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NOCO Boost Plus GB40: What to Know
NOCO rates the GB40 at 1000A peak, which is the lowest headline number of the four lithium packs in this guide. NOCO doesn't publish a separate cranking-amp (CA) figure alongside that peak rating, so there's no way to directly compare the GB40's real sustained output to the CCA number printed on your own battery, a limitation it shares with most lithium jump starters, not something unique to NOCO. Its 6.0L gas / 3.0L diesel ceiling reflects that more modest power budget; it's built for typical passenger vehicles, not big V8 trucks or diesels.
NOCO advertises roughly 24Wh of battery capacity (about 6,600mAh) and says the GB40 can deliver up to 20 jump starts on a full charge. Independent bench testing from TechGearLab, however, measured usable capacity closer to 15.57Wh, a gap of roughly a third versus NOCO's own figure. That doesn't make the GB40 unsafe or unreliable; the same test successfully jump-started a 4-liter V6 three times in cold weather. But it's a real, documented inconsistency between NOCO's marketing spec and what an independent lab actually measured, and it's the reason TechGearLab recommended checking the unit's charge more often than NOCO's own maintenance schedule suggests.
Safety-wise, the GB40 uses NOCO's UltraSafe spark-proof, reverse-polarity-protected clamps and an IP65-rated rubberized housing, and it doubles as a USB power bank with a 100-lumen LED flashlight offering seven modes including SOS and strobe. At 2.4 lb and roughly the size of a paperback, it's the lightest unit in this guide by a wide margin, which is the tradeoff for its lower peak-amp ceiling.
Key Listed Features
Spark-proof, reverse-polarity-protected clamps (UltraSafe technology)
IP65-rated rubberized housing for water and dust resistance
Doubles as a USB power bank and 100-lumen flashlight with 7 light modes
Compact 2.4-lb, 7.7 x 3.2 x 1.7-inch footprint
