How to Charge a Dump Trailer Battery

There's nothing quite so frustrating as charging your dump trailer overnight, getting ready for a big job, and only getting 2 or 3 dumps out of it before the battery is kaput.

Your dump trailer battery is going dead on the regular for one of two reasons: either it's running out of juice faster than you can replenish it, or it's not receiving a full charge to begin with.

To fix either problem, you're going to need a reliable means of charging up (usually by means of your truck). The right charging method for you depends on what you're trying to accomplish: do you need a way to keep your dump powered through a long day's work? Do you just need to maintain a charge overnight? Do you store your trailer for long periods and want to keep the battery functional during this time?

As you'll see below, there are a ton of options for charging a dump trailer. Some of these will work better for you than others, but with one (or more) of these solutions you won't have to deal with a dead dump battery!

*We recommend always using an independent battery for your dump trailer, rather than using your vehicle battery alone, in order to avoid overloading the battery.

In this article:

How to Charge a Dump Trailer Battery from a

7-way connector
Anderson plug connection (winch kit wiring)
DC to DC battery charger
AC to DC battery charger
Solar to DC battery charger

The 12V power terminal on a 7-way connector

1. Charging a Dump Trailer with a 7-Way Connector

This is for you if: Your battery is already charged up, and you just need to keep it that way

This is not for you if: You need to charge a depleted battery

A lot of people assume all they have to do to charge their dump trailer is use their existing 7-way connector via the 12V accessory circuit. It's true that your 7-way connection will maintain a fully-charged battery. However, the 7-way and vehicle alternator wiring are NOT sufficient to charge a low or dead dump trailer battery. After a few dumps, your trailer will slow down, and the dump feature will cease to function.

Also keep in mind that when you go through your 7-way, you need to take steps to make sure you don't drain your vehicle battery. If you have a factory 7-way, you'll have a built-in isolator to protect your vehicle. However, if you have an aftermarket 7-way, you'll need a battery isolator.

Note: If you're not sure whether or not you need an isolator, use a circuit tester to check whether your 7-way 12V accessory circuit has power when your truck's ignition is off. If it does, you need an isolator.

To provide a trickle charge using your 7-way connector, make sure your 12V accessory terminal has power running to it. (You can test it with a circuit tester.) Assuming everything is functioning correctly, you can then run a 10 gauge power wire from the 12V terminal on the trailer 7-way to the trailer's positive battery terminal.

We also recommend unplugging the 7-way connector before using the dump feature, since leaving the 7-way plugged in while dumping the trailer can potentially short out the 12-volt accessory circuit.

Andersen Plug Connection/Winch Wiring Kit

2. Charging a Dump Trailer with an Anderson Plug Connection

This is for you if: If you use your dump trailer occasionally but need to charge your battery throughout the day

This is not for you if: If you use your dump trailer often, you'll probably want a more efficient battery charger

The Anderson plug method is a step up from 7-way connectors. This method essentially consists of Anderson connectors and thick wire gauges (which can be found here in our winch wiring kits).

Because of the larger wire gauge, you'll experience less voltage drop and get a more efficient charge. These kits allow you to charge your trailer battery on the go, so you can keep your battery charged throughout the day. Again, you'll want to use a battery isolator to prevent your tow vehicle being drained when the ignition is off.

To use an Anderson plug connection (again, this can be accomplished with a simple winch wiring kit), connect your dump trailer battery directly to your truck battery, without splicing into the 7-way. However, keep in mind you'll have to make the connection each time you want to use your dump trailer.

NOTE: This is a visual overview of a potential winch wiring kit setup and does not reflect the full wiring requirements of an individual setup. To install a battery charger, follow all manufacturer instructions.

3. Charging a Dump Trailer with a DC to DC Battery Charger

This is for you if: You want the most efficient truck-based charging method

This is not for you if: If you're going to be storing your trailer for long periods, you won't want to rely on this alone

If you want to actually power up your battery from a depleted state, you're best off with a battery charger, since it will charge your batteries faster and put less strain on your tow vehicle battery than an Anderson plug connection. DC to DC chargers use your truck battery to charge your trailer battery, and the best ones include an automatic shut-off to prevent overcharging. (Most traditional "trickle chargers" don't have this feature, so you have to be careful not to overcharge and damage your trailer battery).

Generally speaking, DC to DC battery chargers like the Redarc BCDC install on your vehicle or trailer and are connected with wiring to your tow vehicle battery.

NOTE: This is a visual overview of a potential battery charger setup and does not reflect the full wiring requirements of an individual setup. To install a battery charger, follow all manufacturer instructions.

