Fuse/ Circuit Breaker to inverter

Jasz

Jasz

Joined
Feb 15, 2016
Posts
669
Likes collected
1,129
Location
Essex
Funster No
41,677
MH
Coachbuilt
Exp
Since April 2016
Does anyone have any recommendations for a suitable make of fuse or circuit breaker to go between the battery and inverter. In my case it's a Renogy 1000 (100A?). Hopefully a decent make would be fine regardless of size, but I have read the usual varied reviews of circuit breakers, which would be more convenient.
 
DC breakers are notorisly unreliable unless you buy decent ones which are very expensive.
Like John says a Mega or Midi fuse is the best option.
 
Jasz said:
Does anyone have any recommendations for a suitable make of fuse or circuit breaker to go between the battery and inverter. In my case it's a Renogy 1000 (100A?). Hopefully a decent make would be fine regardless of size, but I have read the usual varied reviews of circuit breakers, which would be more convenient.
Click to expand...
i understood the Renogy inverter had a fuse to already protect it and therefore any fuse is only to protect the wiring to the inverter from the battery. From memory the Renogy instructions dont show a fuse between the battery and inverter --- i am NOT saying you dont need one, just questioning .....

my 3000watt renogy inverter is less than 150mm away from my battery - i dont have a fuse - do i need one is the question?
 
MisterB said:
i dont have a fuse - do i need one is the question
Click to expand...
yes otherwise your cable in effect becomes a fuse that can light fires.


And from memory you wanted to use micro and hob at the same time MisterB , = even more important.

Subscribers  do not see these advertisements

 
Tombola said:
yes otherwise your cable in effect becomes a fuse that can light fires.


And from memory you wanted to use micro and hob at the same time MisterB , = even more important.
Click to expand...
your memory is correct LOL - i have used them both together and checked on the cable, terminals etc and they were cool, i did change up to 35mm cable - which is rated for 250A i think, when i checked the BMS on the battery, i think it said i was drawing around 130A , with them both on full power and as i said, the cables weren't hot or even warm.

but i will heed your advice and fit a fuse !!
 
MisterB said:
your memory is correct LOL - i have used them both together and checked on the cable, terminals etc and they were cool, i did change up to 35mm cable - which is rated for 250A i think, when i checked the BMS on the battery, i think it said i was drawing around 130A , with them both on full power and as i said, the cables weren't hot or even warm.

but i will heed your advice and fit a fuse !!
Click to expand...
If you strip some insulation off the cable and push it against some metalwork you will soon warm it up ;)

"wouldn't do that!" I hear you cry. Well, accidents happen - and THAT is why you fit a fuse.
 
Lenny HB said:
DC breakers are notorisly unreliable unless you buy decent ones which are very expensive.
Like John says a Mega or Midi fuse is the best option.
Click to expand...
Go Mega :) very few Midi fuse holders accept cable larger than 16mm2.

I would also avoid ANL Fuses. Most holders seem to be made of Plastics that distort at higher temps, which is not a lot of use for a high current application. Does not matter how tight and good a connection is, the local temp at a fuse holder stud can reach 100C at 200A and if the fuse holder distorts (like around 5 I have tried :( ) it is no good! I just stick to Mega Fuses now and never had similar issues.
 
so, what size is the next question. As the cable is rated at 250A should i go to 225A?
 
MisterB said:
so, what size is the next question. As the cable is rated at 250A should i go to 225A?
Click to expand...
200 max, I would probably fit a 150 amp as I doubt if you will ever use the max peak power and the inverter would probably trip anyway.

Subscribers  do not see these advertisements

 
I went for a 125A fuse as I don't expect to use more than about 60A at a time, and would need a large cable for 200A.
 
Just discovered this thread via a search and want to make sure I’ve got theirs correct.

When fitting my inverter I need to put a “mega fuse” on the live side.

I presume I don’t need to isolate the feed to the inverter as it can be switched off.
It’s a Renogy.

Also do I just wire up to one leisure battery, I have two, or out the live to one battery and the earth to the other?

Ta in advance

Lenny HB
 
If you get the din rail type yes, it will go in a box. If you get the panel mount, its secured to a panel by two m6 nut and bolt. I used the panel mount in the past, made two little brackets and attached it to a plywood battery box. You better with din type for what you need, and get a two way box.
 
