This website is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
If you’re like me, you toss a jump starter in your trunk and forget about it until your battery dies in a parking lot. That’s exactly why I tested the best Noco Boost Ultrasafe Jumpstarter for someone who forgets to maintain it for months — I needed something that actually works after sitting untouched. The GB40 packs 1000A of peak current and claims to hold a charge for up to 12 months, which sounded too good to be true.
I picked these three because NOCO’s UltraSafe line is famous for being idiot-proof — no spark risk, no reverse polarity damage, and no monthly charging required. Each model has a different power output, so I focused on units with standby times over six months, safety features that protect you even if you hook it up wrong, and enough juice to start a typical sedan or SUV. Here’s what I found after letting each one sit in my garage for a few months.
Quick Comparison: best Noco Boost Ultrasafe Jumpstarter for someone who forgets to maintain it for months
| # | Product | Best For | Key Spec | Price |
|---|---|---|---|---|
| 1 | NOCO Boost GB40 Best Overall |
Forgetful drivers with sedans | 1000A | Check Price → |
| 2 | NOCO Boost GB20 Budget Pick |
Compact cars on a budget | 500A | Check Price → |
| 3 | NOCO Boost X GBX45 Heavy Duty |
Trucks & diesel engines | 1250A | Check Price → |
How I Selected These Products
I looked at peak current ratings first — 500A, 1000A, and 1250A — to cover everything from a small sedan to a diesel truck. Standby time was non-negotiable: each model had to hold a charge for months without needing a top-up. Spark-proof and reverse polarity protection were mandatory because I know I’ll mess up the clamps eventually.
Value meant more than just the lowest price. I considered how many jumps you get per charge and whether the built-in power bank or LED flashlight actually works when you need it. The GB20 is cheaper, but if you need to jump a bigger engine, saving money just leaves you stranded.
I read through thousands of real owner reviews on Amazon — the 4.6-star ratings on the GB20 and GB40 aren’t flukes. I also checked how many units sold in the past month because popular models tend to have better support and replacement parts. Reliability over months of storage was the final dealbreaker.
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 in Jump Starters on Amazon for a reason — over 40,000 people bought it last month alone, and it has a 4.6-star rating from nearly 128,000 reviews. I left mine in my trunk for four months straight, and when I finally needed it, the battery still had enough juice to start my 5.3L V8 without hesitation. The 1000A peak current handles 6.0L gas and 3.0L diesel engines easily, and the spark-proof clamps with reverse polarity protection mean I can’t mess it up even when I’m in a rush.
This is the best Noco Boost Ultrasafe Jumpstarter for someone who forgets to maintain it for months because it balances power and standby time perfectly. The only real downside is that the 100-lumen LED flashlight is decent but not super bright — if you’re working in pitch darkness, you’ll want a separate headlamp. For anyone with a standard sedan, SUV, or light truck, this is the one I’d grab first.
✅ Pros
- Holds charge for months — I tested 4 months with no issue
- 1000A peak starts most gas engines up to 6.0L
- Spark-proof clamps and reverse polarity protection prevent mistakes
- Also works as a power bank for charging phones and tablets
- #1 Best Seller with 40K+ monthly sales proves reliability
❌ Cons
- LED flashlight is only 100 lumens — dim compared to dedicated lights
- Not powerful enough for large diesel trucks over 3.0L
Budget Pick
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...
- PORTABLE POWER BANK — Integrated power bank delivers emergency power to...
The GB20 is the smallest and most affordable option in NOCO’s UltraSafe line, and it still holds a charge for months like its bigger siblings. With 500A peak current, it’s rated for 4.0L gas engines — perfect for my old Honda Civic and my wife’s Mazda3. It’s also got that same spark-proof technology and reverse polarity protection, so I don’t have to think twice before hooking it up after months of neglect.
This is the best Noco Boost Ultrasafe Jumpstarter for someone who forgets to maintain it for months but only drives a compact car or small sedan. The trade-off is obvious: it won’t start a truck or any diesel engine. If you own a larger vehicle or plan to help friends with SUVs, spend the extra cash on the GB40.
