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Author Topic: Reverse polarity  (Read 447 times)

shadyjff1

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Reverse polarity
« on: July 13, 2018, 11:27:42 PM »
I just picked up a 1998 Travel Aire Drifter DT185. Canít find any information online about it. Anyway the guy I got it off of has the battery hooked up backwards. He told me it was the only way to get the lights to turn on. The battery is dead so I got some new ones. My question is how much damage if any could he have done to the unit doing this. I have not gone through the fuses yet but Iím going boon docking soon and need the battery but donít want to hook up and damage the batteries I have, or the unit. Also does anyone know if there is a shut off switch, or any hidden fuses that are on this model?

Isaac-1

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Re: Reverse polarity
« Reply #1 on: July 14, 2018, 01:40:53 AM »
Off hand I am thinking converter, refrigerator control board, air conditioner control board, and possibly water heater control board if it was a DSI model without a pilot light, being from 1998 it could be either way.   In other words everything but the fuse box and the lights.
2002 Safari Trek 2830

viceprice

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Re: Reverse polarity
« Reply #2 on: July 14, 2018, 02:52:26 AM »
Check the actual path of the lead wires for the battery hook up if you have not alraady done so. Should be easier to trace the "ground" for the negative lead. It may not have been reversed.  Sometimes the colors are not your typical red for positive and black for negative, especially if one or both were replaced.
Karen, Kyle and the K9s
1997 Chevrolet C2500 7.4L Silverado
2016 Cougar X-Lite 28RBS

Alfa38User

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Re: Reverse polarity
« Reply #3 on: July 14, 2018, 09:52:28 AM »
Also, any reverse protection fuses from the converter, if equipped, they are blown anyway. Check very carefully as it appears that the previous owner was not a master electrician. Start as viceprice suggests....
« Last Edit: July 14, 2018, 09:54:45 AM by Alfa38User »
Stu
Montrťal, Canada 🍁
Snowbird, Naples Florida
Alfa Gold 38 (2000) 5ver (parked!)

"Of course I talk to myself, sometimes I need expert advise!!!"

Gary RV_Wizard

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Re: Reverse polarity
« Reply #4 on: July 14, 2018, 10:43:00 AM »
Agree with the others, but chances are that few of the potentially damaged items are actually defunct.  Fridge boards and the converter/charger itself seem to be the most susceptible, but there are no guarantees. You will just have to try them to see.

With any sort of luck, the converter had reverse polarity fuses that blew out when the battery was hooked up backwards, but those weren't real common back in 1998.  If you can identify the make/model of the converter or power center (combo 120v breakers & 12v fuses), we can probably tell if it has that protection or not.


Hooking the battery up backwards to get the lights to work makes me think there may have been a major short to ground on the 12v plus side, either near the battery plus cable or on one of the main branch power feeds from the 12v distribution panel to lights and such. It may still be there and need fixing.  Obviously the former owner was no electrician.
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

shadyjff1

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Re: Reverse polarity
« Reply #5 on: July 14, 2018, 04:42:26 PM »
Thanks guy. I love to tinker and never worked on travel trailer so this should be fun to figure out. Only thing is no days off till I hit the road, so I will start working on this in the bush in August

Gary RV_Wizard

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Re: Reverse polarity
« Reply #6 on: July 14, 2018, 07:31:32 PM »
There are fuses on the fridge circuit board for both 12v and 120v power. Maybe on at the furnace too.  Some builders are real good about putting all fuses on one panel, and some take shortcuts and place inline fuses wherever it is easy for the assembly line guys.

Probably no shut-off on a travel trailer.

When you say "hooked up backwards", I read "Positive terminal goes to chassis ground". If that's the case, I would be really careful the first time I tried hooking it up correctly (negative ground). Use a fuse in the cable to the positive terminal. 50A should be plenty, but with everything you know of turned off, 25A or 30A is an even better choice for the initial test. You can go to a higher amp rating once you have everything working ok.
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL