Community Forums

gregsam · 10-24-2012, 08:31 AM

I have a 2004 28RLS by Outback. I will be towing over a long distance for the first time this winter. Does the on board trailer battery charge while the trailer is being towed? I have the standard connector for electric brakes and it does seem to have the 12 volt feed going to the trailer wiring.

Fred1609 · 10-24-2012, 08:32 AM

It should, mine does

RustyJC · 10-24-2012, 09:02 AM

If your tow vehicle has the Pollak RV-style 7-blade connector, the pin outs are as shown on the attached photo.

With your tow vehicle's engine running, you should have +12VDC from pin #4 (+12VDC) to pin #1 (ground). Some vehicles keep pin #4 hot at all times, while others utilize a battery isolation relay to disable pin #4 when the engine isn't running - this keeps any load on pin #4 from discharging the tow vehicle battery if the trailer is left hooked up to the tow vehicle for long periods of time when the tow vehicle isn't running. Therefore, it's best to check for the availability of +12VDC with the engine running just to be sure.

If you have +12VDC on pin #4, your trailer battery should charge from the tow vehicle. Be advised, however, that due to voltage drop and small wire size in most tow vehicles, the trailer battery probably won't charge rapidly from a deep discharge condition - it's better to think of this as a maintenance charge capability.

Rusty

gregsam · 10-25-2012, 04:12 AM

Good thorough info. Will get the volt meter out and start testing. I tow with a 2012 F150 with trailer tow option including electrical.
Thanks

tuffr2 · 10-26-2012, 11:12 AM

If the Battery is a 2004 it may be tim for a new one. I know on all newer set-ups the battery gets charged. My 2011 F-150 charged the battery in my 2008 trailer while towing.

bt76 · 10-26-2012, 01:51 PM

My 05 Outback 21rs does. To know for sure check trailer battery voltage when connected to running tow vehicle, should be around 13.5volts. Helps if your battery is easily accessed.
Good luck.

Stevepd · 11-05-2012, 06:03 PM

Quote:

Originally Posted by bt76

My 05 Outback 21rs does. To know for sure check trailer battery voltage when connected to running tow vehicle, should be around 13.5volts. Helps if your battery is easily accessed.
Good luck.

Please check with someone that can put a meter
while hooked up and you will see what it is charging at. Don't be surprised if it not very
many amps. I would charge for 3 days at a 2 amp
setting to charge properly.

caissiel · 11-05-2012, 09:00 PM

Quote:

Originally Posted by gregsam

I have a 2004 28RLS by Outback. I will be towing over a long distance for the first time this winter. Does the on board trailer battery charge while the trailer is being towed? I have the standard connector for electric brakes and it does seem to have the 12 volt feed going to the trailer wiring.

With truck hooked up and idling press your test switch on your RV panel and observe the battery charge state. It shold be at C.
Now load a known load (DC) and see if it droped to G or F.
On my Ford I had tto run 10 ga wire to trailer pllug to get 23 amps for 2 batteries.