What's a quality fuse and holder to use inline with the battery connection? Mine is getting HOT at half the rated amperage!

[ricardocello]

ANL fuses are rated to 80V.

Most ANL sold anywhere are rated to 32V to handle 12/24V systems.

A much smaller number of them are rated to 80v and are ignition protected.
Victron, Bussmann, maybe a few others.
Then there is the issue of finding a holder also rated for 80v.

A relevant thread from 3 years ago:
https://diysolarforum.com/threads/class-t-vs-anl-fuse.13913/

 

[Gentleman Mike]

I'm still getting the T fuse, but just out of curiosity, my 5 parallel rack batteries each have a 125 amp breaker built in. Theoretically, this should prevent arcing inside an ANL fuse in the case of some kind of catastrophic failure, right? They are wired into a fully enclosed bus bar, and from there a short (1 ft) wire goes to the fuse holder.

I actually had an electrician install my transfer switch and other stuff and mount everything on the wall just because I didn't want to deal with that hassle. He also wired up the batteries while he was there.

The guy was using 6 AWG wire for everything despite me telling him the inverter is rated to draw up to 220 amps from the batteries. I said something along the lines of "I think we should have a fuse or breaker here?" and he said "the manual doesn't call for one so I won't do that".

I also wanted to use a bus bar, but same thing. "The manual doesn't say to use one" and he just paralleled them directly to each other since the batteries have two binding posts on + and -.

He also refused to use a resistor when initially connecting the inverter positive terminal to prevent a spark. Can you guess the reason?

Needless to say, as soon as he was gone, I started rewiring the batteries and I'll never use him again. Will just call a local solar installer if I need more work done on this that I can't handle myself. Someone who actually has experience with these inverter systems. Mainly just wanted him for the main electrical panel and transfer switch wiring to make sure it meets code.

 

[Supervstech]

I'm still getting the T fuse, but just out of curiosity, my 5 parallel rack batteries each have a 125 amp breaker built in. Theoretically, this should prevent arcing inside an ANL fuse in the case of some kind of catastrophic failure, right? They are wired into a fully enclosed bus bar, and from there a short (1 ft) wire goes to the fuse holder.

I actually had an electrician install my transfer switch and other stuff and mount everything on the wall just because I didn't want to deal with that hassle. He also wired up the batteries while he was there.

The guy was using 6 AWG wire for everything despite me telling him the inverter is rated to draw up to 220 amps from the batteries. I said something along the lines of "I think we should have a fuse or breaker here?" and he said "the manual doesn't call for one so I won't do that".

I also wanted to use a bus bar, but same thing. "The manual doesn't say to use one" and he just paralleled them directly to each other since the batteries have two binding posts on + and -.

He also refused to use a resistor when initially connecting the inverter positive terminal to prevent a spark. Can you guess the reason?

Needless to say, as soon as he was gone, I started rewiring the batteries and I'll never use him again. Will just call a local solar installer if I need more work done on this that I can't handle myself. Someone who actually has experience with these inverter systems. Mainly just wanted him for the main electrical panel and transfer switch wiring to make sure it meets code.

Um... #6 to the batteries?

Shut off your system now,!

 

[Gentleman Mike]

Um... #6 to the batteries?

Shut off your system now,!

I fixed that as soon as he left.

He would only use the cables that came with the batteries which were 6 AWG (batteries are rated 50 amp continuous) despite me already having purchased larger gauge lol.

He was a weird guy. I think he was just really out of his element with an inverter system, but he should have at least known that 6 is way too skinny.

He also thought using the resistor to prevent a spark was a bad idea because he somehow thought that would increase the amperage/current and said something about ohm's law. Baffling. I've designed circuits before so I'm not a total idiot when it comes to electricity, it's just that high voltage and current things like this are not something I ever work with so I wanted a "pro" in case I were to make a mistake doing it all myself.

All of his work in the main panel and transfer switch looked good though, I felt I needed to double check after all of that.

 

[chrisski]

I fixed that as soon as he left.

He would only use the cables that came with the batteries which were 6 AWG despite me already having purchased larger gauge lol.

Will you leave him a 5 star review and use him for your next electrical work?

 

[Gentleman Mike]

Will you leave him a 5 star review and use him for your next electrical work?

lol man... he was personally nice enough, so I'm not going to leave any review at all because it would be... a bad one.

 

[rhino]

ANL fuses are rated to 80V. Nothing wrong with using one in a 48V system.

As @Supervstech said it is the ability to extinguish an arc. Class T fuses have much higher interrupting capacity then ANL fuses which may be critical when dealing with lithium batteries especially larger battery banks. Blue Sea has a nice chart that shows this:

http://assets.bluesea.com/files/resources/reference/Quick_Guide_to_Blue_Sea_Systems_Fuses_and_Fuse_Holders.pdf

 

[JWLV]

I fixed that as soon as he left.

He would only use the cables that came with the batteries which were 6 AWG (batteries are rated 50 amp continuous) despite me already having purchased larger gauge lol.

He was a weird guy. I think he was just really out of his element with an inverter system, but he should have at least known that 6 is way too skinny.

He also thought using the resistor to prevent a spark was a bad idea because he somehow thought that would increase the amperage/current and said something about ohm's law. Baffling. I've designed circuits before so I'm not a total idiot when it comes to electricity, it's just that high voltage and current things like this are not something I ever work with so I wanted a "pro" in case I were to make a mistake doing it all myself.

All of his work in the main panel and transfer switch looked good though, I felt I needed to double check after all of that.

Maybe he's a AC guy and doesn't know too much about DC. Or he was just plain lazy and didn't want to do anything extra.

 

[Gentleman Mike]

Maybe he's a AC guy and doesn't know too much about DC.

This I think.

He said I'd never be drawing anywhere near 50 amps from the batteries, but think he didn't consider the fact that if the inverter is putting out 50 amps 120VAC then that's 125 amps plus whatever extra from inefficiencies from the 48 volt batt bank.

 

[Sennen]

If you ever use him again, let him know that this is just my charge cycle from solar going into the batteries... I've only once used more amperage than this on outgoing, so that's much harder to find. (When I took the Sol-Ark 15K and my batteries for its test run at 14KW)

 

[Alarchist]

As @Supervstech said it is the ability to extinguish an arc. Class T fuses have much higher interrupting capacity then ANL fuses which may be critical when dealing with lithium batteries especially larger battery banks. Blue Sea has a nice chart that shows this:

http://assets.bluesea.com/files/resources/reference/Quick_Guide_to_Blue_Sea_Systems_Fuses_and_Fuse_Holders.pdf

That and a T class is a 'semiconductor' fuse, which can act quickly enough to hopefully protect the inverter.

Personally I went for NH type fuse disconnectors which are also high AIC rated, but not as fast as T class.

I also have quite a decent solar charge current as it's a 25.6v system, I noticed 266A the other day and the sun is still low in the sky here, but I use 70mm2 / 2/0 AWG cable for each battery not 6 AWG / 16mm2!