Inverter fuse size question

[landocarlesien]

My RV dealer installed 2, 200ah LiFePo4 batteries (100a BMS) in parallel and a 2000w Xantrex Freedom X inverter. The inverter fuse size is 40a, but it keeps on tripping at around 500w load. Today, when using the toaster, the fuse tripped and the inverter wont even turn on. I think the 40a fuse is the issue, is this the right size? If not, what would the correct fuse size be? Thanks!

 

[Bud Martin]

Are you talking about External 40A fuse installed by the dealer to feed the DC input of inverter?
For 2000W inverter, the DC input fuse of the inverter will be a lot higher than 40A for the inverter to put out 2000W on the AC side of the inverter.
Here is the manual, look at page 21 for the inverter DC cable and fuse size.

https://www.xantrex.com/documents/Power-Inverters/Freedom%20X/Freedom%20X%20Inverter%20Owners%20Guide%20(975-0787-01-01_Rev-F)_ENG.pdf

 

[chrisski]

THat is definetly something the dealer should fix If they put the system together for you. My 2000 watt inverter has a 200 amp fuse. If they did install a 40 amp fuse, I’d also be worried about the size wire they put in. I have 4/0 for 12 volts, but 2/0 would be good also.

FOr correct wire ad fuse, take a look in the inverter manual.

I’m mentioning wire, because I really hope they did not fuse 40 amps for a smaller size wire like 10 gauge.

 

[Bud Martin]

Yep, I wonder if they know what they are doing, you can easily have a fire going.
I also wonder what how they are handling the charging of the LiFePO4 batteries, I hope they install proper charger too.

 

[landocarlesien]

THat is definetly something the dealer should fix If they put the system together for you. My 2000 watt inverter has a 200 amp fuse. If they did install a 40 amp fuse, I’d also be worried about the size wire they put in. I have 4/0 for 12 volts, but 2/0 would be good also.

FOr correct wire ad fuse, take a look in the inverter manual.

I’m mentioning wire, because I really hope they did not fuse 40 amps for a smaller size wire like 10 gauge.

Thanks for the reply. They used 2/0 wiring from the battery to the inverter. Now this is making me think they didnt charge the batteries separately before installing as well

 

[landocarlesien]

Correct.

Are you talking about External 40A fuse installed by the dealer to feed the DC input of inverter?
For 2000W inverter, the DC input fuse of the inverter will be a lot higher than 40A for the inverter to put out 2000W on the AC side of the inverter.
Here is the manual, look at page 21 for the inverter DC cable and fuse size.

https://www.xantrex.com/documents/Power-Inverters/Freedom%20X/Freedom%20X%20Inverter%20Owners%20Guide%20(975-0787-01-01_Rev-F)_ENG.pdf

I can’t even get an appointment until September, which is an issue since I live and work remote full time and need this inverter to work. If the 40amp fuse tripped, I reset it and the inverter still wont turn on, what could be the issue? I check the connections and there is nothing loose. I’m stumped

 

[landocarlesien]

THat is definetly something the dealer should fix If they put the system together for you. My 2000 watt inverter has a 200 amp fuse. If they did install a 40 amp fuse, I’d also be worried about the size wire they put in. I have 4/0 for 12 volts, but 2/0 would be good also.

FOr correct wire ad fuse, take a look in the inverter manual.

I’m mentioning wire, because I really hope they did not fuse 40 amps for a smaller size wire like 10 gauge.

What size battery system and BMS do you have? Based on my post, what is the recommended DC amp size to use? The dealer installed 2/0 gauge wire. Thanks!

 

[chrisski]

If you look in the link that Bud posted and search for fuses, you'll find a max fuse size. A 40 amp fuse on the 12 volt DC side will blow around 500 watts like you have been getting.

Also, what kind of fuse is this? Manuals usually say to put a class T fuse in and those are not cheap to change.

 

[Bud Martin]

Correct.

