Parts Needed to Charge a Trailer Battery for a Winch

Updated 09/23/2011 | Published 09/22/2011

Products Featured in This Question

Starter Solenoid - SPST - 12 Volt - 100 Amp - Continuous Duty - Grounded

(13)

$33.90

CTEK MULTI US 7002 12-Volt Universal Battery Charger w/ Pulse Maintenance and Backup Power

(94)

$199.99

Pollak Single-Pole, Round Pin Trailer Wiring Socket - Vehicle End

(24)

$29.51

Pollak Single-Pole, Round Pin Trailer Wiring Connector - Trailer End

(25)

$46.43

Pollak Circuit Breaker - Cycling/Automatic Reset - 40 Amp - Straight Mount Bracket

(49)

$7.40

Question:

I purchased a deep cycle marine battery to power my winch. I want to connect it to the accessory pin on my 7pin connector. Questions are: Should I put an inline fuse between the 7pin connector and the trailer mounted winch battery? If so, what size would you recommend? Next question is: Would the trucks 12 volt charging system charge the deep cycle battery adequately? Thanks,

asked by: Kirk

Expert Reply:

First, the wiring on a trailer connector can provide a maintenance charge to a 12 volt battery on a trailer but it will not be able to fully charge it. The 12 volt circuit on a 7-Way is already circuit protected so a separate fuse or breaker should not be needed.

There is a way you can provide a charge to the battery from the truck. You would need to equip the truck and trailer with separate single pole connectors independent of the 7-Way. For the trailer side, you would need Pollak Single-Pole, Round Pin Trailer Wiring Connector, # PK11852. It accepts heavy gauge 00 wire (like battery cable). The trailer battery would also need to be grounded to the vehicle frame.

On the truck side, you would use Pollak Single-Pole, Round Pin Trailer Wiring Socket, # PK11851. This connector also accepts 00 gauge wire. On the truck side, you would want to route the wire from the connector to the front of the vehicle and into the engine compartment near the battery. You would then need to mount a battery isolator, # PK5231201, near the battery.

Connect the positive side of the battery to one of the side polls on the isolator. Connect the isolator center pole to a 12 volt ignition source ( a source that is only on when the vehicle key and/or engine is turned on). The last post will first go to a 40 amp circuit breaker, # PK54540, to the post labeled BAT. The circuit breaker will also need to be mounted to a metal surface like the isolator. Then from the AUX post on the circuit breaker, connect the wire you ran up from the single pole.

The battery isolator will allow the vehicles system to charge the trailer battery when the truck is running, but cuts off the feed with the truck off so the vehicle battery will not get drained.

The other option is to attach the trailer battery to the 12 volt circuit on the 7-Way to provide the maintenance charge, but then use a battery charger, # CTEK56353, to charge the battery fully. I have included a link to a video of the charger for you.