Hot points at anl fuses

[Kcdaniels]

My system is 12v two Lithium batteries Wired in parallel For a total of 400 amp hours Connected to a victron multiple plus 2000 inverter.

I just upgraded my wiring from 1/0 to 3/0. I'm using 200 amp anl fuse right before the inverter and another 200amp anl fuse right before the battery cut off switch..

After rewiring to the upgraded 3/0 and running a 1300 watt load for about 10 minutes the only areas of heat are right at both fuse points..

Would it be a better option to up grade these fuses to a t class fuse ? And if so what would be a recommendation for a brand ?

The pictures are before the upgrade to 3/0 wire

 

[Kcdaniels]

more pictures

 

[OzSolar]

How hot? Hotter than before you switched over?

What is the voltage drop across the fuses?

 

[Kcdaniels]

How hot? Hotter than before you switched over?

What is the voltage drop across the fuses?

Well I didn't have my temp gage with me but got hot enough when finger held for about 5 seconds? all other areas of wire were barely warm.
Will have to go back to the trailer to measure voltage drop...trailer is at storage

 

[OzSolar]

Well I didn't have my temp gage with me but got hot enough when finger held for about 5 seconds? all other areas of wire were barely warm.
Will have to go back to the trailer to measure voltage drop...trailer is at storage

Voltage drop = heat

For example .3 volts x 100 amps = 30 watts of heat concentrated in that one spot. Might be a problem, might not be.

Take the system back up to that 1300 watts and then get the total voltage drop from bat neg to inv neg. Same for positive and then look across every connection.

In my experience fuses have less voltage drop than breakers. If there's much difference between ANL and Class T I haven't noticed. Others may be able to speak to that.

 

[Kcdaniels]

Voltage drop = heat

For example .3 volts x 100 amps = 30 watts of heat concentrated in that one spot. Might be a problem, might not be.

Take the system back up to that 1300 watts and then get the total voltage drop from bat neg to inv neg. Same for positive and then look across every connection.

In my experience fuses have less voltage drop than breakers. If there's much difference between ANL and Class T I haven't noticed. Others may be able to speak to that.

Thank you for the help...heading out to the trailer now..will post results..

 

[OzSolar]

Thank you for the help...heading out to the trailer now..will post results..

Great. Take it up to 2000 watts or more while you're at it.

 

[TacomaJoe]

Looks like one battery runs through the shunt but the other doesn't. I had heat from my ANL fuses when I pulled a heavy current, I've since changed over to MRBF on the battery terminal (no heat now).

 

[Kcdaniels]

ok ran up to close to 1400 watts..
temp cool all areas except at fuse area
voltage at batteries was 12.68 v ..fuse at battery cutoff was 12 .47..
fuse at inverter was 12.02

temps at all areas except fuse areas was cool to touch..
fuse at battery cutoff was around 200 degrees Fahrenheit.
fuse at inverter was 381 !!
also noticed that inverter made more noise at 400 watts than it did at almost 1400 watts is that normal ?

all connections recheck and tight...I think it's the cheap fuses ?

measurements were made after about 20 minutes or so running load

 

[Kcdaniels]

ok ran up to close to 1400 watts..
temp cool all areas except at fuse area
voltage at batteries was 12.68 v ..fuse at battery cutoff was 12 .47..
fuse at inverter was 12.02

temps at all areas except fuse areas was cool to touch..
fuse at battery cutoff was around 200 degrees Fahrenheit.
fuse at inverter was 381 !!
also noticed that inverter made more noise at 400 watts than it did at almost 1400 watts is that normal ?

all connections recheck and tight...I think it's the cheap fuses ?

measurements were made after about 20 minutes or so running load

 

[Kcdaniels]

also shunt is showing less draw than inverter shows ? is that normal

 

[Kcdaniels]

Looks like one battery runs through the shunt but the other doesn't. I had heat from my ANL fuses when I pulled a heavy current, I've since changed over to MRBF on the battery terminal (no heat now).

should the positive wire of shunt be connected to positive of first battery instead of the positive of buss bar ?

 

[TacomaJoe]

The positive wire for the shunt can be either, but I like the buss bar location. Your shunt is only measuring what is coming out of the battery on the right. The battery on the left is connected to the negative buss bar and bypasses the shunt. Assuming the batteries are balance, the shunt would read half of what the inverter is using.

My ANL fuses were the cheap ones. Just looking at the fuse element and considering 100A flowing through it, I can imagine some heat.

