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CTEK MULTI US 3300 12-Volt Universal Battery Charger w/ Pulse Maintenance

CTEK Power Inc Battery Chargers

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Code:   CTEK56158



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CTEK Power Inc Battery Chargers - CTEK56158

This powerful, all-weather, four-step charger uses a patented, pulse-maintenance system to charge and maintain all household 12V batteries - cars, campers, mowers, trucks and boats. A practical battery charger fits most applications.


  • Reliable, maintenance-free, 4-step system constantly monitors and maintains 12V battery charge
    • Won't overcharge or undercharge like common trickle chargers
    • Switches automatically to pulse-maintenance phase when full charge has been reached
    • Reduces risk of overheating, sulfation and premature battery failure
  • Easy-to-use, quick-disconnect system
    • Includes 2 battery-cable attachment systems w/ Comfort Connect end plugs - charger plugs right in
      • Eyelet-terminal cable permanently attaches to battery terminals
      • Clamp-terminal cable temporarily clamps to battery terminals
  • Safe, versatile design
    • Approved for indoor and outdoor use
    • Prevents reverse-polarity mistakes
    • Offers (3) 12V current modes
      • Motorcycle icon: lower current for smaller 12V batteries
      • Car icon: higher current for larger 12V automobile and marine batteries
      • Snowflake/AGM icon: special winter mode designed for charging and maintenance in cold weather; also recommended by many AGM battery manufacturers like Optima, Maxima and Odyssey
  • Convenient accessories (sold separately) provide additional security and convenience
    • Know your battery's charge level at a glance w/ optional LED-indicator battery cable
    • Reduce the hassle of charging multiple vehicles w/ additional battery-hookup cables


  • Application: most starter and deep-cycle, 12V, lead-acid batteries - including wet, MF, AGM and most gel batteries
    • Charges batteries w/ capacities from 1.2 Ah - 75 Ah
    • Maintains batteries w/ capacities up to 120 Ah
  • Charge cycle: 4-step, fully automatic charger w/ pulse maintenance
  • Dimensions: 6.5" long x 2-3/8" wide x 1.5" tall
  • Includes:
    • 12V Battery charger (w/ 5' battery-connection cable and 6' power cord attached)
    • 1 Set of 16" battery cables w/ battery-terminal clips
    • 1 Set of 16" battery cables w/ M6 (6.4-mm) eyelet terminals
    • Owner's manual
    • Protective case
  • 5-Year warranty
CTEK MULTI US 3300 bulk charging time chart

This CTEK charger comes w/ two battery cables: one w/ clamp terminals and one w/ eyelet terminals. The 16" long eyelet-terminal cable can be left attached to the battery, and the clamp-terminal cable is great for temporary connections.

CTEK MULTI US 3300 Charger w/ both clamp and eyelet cables

Whenever you want to charge the battery, just plug CTEK's patented Comfort Connect attachment terminal into the receiving end on either of the provided battery cables.

Close-up of CTEK's Comfort Connect plugs

CTEK MULTI US 3300 Charging Process

Safe, four-step process uses switch-mode, pulse-maintenance technology.

  1. Desulfation stage is the initial charging phase. This stage uses electronic pulses to desulfate batteries by converting lead sulfate crystals back to usable sulfuric acid.
  2. Bulk stage is the main charging phase. This stage accounts for 80 percent of the charging process and uses a constant charge level.
  3. Absorption stage completes the charge (to virtually 100 percent) using diminishing current to prevent battery damage.
  4. Pulse-maintenance stage begins 18 hours after the battery is fully charged. In this stage the charger maintains the battery at the optimum charge level of 95 to 100 percent by recognizing any drop in voltage and sending a corresponding pulse of current to keep the battery properly charged. Pulse maintenance can be continued for months at a time.
CTEK MULTI US 3300 charging process chart

A goof-proof design distinguishes CTEK's new-generation chargers from the competition - you don't have to be a mechanical guru to keep your battery working at top efficiency. CTEK's patented charging system monitors your battery, providing exactly the charge it needs during each unique charging stage!

Protects the User

Your personal safety is paramount, and CTEK's spark-free, short-circuit-proof design incorporates a feature that prevents reverse polarity, keeping you safe. You simply cannot make a polarity mistake: The charger will not operate if it is attached incorrectly. In addition, the red alarm light on the charger alerts you if there is a reverse-polarity problem.

