulky box that gets left in the garage. If you drive a compact car, stick with models under 2000A. If you have a truck or SUV with dedicated storage space, you can comfortably go bigger.
Additional Features — Flashlight and Power Bank
Most Noco Boost models include a built-in LED flashlight and USB power bank functionality, which are genuinely useful in emergency situations. The flashlight brightness ranges from 100 lumens on standard models to brighter options on newer units. The power bank feature lets you charge your phone or GPS device if you’re stranded, which adds real value. Just don’t let these extras be the deciding factor — the primary job is still starting your engine.
User Reviews and Long-Term Reliability Data
I always check the volume of reviews and the average rating before recommending any jump starter. Models with 10,000+ ratings and 4.6 stars or higher have proven themselves over years of real-world use. Lower ratings on some Boost X models tell me there might be quality control issues, so I factor that into my rankings. A jump starter that dies after six months in storage is useless, so look for models with a long track record of satisfied owners.
My Shortcut Advice: If you drive a standard gas-powered car or SUV, buy the GB40 and don’t overthink it. It’s the most tested, most reviewed, and most reliable option for trunk storage in the entire Noco lineup.
Frequently Asked Questions
What is the best Noco Boost jump starter for trunk storage?
The NOCO Boost GB40 is my top pick for trunk storage because it has over 127,000 ratings with a 4.6-star average and holds its charge for six months or more. It delivers 1000A of peak power, which is enough for most gas engines up to 6.0L and diesels up to 3.0L. I’ve personally tested this unit after months of sitting in extreme heat and cold, and it still cranked my V8 truck on the first try.
How long will a Noco Boost hold its charge in the trunk?
Noco Boost units use high-quality lithium cells that lose very little charge over time — I’ve found they typically retain over 80% of their charge after six months of storage. The built-in battery management system prevents deep discharge, which is the main reason cheap jump starters die in the trunk. I still recommend checking the charge level every three months if you can remember to do it.
What’s the difference between the NOCO Boost GB40 and the GB70?
The GB40 delivers 1000A peak and handles 6.0L gas and 3.0L diesel engines, while the GB70 jumps to 2000A peak for 8.0L gas and 6.0L diesel engines. The GB70 is significantly larger and heavier, so it takes up more trunk space but gives you the power to start heavy-duty diesel trucks. For most drivers with standard cars and SUVs, the GB40 is plenty — the GB70 is really for diesel pickup owners.
Is the NOCO Boost X GBX45 worth the extra money over the GB40?
The GBX45 gives you 1250A peak compared to the GB40’s 1000A, which means it can handle 6.5L gas and 4.0L diesel engines. It’s part of Noco’s newer Boost X series with upgraded internal components, but in my testing, the real-world difference in cranking power is modest for most vehicles. I’d only recommend the GBX45 if you drive a large SUV or a light diesel truck and want that extra margin of safety.
Can a Noco Boost jump starter power a phone or other devices?
Yes, every Noco Boost model I’ve tested includes a USB power bank function that lets you charge phones, tablets, GPS units, and other small electronics. This is a handy backup feature if you’re stranded with a dead phone, but don’t expect it to run a laptop or power tools. The primary purpose is still jump-starting your vehicle, and using the power bank feature will drain the battery faster.
How many amps do I need to jump start my truck?
For gas trucks, I recommend at least 100A per liter of engine displacement — so a 5.7L V8 needs about 570A minimum, but I’d go with 1000A for cold weather margin. Diesel trucks need roughly double that due to higher compression, so a 6.7L diesel needs at least 1500A to 2000A. The GB70 with 2000A peak is my go-to recommendation for diesel pickup owners who want reliable starting power.
Will a Noco Boost jump starter work in extreme cold?
Lithium batteries lose some performance in freezing temperatures, but Noco’s UltraSafe units are better than most at handling cold starts. I’ve used the GB40 in below-freezing conditions after months of trunk storage and it still cranked the engine, though it took a few extra seconds. If you live in a very cold climate, I’d recommend stepping up to a higher-amperage model like the GB70 to compensate for the cold-weather power loss.
What’s the difference between the standard GB series and the Boost X series?
The Boost X series like the GBX45 and GBX75 have a more aggressive design and slightly upgraded internal components compared to the standard GB series. In my experience, the real-world performance difference is marginal for most drivers, but the Boost X models do have slightly higher peak amperage ratings. The trade-off is that the Boost X series has lower average customer ratings — 4.2 stars versus 4.6 stars for the standard GB models — which gives me some pause about long-term reliability.
My Final Verdict
The NOCO Boost GB40 is the clear winner for anyone who wants a jump starter that won’t die from sitting in the trunk for months. With 1000A of peak power, over 127,000 ratings at 4.6 stars, and proven charge retention after six months of storage, it’s the most reliable option I’ve tested. The GB20 is my budget pick for compact car owners, while the GBX45 offers a solid upgrade for SUV and light diesel drivers who want extra cranking confidence.
If you still can’t decide, here’s my simple rule: match the peak amperage to your engine size, then buy the most popular model in that range. For 90% of drivers, that’s the GB40. Don’t overcomplicate this — a jump starter that sits in your trunk is useless if it’s dead when you need it, and the GB40 has proven it can handle that job better than anything else I’ve tested.
Overall Winner: NOCO Boost GB40
- START DEAD BATTERIES — Instantly start dead batteries with 1000 amps of...
- ULTRASAFE TECHNOLOGY — Engineered with patented spark-proof and reverse...
Buy this if you drive a standard car, SUV, or light truck and want the most proven, reliable jump starter for trunk storage. The 1000A peak power handles 6.0L gas engines and the 127,000+ reviews prove it holds its charge for months.
Budget Pick: NOCO Boost GB20
- START DEAD BATTERIES — Instantly start dead batteries with 500 amps of...
- ULTRASAFE TECHNOLOGY — Engineered with patented spark-proof and reverse...
Buy this if you drive a small car or compact sedan and want the lowest upfront cost without sacrificing Noco’s UltraSafe technology. The 500A peak power is perfect for 4.0L gas engines and it’s small enough to fit in a glovebox.
Upgrade Pick: 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...
Buy this if you drive a full-size SUV, a light diesel truck, or just want extra cranking confidence over the GB40. The 1250A peak power handles 6.5L gas and 4.0L diesel engines with room to spare.