Recycle AC panel, chaining cables, bus bars, what's your experience

[byteharmony]

I'm going to push 275 AMPS at 48v from my batteries.

To do that I'll start with 3 trophy 100 AH batteries.

if it was just 2 I could wire each battery right to the sol ark 15k, but there's 3. Sooo a bus bar.

This video inspired me to post this question:

 

[629658]

I saw a video that had issues with Sol Ark and leg imbalances. I have had zero issues with shutdown due to L1/L2 imbalance. As a rule it’s always better to balance loads inverter or not.

 

[John Frum]

I take it the solark is rated for 12000 watts continous output.

12000 ac watts /.85 conversion factor / 48 volts low cutoff = 294.117647059 service amps
294.117647059 service amps / .8 fuse headroom = 367.647058824 fault amps.

I don't know the battery chemistry or how many batteries you have to share the draw so my answer will have to be generic.

Use a quality busbar system to implement a feeder/branch design.

Each battery should be fused as close as possible to the positive terminal and the inverter should be fused as close as possible to the start of the branch(the busbar).

For this purpose I like fused busbars.
All the fuses should be rated for the maximum voltage expected and minimum breaking capacity should be considered, especially for the battery circuits.
The fuse ampacity rating must not exceed the wire ampacity ratings.

To summarize: each battery and the inverter should all be parraleled to a common set of busbars.

 

[629658]

I take it the solark is rated for 12000 watts continous output.

12000 ac watts /.85 conversion factor / 48 volts low cutoff = 294.117647059 service amps
294.117647059 service amps / .8 fuse headroom = 367.647058824 fault amps.

I don't know the battery chemistry or how many batteries you have to share the draw so my answer will have to be generic.

Use a quality busbar system to implement a feeder/branch design.

Each battery should be fused as close as possible to the positive terminal and the inverter should be fused as close as possible to the start of the branch(the busbar).

For this purpose I like fused busbars.
All the fuses should be rated for the maximum voltage expected and minimum breaking capacity should be considered, especially for the battery circuits.
The fuse ampacity rating must not exceed the wire ampacity ratings.

To summarize: each battery and the inverter should all be parraleled to a common set of busbars.

Agreed just like this:

 

[byteharmony]

Just looked up wire prices and with the VERY short length I have to go I'm planning on running 2x 3/0 10' to a cheap bus bar:

https://www.amazon.com/dp/B09QC1MRZQ/?coliid=I4A9XLJSTJQSR&colid=1Y8EEESJWDISQ&ref_=lv_ov_lig_dp_it&th=1

Then 2 AWG to each of 3 Trophy 100ah eve batteries and to my recycled AC panel.

Fuse each right at the battery with 100a class t fuse.


The trophy's gives me the core 300 AMPS I need to be able to max out my inverter DC. I only have a 100 AMP feed from the grid so with solar, battery and maybe more solar to the generator input in the future I will be able to avoid sol ark overload with a 200 amp draw if I ever get there.

With the recycled panel I can DIY lots of different 48v battery toys that will come to pass in the years to come.

Thoughts?

 

[John Frum]

Fuse each right at the battery with 100a class t fuse.

Pure copper 2 awg wire with insulation rated to 105C insulation in free air can be fused as high as 210amps by ABYC standards.
NEC says 190amps for 90C insulation.
Putting a 100amp class-t fuse on a battery rated for 100 amps give no fuse headroom.
Suggest 150 amp fuse since the bms will be the first line of over-current defense.

 

[byteharmony]

Pure copper 2 awg wire with insulation rated to 105C insulation in free air can be fused as high as 200amps.
NEC says 190amps for 90C insulation.
Putting a 100amp class-t fuse on a battery rated for 100 amps give no fuse headroom.
Suggest 150 amp fuse since the bms be the first line of over-current defense.

Learning a lot here. Am I correct in that the fuse is just a safety net for the breaker AND bms built into the trophy? Why don't they build in a fuse?

 

[John Frum]

Learning a lot here. Am I correct in that the fuse is just a safety net for the breaker AND bms built into the trophy?

Ok so I'm gleaning that the trophy battery has a built in breaker.
If its breaking(AIC) capacity is sufficient then no supplemental over-current protection is required.

Breaking capacity - Wikipedia

en.wikipedia.org

Why don't they build in a fuse?