Protects the Battery

CTEK's patented, switch-mode, pulse-maintenance charging system is scientifically engineered to safely charge your battery by employing the most up-to-date technology. Using carefully monitored, low-grid voltage, CTEK's patented process differs from competitors' chargers in its ability to provide the precise final voltage that your battery needs to maintain optimum charge level. This sophisticated, interactive device will never overcharge or undercharge your battery. You may leave it attached to the battery for months, making it perfect for seasonal vehicle storage.

Won't cause overcharging or overheating. These together can cause gassing and excessive acid concentration that shortens the life of the battery by corroding the lead plates. When overcharged, the battery cells become dried out. Electrolytes "boil dry," generating excessive heat that can cause a fire.

Won't cause undercharging or sulfation. Undercharging can be just as damaging to your battery as overcharging because chronic undercharging leads to sulfation. Sulfation occurs when the lead and lead dioxide of the battery's plates react w/ sulfuric battery acid to produce lead sulfate. This in turn is converted back to lead, lead oxide and sulfuric acid. A small, unavoidable amount of sulfation and gassing naturally takes place as a result of the chemical processes occurring in lead-acid batteries. However, extensive undercharging causes extra lead sulfate to accumulate on the lead plates of the battery. Because the crystalline form of the sulfate cannot hold an electrical charge, excessive sulfation greatly diminishes the charging ability of the battery, eventually rendering it unusable.

Provides desulfation w/ a patented process. Desulfation is the reversal of sulfation damage. The CTEK charger's unique process not only prevents the undercharging that produces excess sulfation, it also includes a desulfating step that can often "revive" a lightly sulfated battery. It accomplishes this w/ carefully monitored electronic pulses of energy that help to break down the lead sulfate crystals, allowing the battery to accept charge once again.

Ensures consistent charging w/ low ripple-wave percentage rate. Ripple-wave percentage is the quantity of disturbances exhibited in current and voltage. Even minor variations in household current can cause undercharging or overcharging, but CTEK's low-ripple design regulates the incoming current before passing it on to your battery. This process can cause the charger to be a little slower than linear chargers but results in a healthier, more productive, longer-lasting battery.

Protects the Vehicle and Its Electronics

The charger is also safe for your vehicle. Its sophisticated circuitry is designed to be compatible w/ today's sensitive electronics and audio equipment. You can confidently charge your battery while it is still in the vehicle: no more hefting heavy batteries or dealing w/ tiresome system resetting! CTEK's low ripple rate eliminates the danger of damaging electronic devices connected to the battery, and it prolongs the battery's service life.

CTEK MULTI US 3300 indicator chart

Indicator lights on the face of the charger light up to show the current charging stage.

Additional Specs:

  • Model: 56-158 (MULTI US 3300)
  • Input voltage: 100 VAC - 120 VAC, 50 Hz - 60 Hz
    • Output power is reduced at lower input voltage; a perfect charge will still be achieved
  • Current: 1.1A rms (at full charging current)
  • Charging current: 0.8A - 3.3A max
  • Back current drain: 1.3 mAh per month
  • Charging voltage: 14.4V - 14.7V
    • Nominal charging voltage: 12V
  • Ripple wave: less than 2 percent variance (max 50 mV rms, max 0.13A)
  • Battery cable fuse: 15A
  • Ambient temperature: -4 degrees F to +122 degrees F
    • Automatic reduction of power at increased ambient temperature
  • Cooling: natural convection
    • Do not cover the charger

56-158 CTEK MULTI US 3300 12V 4-Step, Pulse-Maintenance, Lead-Acid Battery Charger

Video of CTEK MULTI US 3300 12-Volt Universal Battery Charger w/ Pulse Maintenance

Videos are provided as a guide only. Refer to manufacturer
installation instructions and specs for complete information.

Video Vendor Information Ctek
CTEK Battery Charger Vendor Information
Video install ctek universal battery charger 2013 mercedes benz sprinter ctek56158
CTEK Multi US 3300 12-Volt Universal Battery Charger Review

Video Transcript for CTEK Battery Charger Vendor Information

CTEK was founded in Sweden. Basically our parent company is a prototyping company. Prototypes everything from plastics to electronic equipment right down to batteries but we actually consider ourselves a battery company with out batteries. We know everything about them. How to make them last longer and perform better. We just deal with the charging and maintenance end of it. 00:18

We have a patented mode of charging for one thing that we go through. Ultimately what this is going to do is bring our battery up to charge and then shut off completely versus your traditional trickle mode or linear charge like others might do on the market. If you could actually see current and voltage what you would see with those traditional charges you are putting in the same current and voltage high amperage level. We actually consider those toasters a lot of times because they generate more heat than charge and ultimately can toast the battery if not used properly or left on too long. 00:45