REDARC BCDC Charger

Boosts voltage from vehicle battery for efficient charge
Includes built-in isolator to protect vehicle batteryedit
Prevents overcharging
Draws power from vehicle battery OR solar, if available

Also needed for installation: BCDC Installation Kit #e79ZR (for 25-amp BCDC) or #e29ZR (for 40/50-amp BCDC)

4. Charging a Dump Trailer with an AC to DC Battery Charger

This is for you if: You need to charge up at the home base overnight but don't need much juice to get you through the day, or if you'll be storing your trailer for long periods of time

This is not for you if: You want charging on the go and need to stay charged throughout the day

If you don't plan on putting your dump trailer through the wringer and only need a couple of dumps a day, you can simply use an AC to DC charger, plug your dump trailer battery into the wall, and let it juice up overnight. However, if you plan on draining your battery throughout the day with frequent use, you'll want to consider a DC to DC charger or solar charger for staying powered up on the go.

AC to DC chargers (like the one featured below by Bright Way) are also great for maintaining your battery charge if you're not going to be using your trailer for a while. The maintenance stage keeps the battery at optimal charge long term.

Bright Way Smart Battery Charger

Maintains and monitors charge to help extend battery life
Prevents overcharging
LED indicators show charging status and fault conditions

5. Charging a Dump Trailer with a Solar Battery Charger

This is for you if: You plan to store your trailer outside for long periods of time

This is not for you if: If you want a powerful charge to keep you going throughout the day

Solar chargers are a great way to keep your dump charger juiced up while using the most powerful source of energy out there: the sun. Solar chargers are particularly great for keeping your battery charged in between trailer uses (and you won't even have to pay for electricity!).

One of the best ways to store your battery is inside a solar battery box. These boxes lock and protect your battery while providing a maintenance charge via a 10-watt solar panel, so your battery will be ready to go next time you need it.

You can also use a solar trickle charger like this 2.5-watt system for a more economic solar solution.

Just keep in mind that these solar chargers are meant to provide a maintenance charge to your battery, not charge it from a depleted state. For that, you're better off with a DC to DC or AC to DC charger.

Dump Trailer - Solar Battery Charger Diagram

NOTE: This is a visual overview of a potential solar charger setup and does not reflect the full wiring requirements of an individual setup. To install a solar battery charger, follow all manufacturer instructions.

Value Choice: 2.5-Watt Solar Battery Charger

2.5-watt solar panel provides trickle charge during storage
Built-in regulator prevents overcharging

Premium Choice: Solar Battery Box

10-watt solar panel provides maintenance charge — perfect for battery storage
Locking lid provides excellent security
Prevents overcharging when charging 2 batteries (regulator required when charging 1 battery)

Charge a Trailer Battery While Driving: 3 Common Problems (And How to Fix Them)

Redarc's BCDC Charging Process Explained

Related Products

Shop Battery Chargers

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Written by: Amber S.

Updated: 4/9/21

Doug E.

6/19/2022

First of all the Vehicle to trailer connector that is shown in the Picture has a Amperage rating of 15 Amps. This wasn't designed to carry all the time 15 amps much less charge a large battery through it. There will be a voltage drop through the connection the higher the load. I use commercial 7pin connector used by the Truckers on the Semi trailers, these have a rating of 30 amps AND 50 apps on the Big Ground pin. This has worked well for me using 10 Ga or larger wire to the connectors from the vehicle to the trailer isolators charging circuits.

David B.

6/20/2022

I feel like you didn't watch the video all the way Doug, at the 1:09 mark he explains that you won't get the same energy and even after one or two uses you won't be able to charge the battery all the way back. This method is meant to be used as a trickle charge and is the slowest or least efficient method for this application.

Howard

6/18/2022

Quite informative article. I do disagree in one area. When charging with the 7-way connector, if the trailer remains plugged in when dumping, you will be putting 14+ volts to the trailer battery, lowering the amperage draw. The motor will run faster. You should replace the fuse in the factory charge circuit with a 30 amp thermal circuit breaker. If it is overloaded and opens, it will reset itself .

David B.

6/20/2022

As you can read in the article we DO recommend unplugging the 7 way before using the dump feature.

Donald T.

6/17/2022

I have worked in the electrical industry for 40 years (including 5 years in the military). Your video is spot on and the explanation of the charging methods are clear and precise. This is a good teaching aid for all that haven't had a formal background in electrical applications.

Dana S.

4/9/2021

I opted to run 2 awg welding cable from my truck battery to the back by the receiver and installed X-Haibei Pair 175 amp 2 Gauge Battery Quick Connectors directly to the battery cables on my dump trailer. This also allows me to use my cradle mounted12v winch in my back receiver.

Jim

4/9/2021

Does someone make a AC to DC charger that I can just plug into a 7 way connector on a utility trailer?

Jon G.

4/9/2021

We do have AC to DC converters here on our site! I've linked our selection for you to filter through.

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