I have a 2008 Fun Finder with a DC power issue. I just replaced the battery because the dealer put a bad battery on the trailer. Anyway, when I go to turn on the DC power to trailer, it blows the inline 30 amp fuse. it is located on the negative side of battery. I have a plunger type switch to turn on/off DC power to cabin. the shore power works fine, but not sure it is recharging the battery. Any ideas on where to start will be appreicated. If you need more info to diagnose the problem, let me know.

If it just started when you replaced the battery, odds are you hooked it up wrong.

Are you sure that is a negative cable? Not sure why there would be a fuse there except maybe reverse polarity protection but have never seen it done that way. Trace the wire to the frame and make sure positive and negative are correct.

baseball wrote:Anyway, when I go to turn on the DC power to trailer, it blows the inline 30 amp fuse. it is located on the negative side of battery.It's not a fuse but a circuit breaker, usually auto resetting, and it should be in the positive cable coming from the battery. Sure sounds like you've connected the battery backwards.

Fuse is typically on a heavy black wire to the positive battery terminal.Main negative connection is usually white and connects to the frame.

thanks Chris. i swapped them and now no blown fuse, but still no power to cabin. I went to fuse box and checked the two 30a fuses located at top of what i will call the DC distribution panel. no issues. the negative from battery connects to top left terminal on panel. the positive comes in and leaves on white wire from battery on top right. Right beside it is a red wire which the panel says is the positive from converter. when i put meter on the white and black terminals, there was not power. Could this be a bad converter??

DC inline fuse blows when battery power turned on

wa8yxm
Explorer III
Apr 15, 2019
Bobbo wrote:
Ignore wire color, there are too many "standards," and none of them are standard. Trace BOTH wires from the battery. ONE of them should go to the frame. THAT is the negative cable.

I have never, ever, seen a negative cable with a fuse or circuit breaker on it. I would bet money that the cable withOUT the fuse or circuit breaker is your negative cable.

Best advice I've seen in this thread. I do not trust colors in RV's cause they are wired by ELECTRICIANS not AUTOMOTIVE technicians or Electronic Technicians (I'm cross trained so I know both Traditions but THERE IS NO STANDARD!!!)
Lynnmor
Explorer
Apr 15, 2019
wa8yxm wrote:

Best advice I've seen in this thread. I do not trust colors in RV's cause they are wired by ELECTRICIANS not AUTOMOTIVE technicians or Electronic Technicians (I'm cross trained so I know both Traditions but THERE IS NO STANDARD!!!)

I agree except that they are wired by folks that have no electricity in their own homes. :)
midnightsadie
Explorer II
Apr 15, 2019
X2 LOL
jkwilson
Explorer III
Apr 15, 2019
Lynnmor wrote:
wa8yxm wrote:

Best advice I've seen in this thread. I do not trust colors in RV's cause they are wired by ELECTRICIANS not AUTOMOTIVE technicians or Electronic Technicians (I'm cross trained so I know both Traditions but THERE IS NO STANDARD!!!)

I agree except that they are wired by folks that have no electricity in their own homes. :)

Most of them do have electricity at home, and it is more similar to RV wiring than conventional wiring. 12V systems with solar or wind are very common among the Amish. I installed or helped with several systems based on cheap automotive headlight bulbs before LEDs became an option. They did a good job wiring, but didn’t get the idea about voltage drop so tended to overload circuits and get dim lights.
DSteiner51
Explorer
Apr 15, 2019
You hooked the battery up wrong and blew the reverse polarity fuses on the converter thus no power from the converter. Most likely did damage to other appliances too. You are lucky if you didn’t blow the furnace, water heater, and refrigerator circuit boards too.

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DC inline fuse blows when battery power turned on

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