I hate digging around a messy trunk for jumper cables, especially in the rain. If you need a jump starter that lives in your glove box without taking up all your registration and napkin space, you want something truly compact. I tested the smallest Noco Boost models to find the ones that actually disappear inside a standard glove compartment.
Every pick here fits a real glove box with room to spare, delivers enough cranking amps for a typical car or truck, and includes Noco’s UltraSafe spark-proof tech so you don’t have to think twice about using it. I focused on physical dimensions, peak amp ratings, and real-world usability — no oversized units that technically “could” squeeze in.
Quick Comparison: best Noco Boost Ultrasafe Jumpstarter that fits in a glove box without taking up space
| # | Product | Best For | Key Spec | Price |
|---|---|---|---|---|
| 1 | NOCO Boost GB20 Best Overall Pick |
Smallest glove box fit | 500A | Check Price → |
| 2 | NOCO Boost GB40 Most Versatile |
Compact with diesel power | 1000A | Check Price → |
| 3 | NOCO Boost X GBX45 Best Power-to-Size Ratio |
Big engines, small package | 1250A | Check Price → |
How I Selected These Products
I started by measuring every Noco Boost model against a standard glove box opening. If it didn’t slide in with room for the owner’s manual, it was out. I also only considered units with at least 500 peak amps so they could actually start a car, not just look cute.
Value mattered more than the lowest price tag. I ranked units higher if they packed useful extras like a built-in LED flashlight or power bank capability. A jump starter that doubles as a phone charger earns its glove box spot way more than one that just sits there.
I cross-checked thousands of verified buyer reviews to catch any reliability red flags. Models with consistent complaints about battery drain or weak clamps got eliminated. Every pick here has a strong track record of working when you actually need it, not just on paper.
Best Overall Pick
NOCO Boost GB20: 500A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack
500A Peak | 12V | 4.0L Gas Engines | Power Bank | UltraSafe Spark-Proof
- 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 Noco Boost you can buy, and it’s the one I keep in my own glove box. It delivers 500 peak amps, which is enough to jump a 4.0L gas engine, and it doubles as a power bank for charging your phone. The UltraSafe technology means no sparks, no reverse polarity issues, and no worrying about damaging your vehicle’s electronics.
This is the best choice if you drive a smaller car or crossover and want something that truly disappears in your glove box. The trade-off is that 500A won’t start a diesel or a big V8 truck, so if you drive something larger, you’ll want to look at the GB40 or GBX45 below.
✅ Pros
- Smallest footprint of any Noco Boost — fits even cramped glove boxes
- 500 peak amps is plenty for 4.0L gas engines and most sedans
- Built-in power bank lets you charge a phone or tablet in a pinch
- UltraSafe spark-proof and reverse polarity protection for worry-free use
❌ Cons
- 500A won’t start larger V6/V8 engines or any diesel
- No built-in LED flashlight like the larger models have
Most Versatile
NOCO Boost GB40: 1000A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack
1000A Peak | 12V | 6.0L Gas / 3.0L Diesel | Power Bank | 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 for good reason — it packs 1000 peak amps into a box that still fits in most glove boxes. I love that it handles both 6.0L gas engines and 3.0L diesel engines, so it works for everything from a compact sedan to a full-size pickup. The 100-lumen LED flashlight is a handy bonus when you’re stuck in the dark.
This is the sweet spot for most drivers who want one unit that covers multiple vehicles. The only catch is that it’s slightly thicker than the GB20, so if your glove box is already stuffed, you might need to clear a little space to make it fit.
✅ Pros
- 1000 peak amps handles most gas and small diesel engines
- Built-in 100-lumen LED flashlight with multiple modes
- #1 best seller with over 127,000 ratings for proven reliability
- Spark-proof and reverse polarity protection for safe operation
❌ Cons
- Slightly bulkier than the GB20 — measure your glove box first
- Not enough power for larger diesel engines over 3.0L
Best Power-to-Size Ratio
NOCO Boost X GBX45: 1250A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack
1250A Peak | 12V | 6.5L Gas / 4.0L Diesel | Power Bank | UltraSafe Technology
- 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 the Boost X series’ answer to people who need serious power but don’t want a massive brick in their car. It cranks out 1250 peak amps, enough for 6.5L gas engines and 4.0L diesel engines, yet it still fits in a glove box. I tested it on a friend’s diesel truck and it fired right up without hesitation.
This is the pick for truck and SUV owners who need diesel capability but refuse to sacrifice glove box space. The downside is it costs more than the GB40, so if you only drive a small gas car, you’re paying for power you won’t use.
✅ Pros
- 1250 peak amps handles big gas engines and 4.0L diesel engines
- Compact enough for most glove boxes despite the power output
- Works as a power bank for charging phones and tablets
- UltraSafe spark-proof and reverse polarity protection included
❌ Cons
- Higher price than the GB40 — overkill for small gas cars
- Slightly larger than the GB20, so tight glove boxes may be a squeeze
What to Look for in Noco Boost Ultrasafe Jumpstarter that fits in a glove box without taking up space
Buying a jump starter that actually lives in your glove box means balancing size against power. I see people grab the cheapest unit only to find it can’t start their engine, or buy a monster that takes up the whole compartment. Here’s what actually matters when you’re shopping for a Noco Boost that stays out of sight until you need it.
Physical Dimensions and Glove Box Fit
This is the whole point of this list, so start here. Measure your glove box before you buy anything — depth and height matter more than width with these Noco units. The GB20 is the smallest at roughly the size of a thick smartphone, while the GB40 and GBX45 add a bit more bulk. If your glove box is already packed with the owner’s manual, registration, and a tire gauge, the GB20 is your only real option for a clean fit.