We have a patented mode of charging for one thing that we go through. Ultimately what this is going to do is bring our battery up to charge and then shut off completely versus your traditional trickle mode or linear charge like others might do on the market. If you could actually see current and voltage what you would see with those traditional charges you are putting in the same current and voltage high amperage level. We actually consider those toasters a lot of times because they generate more heat than charge and ultimately can toast the battery if not used properly or left on too long. 00:45

We realize that nobody cares about their battery. It is an evil that nobody wants to see and unfortunately nobody cares about it until it is too late and there is a problem where your vehicle does not start or your batteries are discharged to the point where you need to replace them. With our add on series, the comfort indicator, we have simply made your battery visible now. It is a one time installation. You bolt it directly to the battery with the flashing LED lights in there at all times visible you know where your battery stage of charge is at and if you need to charge it. Everything about our charger is we try to make it really safe, easy to use, and very functional. That is part of the quick connect and comfort indicator series that we have launched. Basically the concept behind it is you can have your one time installation on the battery especially with the comfort indicator series with the LED lights in it, now your battery is actually visible. You know at all times when you need to charge your battery and then it is pretty easy to use basically and you can balance your charger from vehicle to vehicle as you need to charge. 02:07

We like to think we have the best charger on the market. We try to stay ahead of the curve with the technology that we are putting into the battery chargers. CTEKs all are back by five year no questions asked warranty. Every household needs one of these chargers. It is a very robust design and it absolutely works on everything. From your lawn tractor, your boat, your RV, your motorcycle, your sports car. It is a very indispensable product to have.

Customer Reviews

CTEK MULTI US 3300 12-Volt Universal Battery Charger w/ Pulse Maintenance - CTEK56158

Average Customer Rating:  ratingratingratingratingrating4.8 out of 5 stars   (5 Customer Reviews)

- CTEK56158

ratingratingratingratingrating by: Bob etrailer employee11/14/2013

Is this review helpful?

Got a booming radio that tends to kill the battery after a day of hanging out at the gravel bar. This charger I installed under the hood and ran the plug to the front bumper. So I have 2 options. 1. If there is power nearby just plug it in and no worries. 2. At the end of the day when back at the house just plug in overnight so battery is fully charged the next day without needing to leave the truck running to charge back up. 107360

- CTEK56158

ratingratingratingratingrating by: Kevin12/26/2012

Is this review helpful?

The CTEK 3300 is being used to keep my hot rod battery charged because it's not a daily driver. It took about one day and then the amber light turned green and has stayed that way for a month now. All I do is unplug the unit from the car and it starts right up. It sure is nice to be able to leave this one hooked up to the car in place of my older one that I would only use for a few hours at a time. So far I'm very happy with it and I would buy another one if I had two batteries to keep charged. 61891

- CTEK56158

ratingratingratingratingrating by: Robert LaBonte10/08/2013

Is this review helpful?

Very well made. Seems to have every needed option.103020

- CTEK56158

ratingratingratingratingrating by: Triple D Ranch07/22/2013

Is this review helpful?

thank's work's good 90944

- CTEK56158

ratingratingratingratingrating by: Joel B.06/30/2011

Is this review helpful?

Great charger's that are made by CTEK E-Trailer's service is great and fast. 18284

Ask the Experts about this CTEK Power Inc Battery Chargers
Expert Answers about CTEK MULTI US 3300 12-Volt Universal Battery Charger w/ Pulse Maintenance - CTEK56158                                         Do you have a question about this Battery Chargers?

  • Can the CTEK MULTI US 3300 12-Volt Universal Battery Charger be Used on a 12 Volt 2 Battery System
  • Yes you can use the CTEK MULTI US 3300 12-Volt Universal Battery Charger w/ Pulse Maintenance, item # CTEK56158, on your vehicle with two batteries. Just attach the cable with eyelets as you would to charge or jump your batteries. Connect the positive lead to the positive post on one battery and connect the negative lead to the second battery negative battery cable connection at the vehicle frame or engine block. This charger maintainer has smart technology that will not allow it to overcharge o
    view full answer...

  • Battery Charger for a Trailer Battery on a Dump Trailer
  • For your larger battery, I do recommend the CTEK MULTI US 3300 12-Volt Universal Battery Charger, part # CTEK56158. This charger is designed for larger batteries like the one on your trailer. This being said, you could also use the 12-volt accessory circuit on your 7-way trailer connector to maintain the battery on your trailer. Be sure to follow any battery manufacturer instructions regarding battery charging.
    view full answer...

