NOCO Boost X GBX155 Review

Table of Contents


It is fair to begin by saying that if you have a small or compact car and looking at portable car jump starters, this jump box is like the proverbial sledgehammer driving a thumbtack—a bit of an overkill (if that’s you, you might want to check our review of the NOCO GB70 – its smaller brother). Unlike the sledgehammer, however, this will not damage anything even if you do use it to jump-start smaller cars, so if you are set on this one, we approve. On the other hand, if you are a truck operator, a fleet owner or operate machinery on a daily basis, read on – if you want something that will safely jump-start 10-litre gasoline and 8-litre diesels (and maybe even more than that), this is one to consider, and we approve even more.

The NOCO is a well-known US brand in the space of jump-starting and car battery charging, and its products are designed in the US.

What’s in the box?

  • NOCO Boost X GBX155 4250A 12V
  • Heavy-Duty Jumper Cable Clamps
  • USB-C Charging Cable
  • Microfiber Storage Bag
  • The manual with 1-Year Warranty

What is not in the box?

  • Hard case
  • 65W Fast charger (you can still charge it with the included USB-C cable though)


Image credit: NOCO

External build

When you take it out of the box, you will notice that it is not the lightest – at 5.82lbs/2.64 kg, you can feel the weight, and you would not carry it around in a handbag – but that is not what it is for. It is to sit and wait for its time to shine – and save you or a fellow trucker or driver from waiting for a tow truck.

The housing is IP65 certified (with USB ports closed), so it can deal with a good bit of water or dust.  


Length: 12.03”/30.5cm

Width: 6.9”/17.5cm (including clamps tucked in)

Thickness: 2.72”/6.9cm

The body of the GBX155 is made of thick and sturdy plastic, as are the clamps with crocodile metal clips, and the cables feel heavy-duty as well. Overall, it feels bulky, sturdy and capable.


Power LED – on (white light) when the unit is ON. It will be orange after the 60-second timeout (described below) countdown until the clamps are removed from the car battery or the unit has been switched off and on again.

Power button – it is what it says on the tin. ON/OFF or Boost restart after the timeout

Reverse polarity LED – clamps are on the wrong car battery terminals (negative on the GBX155 and positive on the car battery, for example). Switch the connection.

Cold LED – the internal temperature is too low. The unit is certified to work from -4F/-20 degrees Celsius. If it is colder, we recommend warming the unit up (worst case, under your jacket) before using it. Once in use, it gets warmer anyway.

Hot LED – typically, it needs to get really hot (over 122F / 50 degrees Celsius) for the unit to signal this, let it cool down.

Error LED – Blinks on/off in various sequences to signal error conditions

Internal battery level – while the internal battery lasts a good while, we recommend checking this occasionally as especially hot/cold conditions drain the battery faster.

Manual override button – to use the override, push the button for 3 seconds. Be careful, though, as using the override disables safety protection and manually forces the boost on. This is only to be used when the battery is too dead to be detected at all by the jump starter.

Fast charge LED – White light is on when the fast charge is active. It turns red in case of an error (see below the troubleshooting).

Functions and features

Jump-starting a dead or weak battery

The main point of a jump starter, really – so what can it jump start? As mentioned in the beginning, it can jump-start up to 8L diesel/10L gasoline engines and anything less than that, possibly even a little more. When it comes to jump-starting a vehicle, there are lots of variables, such as temperature or how “dead” the car battery is but this unit has a 4250A peak current rating which is a lot more than most cars need and overcome any of these variables. It is worth noting that the GBX155 works only with 12V lead-acid batteries. But it does work well.

Watch a hands-on video starting a semi from @mo80fo

…and mrbrk262 starting up a 15L Cummins engine. 

How to jump-start a car or truck battery using GBX155?

