How To Keep Towed Vehicle Battery Charged

With more and more vehicle makers requiring some method of maintaining the battery in a towed vehicle while it is beingness towed, it seemed similar it was a good time to bring this topic forrard in a TechTip. Towed vehicles accept more and more computers running in the background when the vehicle is non existence driven. Apparently, the passive entry organization that recognize the presence of the "fundamental" when one approaches the vehicle is just i case of a computer running in the background. When one prepares to tow a vehicle, the sequence that the vehicle'south computers expect to go through, is disrupted. Some computers that shut down soon subsequently the vehicle is entered or started, are suspended in action and practise not plough off. This means that these computers or modules are running while the vehicle is beingness towed. On newer vehicles button ignition and electric or electronic (steer by wire) power steering systems, many need to be running when towed, draining a towed vehicle battery. The future volition provide more of these scenarios.

Sometimes removing a fuse eliminates the drain, withal when the commencement-up sequence may exist disrupted, then multiple fuses will need to be pulled. Some makers crave that the negative battery cable be removed when preparing to tow, since upward to ten Body Control Modules (BCM) or computers can be operating; removing a handful of fuses is impractical. Each approach has advantages and disadvantages to a RVer. Add into this mix, the fact that nigh vehicle makers are unfamiliar with the systems already available on newer RV chassis' (such every bit Ford, Freightliner and Spartan) to meet the maintenance charging need. As a issue, they default to recommending a third party Towed Charger or Towed Battery Maintainer which needs to be installed on the RV every bit well as the towed vehicle, oftentimes at great attempt or expense. Almost all chassis makers have provided virtually of what is required as standard equipment on their RV chassis. Simply connecting the Tow Vehicle to that provision is practical and price effective.

The History of Towing:

A petty history will provide some perspective hither. During the 80's and early xc's when mod RV'due south became popular, towing a vehicle was the exception, not the norm. Those RV's were equipped with a 'four-wire' connector designed to power the lighting on a boat or utility trailer. Towing a car was not considered, especially since the frame department to which the hitch receiver was mounted, was often added past the RV body maker. This frame extension was primarily planned and installed to carry the rear bedroom of larger (30-34 human foot) RVs mounted on chassis' which were designed for much shorter delivery trucks.  This was the fourth dimension when there were no specific RV chassis designed for the RV market. Conversion was the but mode a chassis could exist used to conduct RV bodies.

As the marketplace began demanding longer motorhomes, the industry responded by building 'purpose-congenital' RV chassis that were longer, had better powertrains, brakes, suspensions, electrical components and and so on to meet the RV maker's needs. The towed vehicle hitch receiver was installed on the bodily vehicle chassis maker's frame however the wiring continued to be a 4 or peradventure six wires accessed through a matching number of pins in a round electrical connector. As the capabilities to tow larger trailers and vehicles increased, the makers moved to 6 (half dozen) pin round or the seven (seven) pin blade connectors that allowed for a trailer brake controller mounted in the RV to exist connected to a trailer. Legislation began to appear that required electric brakes on trailers over a certain weight or carrying chapters and these trailers needed to have a breakaway switch to activate the trailer's (electrically operated) brakes. This required a source of ability (a battery) to be mounted in the trailer to power those brakes when the trailer became separated from the towing vehicle, activating the breakaway switch which applied the trailer brakes.

Around the aforementioned time, RV owners began to tow pocket-size cars and they were met with the need to comply with the braking and breakaway requirements, which the aftermarket jumped to fulfill. The ability source was the vehicle'due south own battery which was far larger than those found on trailers. At that place was piffling concern about the towed vehicle's battery running down while the vehicle was being towed.

With the rise of larger tow behind and fifth wheel trailers, the vehicle makers began offering trailer packages on their pickup trucks and these often included a pin in the trailer electric connector to charge the trailer battery while the trailer was being towed. (See Photos) The trailer and fifth wheel makers started using the black plastic vii pin blade connectors that mated to the standard pickup truck connector. It was a lilliputian of the craven and egg question since the towing vehicle needed to supply the wiring connector and the towed vehicle need to have the mating connector.

Prior to this fourth dimension, the RV industry had piffling standardization of the rear connector, nevertheless between the economy of scale by RV makers using one standard connector and the RVIA (which sets industry standards and enforces compliance) addressing the issue, the industry adopted a 7 (7) pin blade towing connector. This connector had to have, at a minimum, a ground (-) connection, and 1 for the running/marker lights and both signals which doubled as restriction lights. Some had a separate restriction light feed also as a fill-in light connection. Variations included having carve up restriction and signal connections. Add in the Electric Brake line and a Charge (+) line and all seven pins were used depending upon the configuration. With this connector standardized, the RV chassis makers could integrate the 'trailer wiring' needs into their chassis offerings and then RV makers could cull to just use the supplied connections and connector or alter to meet their own wiring needs.

This brings us to the present time. Virtually all modern RV chassis makers take a charge line bachelor at the rear towing connector that is integrated into their electrical organization. Some have this charge line controlled by the RV ignition so that merely being continued does not supply ability, however driving the RV does power the charge terminal in the connector. Often the face of the RV connector comprehend has the pivot layout which shows what connection is in each position on the socket. (See Photograph) Ostend with the body builder that there has not been any variation from what is shown on the cover or in their manual.