Peak Amps and Engine Size
Peak amps tell you how much cranking power the unit can deliver in a quick burst. A good rule of thumb is 500 peak amps for a 4.0L gas engine, 1000 for a 6.0L gas or 3.0L diesel, and 1250 for bigger setups. Don’t overspend on power you won’t use, but don’t undershoot either — a unit that can’t crank your engine is just dead weight in your glove box.
UltraSafe Protection Features
Every Noco Boost in this list includes UltraSafe spark-proof technology and reverse polarity protection. That means you can’t accidentally cause sparks near your battery or hook the clamps up backward and fry your electronics. This is a non-negotiable feature for me — I’ve seen too many cheap jump starters damage cars or scare the owner with a spark show.
Power Bank and Extra Features
Since you’re keeping this in your glove box anyway, it might as well double as a phone charger. The GB20 and GB40 both work as power banks, and the GB40 adds a 100-lumen LED flashlight with multiple modes. These extras don’t add much size but can save your day if your phone dies while you’re waiting for a tow or jump.
Build Quality and Brand Reputation
Noco is the dominant brand in this space for a reason — their Boost line has hundreds of thousands of reviews and a proven track record. You’re paying for reliable battery cells that hold their charge for months, durable clamps that don’t rust, and a case that survives being tossed in a glove box. Skip no-name brands that cut corners on the battery and clamps.
My Shortcut Advice: If you drive a typical 4-cylinder sedan or small crossover, get the GB20 and don’t look back. If you drive a truck, SUV, or anything diesel, jump straight to the GBX45 for the power you’ll actually need.
Frequently Asked Questions
What is the best Noco Boost for fitting in a glove box?
The NOCO Boost GB20 is my top pick for glove box fit because it’s the smallest unit in the lineup at just 500 peak amps. It slides into even tight glove compartments without displacing your manual or registration. If you drive a 4.0L gas engine or smaller, this is the one I’d grab every time.
Can a Noco Boost GB20 start a diesel engine?
No, the GB20 is rated for 4.0L gas engines only and won’t have enough cranking power for diesel engines. You’ll need at least the GB40 with 1000 peak amps for 3.0L diesels, or the GBX45 with 1250 peak amps for 4.0L diesels. Don’t try to make the GB20 work on a diesel — it’ll just drain your battery and leave you stranded.
What’s the difference between the Noco Boost GB40 and the GBX45?
The GB40 delivers 1000 peak amps for 6.0L gas and 3.0L diesel engines, while the GBX45 bumps that to 1250 peak amps for 6.5L gas and 4.0L diesel engines. The GBX45 is also slightly newer and uses the Boost X platform, but both fit in a glove box. The GB40 is better for most drivers, while the GBX45 is worth the extra money if you own a larger truck or diesel vehicle.
How long does a Noco Boost hold its charge in a glove box?
In my experience, a fully charged Noco Boost will hold its charge for about 3 to 6 months in a glove box, depending on temperature. I check mine every season and top it off before winter hits. Extreme heat or cold can drain the battery faster, so don’t just toss it in and forget it for a year.
Is the Noco Boost GB20 worth it for a compact car?
Absolutely — the GB20 is the perfect match for a compact car or sedan with a 4-cylinder engine. It’s cheap enough that you won’t feel bad buying it as a backup, and it fits in the glove box without taking up space. Plus it doubles as a power bank for your phone, which I’ve used more times than I expected.
Can a Noco Boost jump starter power a phone or tablet?
Yes, all three models in this list work as power banks for charging USB devices like phones and tablets. The GB20 and GB40 have standard USB ports, and they’ll give you a few full phone charges before the jump starter itself needs a recharge. It’s a handy backup to have in your glove box even if you never need a jump.
How many peak amps do I need for a 6.0L gas engine?
For a 6.0L gas engine, I recommend at least 1000 peak amps, which is exactly what the NOCO Boost GB40 delivers. The GBX45 with 1250 peak amps gives you extra margin in cold weather or if the battery is completely dead. The GB20 at 500 peak amps won’t cut it for an engine that size.
What’s the biggest mistake people make when buying a glove box jump starter?
The biggest mistake I see is buying a unit that’s too powerful and physically too large to fit. People grab a 3000-amp monster thinking they’re future-proofing, then realize it won’t fit in their glove box at all. Measure your space first, then match the peak amps to your actual engine size — don’t overshoot on power you’ll never use.
My Final Verdict
After testing all three, the NOCO Boost GB20 is my clear winner for anyone who wants a jump starter that truly disappears in a glove box. It delivers 500 peak amps for 4.0L gas engines, works as a power bank, and takes up less space than a thick wallet. The GB40 is the runner-up for drivers who need more power but still want a compact fit, and the GBX45 is the pick if you drive a diesel or large truck and refuse to give up glove box space.
If you’re still on the fence, think about what you drive. A 4-cylinder sedan? Get the GB20 and never worry about fit. A pickup or diesel rig? Go straight for the GBX45 and don’t compromise on cranking power. Either way, you’re getting Noco’s UltraSafe protection and a unit that earns its spot in your glove box.
Best Overall: 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 compact car or sedan and want the smallest jump starter that still starts your engine. It fits in any glove box and doubles as a phone charger.
Runner-Up: 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 need 1000 peak amps for larger gas engines or small diesels and still want a unit that fits in most glove boxes. It’s the most versatile option on this list.
Most Powerful: 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 diesel truck or large SUV and need 1250 peak amps in a package that still fits your glove box. It’s the most power you can get without moving to a full-size jump box.