Blown battery fuse!!!

Photomom

Our T@B was unplugged all last week so I could monitor battery voltage under the parasitic load. It was down to 12.3v yesterday so I plugged in to house A/C to recharge. This afternoon we unplugged and checked to make sure the battery was charged. The SeeLevel monitor had no power, and interior lights wouldn't come on. Everything works fine when the trailer is plugged in to A/C.

I checked the battery and it is at 12.6, but when we pulled the battery fuse, it had blown. It is a 15A fuse.

So between yesterday afternoon and this afternoon, something happened to blow the battery fuse. We haven't even been in there. The ONLY thing that has happened is we got a couple of heavy rainstorms today, but it is hard to understand how that could be the problem. I noted that the battery cutoff switch is quite wet, but I understood that those were meant for marine use and I'd think it would be sealed.

Will buy fuses tomorrow (thought I had some but they are the "mini" size.) But in the meantime, what should we be looking at?

Verna

Photomom, I use 30 amp fuses on my battery. It was that way on my teardrop and that's what my T@B had in it when I bought it. 

A wet switch is enough to blow the fuse if they are switching the positive lead from the battery. I have my switch mounted on the rear cross piece that is directly under the lid to keep it dry. It has not gotten wet in all of this rain and storms we've been having. 

Photomom

Hmmm. The fuse is the one that came from the dealer. Is there a reference somewhere that specifies the correct amperage? Those of you who've gotten T@Bs recently, what fuse did you get?

Also, isn't that supposed to be a MARINE switch?

TerryV6

30 amp was in mine...

Verna

Photomom, is the slot for the wiring in the switch pointing downward? Water should not be getting into the switch if that wiring entrance is at the bottom of the switch. It's easy enough to correct if it is pointed the wrong direction. 

Photomom

Yes, it is pointing downward. And I just ran out to check (how do people who can't keep their trailers at home manage?) and the switch is on the positive side. (I DO NOT want to get into that but I am okay with that.)

I can can buy that we might have the wrong fuse, but we've had this a couple weeks and have camped two weekends. And this isn't the first time it's rained, or the first time we've charged the battery!

RollingLagrima

My 2016 (delivered in 2015) came with a 10 amp which promptly blew. Bear in mind that the individual dealers not the factory are the ones supplying the batteries and wiring that inline fuse housing. After my experience and others on here telling me to swap out the blown 10 for a 30 (dealer told me to switch it out with a 20 when I called to ask what was up with the blown 10), I did put a 30 in, and have had no issues since...

Verna

Photomom, put in a 30 amp fuse, chalk it up to a learning experience. If the wiring entrance is pointing downward, the wiring should be dry inside the switch. Sometimes there are just fuse gremlins that go around messing with the fuses to make us think . Don't overthink this one. There is no harm to anything except the fuse. 

ChanW

Photomom, it could be that the fuse blew when you plugged it in, after having discharged the battery to a low point. 

The slight surge from the converter/charger could easily have been over 15A. I'm pretty sure the battery fuse should be 30A.

Tabaz

My dealer incorrectly had a 20 amp fuse in the fuse socket. Look very closely at the fuse holder. You should see "30" somewhere on it.

Ratkity

Ditto what Verna, Chan and Outback (and others) said. 30 amp fuse. I blew it once by accident. No harm. Matter of fact, I need to go pull mine because next few weekends are not for camping!

Photomom

The fuse holder says "30A Max". That would be the rating for the fuse holder itself. I am going thru my bag of product info and there is no T@B manual of any kind. 

Tabaz

The 30 amp rating is for the wire going into and out of the fuse holder - not just the holder.

Photomom

ChanW said:

Photomom, it could be that the fuse blew when you plugged it in, after having discharged the battery to a low point. 

The slight surge from the converter/charger could easily have been over 15A. I'm pretty sure the battery fuse should be 30A.

Is there some kind of sequence to follow? We basically just plugged the trailer in to the garage outlet. 

Tabaz

Yes! The sequence is put in a 30 amp fuse at the battery. Plug in to shore power.

RZRBUG

Actually, the converter has a built-in delay.  When you plug in, power is only sent from the converter after about 30 seconds, if my memory serves correctly.  I once thought I had something wrong with my A/C because I kept expecting it to start immediately.

ChanW

Hmm. Good point, Photomom.
I suppose we could go by the wire gauge/length it's protecting, to determine the fuse required.
Or contact the manufacturer. 

Photomom said:

The fuse holder says "30A Max". That would be the rating for the fuse holder itself. I am going thru my bag of product info and there is no T@B manual of any kind. 

Verna

https://tab-rv.vanillacommunity.com/discussion/163/fuse-inventory/p1

If you look at the fuse amperage designations on PXLated's converter, the last 12V fuse is designated as "Battery Charger" and it is a 30 amp fuse. You should protect one fuse with the same size fuse, right ? Therefore, a 30 amp fuse should be in both places--converter and the battery.

