Car care

Best car battery chargers tested

Best car battery chargers tested

26 Feb, 2018 1:15pmKim Adam

We find out which device has the power to keep your car’s battery in tip-top condition

Battery chargers have long stopped being just for when you’ve left the lights on and can’t start the car. The latest models are packed with electronics, designed not just to charge a battery, but also to recondition it and keep it topped up when it’s left unused for long periods.

Plus, the best can handle the latest types, including lithium, and power-hungry tech such as stop/start. So which is the charger to keep your car’s battery at its best? We headed to CTEK’s Swedish HQ and R&D centre to find out.

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How we tested them

Thanks to the extensive facilities at our disposal, we widened the range of our test. But at its heart was still charging a flat battery, which we monitored until it was full, calculating the mean average charge rate. We also checked the minimum voltage each charger would work from, its efficiency and EMC (electromagnetic compatibility). Instructions and displays were assessed as well, plus we looked at supplied leads and accessories, before checking for sparks during typical misuse. The final factor was price from online retailers.


The standout producers here were CTEK and its US rival NOCO. CTEK just hangs on to its title with the CT5, but it was very close with NOCO’s big G7200. However, NOCO gets the nod among the smaller chargers, with the versatile G3500 coming out ahead of CTEK’s MXS 3.8.

  1. 1. CTEK Time To Go CT5
  2. 2. NOCO Genius G7200
  3. 3. NOCO Genius G3500


CTEK Time To Go CT5

Price: Around £91
Mean current supply: 4.9Amp
Rating: 5.0

If battery chargers are a mystery to you, this is the one to buy. It has all the various charging stages of other CTEK units, but doesn’t confuse you with them. Instead, there’s a more useful progress display indicating when to try to start the car after a flat battery. The downside is limited instructions. Clever electronics meant it charged close to its 5Amp rating, plus it passed our electromagnetic compatibility and misuse tests. Neat and very effective.

Buy now from Amazon

NOCO Genius G7200

Price: Around £90
Mean current supply: 5.2Amp
Rating: 4.5

There’s lots to like about this US import that came so close to toppling CTEK. It’s supplied with leads that are almost a metre longer than its Swedish rival’s and has the widest clamps on test at 35mm. It just topped the CT5 in the charging test, hitting the 80 per cent ready-to-start point around 40 minutes sooner, in just over nine hours. But its mean charge was nowhere near its rated 7.2Amps. It’s a bulky unit that features a progress display, plus a variety of charge modes, including lithium and 24V.

Buy now from Amazon

NOCO Genius G3500

Price: Around £55
Mean current supply: 3.4Amp
Rating: 4.5

More compact than its more powerful sibling, this is still a bit bigger than the similar MXS 3.8, yet has many of the features of the G7200, including the ability to work with lithium batteries. There are modes for reconditioning, charging when cold and 6V batteries, plus useful long leads and big clamps. It hit the 80 per cent charge point in just over 14 hours, almost an hour longer than the MXS 3.8, but the NOCO’s versatility gives it the edge here.

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Price: Around £54
Mean current supply: 3.6Amp
Rating: 4.0

The 3.6Amp predecessor of this product won our 2012 test, but the MXS 3.8 has to settle for a recommendation this time. As with the other CTEK, it pretty much does what it says on the tin, getting impressively close to its claimed 3.8Amps when charging. It comes with a neat storage bag for the charger, the good instructions and unused connection lead. There’s a handy motorcycle mode for small batteries, but overall it can’t match the versatility of the Genius 3500 or its long leads.

Buy now from Amazon

Sealey Compact Auto Maintenance Battery Charger SMC14

Price: Around £69
Mean current supply: 3.1Amp
Rating: 3.0

Another substantial unit, this time from Sealey and boasting an 8Amp charge; the highest on test. But that didn’t translate into rapid charging, because the electronics only delivered close to that in pulses, bringing the average down to a disappointing 3.1Amps and a charge time of more than 15 hours. It has a useful range of modes, including reconditioning, and charging progress is shown on the LED display. It passed our misuse tests, but our sample tripped up in the EMC assessment.

Buy now from Amazon

Victron Energy Blue Smart IP65 Charger

Price: Around £90
Mean current supply: 6.7Amp
Rating: 3.0

The Victron is unique in this test because it is linked to a smartphone app, which shows the state of charge and the rate. You can also change the charger’s settings from your phone while it’s within Bluetooth range. And that charging is pretty effective, getting close to its 7Amp rating and hitting the 80 per cent charge mark two hours quicker than any rival, at just over seven hours. But it sparked in our wrong polarity test and the display was slow to alert us. It was also marginal on the EMC test.

Buy now from CCL Components

Optimate 5 Start/Stop

Price: Around £74
Mean current supply: 3.5Amp
Rating: 3.0

This latest version of the Optimate 5 still shows the individuality we saw in our last test. The display is not the most intuitive to use and you really need the instructions to hand. It is also the only one with part-insulated clamps. Optimate says this is useful in the motorcycle market, where battery connectors are small, with limited space around them, making it popular among bikers. We also could not get a spark from the connectors in our misuse test. In the charge test it was a match for the small CTEK and NOCO, although a bit short of its 5Amp rating.

Buy now from Amazon

AA Battery Charger & Maintainer

Price: Around £29
Mean current supply: 0.9Amp
Rating: 2.5

A best-seller on Amazon, no doubt thanks to the price, this is more of a maintainer than a charger. We stopped our test after 30 hours with some way still to go before the battery was fully charged. That wasn’t a surprise given the low charge rate, a bit below its 1.2Amp rating. This performance is highlighted in the instructions, but the Amazon listing isn’t so clear. Still, it does say it’s “used and approved by AA patrols”. It works as a maintainer with the longest leads here and passed our misuse and EMC tests.

Buy now from Amazon

Ring Advanced Smart Charge RSC706

Price: Around £60
Mean current supply: 3.7Amp
Rating: 2.0

This tops a new range of chargers from Ring which, compared with its rivals here, has a very minimalist design. But the styling doesn’t work for us because the controls aren’t clearly linked to the display and the symbols on the casing look like they should be on a music player. Once set up, charging was nowhere near the 6Amp rating and we had sparks coming from the clamps from residual current after disconnecting the leads. Our sample unit also had problems with the EMC assessment.

Buy now from DRB Car Spares

Battery chargers are incredibly useful, but should the worst happen you will need a jump starter pack. Click here to read our best mini jump starter packs test.

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