Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > THE OWNER'S CORNER FORUMS > Newmar Owner's Forum
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
 
Thread Tools Search this Thread Display Modes
 
Old 06-10-2020, 09:35 PM   #1
Senior Member
 
Join Date: Mar 2011
Posts: 202
Inverter : Melted Fuse and fuse block

Magnum inverter errored today; stopped inverting; and would not allow "Auto Connect" so no 110v power to the coach...

Looking at the graphs the inverter was pulling ~150Amps @ ~12.6 volts when it shut down.

Click image for larger version

Name:	inverterOff.jpg
Views:	79
Size:	173.6 KB
ID:	289095

The coach had 12v power; and the solar charger was reporting good battery voltage.

Magnum's "Low Battery Volts" error seemed strange, until... I checked the fuse from the battery bank to the inverter. It was blown, and the fuse block was melted...

Not being familiar with this type of fuse, I grabbed my wrench to remove the wires from the lugs; and discovered the nuts were only finger tight - on both sides of the fuse block.

Click image for larger version

Name:	fuseMelted.jpg
Views:	89
Size:	147.9 KB
ID:	289096

Question: Would loose nuts cause a 150 amp load to exceed the 350 amp fuse rating? Or do I have another problem I need to track down?

In the meantime; I've rewired the electric panel to eliminate the inverter - so we can run on shore power; and I have a replacement fuse and block on order. I'll ask Newmar to ship replacements too under warranty...
ChrisFSB is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 06-10-2020, 11:13 PM   #2
Senior Member
 
Luv2go's Avatar
 
Newmar Owners Club
Nor'easters Club
Appalachian Campers
Ford Super Duty Owner
Coastal Campers
Join Date: Dec 2007
Posts: 2,462
Short answer, yes.

Long answer, the increased connection resistance due to the finger tight nuts at 150A heated the thermal elements in the fuse up until it blew, the same as the fuse would at over 350A (usually way over 350A) with properly tightened connections.
__________________
Stewart, Brenda and kids
2008 Newmar Canyon Star 3410, now at a new home
2006 Roadtrek Versatile 210
Luv2go is offline   Reply With Quote
Old 10-15-2020, 03:02 PM   #3
Senior Member
 
Vickie 4369's Avatar
 
Join Date: Nov 2012
Location: WATERBURY, CT.
Posts: 1,194
Quote:
Originally Posted by ChrisFSB View Post
Magnum inverter errored today; stopped inverting; and would not allow "Auto Connect" so no 110v power to the coach...

Looking at the graphs the inverter was pulling ~150Amps @ ~12.6 volts when it shut down.

Attachment 289095

The coach had 12v power; and the solar charger was reporting good battery voltage.

Magnum's "Low Battery Volts" error seemed strange, until... I checked the fuse from the battery bank to the inverter. It was blown, and the fuse block was melted...

Not being familiar with this type of fuse, I grabbed my wrench to remove the wires from the lugs; and discovered the nuts were only finger tight - on both sides of the fuse block.

Attachment 289096

Question: Would loose nuts cause a 150 amp load to exceed the 350 amp fuse rating? Or do I have another problem I need to track down?

In the meantime; I've rewired the electric panel to eliminate the inverter - so we can run on shore power; and I have a replacement fuse and block on order. I'll ask Newmar to ship replacements too under warranty...

We have twins, thanks for chiming in on my thread.

Like I said this is a crappy set up, that fuse block needs to have nuts under the fuse so proper torque can be applied to the connection.

If the plastic gets even remotely warm it will deform causing lost tension and lose connection, High amperage draw due to increased resistance.

I suggest you switch to either blue sea or the ME-400F https://www.invertersupply.com/index...hoCBXMQAvD_BwE
__________________
My name is Ted, My coach 2019 NEWMAR Ventana 4369 (Vickie) Cummins L9 451 Horsepower.
Vickie 4369 is offline   Reply With Quote
Old 10-15-2020, 04:08 PM   #4
Senior Member
 
Join Date: Mar 2011
Posts: 202
I used : Marinco Power Products Class T Fuse Holder with 2 Additional Studs

with 350A Blue Sea Systems Class T Fuse

also added a battery disconnect switch to the inverter.


>> proper torque
Do you have a suggestion in ft/lb that these should be torqued to?
ChrisFSB is offline   Reply With Quote
Old 10-15-2020, 04:35 PM   #5
Senior Member
 
Join Date: Sep 2018
Posts: 970
Quote:
Originally Posted by ChrisFSB View Post
I used : Marinco Power Products Class T Fuse Holder with 2 Additional Studs
>> proper torque
Do you have a suggestion in ft/lb that these should be torqued to?
From the Marinco data sheet:

Recommended torques:
Both 10mm (3/8”) and 12mm (1/2”)
studs: 21.5 Nm (15.9 lbf)
OldWEB is offline   Reply With Quote
Old 10-15-2020, 04:42 PM   #6
Senior Member
 
Join Date: Sep 2018
Posts: 970
Poor setup for sure!

As can be seen in the OP picture, the two rubber or plastic insulators had melted, most likely the cause of them loosening off. As Luv2go chimed in, the heat caused the thermal link in the fuse to open prematurely, that is how thermal fuses work, the melting of the thermal link with (usually) too much current.
I would recommend like Vickie 4369 says and install a 2nd nut under the fuse or even in any connection block like this, then you have metal to metal to torque too.
OldWEB is offline   Reply With Quote
Old 10-15-2020, 05:13 PM   #7
Senior Member
 
Join Date: Mar 2011
Posts: 202
Quote:
Originally Posted by OldWEB View Post
I would recommend like Vickie 4369 says and install a 2nd nut under the fuse or even in any connection block like this, then you have metal to metal to torque too.
Thanks - will do!
ChrisFSB is offline   Reply With Quote
Old 10-15-2020, 05:36 PM   #8
Senior Member
 
Vickie 4369's Avatar
 
Join Date: Nov 2012
Location: WATERBURY, CT.
Posts: 1,194
Quote:
Originally Posted by ChrisFSB View Post
I used : Marinco Power Products Class T Fuse Holder with 2 Additional Studs



with 350A Blue Sea Systems Class T Fuse



also added a battery disconnect switch to the inverter.





