Parts Needed to Add +12V Charge Wire to 7-Way on 2017 Subaru Outback

Question:

I had a 7-way and a hitch put on my 2017 Outback. There is not a charge wire connected to the 7-way. My concern is that charging two batteries off of the cars alternator would damage it or invalidate the warranty. Running the charge wire looks fairly straight forward. Are there other concerns?

asked by: John P

Expert Reply:

All you need to add an active +12V power feed to your existing 7-way trailer socket is 10-gauge wire # 10-1-1, a 40-amp auto-reset circuit breaker # 9510 and ring terminals # 44-5310A. The breaker will install at the battery. Connect the copper-color terminal to the battery and the charge wire to the other terminal.

You will want to keep the breaker's 40-amp capacity in mind as you apply a load on the trailer/output end to avoid tripping the breaker. If overloaded it will re-set once it cools. Note that his charge line can MAINTAIN a charged battery but it does not deliver enough power to re-charge a depleted battery.

For an actual full-charge for a depleted battery you need an AC powered battery charger like # CTEK56353. I have owned one of their chargers for about 6 years and it has worked perfectly in continuous use on mower, motorcycle and vehicle batteries.

expert reply by: Adam R