CTEK OEM Chargers

Review: CTEK Multi US 3300 & Multi US 7002 12-Volt Battery Chargers 11

As some one with a small car collecting problem, I don’t always get a chance to drive all my cars all the time. Some are stored in remote locations. Some are less amenable to rainy weather (the Atom). Some stay parked when gas prices are higher (the Hummer). Some might not be running at the moment (ahem, Ferraris). And some I simply don’t feel like driving sometimes. What this all means, however, is that I’ve become quite used to having to deal with dead batteries, and quote handy with jumper cables.

In the past, I’ve used the ubiquitous Schumacher brand battery chargers (which you can find at any local hardware store) to keep my menagerie of batteries ready to go, but I’ve had more than one of them go bad on me over the last year, so I went looking for an upgrade. And I found it – in CTEK‘s Multi US series 12-volt chargers.

I hadn’t heard of CTEK before… or at least I thought I hadn’t. Then I discovered that CTEK Sweden had actually been providing OEM-branded battery chargers to really high-end auto manufacturers like Ferrari:

and Maserati:

and Aston Martin, and Porsche, and Bentley, and Mercedes-Benz:

CTEK OEM Chargers

and well… you get the idea. By comparing these photos, it’s easy to see that all those OEM chargers are simply a relabeled CTEK US 800:


You can pick up a CTEK 800 for just over $30 from most online retailers. Or, if you want a bright red one with a horsey sticker on it, you could pay over $400 at your local Ferrari dealer instead. That’s an expensive sticker.

Once I realized that the prestige-brand car companies were willing to trust (and warranty) their delicate electrical systems with a CTEK charger, I went shopping for a couple of my own. Amazon had them on special for 40% off,  so I picked up a CTEK Multi US 3300 (list price is $74.99):

CTEK Multi US 3300

CTEK Multi US 3300

and a CTEK Multi US 7002 (list price is $149.99):

CTEK Multi US 7002

CTEK Multi US 7002

Both chargers share the same basic features:

  • They charge all major types of 12-volt lead-acid batteries (Wet, Maintenance Free, Gel, AGM and Ca).
  • They come with two sets of interchangeable connection leads: one with clamps (for attaching to any battery) and one with eyelet terminals (for long-term connection to a battery).
  • They provide “maintenance pulse charging” which keeps fully charged batteries charged and increases their battery life.
  • They include a patented desulphation function that can actually recover slightly sulphated batteries and extend their life.
  • They come with a 5 year warranty.

Their big differences are in the charging and maintenance amperage ratings:

  • 3300: 12Ah to 75Ah charging / 12-120Ah maintenance
  • 7002: 14Ah to 150Ah charging / 14Ah to 225Ah maintenance

and in the number of “smarter” charging steps and charge modes they offer:

  • 3300: Four step, automatic switch charging with three separate charge modes
  • 7002: Eight step, automatic switch charging with four separate charge modes

The CTEK Multi US 7002 offers all eight charging steps in CTEK’s “smarter charging” method, which are:

  1. Cleaning (Desulphation): cleans up an undercharged battery so it can begin accepting a charge
  2. Testing (Soft Start): verifies that the battery is in a suitable condition to accept a charge
  3. Rapid Charge (Bulk): quickly charge the battery up to 80% capacity so it’s operational as soon as possible
  4. Slow Charge (Absorption): slows down the charging near full capacity so the battery doesn’t become overcharged and damaged
  5. Analysis – validates that the battery is retaining its charge
  6. Recondition – brings a dead battery back to to it’s maximum potential
  7. Frequent Maintenance (Float) – checks the charge level frequently to keep it at 100%
  8. Infrequent Maintainance (Pulse) – checks the battery less frequently so it can survive long-term storage
CTEK 8 Step Charging Process

CTEK 8 Step Charging Process

The 3300 offers only steps 1, 3, 4, and 8, but that’s still more than adequate for most uses (and more than the CTEK US 800 you’d get with your Ferrari will do). I wanted a 7002 in the garage primarily so I could test out the reconditioning mode, since I had a dead battery in my 1992 Ferrari 512TR that my Schumacher “smart” battery charger refused to even attempt to charge. I connected the CTEK Multi US 7002 to the battery and chose the reconditioning mode. The following morning, the battery was at 100% and the car started right away. My 7002 paid for itself in its first 24 hours of ownership!

Both units have easy-to-read LED indicators of where the charger is in its charging process, as well as an incorrect polarity indicator – which came in handy today when I hooked the 3300 up to my Ariel Atom and didn’t look closely at the terminal colors. In my defense, it was dark, and the entire Odyssey battery is bright red, so it’s hard to see the positive terminal. 🙂

The 3300 lets you select from three modes:

  1. 14.4V/0.8A – for most small batteries (like motorcycle batteries)
  2. 14.4V/3.3A – for most car batteries, including wet, maintenance free, and most gel batteries.
  3. 14.7V/3.3A – for cold weather situations, or for most AGM batteries such as Optima, Maxxima, and Odyssey (which is what I have in the Atom)

while the 7002 offers four modes:

  1. 14.4V – for most car batteries, including wet, maintenance free, and most gel batteries
  2. 14.7V – for cold weather situations, or for most AGM batteries such as Optima, Maxxima, and Odyssey
  3. 13.6V – operates at a constant voltage of 13.6V where maximum capacity is important, such as maintaining floor sweepers, golf carts, etc.
  4. 15.7V – used when reconditioning for recovering deep discharged flooded batteries where there is likely high acid weight on the bottom and low on the top, or some spiral cell AGM batteries that have been deep cycled.

I tested most of the modes on both chargers on a variety of my batteries (lawn tractor, Sea-doos, scooter, and cars) with excellent results across the board. These chargers really are smarter than my older ones… which are now all gathering dust in the corner.

My plan is to purchase a few CTEK US 800s to hard-wire into my cars (replacing the older Shumacher float chargers I currently have in there), use the Multi US 3300 on the Atom (which has an AGM battery) and keep the Multi US 7002 handy in the garage for use where needed. Because all the chargers come with interchangeable connection leads, I can hard-wire the leads to each car’s batteries, and then use any of my CTEK chargers on any of my cars.

My final analysis is that the CTEK chargers are a bargain (as long as you buy the ones that actually say CTEK on them). They offer useful features, versatility, and ultimately what’s most important for any car owner: the ability to just get in and drive.