Your power needs don't stop when the engine does. The Smartpass 120S delivers fast alternator charging, keeping your house battery ready for the essentials. And it protects your starter battery, prioritizes power, and can jump start your engine.
Your rig doesn't just sip power - it gulps it. From fridges and lights to inverters and air compressors, your house battery works hard to keep everything running. The Smartpass 120S takes up to 120 amps of alternator power and sends it straight to your service battery for fast, efficient charging while you drive. It's made for long travel days, remote locations, and energy-hungry builds that don't have time to wait for a slow trickle charge.
When you're parked for the night and the sun's already set, you don't want to play power manager. The Smartpass 120S handles it for you. With a built-in Battery Guard, it keeps your mission-critical systems - like emergency lights and communication - running longer by disconnecting non-essential loads when battery voltage drops. It's the kind of invisible support that lets you focus on the adventure, not what's happening behind the fuse panel.
Your starter battery might not power your lights or fans, but it's the only reason you're getting out of camp tomorrow. That's why the Smartpass 120S prioritizes charging your starter battery once the house battery is full - and it isolates the two to make sure you're never caught off guard by a drained crank battery.
Every overlander and RV owner has had that moment: you turn the key and get nothing but silence. The Start Assist feature is your built-in backup plan. It lets you pull power from your house battery to boost your starter, helping you get going without jumper cables or roadside help. You can hope you won't need it - but you'll be glad it's there when the time comes.
Big inverters and cabin heaters - some gear draws a lot of power fast. The Smartpass 120S is designed to handle up to 350 amps for short bursts, giving your system the breathing room it needs to keep those high-demand devices running without interruption. It's not just tough - it's ready for the real-world loads your setup is built to handle.
If you're building a system that needs to work hard and never let you down, this is the next level. The Smartpass 120S pairs with the D250SE (sold separately) to create a 140A smart charging system that covers solar, alternator, lithium, and full-system battery protection. Together, they manage your entire energy flow - from charging to load prioritization to backup starting power. It's everything you need when you're far from help and your electrical system has to just work.
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Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.
Hi everyone, Steven here with etrailer.com. Today, we're looking together at our CTEK Smart Pass 120S Smart Battery Charger. This is a DC to DC charger, and it's 12 volts or 120 amps. So folks, this will give you 120 amps of fast charging from your alternator. So it's gonna keep your house battery charged while you're driving, so it's gonna be perfect for high energy setups. It's also gonna automatically prioritize key systems like your fridges, fans, lights, those kind of things.
And it's gonna protect your starter battery, and it's gonna prevent overcharge, that way you're never left stranded. And it also has a built-in jumpstart assist they call it, and that basically just means it uses your house battery in the event that your start battery on the main battery for the engine is really, really low, in case of emergency, it can then use the house battery through this and help jumpstart that. It can support up to 350 amps for inverters, heaters, and other demanding devices as well. You get these two brackets to help assist in installation. You get these two connectors.
And of course you get the cables included as well for installation. So very simple install, follow the instructions that come with it, and you should have no problems. You can wire this up multiple different ways. It works with smart alternators, lithium, AGM, and other 12 volt batteries as well. Folks, that's gonna wrap it up for our quick look together.
I'm Steven, thanks so much for your time. And as always, we'd love to hear your feedback, tell us how you're using it, show us how you're using it with some photos maybe as well, thank you.
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