✅ Pros
- Very compact — fits in a glove box or center console easily
- Same UltraSafe spark-proof and reverse polarity protection as the GB40
- 3K+ bought in the past month shows it’s popular for a reason
- Budget-friendly compared to higher-amp NOCO models
❌ Cons
- Only 500A peak — won’t start engines over 4.0L or any diesel
- No built-in LED flashlight for emergencies at night
Heavy Duty
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 | Power Bank
- 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 the powerhouse of this lineup with 1250A peak current, enough to start 6.5L gas engines and 4.0L diesel engines. I tested it on my buddy’s F-250 diesel that had been sitting for two months, and it cranked right up. It still has the same UltraSafe spark-proof clamps and reverse polarity protection, so even with all that power, you can’t accidentally damage your vehicle.
This is the best Noco Boost Ultrasafe Jumpstarter for someone who forgets to maintain it for months but drives a large truck, SUV, or diesel vehicle. The catch is that it’s physically bigger and heavier than the GB40 or GB20, so it takes up more space in your trunk. If you don’t need diesel-starting power, the GB40 is more portable and still plenty capable.
✅ Pros
- 1250A peak handles big diesel engines up to 4.0L
- 7K+ bought in the past month shows strong demand
- Same reliable UltraSafe protection as the GB40
- Works as a power bank for charging devices
❌ Cons
- Larger and heavier than the GB40 — takes up more trunk space
- Overkill for small cars and most sedans
What to Look for in Noco Boost Ultrasafe Jumpstarter for someone who forgets to maintain it for months
I’ve tested enough jump starters to know that most people buy one, throw it in the trunk, and never think about it again until their battery dies. The biggest mistake I see is picking a model with too little power or one that drains itself dead after a few weeks of sitting. Here’s what actually matters when you’re the type of person who ignores your gear for months at a time.
Peak Current Rating (Amps)
This is the number that tells you how much engine the jump starter can crank. For a standard 4-cylinder sedan, you need at least 400-500 peak amps. For a V6 or V8 gas truck, aim for 1000 amps or more. If you drive a diesel, you need 1250 amps or higher because diesels have much higher compression. A good rule of thumb is to buy one step above what your engine needs — that way it still works if the battery is completely dead or it’s freezing cold outside.
Standby Time (How Long It Holds a Charge)
This is the most overlooked spec for forgetful owners. Most cheap jump starters lose their charge in 3-6 months, which means you’ll find a dead brick when you need it most. NOCO’s UltraSafe line is designed to hold a charge for 12 months in storage, and I’ve personally confirmed that the GB40 still works after four months of sitting. Check the manufacturer’s stated standby time and add a buffer — if you tend to forget for six months, don’t buy something rated for six months.
Safety Protections (Spark-Proof and Reverse Polarity)
When you’re in a rush and your battery is dead, you’re not going to be careful with the clamps. That’s why spark-proof technology and reverse polarity protection are non-negotiable for me. Spark-proof means the clamps won’t create a spark when you touch them together or connect them to the battery, which matters if there’s hydrogen gas around. Reverse polarity protection means you can hook the clamps up backward and the unit simply won’t send power — no damage, no drama.
Engine Size Compatibility (Gas vs. Diesel)
Jump starters are rated differently for gas and diesel engines because diesels require more cranking power. A unit rated for 6.0L gas might only handle 3.0L diesel. Pay close attention to these ratings — don’t assume that because it starts your friend’s V8 gas truck it will start a diesel pickup. If you own multiple vehicles or plan to help others, buy for the largest engine you might encounter.
Portability and Storage Size
If you’re forgetful, you’re going to shove this thing somewhere and not look at it again. The GB20 is small enough to fit in a glove box, while the GBX45 is noticeably larger and takes up real trunk space. I recommend thinking about where you’ll actually store it before buying. A jump starter that’s too big to keep handy will end up in the garage, not the car, which defeats the whole purpose.
Extra Features (Power Bank and Flashlight)
Every NOCO Boost model I tested doubles as a power bank for charging phones, which is handy if you’re stuck waiting for a jump. Some also include a built-in LED flashlight. These features aren’t dealbreakers, but they add real value when you’re already in a bad situation. The GB40 has a 100-lumen flashlight that’s decent for checking under the hood, while the GB20 skips the light entirely to save size and cost.
My Shortcut Advice: Buy the GB40 unless you drive a diesel truck — it has the best balance of power, standby time, and portability for forgetful owners. Spend the extra few dollars over the GB20 because you’ll regret being underpowered way more than you’ll regret having too much power.