Raul said:
If you get the din rail type yes, it will go in a box. If you get the panel mount, its secured to a panel by two m6 nut and bolt. I used the panel mount in the past, made two little brackets and attached it to a plywood battery box. You better with din type for what you need, and get a two way box.
Click to expand...

Can I be a pain and ask you to put a link up so I know exactly what I’m looking for.

I guess these take a reasonable size cable as the one supplied with the inverter is quite chunky ( non technical term) 😊
 
Silver-Fox said:
Can I be a pain and ask you to put a link up so I know exactly what I’m looking for.

I guess these take a reasonable size cable as the one supplied with the inverter is quite chunky ( non technical term) 😊
Click to expand...
The panel mount takes lugs, so any size cable will fit. What amperage are you looking for? Then I will link a din rail type.

Subscribers  do not see these advertisements

 
Raul said:
The panel mount takes lugs, so any size cable will fit. What amperage are you looking for? Then I will link a din rail type.
Click to expand...

You mentioned an 125A breaker earlier.

I have no idea how to work out what I need.
It was mentioned on another thread I asked on about running electrical items at around 500w as I have two 110AH batteries at the mo but will be upgrading the batteries within a year.

Hope this helps 😊
 
Raul said:
I mentioned the 125a for the OP, in your case if you expect a 500w then a 40A you just get away with, or a 60A to service up to 700w. Either one, make sure you got at least 16mm2 cable.

Outback DIN Mount Breaker 60A 150VDC

www.bimblesolar.com www.bimblesolar.com

Outback DIN Mount Breaker 40A 150VDC

www.bimblesolar.com www.bimblesolar.com
Click to expand...

Thankyou for your time and effort on this.
Unfortunately this type of stuff sails over my head on the technical side.

I’ll measure the cable that came with the inverter and post that up.

Thanks again 👍
 
I got a 1000W Renogy inverter, which I think came with 16mm cables. I changed these for 25mm cables to be on the safe side (also slightly longer). I used a 125A breaker as the cables should cope with that current.

Subscribers  do not see these advertisements

 
Jasz said:
I got a 1000W Renogy inverter, which I think came with 16mm cables. I changed these for 25mm cables to be on the safe side (also slightly longer). I used a 125A breaker as the cables should cope with that current.
Click to expand...

Did you use the type of breaker Raul is recommending?

If so what type of box does it fit into as I’ll get it all ordered.

Thanks
 
Silver-Fox said:
If so what type of box does it fit into as I’ll get it all ordered.
Click to expand...
If it's a DIN rail type of breaker, it fits on a DIN rail. That's the metal bar that you find at the back of a mains consumer unit, that all the RCDs and MCBs clip onto. They are a standard size, and should fit nicely when the box front cover is fitted. A small consumer unit box, like they use for a garage or a shower unit, will work.
www.screwfix.com

MK Sentry 4-Module Unpopulated Enclosure Only Consumer Unit - Screwfix

Order online at Screwfix.com. Empty metal enclosure with a top-hinged door ensures door is closed when unit is not in use. FREE next day delivery available, free collection in 1 minute.
www.screwfix.com www.screwfix.com
You only need a '2-module' one, as that DC breaker looks like it is 2 modules wide, but you might only be able to buy a 4-module box.. They supply blanking plates to fill the holes in a 4-module box. Ask for an 'unpopulated' box, otherwise you might get one with an RCD and MCB that you don't want.
 
Last edited:
autorouter

Thanks for the info/link.

I’m ok with home wiring and now I know it’s like house stuff alls good 👍

Time to spend 👍😊
 
autorouter Raul

Sorry to be a pain but would the item in the picture below do the job?

73081C68-F607-4F4B-9F17-BBD308F28248.png
 
The box yes, but that breaker is really pants. You can’t build a effective DC breaker for that money, it needs to have a KA rating, and test accreditation. DC arc it’s dificult to extinguish, electromagnetic contacts is needed.

Subscribers  do not see these advertisements

 

Join us or log in to post a reply.

To join in you must be a member of MotorhomeFun

Join MotorhomeFun

Join us, it quick and easy!

Join us

Log in

Already a member? Log in here.

Latest journal entries

Back
Top