CTEK D250S Dual Battery Charger 12V- 20a, 5 step, Heavy Duty

CTEK D250S Dual Battery Charger 12V- 20a, 5 step, Heavy Duty

Item # CTEK40186

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CTEK D250S Dual Battery Charger 12V- 20a, 5 step, Heavy Duty Vehicle Battery to Auxiliary Battery CTEK40186
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  • Battery Charger
  • CTEK Power Inc
  • Car/Truck/SUV
  • Lawn Mower
  • Boat
  • RV/Camper
  • Vehicle Battery to Auxiliary Battery
  • DC to DC
  • 12V
  • Charges/Maintains
Call 800-298-8924 to order CTEK Power Inc battery chargers part number CTEK40186 or order online at etrailer.com. Free expert support on all CTEK Power Inc products. Guaranteed Lowest Price and Fastest Shipping for CTEK D250S Dual Battery Charger 12V- 20a, 5 step, Heavy Duty. Battery Chargers reviews from real customers.

  • All Info
  • Reviews (2)
  • Q & A (134)
  • Videos (1)
  • Photos
  • Why etrailer?

CTEK Power Inc Battery Chargers - CTEK40186

  • Uses a vehicle alternator or solar panel for a power source for automotive, truck, tractor, marine, or RV use
  • Ideal for charging vehicles that do not have access to power grid
  • Works well with the CTEK SmartPass (CTEK56676 - sold separately)
  • 2-Year warranty

40-186 CTEK D250S Dual Battery Charger 12V- 20a, 5 step, Heavy Duty

Replaces CTEK Power Inc CTEKD250S (56-677)

Video of CTEK D250S Dual Battery Charger 12V- 20a, 5 step, Heavy Duty

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

Video Transcript for CTEK Power Inc Battery Chargers - Battery Charger - CTEK40186 Review

Speaker 1: Today we're taking a look at the CTEK dual battery charger. This unit is a 20 amp on board charger that can charge your service batteries while on the move. It charges the service batter either from an alternator or from a solar panel or from a combination of both. With selectable charge voltages, the charger is optimized also, for AGM batteries. It delivers a fully automatic five step charge that will charge, condition, and maintain any 12 volt lead acid service batter from 40 to 300 amp hours. This unit can be connected directly to solar panels, and it has a built in regulator, and maximum power point tracker to ensure that maximum power is generated from a solar panel.

It can also deliver a maintenance charge to the starter battery from a solar panel or the service battery.It does work well in conjunction with the CTEK smart pass that's available at etrailer.com and sold separately with part number CTEK56676. I also want to point out that located here on the top portion of the unit, you have a series of indicator lights. These lights make it very easy to know when there's an issue. You take the lights that show up. You look in the included manual, and you look up the fault indications to see what the issue is, and the recommended resolution to fix the issue.I do want to go over the inputs with you real quick.

Now, all these terminals are able to connect very easy. You can take that out, make your connection, thread it back in, then it can be tightened all the way down with an Allen wrench. Basically, right here, this is the input solar panel. This one right here is input alternator. This one right here is the output for the service battery, and this one right here is your ground connection.

You have two small cables on this side. The red one is smart alternator cable. The black one is AGM cable. Then this right here is your temperature sensor. When it comes to the input, that's 11.5 to 23 volts or 25 amps.

Output, maximum is 14.4 volts or 20 amps. Battery capacity is 40-300 amp hours, and the recommended solar panel size is 50-300 watts.Now when it comes to the actual dimensions of this unit, I took a measurement edge to edge going this direction, got a measurement of about four and 5/16 of an inch. Length, just measuring the base was about seven and a half inches long. The overall thickness or height from bottom to the very top was about two and a half inches tall. Mount holes are separated apart from one another going this direction by about three and 9/16 of an inch, and then this direction on center by about six and 9/16 of an inch.That's gonna do it for today's look at the CTEK dual battery charger.

