Review & guide: Noco Genius5 battery charger

Last modified on:

10 December 2022

The Noco Genius5 is a capable bit of kit and very user friendly.

Safety notice and disclaimer: For information only. Follow the user guide. If the information in this guide differs with the user guide, then follow the user guide. Charging batteries can be dangerous, so pay attention to all warnings etc. Also, check your battery and/or car user guide to avoid damaging electronic components… that sort of thing gets expensive fast.

Also read:
Guide to charging different car battery types
Guide to commons car battery types & technologies

Overview of the Noco Genius5

TLDR: if you need a charger for your car battery, (or similar), then you aren’t going to go far wrong with this. With 5 amps of power, this is really the base charger in the Noco Genius range. (I’m discounting the low power ‘Genius1’ charger, because at 1 amp, it isn’t really powerful enough to charge car batteries… unless you just need a trickle charger). The Genius5 is rated for batteries up to 120Ah. Noco have a big range or products, but the Genius5 easily supports the charging needs of 95% of car drivers and enthusiasts.

Build quality and appearance

It feels well built, and the tough plastic casing looks splash resistant (the manual confirms that it is IP65 rated). The buttons are simple and responsive ,with nice clear indicator lights that include warning lights e.g. incorrect polarity, battery issues, charger overheating and high-voltage. These warning lights are useful for those that haven’t kept the small user manual in a safe place. They are also lacking in many of the CTEK charger range.

Cables and accessories

The cable between the charger unit and the terminals is long, longer than it’s direct competitor in the CTEK range – the MXS 5.0. It also comes with a set of clamps that can be removed and used as eyelet terminal connectors (see image below). This is a bonus as the CTEK charging cable doesn’t do this, you have to buy a separate cable. But like the CTEK range of chargers, Noco also offer a wide range of accessories.

Charging and charging times

As a 5-amp charger, it is compatible with batteries of up to 120Ah in size. The Genius5 will top up the batteries of most vehicles (even diesels) in just a few hours. For an idea of how long it takes to charge a flat battery – an 80 amp-hour battery could take up to 12 hours give a full charge. Once charged, the Genius5 can be left on to maintain (trickle-charge) the battery without worrying about over-charging (which could damage a battery, and reduce it’s useful life).

If you need to get going quicker, then you could check out some of the newer portable lithium jump-starter batteries, like the Noco Boost GB40).

READ: Should you buy the Noco Genius5, or the CTEK MXS 5.0?

The Noco Genius5 can also be used to attempt to repair batteries (e.g. stratified or sulphated), although modern batteries and automotive charging systems usually prevent these sorts of issues from occurring. Often, when the battery in a modern and frequently used car suddenly goes flat, it needs to be replaced.

Notes for the beginner:
With most cars, connect red to red (positive terminals), black to black (negative terminals), then plug the charger in and select the correct mode. When disconnecting, reverse the process by disconnecting the negative first. Don’t charge in a space that isn’t well ventilated. Don’t leave unattended. In fact, read the manual. All of them (see the note above).

Link to the Noco Genius5 user guide

Alternatives to consider:

Car battery chargers

Noco Genuis Gen5x1 (Buy | Review) – a 1 amp charger for smaller batteries, or great for trickle charging all batteries
Noco Genuis10 (Buy | Review) – 10 amp charger for larger batteries and/or faster charging, and great for trickle charging all batteries.
CTEK MXS 5.0 (Buy | Review) – very popular all-round charger with slightly different features. Has been the recommendation of many OEM companies for a while now.
CTEK MXS 5.0 Test&Charge (Buy | Review) – as above + ability to test the battery, starter motor and alternator (generator).

Lithium battery boosters (for starting a car with a dead battery)

Noco Boost GB40 (Buy | Review) – most petrol/diesel engines car / light van

The newer Noco BoostX range (GBX45 GBX55 GBX75) have improved battery tech for more jump power and faster charging times.

Advantages of the Noco Genius5

Great looking device, branding and quality packaging (if that matters to you!)
3-year warranty.
Great visual indicator on battery charging status and charging issues via a range of LED lights (better than, say, some of the CTEK chargers).
Temperature compensation tool will alter the behaviour of the battery charger to optimise charging, reduce the chance of over charging and help elongate battery life in extremes of temperature.
Charging clamps can be removed from the charging cable so that the cable’s eyelets can be directly attached to your bar battery
Great range of accessories:
- Extension leads.
- Battery terminal plugs (to be left in place and allow easier and faster connection to the charger).
- Exterior plugs (to connect to outside of a vehicle, e.g. caravan, RV, camper etc.
- Solar chargers.

