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


Reply
 
Thread Tools Display Modes
 
Old 02-11-2024, 05:42 PM   #1
Bus Nut
 
ermracing's Avatar
 
Join Date: Jun 2018
Location: Claremont, NH
Posts: 479
Year: 2003
Coachwork: Bluebird
Chassis: International 3800
Engine: DT466E (195hp, 520tq)
Fuse size for 3000w inverter

I have a Go Power 3000 inverter/charger and it has a 400amp Type T fuse on the input wire. This fuse came as part of the kit when the inverter was purchased and everything is fine (been using it for about 5 years). I'm planning an extended trip and I've been stocking up on spare bits to carry with me, but I accidently bought a 450amp one.

Will this slightly larger one be okay to use as a replacement (which I hope I won't have to use), or should I return it and buy a 400amp one?

Thanks,
Dave

__________________
Dave
ermracing is offline   Reply With Quote
Old 02-11-2024, 08:12 PM   #2
Mini-Skoolie
 
Join Date: Nov 2021
Posts: 63
Year: 1995
Chassis: International
Engine: DT466NGD
Fuse

I would get the 400A fuse I have seen those fuses melt the fuse holder and wire with proper wire guage about 3" of wire each side of fuse holder and not blow the fuse . I would go under 400A with that fuse or use a DC Breaker at Maybe 375A . Have you ever blown that fuse ?
Vapor Ghost is offline   Reply With Quote
Old 02-11-2024, 08:19 PM   #3
Bus Nut
 
ermracing's Avatar
 
Join Date: Jun 2018
Location: Claremont, NH
Posts: 479
Year: 2003
Coachwork: Bluebird
Chassis: International 3800
Engine: DT466E (195hp, 520tq)
No, I have never blown the fuse. I'll contact the store and get the 400a version and look into the breaker as well.

Thanks.
__________________
Dave
ermracing is offline   Reply With Quote
Old 02-11-2024, 09:10 PM   #4
Bus Crazy
 
Join Date: Jun 2016
Location: Orange County, CA
Posts: 1,353
Year: 1990
Coachwork: Crown, integral. (With 2kW of tiltable solar)
Chassis: Crown Supercoach II (rear engine)
Engine: Detroit 6V92TAC, DDEC 2, Jake brake, Allison HT740
Rated Cap: 37,400 lbs GVWR
Fuses and circuit breakers protect the wiring, not the connected load item. Therefore, fuse size is determined by the wiring gauge. I hope you're using 4/0 cable for an inverter that large; if not, there will be significant voltage drop when drawing high current. FYI, for my Magnum MS2000 I use 4/0 welding cable for the positive and negative cables from the main DC busbar, with a 250A ANL fuse on the positive.

Class T fuses are very quick-acting, making them excellent as battery bank catastrophe fuses (on the negative). A slower-acting fuse is better for inverters and reactive loads.

John
Iceni John is offline   Reply With Quote
Old 02-12-2024, 06:23 AM   #5
Bus Nut
 
ermracing's Avatar
 
Join Date: Jun 2018
Location: Claremont, NH
Posts: 479
Year: 2003
Coachwork: Bluebird
Chassis: International 3800
Engine: DT466E (195hp, 520tq)
Yes, it is 4/0 cable.
__________________
Dave
ermracing is offline   Reply With Quote
Old 02-13-2024, 03:55 PM   #6
Mini-Skoolie
 
Join Date: Jul 2021
Posts: 35
The value of the fuse should accomplish 2 goals: 1) protect the downstream wires (as Icini John stated) and 2) allow the connected loads to perform their job.
For job 1) If your 4/0 wire is in free air (not conduit or in a wall) and the insulation is rated to 90 degC (which is common) then it is rated for 405 amps. Adding a 450A fuse is a mismatch as a current of say 430A could melt the insulation and short the wire without blowing the fuse.

For Job 2) A 3000W inverter running at full power using 12 volts will draw 250A in theory. Because many inverters are 90% efficient they will need 278A DC to create 3000W on the AC side and if the batteries drain down to 11V the inverter will pull 303A to create the same 3000W. Many people size fuses by adding 25% "headroom" which gets you to ~379A and means that a 380-400A fuse is the sweet spot.
A 250A fuse may work well in most situations, (most folks don't drive their inverters near max capacity) but it could blow even when the inverter was functioning correctly and within spec.

Finally, a value that a class T fuse brings to a main battery cable is high AIC which is the ability to interrupt very high currents. If you are using lithium batteries these have the potential to generate dead-short current in the range of 10,000A which can overwhelm and arc across lesser fuses and many breakers. So it may result in less AIC protection if you replace your class T fuse with a breaker.
Jono14 is offline   Reply With Quote
Old 02-13-2024, 05:14 PM   #7
Mini-Skoolie
 
Join Date: Nov 2021
Posts: 63
Year: 1995
Chassis: International
Engine: DT466NGD
Fuse

I would invest in a clamp on ampmeter and see how many amps your pulling.. And It's probubly not a good idea to run the Coffee pot and Microwave at the same time.. Fuses are cheep insurance keep a few on hand . I would tend to under size fuses or breakers.. I don't think most with a 3000w inverter actually intend to pull 3000W. If so you might want to rethink your system.
Vapor Ghost is offline   Reply With Quote
Old 02-13-2024, 09:24 PM   #8
Bus Nut
 
ermracing's Avatar
 
Join Date: Jun 2018
Location: Claremont, NH
Posts: 479
Year: 2003
Coachwork: Bluebird
Chassis: International 3800
Engine: DT466E (195hp, 520tq)
I've been converting most items I use in the bus to 12v so generally the inverter gets used less and less. The big items would be a 700w microwave, the 1500w engine block heater (rarely) and my little MIG welder, also used infrequently. As I said, the fuse has never blown using any of these.

I think the highest draw I've seen on the inverter control panel has been around 160amp at 12v or just under 2000 watts.

Thanks for all the input.
__________________
Dave
ermracing is offline   Reply With Quote
Old 02-14-2024, 11:36 AM   #9
Bus Nut
 
nikitis's Avatar
 
Join Date: Jun 2023
Location: South Carolina
Posts: 790
Year: 1995
Coachwork: Thomas
Chassis: International 3800
Engine: T444E
Rated Cap: 29
You can run a 110v mig welder fine on a 30+ amp line. I've thrown it a few times on a 20A line. A 220v welder might need a 50 Amp minimum setup in my experience if you don't want to throw it.
nikitis is offline   Reply With Quote
Old 02-17-2024, 05:35 PM   #10
Mini-Skoolie
 
BriteLeaf's Avatar
 
Join Date: Feb 2017
Location: Atlanta, TX
Posts: 58
Year: 1990
Coachwork: International
Chassis: Carpenter
Engine: Cummins 5.9
Rated Cap: 78
I’m using a 60A marine breaker for my setup.
It’s been working great for a couple of years now.
__________________
Never argue with a dragon, 🐉 for thou art crunchy and go well with ketchup. 😋😜🤓😎
BriteLeaf is offline   Reply With Quote
Reply

Thread Tools
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


» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 07:01 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2024, vBulletin Solutions, Inc.