>> proper torque

Do you have a suggestion in ft/lb that these should be torqued to?


15 lb ft
__________________
My name is Ted, My coach 2019 NEWMAR Ventana 4369 (Vickie) Cummins L9 451 Horsepower.
Vickie 4369 is offline   Reply With Quote
Old 10-15-2020, 08:04 PM   #9
Senior Member
 
Vickie 4369's Avatar
 
Join Date: Nov 2012
Location: WATERBURY, CT.
Posts: 1,194
Quote:
Originally Posted by ChrisFSB View Post
I used : Marinco Power Products Class T Fuse Holder with 2 Additional Studs

with 350A Blue Sea Systems Class T Fuse

also added a battery disconnect switch to the inverter.


>> proper torque
Do you have a suggestion in ft/lb that these should be torqued to?
I had added shut off switches to all 3 Positive leads when I installed the Lifeline batteries, that made it easy to fix the fuse situation.

Ted.
Attached Thumbnails
Click image for larger version

Name:	IMG_5992.jpg
Views:	49
Size:	385.2 KB
ID:	304863  
__________________
My name is Ted, My coach 2019 NEWMAR Ventana 4369 (Vickie) Cummins L9 451 Horsepower.
Vickie 4369 is offline   Reply With Quote
Old 10-15-2020, 08:38 PM   #10
YC1
Senior Member
 
YC1's Avatar


 
Join Date: Jun 2011
Location: FL
Posts: 10,794
Yep, loose nuts running around create electron friction which is the same thing that lights an incandescent bulb. Fuses melt do to heat. That can be external heat as you have found. Of course it was a combination of the heavy current flowing in the fuse and the added heat nearby.

Annual maintenance should include finding these large nuts and tightening them.

A carefully wrapped wrench can even do it while the circuits are live if you are incredibly careful.
__________________
Certified Senior Electronic Technician, Telecommunications Engineer, Telecommunications repair Service Center Owner, Original owner HR 2008

.
YC1 is offline   Reply With Quote
Old 10-16-2020, 02:21 PM   #11
Senior Member
 
Vickie 4369's Avatar
 
Join Date: Nov 2012
Location: WATERBURY, CT.
Posts: 1,194
Quote:
Originally Posted by YC1 View Post
Yep, loose nuts running around create electron friction which is the same thing that lights an incandescent bulb. Fuses melt do to heat. That can be external heat as you have found. Of course it was a combination of the heavy current flowing in the fuse and the added heat nearby.

Annual maintenance should include finding these large nuts and tightening them.

A carefully wrapped wrench can even do it while the circuits are live if you are incredibly careful.
If they were backed by nuts instead or plastic, they would never come lose.

Ted.
__________________
My name is Ted, My coach 2019 NEWMAR Ventana 4369 (Vickie) Cummins L9 451 Horsepower.
Vickie 4369 is offline   Reply With Quote
Old 10-16-2020, 02:29 PM   #12
Senior Member
 
Skip426's Avatar


 
Join Date: Apr 2011
Location: Powell River, B.C.
Posts: 27,894
If you'll get onto Newmar , maybe with multiple customer complaints they'll change suppliers of the fuse holder .
__________________
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.
Skip426 is offline   Reply With Quote
Old 10-18-2020, 06:33 PM   #13
Senior Member
 
Vickie 4369's Avatar
 
Join Date: Nov 2012
Location: WATERBURY, CT.
Posts: 1,194
Quote:
Originally Posted by Skip426 View Post
If you'll get onto Newmar , maybe with multiple customer complaints they'll change suppliers of the fuse holder .
I formed a letter to Newmar with links to this and my thread.

Hopefully they take it seriously and look at this and come up with a solution or use my solution.

Ted.
__________________
My name is Ted, My coach 2019 NEWMAR Ventana 4369 (Vickie) Cummins L9 451 Horsepower.
Vickie 4369 is offline   Reply With Quote
Old 10-19-2020, 08:19 AM   #14
YC1
Senior Member
 
YC1's Avatar


 
Join Date: Jun 2011
Location: FL
Posts: 10,794
A nut and washer on first, then the fuse, then the rest of the hardware would allow the connections to be properly tight and provide a bit of extra heat sink. There should be little heat build up there of course.

I have replaced thousands of fuse blocks in my business over the years and it usually comes down to finding a loose connection on one end.

Yes there are better built fuse blocks and we always looked for top of the line products.
__________________
Certified Senior Electronic Technician, Telecommunications Engineer, Telecommunications repair Service Center Owner, Original owner HR 2008

.
YC1 is offline   Reply With Quote
Reply

Tags
fuse, inverter



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Antenna up switch and cut off fuse melted a1kaching Class A Motorhome Discussions 2 10-02-2019 09:48 PM
Engine classifications: big block vs small block Deucenut Cummins Engines 3 06-05-2017 05:06 PM
To Block or Not To Block live4thedash Class A Motorhome Discussions 12 12-07-2016 10:47 PM
Melted Fuse Chuck Q Going Green 4 08-02-2016 09:28 AM
450 small block vs 500 big block StuartS Class A Motorhome Discussions 5 03-15-2015 09:28 AM

» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 09:21 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2023, vBulletin Solutions, Inc.