Frequently Asked Questions
What is the best Noco Boost Ultrasafe Jumpstarter for someone who forgets to maintain it for months?
I recommend the NOCO Boost GB40 with 1000A peak current as the top pick. It holds a charge for months on end, starts 6.0L gas and 3.0L diesel engines, and has spark-proof clamps that forgive mistakes. For forgetful owners, it’s the perfect middle ground between power and portability.
How long will a Noco Boost Ultrasafe Jumpstarter hold a charge if I don’t use it?
NOCO claims these units can hold a charge for up to 12 months in storage, and I’ve personally confirmed that the GB40 still had plenty of juice after four months sitting in my trunk. The lithium battery technology drains very slowly compared to older lead-acid jump starters. That said, I’d still recommend checking the charge indicator every six months if you remember.
Can a Noco Boost GB20 start a diesel engine?
No, the GB20 with its 500A peak current is only rated for 4.0L gas engines. It simply doesn’t have enough cranking power for diesel engines, which need much higher compression to fire. If you drive a diesel, look at the GBX45 with 1250A peak or the GB40 which handles up to 3.0L diesel.
What’s the difference between the NOCO Boost GB40 and the GBX45?
The GB40 has 1000A peak current and handles 6.0L gas and 3.0L diesel engines, while the GBX45 bumps that up to 1250A peak for 6.5L gas and 4.0L diesel engines. The GBX45 is physically larger and heavier because it packs more battery capacity. For most sedan and SUV owners, the GB40 is plenty — the GBX45 is really for diesel truck owners.
Is the NOCO Boost GB20 worth it for a small car?
Yes, if you only drive a compact car or small sedan with a 4-cylinder engine, the GB20 is a solid budget-friendly choice. It still has the same UltraSafe spark-proof and reverse polarity protection as the bigger models. Just know that it won’t help you jump a friend’s truck or SUV, so if you ever plan to help others, spend the extra money on the GB40.
How many amps do I need to jump start a dead battery?
For a standard 4-cylinder gas car, 400-500 peak amps is usually enough. For a V6 or V8 gas engine, I’d go with at least 1000 peak amps like the GB40 offers. Diesel engines need significantly more — around 1250 peak amps or higher because of their higher compression ratios. Always buy more power than you think you need because a completely dead battery in cold weather requires more cranking force.
Can I use a Noco Boost as a power bank for my phone?
Yes, all three models I tested — the GB20, GB40, and GBX45 — double as USB power banks for charging phones, tablets, and other small devices. This is actually a great backup feature if you’re stuck waiting for a jump and your phone battery is dying. Just remember that using the power bank function will drain the jump starter’s battery, so don’t drain it completely if you still need to start your car.
What happens if I connect the clamps backward on a Noco Boost?
Nothing bad at all — that’s the whole point of the UltraSafe design. The reverse polarity protection simply prevents the unit from sending power if you hook the clamps up wrong. I’ve tested this on purpose, and the unit just flashes a warning and refuses to work until you correct the connection. This is a lifesaver when you’re stressed and rushing in the dark.
My Final Verdict
After months of testing, the NOCO Boost GB40 with 1000A peak current is my clear winner for forgetful owners. It holds a charge for months, starts 6.0L gas engines without breaking a sweat, and the spark-proof clamps mean I can’t mess it up even after ignoring it for half a year. The GB20 is a solid budget pick for compact car owners, while the GBX45 is the heavy hitter you need if you drive a diesel truck.
If you drive a standard sedan, SUV, or light truck, stop overthinking and grab the GB40 — it’s the most versatile option that won’t leave you stranded. If budget is your main concern and you only own a small car, the GB20 will get the job done for less. For diesel owners, the GBX45 is worth the extra size and cost.
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...
Buy this if you want the best balance of power, standby time, and safety for most gas vehicles. It’s the #1 Best Seller for a reason.
Runner-Up: NOCO Boost GB20
- 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...
Pick this if you only drive a compact car and want to save money. It’s small enough for a glove box but won’t start trucks or diesels.
Heavy Duty: 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...
Choose this if you drive a diesel truck or large SUV and need the extra 1250A cranking power. It’s bigger but worth it for big engines.