How to use a NOCO Boost
Attach the clamps, power the unit on, start the vehicle, then power it off. Those are NOCO's four steps. The rest of this page is what the lights mean when it does not go to plan.
Checked against sources on by the TrueAmps editorial team.
The four steps
- Attach the clamps. Red to the positive terminal, black to the negative, before you power the unit on.
- Power on. Press the power button. The Boost LED lights white when boost is active.
- Start the vehicle.
- Power off and remove the clamps. NOCO also notes you can power off and on again to reset the unit.
Paraphrased from NOCO's GB40 how-to page, checked September 24, 2026. Read the user guide that came with your unit before first use; it carries the full safety warnings.
What the lights mean
| What you see | What NOCO says it means | What to do |
|---|---|---|
| White power LED | The unit is on | Nothing, it is ready |
| White Boost LED | Boost is active | Start the vehicle |
| Error LED solid red | Reverse polarity | Swap the clamps |
| Error LED blinking red, clamps correct | Internal battery too hot | Let it cool, move it somewhere cooler |
| Boost LED will not come on, clamps correct | Vehicle battery below 2 volts | Remove loads and retry, or see Manual Override below |
Manual Override, and why NOCO warns about it
If the vehicle battery is too flat for the Boost to detect, NOCO provides Manual Override: hold the button for three seconds and the Boost LED flashes white. NOCO's own warning is that this disables the safety protection and forces boost on, and that it is only for a battery too low to be detected. Connect the clamps correctly before you use it.
Which Boost for your engine
The steps are the same across the range; the engine rating is not. Jump starters by engine size lists all eight models side by side.
- NOCO Boost Sport GB20: gas up to 4.0 L
- NOCO Boost Plus GB40: gas up to 6.0 L
- NOCO Boost X GBX45: gas up to 6.5 L
- NOCO Boost X GBX55: gas up to 7.5 L
- NOCO Boost HD GB70: gas up to 8.0 L
- NOCO Boost X GBX75: gas up to 8.5 L
- NOCO Boost Pro GB150: gas up to 9.0 L
- NOCO Boost X GBX155: gas up to 10.0 L
Questions people ask
Why is the red light on my NOCO Boost solid?
On the GB40, NOCO lists a solid red Error LED as reverse polarity: the clamps are on the wrong terminals. Swap the connections.
Why is the red light on my NOCO Boost blinking?
NOCO lists a blinking red Error LED, with the cables connected properly, as the internal battery being too hot. Let the unit cool, or move it somewhere cooler.
Why won't my NOCO Boost turn on the boost light?
NOCO says the Boost LED stays off when the connected battery is below 2 volts. Remove all loads and try again, or use Manual Override, which NOCO warns disables the safety protection.
How do I charge my NOCO Boost?
Over its USB input. NOCO's GB40 data sheet lists 3 hours from a 2 A USB source and 6 hours from 1 A.