Mouseketab

I usually make sure the A/C is off when plugging in to power.

jkjenn

Out of curiosity,  are you using a surge protector? 

Photomom

We have a whole house surge protector on the circuit breaker panel. There are electronics in just about everything. 

Photomom

Verna said:

http://tab-rv.vanillaforums.com/discussion/163/fuse-inventory#latest

If you look at the fuse amperage designations on PXLated's converter, the last 12V fuse is designated as "Battery Charger" and it is a 30 amp fuse. You should protect one fuse with the same size fuse, right ? Therefore, a 30 amp fuse should be in both places--converter and the battery.

Yes, that makes sense. After I have coffee I will go out and buy fuses. 

Photomom

Verna said: Sometimes there are just fuse gremlins that go around messing with the fuses to make us think . Don't overthink this one. There is no harm to anything except the fuse. 

I was an electronics tech in the service and put myself through college repairing computers. No gremlins, there's a reason for everything. In this case I'm not surprised the reason is the dealer put in the wrong fuse, given some of his other mistakes.

ScottG

Photomom said:

The fuse holder says "30A Max". That would be the rating for the fuse holder itself. I am going thru my bag of product info and there is no T@B manual of any kind. 

The T@B manual can be downloaded from the "Customer Resources" link on the T@B web page. It says...

"If there is an electrical problem, first check the 20-amp fuse at the battery then check the fuses located in the converter. Do not replace battery fuses with anything other than a 20-amp fuse."

Of course, the manual is outdated, and appears to cover more than just the T@B.

My 2015 has a 30A fuse at both the battery and the converter. The wire connecting them is 10g, which is rated for 30A. So, like everyone else, I say go with a 30A fuse!

Ratkity

Photomom said:

Verna said: Sometimes there are just fuse gremlins that go around messing with the fuses to make us think . Don't overthink this one. There is no harm to anything except the fuse. 

I was an electronics tech in the service and put myself through college repairing computers. No gremlins, there's a reason for everything. In this case I'm not surprised the reason is the dealer put in the wrong fuse, given some of his other mistakes.

Hijack thread! @Photomom Thank you for your service.  

Verna

Photomom said:

I was an electronics tech in the service and put myself through college repairing computers. No gremlins, there's a reason for everything. In this case I'm not surprised the reason is the dealer put in the wrong fuse, given some of his other mistakes.

Then the logical explanation is either a power surge or static electricity produced when inserting the fuse in a live circuit. Gremlins to those who haven't worked with electronics. 

Thank you, Henrietta, for your service! Which branch of the service? My Daddy was one of the Chosin Few in the Marines, having served on the Korean War. 

Photomom

Fuse replaced and all appears well! If it weren't for the forum I'd have assumed 15A was correct, or possibly 20A if that is what the manual says. LG really should update its documentation.

jkjenn

Photomom said:

We have a whole house surge protector on the circuit breaker panel. There are electronics in just about everything. 

But none on the T@b at the time? 

Photomom

jkjenn said:

Photomom said:

We have a whole house surge protector on the circuit breaker panel. There are electronics in just about everything. 

But none on the T@b at the time? 

No, the tab was plugged into an adapter then into an outlet in the garage. The garage outlets are protected by the whole house surge protector, so I wouldn't think the progressive one I got for campgrounds would be necessary. ???

jkjenn

Photomom said:

jkjenn said:

Photomom said:

We have a whole house surge protector on the circuit breaker panel. There are electronics in just about everything. 

But none on the T@b at the time? 

No, the tab was plugged into an adapter then into an outlet in the garage. The garage outlets are protected by the whole house surge protector, so I wouldn't think the progressive one I got for campgrounds would be necessary. ???

You wouldn't think,  but it seems as though a surge can occur from just plugging in.  I am  keeping an informal tab on people in different circumstances and I have yet to see an I stance of a blown fuse when someone was using a surge protector. I realize it's anecdotalanecdotal,  but it is a matter of curiosity for me. 

Photomom

jkjenn said:

Photomom said:

jkjenn said:

Photomom said:

We have a whole house surge protector on the circuit breaker panel. There are electronics in just about everything. 

But none on the T@b at the time? 

No, the tab was plugged into an adapter then into an outlet in the garage. The garage outlets are protected by the whole house surge protector, so I wouldn't think the progressive one I got for campgrounds would be necessary. ???

You wouldn't think,  but it seems as though a surge can occur from just plugging in.  I am  keeping an informal tab on people in different circumstances and I have yet to see an I stance of a blown fuse when someone was using a surge protector. I realize it's anecdotalanecdotal,  but it is a matter of curiosity for me. 

Hmmm. It would be no trouble to use it at home, and can't hurt, I suppose.