CTEK RB 4000 Portable Jump Starter — The “Rescue Brick”
If there’s one thing every car owner learns eventually, it’s this: batteries go flat when you least expect it. They die on cold mornings, after five days of not driving, or when you’ve left the boot light on for longer than is socially acceptable. That’s where the CTEK RB 4000 steps in, it’s not just a battery booster, it’s a portable lifesaver… on paper at least.
Here’s what you need to know about this rather curvaceous little brick of Swedish engineering.
The CTEK RB 4000, alongside its slightly smaller RB 3000 sibling, marks something of a milestone for the Swedish charging specialists. Known for years as the go-to name in workshop-grade and enthusiast battery chargers and maintainers, CTEK has traditionally stayed firmly in the professional lane.
These two units are different. They’re CTEK’s first brand-new, fully portable “pro-consumer” jump starters (boosters) that are designed to bring proper, no-nonsense starting power to everyday drivers, campers and off-roaders without dumbing things down. In short, it’s a big first… and a fairly bold step into a market that’s already packed with cheaper, shoutier alternatives.
Power, Starting Ability & Real‑World Use
CTEK claims this unit can deliver up to a 4000 A peak current and is capable of up to 45 jump starts on a single charge. That’s not just hyperbole, it genuinely gives you enough oomph to start cars with deeply discharged 12V lead‑acid batteries, covering everything from your daily runaround to bigger engines that can be a bit grumpy when their battery dies.
In practical terms, that’s plenty for regular DIY mechanics, van-lifers and anyone who’s ever had to ask a neighbour for a jump start. One full charge and you’re not just getting one go, you’ve got a small arsenal of starts. It’s ideal for families with multiple cars, or if you’re running kit that spends a lot of time parked up.
In fact, because of all the press cars I’ve had over winter, I hadn’t driven Deux Smurf, our 1996 Toyota Surf for around a month, and as a consequence, her battery was flat. Out with the RB 4000, and it started her up ten times on the trot - I got bored after that!
The RB 4000 also plays nice with many common battery types — WET, AGM, EFB, GEL and more, so it’s not picky about what it wakes up. Just make sure you check what’s in your car before assuming it’s a one‑size‑fits‑all solution.
Build & Features: A Little More Than Just a Jumper
One of the selling points here is that this thing isn’t just a brute power pack; it’s a proper multi‑tool:
USB‑A and USB‑C ports for charging phones, tablets and other devices, great when you’re out and about or stuck on the roadside.
An integrated LED torch with multiple lighting modes, handy when you’re trying to find gloves or bonnet latches in the dark, or signalling for help.
Ergonomic design with LEDs that show status and ease of use, which means no squinting at tiny indicators.
A robust, Swedish‑inspired design that doesn’t feel like it’s going to fall apart first time you need it.
It also has spark‑proof and reverse polarity protection, which means even if you briefly connect it wrong, you’re far less likely to see flames, smoke, or curse words.
At around 1.2 kg and roughly 24 cm long, it isn’t the smallest, but it’s compact enough to live in the glovebox or boot without dominating space. It also comes with its own storage case.
Charging & Battery Life
Charging the unit itself takes around 3-1/2 hours via USB‑C, which is about what you’d expect — not instant, but also not glacial.
The internal battery is rated at around 88.8 Wh (~24 000 mAh), and CTEK says it can hold a charge for around 8-months without significant drain. That’s useful if you charge it up in September, stick it in the car, and forget about it until one winter evening when the car decides it’s done for.
Battery Indicator, Jump Stats & Charging Phones
One of the neat little bits on the RB 4000 is its digital percentage power indicator — rather than just a row of lights, you get a clearer sense of how much juice is left in the pack before it needs recharging. That’s a proper quality‑of‑life improvement over the “guess by two bars” set‑ups you get on cheaper units. It’s especially handy if you’ve used it a couple of times and want to be sure there’s enough left for a few more starts, or to juice up a phone in an emergency.
For phone charging, depending on the device, the RB 4000 can give you multiple full phone charges off a full charge of its internal battery. For example, my iPhone 13Pro can be recharged roughly 7 times from 0–100% using the USB ports.
Where it Fits (and Where it Doesn’t)
In the world of car kit, the RB 4000 sits firmly in the “get out of jail free” category. It also doesn’t come cheap. At around £400 you’re paying a premium for the compact form factor and convenience, but if you’ve ever been stood in the cold, waiting for someone to turn up with jumper leads, you’ll know it’s worth its weight in annoyance‑free starts.
Final Thoughts — Why Choose the CTEK RB 4000?
When you start looking at portable jump starters, there’s no shortage of budget units out there; the Ring RPPL400, NOCO GB40 and similar packs have helped a lot of stranded drivers get going over the years, including myself, and they absolutely earn their place in many gloveboxes. They’re affordable, they work, and for occasional use they’re fine.
So why would someone spend a fair bit more on the CTEK RB 4000? The answer comes down to confidence and capability.
Firstly, the power delivery on the CTEK isn’t a token bump, it’s genuinely stronger. With a 4000 A peak current and enough internal capacity for around 45 starts on a full charge, it’s not just a single-use or once-in-a-blue-moon tool, it’s something you can rely on again and again, for multiple vehicles and in tougher conditions. That’s a lot more starts than most budget rivals promise, and when you’ve got a family car, a camper or a second car that’s rarely driven, that headroom matters.
Secondly, build quality and protection are at a different level. CTEK doesn’t just throw jumper leads and a battery in a box, the RB 4000 includes spark-proof and reverse-polarity protection, a robust casing built to last, and an easy-to-read percentage power indicator. Cheaper units often get the basics right, but they skimp on these detail features that reduce risk and make the unit genuinely effortless to use when you’re standing in the cold trying not to swear.
Then there’s the holding power. CTEK claims the RB 4000 can sit for up to eight months on standby with minimal drain, meaning you can buy it, stick it in the boot and pretty much forget about it until you need it, without that sinking feeling when you power it up and realise it’s flat. That’s a level of reliability you don’t always get from cheaper jump packs that bleed down faster.
Finally, it’s the all-round functionality. USB-A and USB-C outputs, an integrated LED torch, and a form factor that feels solid rather than flimsy make this more than just a jump starter, it’s genuinely useful roadside gear. For anyone who travels regularly, camps, or just wants that bit of extra peace of mind, that all-in-one usability is worth the premium.
Put bluntly: if you’re buying a starter you hope you never have to use, going cheap makes sense. But if you want something you’ll trust and reach for confidently, even in winter mornings, the CTEK RB 4000 earns its place.
Verdict: Not the cheapest — but one of the most dependable and genuinely capable portable boosters you can buy.
Oh, and I’d better not forget about the 2-year warranty!
Website: CTEK RB 4000
