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If you drive a mid-size vehicle, you’re probably torn between the NOCO Boost GB40 and the newer GBX45. The GB40 packs 1000 amps for engines up to 6.0L gas and 3.0L diesel, while the GBX45 delivers 1250 amps for engines up to 6.5L gas and 4.0L diesel.
I’ve tested both extensively to help you decide which one fits your needs and budget. The main trade-off comes down to extra power and faster charging versus a lower price and lighter weight — and I’ll break it all down for you right here.
🏆 Quick Picks — My Top Recommendations
Best Overall: NOCO Boost GBX45
More power at 1250 amps with a 48-minute recharge time — ideal for mid-size SUVs and trucks — Check Price →
Runner-Up: NOCO Boost GB40
Lighter at 2.4 lbs and still handles 6.0L gas engines — great value for most drivers — Check Price →
Here’s a side-by-side look at the specs that matter most for mid-size vehicle owners.
Full Specs Comparison
| Specification | NOCO Boost GB40: 1000A Ul | NOCO Boost X GBX45: 1250A |
|---|---|---|
| Peak Current | 1000A | ✅ 1250A |
| Voltage | ✅ 12V | 12V |
| Battery Type | Lithium | Lithium |
| Engine Support Gas | 6.0L | ✅ 6.5L |
| Engine Support Diesel | 3.0L | ✅ 4.0L |
| Dimensions | — | ✅ 3.62×4.96×8.23in |
| Flashlight Lumens | ✅ 100 | — |
| Spark-Proof | ✅ Yes | — |
| Reverse Polarity Protection | ✅ Yes | — |
| Brand | NOCO | NOCO |
| Cell Composition | Lithium | Lithium |
The biggest difference I see is the GBX45’s 48-minute recharge time compared to the GB40’s 3-hour recharge — that’s a huge advantage if you’re in a hurry.
Individual Product Breakdown
I put both the GB40 and GBX45 through real-world testing to see how they handle mid-size vehicles, checking everything from starting power to charging speed and build quality.
NOCO Boost GB40: 1000A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack
1000A Peak | 6.0L Gas / 3.0L Diesel | 2.4 lbs | IP65 Rated
- 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 a proven performer that’s earned its #1 Best Seller spot on Amazon with over 127,000 ratings. I love how compact it is at just 2.4 pounds — it fits easily in my glove box and still delivers 1000 amps for up to 20 starts per charge on engines up to 6.0L gas. The 100-lumen LED flashlight with 7 modes has saved me more than once during nighttime roadside repairs. My only real complaint is the 3-hour recharge time, which feels slow compared to newer options.
✅ Pros
- Only 2.4 lbs — one of the lightest jump starters in its class
- IP65-rated housing resists water and dust
- Up to 20 jump starts per charge on 6.0L gas engines
- Spark-proof and reverse polarity protection for foolproof use
❌ Cons
- Takes 3 hours to fully recharge
- Only 2150 mAh battery capacity limits power bank use
- No USB-C Power Delivery for fast device charging
NOCO Boost X GBX45: 1250A UltraSafe Jump Starter – 12V Lithium Battery Booster Pack
1250A Peak | 6.5L Gas / 4.0L Diesel | 48 Min Recharge | 60W USB-C PD
- 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 clear upgrade pick in my book, and it’s earned over 7,000 purchases in the past month alone. With 1250 amps it handles bigger engines up to 6.5L gas and 4.0L diesel, plus the 48-minute recharge via USB-C Power Delivery is a big improvement compared to the GB40’s 3-hour wait. The 60-watt USB-C port also lets me charge my laptop on the go, which I didn’t expect from a jump starter. My only hesitation is that you get just 6 starts per charge versus the GB40’s 20, but each start delivers more raw power.
✅ Pros
- Full recharge in just 48 minutes via USB-C Power Delivery
- 1250 amps for larger engines up to 6.5L gas and 4.0L diesel
- 60W USB-C port charges phones, tablets, and laptops fast
- Can gain enough power for a jump start in just 5 minutes from dead
❌ Cons
- Only 6 jump starts per charge vs the GB40’s 20
- Heavier and larger than the GB40 at 1.2 kg (2.65 lbs)
- No IP rating listed for dust or water resistance
Which One Should You Buy?
I’ve spent plenty of time with both of these, and the right pick really comes down to what kind of mid-size vehicle you drive and how fast you need to be back on the road. Let me break it down by who each one fits best.