I can’t even get an appointment until September, which is an issue since I live and work remote full time and need this inverter to work. If the 40amp fuse tripped, I reset it and the inverter still wont turn on, what could be the issue? I check the connections and there is nothing loose. I’m stumped

We need clarification or the pictures of they they have installed.
Fuse is one time use, once it blows you do not reset the fuse.

 

[landocarlesien]

If you look in the link that Bud posted and search for fuses, you'll find a max fuse size. A 40 amp fuse on the 12 volt DC side will blow around 500 watts like you have been getting.

Also, what kind of fuse is this? Manuals usually say to put a class T fuse in and those are not cheap to change.

They installed the below manual resettable circuit breaker.
https://www.walmart.com/ip/40A-Circ...did=&affiliates_ad_id=568824&campaign_id=9383

Could this incorrect fuse have damaged the inverter?

I just looked all of that up from Buds link. Ill buy one of those Class T fuses today. Since the dealer cant get me on the schedule until September (I already had a scheduled appointment), I would need to take care of this myself. Just so I dont screw anything up, would I need to disconnect the Victron solar charge controller before disconnecting the battery? I am also going to charge the batteries separately before hooking everything back up because i doubt they did that

 

[landocarlesien]

We need clarification or the pictures of they they have installed.
Fuse is one time use, once it blows you do not reset the fuse.

 

[Bud Martin]

So they install 40A circuit breaker, the crappy $20 one at that and probably can get the same crappy one for $12 ~ 15 on Amazon, not the real BUSSMAN circuit breaker. Did they read the inverter manual? They should know better what the rating should be for particular size inverter if they have been in business doing installation.
At this point I wonder if the circuit breaker is actually reset, breaker cannot damage the inverter. the breaker just trips early due to overload..
Do you have DC Voltmeter?

 

[12VoltInstalls]

Since the dealer cant get me on the schedule until September (I already had a scheduled appointment), I would need to take care of this myself.

The dealer should take you today because they screwed you over and did something very, very wrong. On second thought: I wouldn’t want them working on my stuff ever again unless you have like 125% coverage for fire snd don’t have anything you can’t live without in the camper.

 

[12VoltInstalls]

l? They should know better what the rating should be for particular size inverter if they have been in business doing installation

This is way too common.
Like 90% around here.

I worked for a place that the owner ran 2 gage - 2 gage, not 2/0 - on a tilting car hauler winch trailer. Because it tilted it needed to run to the hinge point and back so like 18’ run total. Winch was rated 3HP so it was 200A or more under load.

it’s about taking money, and not about doing good work, anymore

 

[Bud Martin]

The other very important thing is the charger for your expensive new Littium batteries. What did they install?
OP must ask them that question and show OP what they install.
Did they install WFCO?

Past Generation - WFCO Electronics

As the leading power supplier to the RV industry, WFCO’s lineup would not be complete without supporting lithium-ion batteries. The Lithium-Ion Solution is comprised of three options, designed for easy installation and use in both the OEM and Aftermarket, and can safely charge any lithium-ion...

wfcoelectronics.com

 

[chrisski]

For the Solar panels, it’s not so much as disconnecting the SCC or Solar Panels as it is making sure no power is going in, like doing the work at night when they produce no power, or tripping a breaker. Either way, a multimeter needs To ensure the line is not hot.

THe battery can be shut off Easy enough, but the comment I’ll make on that is the protection, like the fuse needs to be before the switch.

If you are getting a class T fuse, just make sure you get the holder. This is not just bolt the fuse in, but the fuse and fuse holder. I like the covered fuses also. I don’t like hot terminals so close to the inverter I may be doing adjustments to. You may be in luck with the studs. It may be 5/16ths already so it may be a drop in fit.

THe reason these Class T fuses are in the manuals, especially for the lithium batteries, is they can deliver so much more amps so quick, they can blow lesser fuses and then the current still flows through the circuit by arcing across the gap. That is the higher AIC rating of these fuses.

When you get this figured out how you’re going to fix for the short term, perhaps for the appt in September, they can move the fuse you buy before the switch.

That underrated fuse is definitely causing you the issues. 40 amps is not good for a 2000 watt inverter for 12 VDC, 24 VDC, or 48 VDC systems.