Disadvantages of the Noco Genius5

User manual is small, flimsy and light on detail regarding different battery types and information.
Warranty period is shorter than the comparable CTEK MXS 5.0 charger, which has a five year warranty.
Desulphation only appears to run when selecting the Repair mode. CTEK chargers detect sulphation (and attempt desulphation, if required) at the beginning of every charge cycle.

Noco Genius5 Charging modes:

12v
6v
12v AGM
12v Lithium
Force charge
Repair

Charging different types of car batteries with the NOCO Genius 5 charger

Unlike CTEK battery chargers, the NOCO range of chargers have a Standby mode where the charger is not outputting any power to its terminals, or any battery that is connected. Standby mode consumes very little electrical power.

In car charging

Normal charging:
I haven’t yet understood if the Noco chargers stand behind their product and say it is safe to use their chargers on the battery in the car – I’m waiting on a reply from their customer support.

Note for “Repair” mode
The Repair mode uses higher voltages (up to 16.5v) and may use rapid pules of current. This *could* interfere with sensitive electronics. Noco say you should disconnect a battery before attempting to use the repair mode. However, CTEK do say that it is safe to use this in most normal cars.

12v Mode – how to charge a wet cell battery with the Noco Genius5 charger

The 12 volt mode is designed to work with several variations of lead-acid battery technology, including: Wet Cell, Gel Cell, Enhanced Flooded (also known as EFB), Maintenance-Free and Calcium batteries. You can learn more about these battery types in the car battery technology guide.
Push the mode button to cycle through charging modes until the 12V indicator light is lit.

12v AGM – how to charge AGM batteries with the Noco Genius5

AGM batteries need a slightly higher charging voltage. So this mode could damage other battery types if used incorrectly.
Push the mode button to cycle through charging modes until the 12V AGM indicator light is lit.

6v Mode – Noco Genius5 for charging 6V batteries

The six volt mode is designed to work with several variations of lead-acid battery technology, including: Wet Cell, Gel Cell, Enhanced Flooded(also known as EFB), Maintenance-Free and Calcium batteries. You can learn more about these battery types in this Guide to common car battery technologies.

Press and hold the Mode button for three seconds to enter 6V Charge Mode.

12v Lithium mode – how to charge Lithium batteries with the Noco charger

Only for 12v lithium-ion batteries, which the manual states includes 12V lithium-ion-phosphate. Little detail on other types on Lithium iron phosphate. This is probably quite a specialised use case. But it isn’t available on many of the CTEK chargers, like the popular MXS 5.0, so if you need it then the Noco Genius battery chargers will be the one to pick.

Push the mode button to cycle through charging modes until the 12V lithium indicator light is lit.

How to use Noco Force mode – overcome charging issues with deeply discharged batteries

Caution: using this mode will disable all safety measures, including reverse polarity protection, and make the charger’s connections live even when not connected to anything. Be careful.

Sometimes, when a battery is excessively discharged, the voltage can drop so low that the internal resistance becomes (relatively) too high. In which case a battery charger may not recognise it is connected to the battery. If you connect the charger to the battery and nothing happens, then you can attempt to use “force” mode to drive a charge current through the battery for five minutes in order to raise its voltage.

If a battery is capably of accepting a charge, then using Force mode should raise its voltage to a level where regular charging modes will work. After five minutes, the charger will exit Force mode and revert to normal charging. If normal charging is not possible after using Force mode, then the battery may need to be replaced.

To use the Force (mode), press and hold the ‘Mode’ button for five seconds.

Using the Noco Genius5 to restore a car battery: 12v Repair Mode

If a battery is refusing to take or hold a charge, or if appears to charge but does not produce the expected power output, then it might be suffering from stratification or sulphation. You can use the Repair mode to try and solve stratification or sulphation issues. These conditions can occur in older batteries, batteries that haven’t been charged properly (e.g. lower than optimal charging current), have been deeply discharged, or have stood idle for some time.