Customer Reviews

CTEK D250S Dual Battery Charger 12V- 20a, 5 step, Heavy Duty - CTEK40186

Average Customer Rating:  5.0 out of 5 stars   (2 Customer Reviews)

- CTEK40186

I ordered two of these, one to charge the battery in our 4runner and one to charge the battery in our camper trailer. These were a better choice for us because they bulk charge at 14.7 volts. Our batteries which are Batteries Plus X2 Power need 14.7-14.8 volts for a full charge. This battery is made by Northstar and is their Pro Series Battery. it came within a few days and well packed. I have never been disappointed ordering from etrailer. Great communication and service. 611923

- CTEK40186

Mine was a simple project. I used this CTEK unit to keep a large auxiliary battery property charged in the back of a pickup truck. This setup was critical for powering a CPAP machine enabling me to sleep at night. After 36 days on the road in Canada and Alaska I'm pleased to report flawless results. With 10,400 driving miles, including much washboard gravel this charger is perfect... I soon forgot it was even there. 565635


Ask the Experts about this CTEK Power Inc Battery Chargers

  • How to Charge a Trailer Battery for Use with a Bulldog Jack
  • What you described is actually the best solution! Connecting your battery to 12V Power wire from the 7-Way on your trailer is a great way to provide a maintenance charge on your battery to operate a Bulldog jack like part # BD500199. Mounting a battery inside a box like part # 329-HM300BKS inside your trailer will further help to keep your battery safe from the elements (although battery boxes do a pretty good job at that). Please note that the 12V power from your vehicle will not...
    view full answer...

  • Wiring a Trailer With Dual Batteries and Solar Charger
  • Let's try and take this one at a time to make things easier; to start with the black wire from the 7-way plug (the 12V) should be run to the pair of 12V batteries you already have in the battery box. In terms of grounding they will be grounded through your charger, such as in the accompanying diagram of the CTEK D250S Dual Battery Charger # CTEK40186, which you would want to use with the SmartPass CTEK56676. The LED lights each need to be grounded to the frame of your trailer; they...
    view full answer...

  • Recommended Trailer Battery Charging System for Enclosed Motorcycle Trailer for Tools and Mattress
  • You can absolutely use a battery in your trailer to do all the things you desire. You will simply want to get a deep cycle battery and get the amp hour rating you desire. The CTEK D250S Dual Battery Charger 12V- 20a, 5 step, Heavy Duty# CTEK40186 along with the discontinued CTEK SmartPass Energy Management Unit for CTEK D250S DUAL Battery Charger CTEK56676 are a great combination for that as the D250S alone will not work well on the high-capacity deep cell batteries. Instead...
    view full answer...

  • Adding a 7-Way Trailer Connector to a 212 Subaru Outback and How to Charge Trailer Battery
  • I do have a video that will be very helpful when installing a 7-Way connector on your 2012 Subaru Outback. I have linked that video for you. But not all parts of the video will apply to your situation simply because of the type of brake controller you are using. So you can just ignore those parts. You will need # ETBC7 which comes with the 7-Way and the wiring and other accessories you will need. The installation is not difficult and if you have even a little experience with automotive...
    view full answer...

  • Best Way To Power an Enclosed Travel Trailer
  • I do have a few options for you to power a cordless drill, lights, and coffee pot inside you enclosed travel trailer but using a solar panel would not be the best or most cost effective setup. Basically, you are going to end up having to cover the entire roof of your trailer to power the above items. Instead, I recommend purchasing a 12 volt auxiliary battery like the one you would find in a car and then using a power inverter like part # WC3720 as well as a battery charger like part...
    view full answer...

  • Recommended Vehicle to Trailer Battery Charger with Solar Power Option
  • The CTEK battery charger # CTEK56353 is a great charger for when you have shore power, but will not work for a vehicle to trailer battery charger. To charge your trailer battery from your Outback 2.5i, you will need a different type of charger. If you are a fan of the CTEK brand, then you would want the CTEK D250S Dual Battery Charger 12V- 20a, 5 step, Heavy Duty # CTEK40186. This will allow you to use your vehicle battery to charge your trailer battery without draining your vehicle...
    view full answer...

  • How to Connect Auxiliary Battery to Popup Camper 7-Way for Off Grid Camping
  • If you were wanting to just plug in your current 7-Way on your popup to a 7-Way that is connected to your auxiliary battery then you could install the Hopkins # HM47210 on your trailer. Then you would need to ground the white wire to a clean, bare-metal surface on your trailer and run some 10 Gauge Wire # 10-1-1 from the Red wire on this connector to your battery. Even though this would work it wouldn't be as clean as just hardwiring your battery into the 12V Power circuit on your trailer....
    view full answer...