As always, it is best to read the manual, but here are the basic steps:

  • Switch off anything that can drain the battery during the start (typically lights, AC, radio, etc.). You need as much current available for starting as possible
  • Find your car’s battery (for large semis with 2 batteries, you might need to connect to jump starters)
  • Connect the jump starter to the right terminals (red = positive, black = negative, the reverse polarity protection would warn you if you have it the other way around)
  • Press the power button to begin jump-starting, and all LEDs will flash once. If the battery is properly connected to the jump starter, the white boost LED will illuminate, and the battery charge LEDs will chase.
  • Once the battery is detected, you have 60 seconds to start the engine. Otherwise, you will need to restart the jump starter and start over.
  • If the vehicle does not start right away, wait 20-30 seconds and try again but don’t do this more than 5 times, the unit then needs to rest for about 15 minutes not to get damaged.
  • Once you are up and running, switch the unit off.


Manual override – if your car’s battery is so dead that it is less than 3V, it is quite possible that the jump starter will not detect it and will not initiate a starting sequence. This is the time to use the manual override.

Once you set the manual override, there is no 60 seconds window, no reverse polarity protection or no spark-proof. The jump starter just keeps feeding your car’s battery to maximize the number of attempts to get you going. We do recommend, however, to keep checking the jump starter to make sure it is not getting too hot.

US/Canada version


Charging the GBX155

Another thing to note is to make sure that your NOCO is charged (regularly). As with any battery-powered tool, it slowly loses charge over time, and you do not want to end up with an empty jump starter. The GBX155 comes partially charged out of the box but needs to be fully charged prior to use. You can charge it through the USB C port (cable included) from any USB source but be prepared – if you use a normal phone charger, it will take about 2 days to charge fully. Depending on what you use, the time to a full charge varies, obviously. The USB-C IN/OUT port is capable of receiving up to 60W so the fastest way to charge it is to use NOCO’s own 65W charger (HERE) – using this one, the charge will take about 2.5 hours.

Charging speed
2.5W charger - 64 hours
5W charger - 32 hours
10W charger - 16 hours
60W charger - 2.7 hrs

Power bank

The GBX155 has 3 USB ports – 2x 2.1A USB A (“normal” USB) and one USB C port, which works both ways – to charge other things as well as to charge the jump starter itself. The ports are strong enough to charge the usual array of phones, iPads, tablets, torches, etc., but on top of that, the 60W USB C port is able to power a laptop for a while. For how long depends on a model, etc., though.  

Flashlight/strobe/emergency beacon

The LED light in the unit has several modes which can be used for emergency signalling as well as a flashlight.



There is a whole host of accessories, but we would suggest the following 3:

Hard case:



This thing is a beast. It will start a vast majority of vehicles, large or small. The build quality is great, and it is simple to use. We have no problem recommending this one.  Who is it best for? Truckers, bus drivers, motorhome owners, tractor/machinery operators, folks with ATVs, campervans, boats and anyone in between. Yes, it is on the higher end price-wise but it pays for itself by one commercial service call that does not need to be made. 

9Our score
A Beast!

  • Power, power and power again
  • Build quality
  • Features like reverse polarity protections, USBs, flashlight, etc
  • Only comes with a cloth pouch
  • Charging times

Where to buy


Or scan the QR code below:

Noco 155 UK


Or scan the QR code below:



No, the jump starter only comes with a soft pouch. If you want a hard case (recommended), get the NOCO GBC015 Boost Pro EVA Protection Case HERE

No, we recommend getting NOCO’s own U65 65W USB-C Charger 

The majority of motorhomes have engines smaller than 8litres so you should be able to jump-start it just fine. 

You have 60 seconds to attempt the start from when the battery is successfully “found” by the jump starter. This is to save the power and miximise the number of possible attempts.  

This mode allows you to jump-start even when your car’s battery is less than 3V (practically dead)


Do you have any questions about this product?

Get in touch, we will be happy to help. 

Martin Shaw
Martin Shaw

Martin is an automotive enthusiast with a deep passion for all things cars. He has spent the last decade immersing himself in the industry, reading up on the latest models, attending car shows, and tinkering with his own vehicles. Loves: family, all things cars (apart from selling them), pizza.

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