Properly Wiring a Tow Vehicle

While all makers of apartment towing systems have a 'four (iv) wire' circular connector, most can supply a six (half-dozen) wire coiled cable with either a six (6) wire connector on either one or both ends. In today'southward RV towing environs, four (4) wires are not enough, yet installers and shops are often tiresome to change. The connector on the RV end of the cable may be a 7 (seven) pin blade connector with a four (4) or half dozen (six) pin connector on the other (tow vehicle) end. The latter are smaller and are a better fit for the front finish of a tow vehicle. The aftermarket has jumped into the void with half dozen (6) pin round to vii (vii) pin blade adapters that accept the six (half-dozen) pivot connexion from the coiled cable which is plugged into this adapter that fits the connector on the jitney. Some of these adapters accept an internal wire that can exist moved to provide the bombardment charge connection on a specific terminal. We highly recommend the half-dozen (6) wire cablevision and connector approach to wiring a towed vehicle for the convenience, safety and flexibility that this alternative provides. An adapter placed on one end of the cable extension becomes the motorbus end of the cable.

It should be cross wire-tied to the cablevision as shown in the photo to ensure a tight connection between the two. The RV towing companies have produced cables that take a six (6) pivot round connector on ane cease and a seven (vii) pin blade connector on the other end. This is as well a suitable alternative, although smaller dealers may non stock this cable. The apply of the six (6) pin version and adapter is always a good alternative.

Tow Vehicle Wiring for Battery Charge Maintenance

So where does that get out the RVer which has a seven (7) pin blade connector on their RV?
Notation: If the tow vehicle maker requires a fuse (or fuses) to be removed to flat tow, then follow that direction. Yous can install a RVing FuseSwitch™, (or a similar Bypass Switch or Fusemaster to simplify the fuse removal).  A charge line does not eliminate this requirement.
First, review the chassis or RV Maker'due south possessor's manual or phone call their Customer Service team to confirm that the connector has the charging source of power, what the concluding layout is and whether a fuse or circuit breaker needs to be installed to permit the ability to catamenia to the rear connector. Many newer coaches have the connection and on some, it is controlled through the ignition switch.

Wiring the towed vehicle using the 6-wire cablevision connectedness, requires that the wire from the battery (more than about making the connection on the towed vehicle follows) is connected to the 'A' or 'A+' last molded into the back of the connector. Use a xiv-gauge (or larger) wire preferably with Red insulation, then that information technology is easily distinguished from the others and is large plenty to carry the necessary accuse current (commonly a maximum of xv amps). The other critical connection is the ground (marked G or GND) on the connector and it is the single larger pivot of the six (6) pins. Use a 14-gauge (or larger) wire (preferably White or Black in colour), then run both wires up to the Underhood Fusebox area of the towed vehicle. Ensure that the Red-wire is protected with plastic loom where it passes nigh sharp metallic and that it is routed safely effectually moving or hot components. This basis (White or Black) wire should be connected using an appropriately sized ring connector to one of the studs that the vehicle maker provides for grounding under the hood (see photos). The white wire from the apartment iv wire ribbon cable that is used to provide ability to the taillight/marker, left and right indicate (& brakes) can be separated from the ribbon, cut to the required length and connected to this stud also. This saves the claiming of trying to install two ground wires into the tow vehicle connector.

The Red (+12V) wire should be connected to one concluding on a 15 Amp, 12-volt circuit breaker using a suitable ring connector or fuse holder for the plug-in mode circuit breaker. Alternatively apply a suitable fuse holder that volition take a 15-amp fuse and adhere it using a barrel connector to the red wire. The reward of using an motorcar reset circuit breaker is that if information technology is over loaded it will reset and if the overload is cleared, it will continue operating, otherwise it volition continually bike on an off until the issue is resolved. A fuse in the same scenario volition blow and demand to be replaced. It is a personal decision as to which one to use.
If using a fuse holder then install a ring connector on the other of its wires and connect it to i of the bombardment terminals establish in the Underhood Fuse Box (shown circled in the photo). Likewise, if using a standard automotive excursion breaker and then put a suitable ring connector on each end of a short red wire, connecting one to the battery final in the Underhood Fuse Box and another band connector to the other remaining circuit breaker terminal.

The RV'south charging system will charge/maintain the tow vehicle battery in the same way every bit it charges and maintains the chassis and passenger vehicle batteries while the RV is existence driven. It is important to ensure that the tow vehicle battery is not severely discharged since the wiring is designed to maintain a fully charged battery, non act as a heave to this battery.

This approach eliminates the need for an accessory towed charge organisation and is really all that is required. Using the existing tow cable extension betwixt the vehicles is safer than an additional wire harness. Since this approach uses the chassis maker'southward protection arrangement and wiring up to the chassis connector, which greatly reduces or eliminates the work involved on the RV. A RVing Tow Vehicle Battery Maintainer Kit is available from RV Parts Plus, should you prefer to order a Tow Vehicle kit.

If the RV Chassis does not have a provision for battery charging/maintenance and then the RVer can decide whether to install a similar circuit breaker, or fuse holder in a new wire run from the chassis battery to the rear towed vehicle connector. Ensure that in that location is also a practiced ground connection to the connector. Alternatively utilise a purpose-congenital aftermarket maintenance/charger making the aforementioned type of connections using their kit.

Source: https://www.rv-partsplus.com/blogs/tt-102-installing-a-12-volt-charge-line-to-maintain-the-towed-vehicle-battery

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