  • Is it Safe to use a CTEK Battery Charger for Long Periods of Time on a Stored Vehicle
  • You should have no problem setting this battery charger and leaving it for months on end, unattended. The CTEK Battery Chargers work very differently than the old, traditional battery tenders. The old tenders used a trickle charge. Basically they constantly applied a little bit of power. This wastes electricity and can lead to some lead acid batteries overflowing, which is a big problem. The CTEKs do not trickle. Instead they detect that the battery has lost some charge. Then the charger k
    view full answer...

  • Can a CTEK Battery Charger be Used to Charge a Deep Cycle Battery While Using Lighting in a Trailer
  • Yes, you can use the CTEK US 3300 12-Volt Battery Charger, item # CTEK56158, to charge a battery while using the lights in the trailer. One thing to keep in mind is that the smaller battery charger will not be able to keep up with the lighting use in the trailer and the battery will eventually be drained, if not allowed to charge when the lights are not being used. It will not harm the charger. A better option is a charger that has a supply mode. The CTEK MULTI US 7002 12-Volt Universal Batte
    view full answer...

  • Can 12 Volt Accessory Circuit on a 7-Way Trailer Connector be Used to Maintain a Deep Cycle Battery
  • The 12 volt accessory circuit on a 7-Way can maintain a battery, it just will not be able to charge it. Since we are talking about maintaining a charge, a regulator will not be needed since the 12 volt accessory circuit does not have the capacity to charge the battery. So it will not overcharge any of the cells. Since a deep cycle battery is designed to discharge most of its charge at once, I would recommend connecting the 12 volt accessory circuit first to a 40 amp circuit breaker, # PK5454
    view full answer...

  • What is the Warranty On the CTEK Multi US 3300 12-Volt Universal Battery Charger, # CTEK56158
  • The warranty statement can be found in the instructions for the CTEK Multi US 3300 12-Volt universal Battery Charger, # CTEK56158. It has a limited 2 year warranty from the date of purchase. The complete statement can be found on pages 12 and 13 of the instructions. A colleague uses this charger and has been very impressed with its performance and has stated this often. As a result, he has had to loan it out to other co-workers, all of which have had success with the charger. I have included
    view full answer...

  • Can the Breakaway Battery Charger on a Car Hauler be used to Charge a Large Winch Battery
  • Using the breakaway battery charger to charge another battery on the trailer is not recommended. The larger battery you are using to operate the trailer winch would take an extremely long time to charge with a breakaway charger and would likely never charge fully with the limited amount of time the trailer is connected to the vehicle, even if towing long distances. The breakaway battery may not be charged sufficiently in this situation either. The best bet for charging the winch battery is to
    view full answer...

  • Charging Six 6-Volt Batteries in a 12 Volt System with 1 Battery Charger
  • You can choose multiple batteries provided they are connected in parallel to remain a 12 volt system. You will connect the positive terminal at the first battery positive post and the negative terminal to the first battery negative post. If you have 2 banks of 3 batteries, you would have to separate the 2 banks of batteries and charge each set of 3 separately. You will want to use a larger charger that can handle a higher ah rating. The CTEK MULTI US 7002 12-Volt Universal Battery Charger, #
    view full answer...

  • Wiring a Battery, Power Inverter, and Charger on a 1980 Coleman Tent Trailer
  • First, the wiring from a trailer connector will provide a maintenance charge to a trailer battery, but will not up-charge it. If that is sufficient for your needs then you would have the trailer connector, trailer side, 12 volt circuit attached to your charger. The charger would then connect to the battery, and the inverter would connect to the battery. Bascially, you will have the 12 volt power wire go to the positive of the charger. Ground the charger to the trailer frame. The positive of t
    view full answer...

  • Will CTEK Battery Charger Charge Battery Without Damaging It?
  • If the car battery is merely discharged but otherwise in good repair, using a CTEK charger will not damage it. CTEK chargers will not over charge a battery, once full charge is reached, the charger switches to pulse maintenance, which maintains the charge rather than applying full power to the battery. A charger like the CTEK Multi US 3300, part # CTEK56158 would be best suited for a car battery. The charger is suitable for deep-cycle batteries. This charger features three modes, one for smal
    view full answer...

  • Can the CTEK US 3300 Battery Charger be Used to Charge a Car Battery
  • The charger you would want to use for car batteries is the CTEK MULTI US 3300, # CTEK56158, that you have referenced. It is designed specifically for 12 volt car batteries. I have included a link to some video reviews for you.
    view full answer...

