What besides reversing cables causes Converter fuses to blow

jesse.m.jm wrote:
My old 2003 did, but I have not read all the manuals yet to see if the 2009 does or not.

Your 2009 will have a "smart" converter too but it's probably a WFCO which are notorious for NOT going into boost mode which considerably lengthens charging time.

I know of basically 4 things

First, as you know reversal of the battery leads

Second A short, if he shorted the leads WITH THE CONVERTER ON (plugged in) it is possible in some cases for a converter to out just enough to pop those fuses.. Usually this indicates the wrong fuse used (IE: 2 30 amps will blow if your converter is an 80 amp, 3 won't, or 2 40s)

That short can be in 3 places.. It can be a bad circuit in the RV, or it could be shorted cells (Plural) in the battery, or it could be an accident during battery removal/replacement as described above.

(I counted it twice in my 4 both shorts in the RV and accidental install goof count as one, Shorted cells as other)

Finally Fuses sometimes fail, for no describable reason, Vibration and age is one theory,

Glad to hear your's was not a disaster. An owner who "forgets" the charger is connected can pull a positive cable from the battery accidentally touch the cable to something metal and there goes the fuses...

Scenario...

Previous owner sees that his converter is not working and decides a new "bigger" toy hauler is the hot ticket. You never know...

Thanks everyone. I checked the batteries and they are correctly hooked up at this point. We bought the trailer yesterday from the previous owner, so he may have reversed them at some point and didn't realize the converter fuses were blown. I put new fuses in and everything is working good now, I just wanted to know kind of what else might have caused it so I knew where to look if they blew again.

Roy, i'm not sure if this one has a smart converter or not. My old 2003 did, but I have not read all the manuals yet to see if the 2009 does or not.

Nothing as tricky as finding out someone had "reversed charged" one or more batteries. Drained it down to zero then slow charged reversed and "viola" + means ground. Verify with a meter WHILE making sure the - minus - sign does not pop up when you touch the posts correctly.

I sort of agree with Brian, but I'd take a meter and verify that the connections are positive to positive & negative to negative first. It never hurts to check and it isn't difficult to do.

shorting out the cables when the converter is on will blow the fuses. I'd just replace them, hook it up to a battery and turn it on. Should be fine. Be careful of polarity.

Brian

Thats about the only thing that will blow the two 40AMP fuses. It only takes one little spark in reverse order to do this. I always make sure the cables are connected correctly by finding the word "NEG" or the symbol "-" on the battery case and make sure this is the terminal going to the trailer frame ground.

You might take a look at the battery fluids in the battery. I see you have a older YR model trailer which probably does NOT have a smart mode converter/charger in it. A single mode converter/charger will put out a constant 13.6VDC which is right on the border line of boiling out battery fluids. This could be a another source of high current being drawn if the battery fluids get below the core level and cause a battery shorted cell...

If you do not have the smart mode converter/charger it is probably a good idea to check your battery fluids on an every couple of weeks basis just to make sure the fluids are not being boiled out...

just a couple of thoughts here...
Roy Ken