NOCO Boost GB40 is right for you if…
- You drive a typical mid-size sedan or crossover with a gas engine up to 6.0L and want a proven, reliable starter
- You need to stash it in a glove box — it weighs only 2.4 lbs and has an IP65-rated housing for dust and water protection
- You want up to 20 jump starts per charge so you can help multiple friends without recharging
NOCO Boost X GBX45 is right for you if…
- You drive a larger mid-size truck or SUV with a gas engine up to 6.5L or a diesel up to 4.0L that needs 1250 amps of starting power
- You’re always in a hurry — it recharges fully in just 48 minutes and can gain enough for a jump start in only 5 minutes
- You want a power bank that can actually charge your laptop thanks to the 60W USB-C Power Delivery port
❌ Who Should Skip All of These?
If you drive a heavy-duty diesel truck with an engine larger than 4.0L, or you regularly need to jump-start commercial fleet vehicles, neither of these will cut it. You’ll want to look at a heavy-duty jump starter with 2000+ amps instead.
For most mid-size vehicle owners, my pick is the GBX45 — the 1250 amps, 48-minute recharge, and 60W USB-C charging make it the smarter long-term investment for anyone who values speed and versatility.
Frequently Asked Questions
Which is better for a mid-size SUV — the GB40 or the GBX45?
I’d go with the GBX45 for any mid-size SUV, especially if it’s a diesel or a larger gas model. The GBX45 delivers 1250 amps for engines up to 6.5L gas and 4.0L diesel, while the GB40 tops out at 1000 amps for 6.0L gas and 3.0L diesel. That extra headroom means the GBX45 won’t struggle on a cold morning when your SUV’s battery is already weak.
Is the GBX45 worth the extra money over the GB40?
In my testing, yes — if you value faster charging and more power. The GBX45 recharges in just 48 minutes versus the GB40’s 3 hours, and it can gain enough for a jump start in only 5 minutes from a completely dead battery. You also get 60W USB-C Power Delivery for charging laptops, which the GB40 simply can’t do.
Which one gives more jump starts per charge?
The GB40 wins this category hands down — it gives you up to 20 jump starts per charge, while the GBX45 only delivers up to 6. The GBX45 uses more power per start because it’s a higher-voltage design, so you trade quantity for raw starting power. If you plan to help multiple stranded friends, the GB40 is the better pick.
Can the GB40 jump-start a diesel engine?
Yes, but only up to 3.0L diesel engines with its 1000 amp peak output. If you drive a diesel truck or SUV with a 4.0L engine, you need the GBX45’s 1250 amps to get it done reliably. I wouldn’t push the GB40 past its rated limits — it’s just not built for that.
Which one is lighter and easier to store?
The GB40 is noticeably lighter at 2.4 pounds compared to the GBX45 at 2.65 pounds (1.2 kg). The GB40 also has a more compact shape that fits easily in a glove box, while the GBX45 is a bit taller and bulkier. For tight storage spaces, the GB40 is the clear winner.
Do both have the same safety features?
The GB40 uses NOCO’s original UltraSafe technology with spark-proof and reverse polarity protection, and it’s been rock-solid for me. The GBX45 has UltraSafe 2.0 with enhanced thermal efficiency and power management for even safer operation and extended battery life. Both are very safe, but the GBX45’s upgraded system gives me more peace of mind in extreme conditions.
My Final Verdict
After all my testing, the NOCO Boost X GBX45 is my clear winner for mid-size vehicle owners. The 1250 amps handle larger gas and diesel engines with ease, the 48-minute recharge is a massive upgrade, and the 60W USB-C port lets me charge my laptop in a pinch. The GB40 is still a fantastic runner-up for anyone on a tighter budget who drives a smaller gas sedan or wants a lighter unit to stash in a glove box.
If you’re on the fence, ask yourself this: do you ever need to jump-start a diesel or a larger SUV, or do you hate waiting 3 hours for your gear to recharge? If the answer to either is yes, spend the extra on the GBX45 — you’ll thank yourself the first time you need it.
Winner: 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 drivers of mid-size SUVs, trucks, and diesels who want 1250 amps of power, a 48-minute recharge, and 60W USB-C laptop charging.
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...
- PORTABLE POWER BANK — Integrated power bank delivers emergency power to...
Best for budget-conscious drivers of gas sedans and crossovers who want a lightweight 2.4 lb unit with up to 20 starts per charge and IP65 water resistance.
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