 

[Kcdaniels]

The positive wire for the shunt can be either, but I like the buss bar location. Your shunt is only measuring what is coming out of the battery on the right. The battery on the left is connected to the negative buss bar and bypasses the shunt. Assuming the batteries are balance, the shunt would read half of what the inverter is using.

My ANL fuses were the cheap ones. Just looking at the fuse element and considering 100A flowing through it, I can imagine some heat.

what would be the correct connection...what should I move ?

 

[TacomaJoe]

The negative from the left battery needs to move from buss bar to the bottom terminal of the shunt. Looks like it will need a longer wire. Note that the negative from the right battery should be the same length as needed for the left battery to keep things balanced.

 

[Kcdaniels]

The negative from the left battery needs to move from buss bar to the bottom terminal of the shunt. Looks like it will need a longer wire. Note that the negative from the right battery should be the same length as needed for the left battery to keep things balanced.

Ok think I understand... Will change left battery negative to the negative of the shunt...which would be the same as where I have the negative from battery to shunt then on the load side of shunt connect to negative buss bar??
Also would these fuses be a better choice ?

 

[629658]

Ok think I understand... Will change left battery negative to the negative of the shunt...which would be the same as where I have the negative from battery to shunt then on the load side of shunt connect to negative buss bar??
Also would these fuses be a better choice ?

I used Victron mega fuses 48v 300amp. All negative connections need to go through the shunt. Class T would be more appropriate actually. You can see on my photos two 4/0 negatives from the inverter stacked on one side of the shunt on the other side of the shunt is a short flexible bus bar attached to the negative side of my main bus bar. So everything on the negative flows through the shunt. I also have the shunt power on the positive bus.

 

[mikefitz]

You fusing concept is incorrect . The fuses need to be as close as practical to the batteries and to a distribution buss bar.
The fuse protects the cable and anything on the end of the cable.
A fuse is needed in the feed to each MPPT controller, AC charger or load.
A MRBF fuse is OK for lithium at 12 volts for the main battery fuse. Class T is better with a higher withstand current at 20 k amps. MRBF is 10k amps. MEGA are only 2k amps rated, this is OK for distribution within the system but too low for a main battery fuse.
Consider MRBF with BlueSea holders directly on the battery positive.

MRBF Terminal Fuse Block - 30 to 300A - Blue Sea Systems

Easily and economically satisfies ABYC 7 circuit protection rule by mounting on a 3/8 battery post, battery switch or bus bar.

www.bluesea.com

The heating effect you are experiecing may be due to poor contact and/or low quality fuse and/holders.

For distribution fuses the Victron Lynx power in incorporate buss bars and fuse holders.

Lynx Power In - Victron Energy

Connect batteries to the Lynx DC distribution system with the Lynx Power In, a modular DC busbar. Find a dealer nearby.

www.victronenergy.com

Or fuse holders,

Fuses & fuse holders - Victron Energy

With Victron Energy's fuses and holders you can connect several fuse holders together. Find a dealer nearby.

www.victronenergy.com

Mike

 

[629658]

You fusing concept is incorrect . The fuses need to be as close as practical to the batteries and to a distribution buss bar.
The fuse protects the cable and anything on the end of the cable.
A fuse is needed in the feed to each MPPT controller, AC charger or load.
A MRBF fuse is OK for lithium at 12 volts for the main battery fuse. Class T is better with a higher withstand current at 20 k amps. MRBF is 10k amps. MEGA are only 2k amps rated, this is OK for distribution within the system but too low for a main battery fuse.
Consider MRBF with BlueSea holders directly on the battery positive.

MRBF Terminal Fuse Block - 30 to 300A - Blue Sea Systems

Easily and economically satisfies ABYC 7 circuit protection rule by mounting on a 3/8 battery post, battery switch or bus bar.

www.bluesea.com

The heating effect you are experiecing may be due to poor contact and/or low quality fuse and/holders.

For distribution fuses the Victron Lynx power in incorporate buss bars and fuse holders.

Lynx Power In - Victron Energy

Connect batteries to the Lynx DC distribution system with the Lynx Power In, a modular DC busbar. Find a dealer nearby.

www.victronenergy.com

Or fuse holders,

Fuses & fuse holders - Victron Energy

With Victron Energy's fuses and holders you can connect several fuse holders together. Find a dealer nearby.

www.victronenergy.com

Mike

I agree class T fuses are better. I used modified Victron Power Ins to fuse each battery despite the fact that each battery has a 200a breaker and the Sol Ark has breakers on each battery lead.