Read my full guide to common car battery technology and my guide to charging different battery types (EFB, AGM, etc) to understand more about sulphation and stratification, the operating conditions that can cause these issues to occur, and the battery types that are more prone to suffering from these issues.

The repair mode will run for four hours. Access the Repair mode from standby mode (with the charger already connected to the affected battery) by pressing and holding for three seconds. The Noco manual recommends you try to fully charge the battery before running the Repair mode.

Conclusion – should you buy a Noco Genius5 car battery charger?

You won’t go far wrong with the Genius5. If you need something simple and user friendly then this is a good buy. However, if you are using batteries that are more prone to stratification (e.g. wet cell batteries), then it might be worth looking at a different charger, such as the CTEK MXS 5.0, which will automatically detect and attempt destratification when charging wet cell batteries. CTEK also say you can usually use the Repair mode without disconnecting and removing the battery – which is not recommended with the Genius5.

Which to buy: CTEK MXS 5.0 OR Noco Genius5 battery charger?

Where to buy the Genius5

Amazon usually has frequent deals on the Noco Genius range of chargers.

Any questions? Drop a comment below.

Published on

11 February 2022

Cars

Oliver Jobson

Tags:

automotive accessories, battery charging, car battery, reviews and how to guides

Comments

3 responses to “Review & guide: Noco Genius5 battery charger”

Ulgen Cezayirlioglu

7 December 2022

You have given much information that even the user guides do not give by doing lots of investigation.

For that thanks a lot.

BUT
It was not untill the NOCO article that I did not realise you personally favoured the CTEK for some reason unknown to the reader.
I have both devices and tested both against each other over the years. CTEK is better only for the fact that it is more for folks who are simple minded(plug and forget) and has 5 years of warranty.

CTEK lacks 6V charging, CTEK lacks Lithium, CTEK lacks forced mode, NOCO has better cable length, higher quality clamps, NOCO has option to run repair mode seperately..

They both do not definitely say you can or cannot use the charger on a battery installed on the car. CTEK says “they do not assume there would be a problem” but for not to be held accountable they tell to ask the car manufacturer. Accept for the few devices matched and sold with collectors cars, nothing is for sure. When the manufacturers are subjected to the question of compatibility, all manufacturers answers “on your own risk”. How could they say anything else when both cars and charger models change all the time. When asked, even BMW and Rolls Roys said they would not say that “your store baught standard CTEK 5.0” is capable of charging the battery in the car with absolute certainty. Trully If you had asked NOCO the question you asked CTEK, they would provide you with the same answer. As you certainly know but cleverly disguise from the reader, both companies make accessories made to connect their chargers when the battery is still installed on the car.

I am also very sad that on multiple instances you kept on saying you “wont go far wrong” with NOCO as if there was “some thing wrong” with the decision to go with NOCO.

Conclusion: They are both extremely good, equally capable, just as expensive and easy to use. But now I have my doubts about the information you had given and I had not confirmed from any other source.

I used to enjoy your articles.

Very very sorry.
Oliver Jobson

10 December 2022

Ok – interesting take, although I appreciate the time taken, I’m also intrigued by your response. Yes, the CTEK does lack 6v charging, lithium, etc. But as a car charger for the average person? 6v charging and lithium battery charging isn’t needed and is just a complication. So, in my opinion, the CTEK is the better product. It automatically runs repair mode, is easier to use, and has a longer warranty. It’s also been sold as an OEM charger in many premium marque dealerships like Porsche and BMW.
I have never at any point stated that the NOCO can definitely be used to charge with the battery in the car (I never received a response from their customer support team. This is in contrast to CTEK’s customer support team who have always been very responsive and provided detailed answers to questions). CTEK have told me that it should be ok in most cars, but you should check before using. I did also say you should read all relevant manuals to check before using it on your car. Yes, both CTEK and NOCO make products to allow you to charge the battery whilst still in the car – such as a cigarette lighter adapter, or battery terminal ring connections (which I do mention in the article) – but at no point have I heard either manufacturer say that it will be safe to use these in all cars.
I’m sorry that my article made you “very sad” – that was not my intention.
Billy bob

2 August 2023

Genius5 Can be used to charge whilst battery’s connected in the car, just received a response from their customer support today.