Tested! NOCO Genius Boost GB40-Emergency Jump Starter

Tested! NOCO Genius Boost GB40-Emergency Jump Starter

by Mike Kojima

Having a dead battery really sucks. Not only can it leave you stranded, but you are also dependent on finding a good samaritan that is willing to give you a jump start. Not only is this bad because you are depending on luck, but it also exposes you to danger as you ask perfect strangers for help.

Even the best of us make mistakes- like leaving our lights on or the keys in the ignition in the garage that can cause your battery to go dead. Modern cars with a lot of electronics have a lot of “dark” current that can cause the battery to go dead in as little as two weeks of not driving.

Finding someone to give you a jump is lame. Besides having to ask a stranger, jump starting has its own intrinsic hazards. If you are not careful with reverse polarity, you will cause a short circuit and extreme heating that can cause burns, fires, and damage the car's electronics. 

Being careless with cables can also cause a lot of sparks, which can be especially hazardous because batteries often have explosive hydrogen gas in and around them that the sparks can ignite. Battery explosions can result in a shower of sulfuric acid- not fun and really bad for your heath. It is also bad form to blow up a helpful kind stranger's battery and shower him and his car with acid!

If you know what you are doing and make the final jumper cable battery connection to a chassis ground away from the battery to reduce the sparking hazard, sometimes the car will hardly crank. This is because the long ground path through the chassis when jumping often diminishes the power available to start the car.  

Today with advances in battery technology, jumping is a thing of the past if you have the right equipment. With lithium ion battery technology, you can now have a backup jumper battery that can easily start your car and can fit in the palm of your hand.

Being skeptical that something so small could do the job, we acquired an NOCO Genius Boost Plus GB40 jumper battery which is about the same size as a couple of DVD cases stacked up. We gave it a somewhat challenging test. We let the battery in our Project STI go completely dead by leaving the lights on then letting it sit for a week. Would the GB40 start it? 


You first attach the GB40's leads to the battery. Since they only have to reach the battery pack, they can be short and thus not lose too much power to resistance. 

The leads have a directional connector that can only be hooked up one way to the battery pack, and there is no way for the leads to get crossed up. The battery pack also has electronics that can detect reverse polarity and shut off. 

The power is kept totally separate so you don't have to be super paranoid about shorting, you can just hook it to the terminals and that's it.


Next, you plug the leads into the Norco battery pack. Make sure the battery pack is switched off before you do this. Before the pack is turned on, nothing is energized so no problem!

The GB40 battery pack has 1000 amps of cranking power out of this tiny battery pack! The battery pack has indicator lights for reversed polarity and when the thermal overload protection circuit is engaged. 

The battery pack also has an override switch that can briefly shut off the thermal protection circuit for extreme use, such as a very dead large battery on a big displacement engine during cold conditions when engines are harder to start. The battery pack can start a 6-liter gas engine or a 3-liter diesel 20 times on a single charge.


Once everything is attached, turn the unit on by hitting the power switch. Then, you can start the car normally. Project STI was so dead, the dash lights would not come on. To our surprise, the car cranked strongly and started right up!

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