Semi truck jump starter: match the voltage, then the engine size
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Quick answer
First match your truck's starting system voltage, 12 V or 24 V, then check the jump starter's engine-size rating for diesel. NOCO rates its Boost MAX GB250+ for 12 V systems on gas and diesel engines up to 16 liters, and its GB251+ for 24 V systems up to 32 liters, both for semi-trucks up to class 8. A car-sized booster such as NOCO's GBX155 is rated only to 8 liters of diesel, which suits pickups, not big rigs.
Three NOCO boosters compared
| Spec | NOCO GB250+ | NOCO GB251+ | NOCO GBX155 |
|---|---|---|---|
| System voltage | 12 V | 24 V | 12 V |
| Rated current | 5,250 A | 3,000 A | 4,250 A |
| Engine rating | Gas and diesel up to 16 L | Gas and diesel up to 32 L | Gas up to 10 L, diesel up to 8 L |
| Vehicles listed | Semi-trucks up to class 8, buses, motorhomes, equipment | Semi-trucks up to class 8, buses, motorhomes, equipment | Not listed for semis |
| Battery | 242 Wh | See note below | Internal power bank, 60 W USB-C |
| Recharge | 8.5 h | 8.5 h | 2.7 h full via USB-C |
NOCO's GB251+ page gives two battery figures, 137 Wh and 242 Wh, so we leave it out of the table. Its larger GB500+, rated for both 12 V and 24 V up to 45 liters, was out of stock at NOCO and not listed on Amazon when we checked in October 2026.
12 V or 24 V: check before you buy
- Look at the batteries and starter: the truck's manual or the starter label tells you the starting voltage.
- Match exactly: NOCO sells separate 12 V (GB250+) and 24 V (GB251+) boosters; only its GB500+ covers both.
- Engine size: NOCO rates each booster by maximum engine displacement for gas and diesel. Check your engine's liters against that number, not just the amps.
A higher amp number on a 12 V booster does not make it suitable for a 24 V system.
How these boosters work at the truck
- 60 second window: NOCO says to start the vehicle within 60 seconds after pressing the power button. After that the unit times out and must be switched off and on again.
- Spark-proof clamps: NOCO lists its UltraSafe spark-proof design with reverse polarity protection on all three.
- Voltmeter: the Boost MAX models include a voltmeter to help pinpoint battery problems, which doubles as the countdown timer.
- Recharging: the Boost MAX units recharge from the vehicle's 12 V auxiliary port or NOCO's 4 A adapter in 8.5 hours; the GBX155 uses 60 W USB-C.
Follow the truck maker's jump-starting instructions and NOCO's manual for clamp order and connection points.
Why a car jump starter falls short
NOCO's own ratings show the gap. The GBX155 is a 4,250 A booster but is rated only to 8 liters of diesel. The GB250+ handles 16 liters on the same 12 V, and NOCO rates the 24 V GB251+ for 32 liters with fewer amps. If your truck's diesel is 8 liters or less, a Boost X class booster like the GBX155 is within its rating; for a class 8 semi, look at the Boost MAX range. See our car jump starter guides for passenger vehicles.
Extras for the cab
- USB charging: the Boost MAX models have two 2.1 A USB ports for phones and tablets.
- Light: NOCO lists a 2,200 lumen light on the GB500+ and a light on the GB250+; the GBX155 has a 500 lumen light with SOS and strobe.
- Storage: keep the booster charged and in the cab; NOCO says the GBX155 can go from 0% to jump starting with 5 minutes of charge.
- Roadside kit: see our car emergency kit guide for what else to carry.
What to look for when you buy
12 V class 8 trucks: NOCO Boost MAX GB250+
Best for: 12 V semis, motorhomes and heavy equipment
NOCO lists 5,250 A for 12 V systems, gas and diesel engines up to 16 liters, semi-trucks up to class 8, spark-proof clamps, a voltmeter, two USB ports and a 242 Wh battery.
Watch out: 12 V only; it is a large, heavy-duty unit with an 8.5 hour recharge.
See options on Amazon (opens Amazon in a new tab)24 V systems: NOCO Boost MAX GB251+
Best for: 24 V trucks, buses and equipment
NOCO lists 3,000 A for 24 V systems, gas and diesel engines up to 32 liters, semi-trucks up to class 8, spark-proof clamps, a voltmeter and two USB ports.
Watch out: 24 V only; NOCO's page gives two different battery capacities.
See options on Amazon (opens Amazon in a new tab)Pickups and light trucks: NOCO Boost X GBX155
Best for: Diesel pickups up to 8 liters, not class 8 semis
NOCO lists 4,250 A for 12 V, gas engines to 10 liters and diesel to 8 liters, 60 W USB-C charging in and out, a 2.7 hour recharge and a 500 lumen light.
Watch out: Not rated for large semi-truck engines.
See options on Amazon (opens Amazon in a new tab)Questions people ask
- What size jump starter do I need for a semi truck?
- Match the truck's 12 V or 24 V system and check the engine-size rating; NOCO rates its GB250+ to 16 L at 12 V and its GB251+ to 32 L at 24 V.
- How many amps does it take to jump start a semi truck?
- Amps alone do not tell you; NOCO's 3,000 A GB251+ is rated for larger engines than its 4,250 A GBX155 because it runs at 24 V.
- Can a car jump starter start a semi?
- Usually not; NOCO's GBX155 car booster is rated only to 8 liters of diesel.
- How long do I have to start the truck?
- NOCO says to start the vehicle within 60 seconds of pressing the power button, then reset the unit for another try.