Batteries fuse disconnects and the like

[Isetech]

So once again lots of confusion, where do you install busbars, fuses and switch disconnects for batteries for inverters.

If you have one battery 100 amp/hr, its simple you fit a fuse disconnect with a 125 amp fuse, using a 25 mm fine stranded battery cable designed fot the application.

If you have you 2 x 100 amp/hr batteires and 1 x inverter: Then you can to connect them in cascade parallel using the same 25 mm cable (because most lithium 100 amp/hr batteries only have 25 mm terminals) connected to a 160 amp fuse disconnect with 125 amp fuses and all is good. Or you could just connect both batteires to a 200 amp fuse disconnect and a 50 mm battery cable from the fuse disconnect to the inverter.

Now we move onto 3 batteries with 1 inverter, this is where it gets a little more complicated, now you have 3 batteries, some will say it fine you just run a 25 mm cable from each battery to a bussbar, connect the busbar to the inverter using bigger cable 50/70 sqmm. The question some will ask, what protects the cable from the battery to the fuse switch disconnect, the reason you are a fuse is to protect the cables, how do you protect the cable from the battery to the 200 amp fuse? You could once again connect the batteries in cascade parallel (like the cabinet batteires) and take the leads at the end and connect all 4 (2 red and 2 black) to the 200 amp fuse.

Wall mounting lithium batteires is an expensive installation method, if you plan to fit more than 2.

Mabye use a Vitctron busbar bar with fuse protection, a 100 amp fuse would protect the battery cable, but what about a double pole disconnect ? Why do you need one.

To throw a spanner in the works, if the terminals are like sosket outlets and you can just unplug them why the double pole switch disconnect, why not just fuse protection?

On some batteries the teminals are closed with the a cover which requires a tool to remove the cover to access the terminals.

[Actrox]

So once again lots of confusion, where do you install busbars, fuses and switch disconnects for batteries for inverters.

If you have one battery 100 amp/hr, its simple you fit a fuse disconnect with a 125 amp fuse, using a 25 mm fine stranded battery cable designed fot the application.

If you have you 2 x 100 amp/hr batteires and 1 x inverter: Then you can to connect them in cascade parallel using the same 25 mm cable (because most lithium 100 amp/hr batteries only have 25 mm terminals) connected to a 160 amp fuse disconnect with 125 amp fuses and all is good. Or you could just connect both batteires to a 200 amp fuse disconnect and a 50 mm battery cable from the fuse disconnect to the inverter.

Now we move onto 3 batteries with 1 inverter, this is where it gets a little more complicated, now you have 3 batteries, some will say it fine you just run a 25 mm cable from each battery to a bussbar, connect the busbar to the inverter using bigger cable 50/70 sqmm. The question some will ask, what protects the cable from the battery to the fuse switch disconnect, the reason you are a fuse is to protect the cables, how do you protect the cable from the battery to the 200 amp fuse? You could once again connect the batteries in cascade parallel (like the cabinet batteires) and take the leads at the end and connect all 4 (2 red and 2 black) to the 200 amp fuse.

Wall mounting lithium batteires is an expensive installation method, if you plan to fit more than 2.

Mabye use a Vitctron busbar bar with fuse protection, a 100 amp fuse would protect the battery cable, but what about a double pole disconnect ? Why do you need one.

To throw a spanner in the works, if the terminals are like sosket outlets and you can just unplug them why the double pole switch disconnect, why not just fuse protection?

On some batteries the teminals are closed with the a cover which requires a tool to remove the cover to access the terminals.

Why can't we use 125A DC Double Pole circuit breakers instead of fuses and fuse holders?

[GCE]

Why can't we use 125A DC Double Pole circuit breakers instead of fuses and fuse holders?

Be careful using DC circuit breakers - the majority are polarized meaning you can only feed through in one direction and they are not suitable for charging and discharging that you have associated with batteries - Read the small print

[Actrox]

Be careful using DC circuit breakers - the majority are polarized meaning you can only feed through in one direction and they are not suitable for charging and discharging that you have associated with batteries - Read the small print

Yes correct. But if you use bi directional circuit breaker, would that be correct?

[Justloadit]

Yes correct. But if you use bi directional circuit breaker, would that be correct?

or connect the breaker in series with the second terminal and the return would be on the same side as entry. This off course would require a 4 pole breaker

[Isetech]

I see many people are choosing top leave out the double pole disconnector at each batterry, just fitting abusbar and one fuse disconnect at the inverter.

The question you need to ask before you do this, does the battery have build in overload protection?

The cable from the battery is normally only 25/35 sq mm, the fuse a 200 amp fuse with a 50 mm wire from the fuse holder to the inverter, which means beside the double pole isolator, the 25 mm cable is not protected.

My thought are rather use a Victron power link and fuses for each battery.

I have noticed Victron dont use double pole battery isolator. disconnects.

[Thys LOW Elektries]

I have also seen a number of installations with no fuse installed for disconnect since "each battery has a breaker of its own"

Not sure how safe is it to use those breakers but I believe a disconnect fuse must still be used