  • Can the CETEK Battery Charger # CTEK56158 Be Used While RV Battery is Connected
  • The CTEK Multi US 3300 can indeed be used while your RV battery is connected. Since the converter will not come into play unless the RV is plugged into shore power, the converter will not be damaged. To see the owners manual and instructions, click the provided link.
    view full answer...

  • Recommended Battery Charger for Marine Battery Running Backup Sump Pump
  • What you are wanting to do is certainly possible, but because the # CTEK56158 does not have a maintenance mode, it could not be permanently connected to the battery and forgotten about. My contact at CTEK tells me that their 7002 model, part # CTEK56353 does have a maintenance mode and could be continuously used to maintain your marine battery while remaining connected to the battery, and while the battery remains connected to the pump. Once the charger senses a voltage drop in the battery,
    view full answer...

  • Is a Back Up Battery for a Boat Sump Pump Needed in Addition to the Trailer Battery
  • If you will be leaving the boat in the water then having a battery back up would be recommended. Or, at the very least, store a spare battery that is not connected to anything in case it is needed. If the boat will not be stored in the water then leaving the pump connected to the regular trailer battery will be fine. Using a charger like # CTEK56158 is the best way to charge and maintain a 12 volt battery. I own one of these chargers and it works great; much better than a trickle charger sinc
    view full answer...

  • CTEK Battery Charger Does Not Stay in Desulfation Stage for More than a Few Seconds
  • There is no set time for each charging phase for CTEK battery charger # CTEK56353. If the battery is at or above the terminal voltage preset level then it will go on to stage 2. This would mean that the battery does not necessarily have sufficient lead sulfate crystals that need to be converted back to sulfuric acid. Also, on batteries that are completely dead or have excessive sulfation, the charger will not be able to resurrect it. Check to make sure that the connection points on the batter
    view full answer...

  • Does the Ctek Battery Charger Restart if it is Unplugged
  • If you lose power to the CTEK MULTI US 3300 12-Volt Universal Battery Charger # CTEK56158 that you referenced it will start over in the default car setting. I can speak from experience because I own a Ctek battery charger and have unplugged it and then after replugging it back in found that everything on the controller restarts and goes back to default. So if your charger loses power you will need to reset it to the correct setting if not using the default setting. I attached an FAQ articl
    view full answer...

  • Can Two 12 Volt Batteries Connected in Parallel be Charged Through a Switch Using a CTEK Charger
  • You can charge 2 batteries when they are connected in parallel using a CTEK battery charger such as # CTEK56158. However, it will take longer to charge the batteries when they are connected compared to if you were to charge each one separately. The best battery charger to use for charging batteries in parallel would be # CTEK56353. It has a higher amperage output and will charge faster. I have included a link to our FAQ article on battery chargers for you.
    view full answer...

  • What Does the Pulsing Do In the Desulfation Stage of a CTEK Battery CHarger
  • The first stage of the charging process for the CTEK battery charger # CTEK56158 is the desulfation stage. The charge sends periodic shots of power to the battery, or pulses of electricity, which is what changes the lead sulfate crystals back into sulfuric acid. When a battery gets used more and more lead crystals form and lower the capacity of the battery. By changing the lead crystals back to sulfuric acid the battery can be revitalized. I have included a link to our FAQ article on battery cha
    view full answer...

  • Can CTEK Battery Charger # CTEK56158 be Used Continuously for 6 Months
  • You would want to put the CTEK battery charger # CTEK56158 in the snowflake mode for winter which is a setting for temperatures below 41 degrees F. You can leave the charger on the whole time it is in storage. The charger will not overcharge the battery and will maintain the optimal charge level while it is in storage. I own this charger myself and it works quite well. I have linked a video review, instructions, and an FAQ article on chargers to the right.
    view full answer...

  • Can the 12 Volt Circuit in 7-Way Trailer Wiring Charge a Trailer Mounted Battery
  • First, when you connect the CTEK battery charger to the trailer battery you will need to ground it somewhere other than the battery negative post. It will need to ground to the trailer frame or another clean metal surface. The 7-Way wiring is not large enough and, most likely, the alternator on the vehicle is not strong enough to push back enough amperage to charge the trailer battery. The 7-Way wiring can provide a maintenance charge only to the battery. This will keep the battery at the cur
    view full answer...

Info for this part was:

Test Fit:
Joe V

Expert Research:
Michael L

Video by:
Andrew K

Expert Research:
Patrick B

Expert Research:
Michael H

Expert Research:
Jameson C

Expert Research:
Rachael H

Video Edited:
Chad S

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