  • Diode to Prevent Back Feeding from Trailer Battery to Running Lights
  • For a diode I recommend # RM-790 which is rated for 85 amps. However, trailer wiring, both on the trailer and on the vehicle side, is too small to charge up a regular battery. And most vehicle alternators are unable to push back the amperage required to charge up a regular battery. At best it will provide a maintenance charge and keep the battery from depleting. It can charge up a small breakaway batter such as # HM20008 though. But these batteries are rated much lower than a regular...
    view full answer...

  • Can a CTEK Battery Charger be Used to Charge a Battery Through 7-Way on Trailer
  • The CTEK D250S Dual Battery Charger # CTEK40186 can be spliced into the 12V Power wire from the 7-Way on your trailer. It then connects to your trailer battery and provides a maintenance charge. This basically just help to keep your battery from draining, it will not necessarily charge it. To charge your battery you will also need to add a solar panel like part # PTW2997 and connect it to the CTEK battery charger as well. The CTEK charger will then from the solar panel and your 12V power...
    view full answer...

  • Installing DC Power And Power Inverter To Cargo Trailer
  • For DC electricity, I can help you out. You can run a 10 gauge wire like # 10-1-1 sold by the foot from a 6-way or 7-way connection from the 12V to a deep cycle 12V battery and then run the battery to a ground on the trailer. You can use a solenoid like # TR118665 in your tow vehicle if you want to ensure you don't drain the vehicle battery when your truck isn't running. This will isolate the deep cycle 12V trailer battery. To charge your battery, you can use a CTEK D250S DUAL Universal...
    view full answer...

  • Recommended Battery Isolator For House Battery and Solar Panel Charger
  • For your application, you will want the Deka Battery Isolator - 120 Amp, # DW08771. This will enhance your alternator performance and allow you to efficiantly charge your battery. This will protect your main starting battery from auxilary drain and regulate current for multi-battery systems. We will want the Deka Battery Isolator Installation Kit for Standard Alternators, # DW08769. This kit will give complete instructions, various terminals and connectors, 15 feet of wire and a...
    view full answer...

  • DC to DC Charger and Solar Panels for Best Charging of Multiple Batteries
  • The CTEK D250S Dual Battery Charger 12V- 20a, 5 step, Heavy Duty # CTEK40186 has a maximum output of 20 amps. When used with the (discontinued) CTEK SmartPass Energy Management Unit for CTEK D250S DUAL Battery Charger CTEK56676, my contact at CTEK said it has a max amperage output of 120 amps not the 80 they have previously stated in the past. This combination will allow 14.4 volts and 120 amps to pass to your batteries whether using solar or alternator. He also stated that you can...
    view full answer...

  • Adding a Battery to a Trailer with a 4-Way Connector
  • To run a charge line to your battery you will first need to install a 7-Way on your trailer. This can be done using the Epicord 7-Way Molded Trailer Plug with Junction Box # 277-000141. The Black wire in the junction box is the one that will carry the 12V power. Just simply use a ring terminal like part # 44-5310A and run 10 Gauge Wire # 10-1-1 to the positive terminal on your battery. The 4 wires that are currently on your trailer and tow vehicle are only for the lights and are not...
    view full answer...

  • Trailer Battery Charger and Power Inverter for Coleman Pop-Up Camper with Deep Cycle Battery
  • For a DC battery charger to maintain your trailer's deep-cycle battery I suggest the Redarc In-Vehicle BCDC 40-Amp Battery Charger # 331-BCDC1240D. This unit installs in your vehicle and delivers charging and maintenance current to keep your trailer battery topped off. This is made for high-capacity batteries of 200 amp-hours and above. It also allows the option to add a solar panel to provide a secondary power input. You will also need MIDI Fuse Kit # 331-FK60. A lower-price option...
    view full answer...

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Info for this part was:

Edited by:
Tyler C
Expert Research:
Michael H
Expert Research:
Jameson C
Expert Research:
Adam R
Installed by:
Cole B
Written by:
Matthew S
Photos by:
Jeffrey L

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