IMO its because newbies want breakers and think fuses are old fashioned.
A means of administrative disconnect can be handy though.

 

[John Frum]

If I were to include a class-t fuse in addition to the breaker it would mean I don't trust the breaker.

 

[629658]

Just looked up wire prices and with the VERY short length I have to go I'm planning on running 2x 3/0 10' to a cheap bus bar:

https://www.amazon.com/dp/B09QC1MRZQ/?coliid=I4A9XLJSTJQSR&colid=1Y8EEESJWDISQ&ref_=lv_ov_lig_dp_it&th=1

Then 2 AWG to each of 3 Trophy 100ah eve batteries and to my recycled AC panel.

Fuse each right at the battery with 100a class t fuse.


The trophy's gives me the core 300 AMPS I need to be able to max out my inverter DC. I only have a 100 AMP feed from the grid so with solar, battery and maybe more solar to the generator input in the future I will be able to avoid sol ark overload with a 200 amp draw if I ever get there.

With the recycled panel I can DIY lots of different 48v battery toys that will come to pass in the years to come.

Thoughts?

My original idea was 4/0 from inverter to buss bar then 2/0 from batteries to buss bar. Battery guy suggested to stay with 4/0 for everything so that’s what I did. That crap is like buying gold. I used this:

Ancor Marine Grade Primary Wire and Battery Cable https://a.co/d/06MZEVM

If you’re in the market I have a box of 2/0 I’d sell reasonably. I ordered it before I decided to go with 4/0. I’ll check but I think I have 30 ft of both red and black. I also have 5/16 “ lugs to go with it. Nice wire just not the size I went with

 

[629658]

If I were to include a class-t fuse in addition to the breaker it would mean I don't trust the breaker.

Breakers protect the batteries fuses protect the wire.

 

[John Frum]

Breakers protect the batteries fuses protect the wire.

I'm skeptical of your claim.
How would that work?

 

[byteharmony]

Ok so I'm gleaning that the trophy battery has a built in breaker.
If its breaking(AIC) capacity is sufficient then no supplemental over-current protection is required.

Breaking capacity - Wikipedia

en.wikipedia.org

IMO its because newbies want breakers and think fuses are old fashioned.
A means of administrative disconnect can be handy though.

Talked to Dan at trophy. Fantastic support btw!

He is confidant in his breaker. For the small cost of fuse I'll add it with the proposed head room.

If I were to include a class-t fuse in addition to the breaker it would mean I don't trust the breaker.

Breaker and bms, both true. I have had enough failed fancy electronics to know the value of a cheap fuse insurance policy.


I believe they also disconnect under different conditions.

My original idea was 4/0 from inverter to buss bar then 2/0 from batteries to buss bar. Battery guy suggested to stay with 4/0 for everything so that’s what I did. That crap is like buying gold. I used this:

Ancor Marine Grade Primary Wire and Battery Cable https://a.co/d/06MZEVM

If you’re in the market I have a box of 2/0 I’d sell reasonably. I ordered it before I decided to go with 4/0. I’ll check but I think I have 30 ft of both red and black. I also have 5/16 “ lugs to go with it. Nice wire just not the size I went with

I want it. I'll direct message you when I'm out of the hot tub. ?

I'm skeptical of your claim.
How would that work?

I believe it has to do the how fast class t fuses break.

Thx everyone!

Also may change from 3 trophy batteries to more. The fourth powering my lawn tractor. X more in the pontoon boat, golf cart and snow mobile ?.


Those are LOOOOONNNnnng term plans.

 

[John Frum]

He is confidant in his breaker. For the small cost of fuse I'll add it with the proposed head room.

Is "it" a fuse?

 

[John Frum]

I believe it has to do the how fast class t fuses break.

In a dead short which is the nightmare scenario, the BMS OCP will trip in microseconds.
If it fails then the breaker or fuse will trip in milliseconds.
I have not looked at the trip curves because we don't have specifics to refer to, but even then I'm not sure it would be predictable which would trip first.

 

[byteharmony]

Is "it" a fuse?

Yes, class t fuse.

More specifically, Dan recommended a fuse between the bus bar and inverter.

Wil does as well. Fyi, I think Wil miss spoke on his braker being too small. A breaker that is too small will trip faster not slower. It may not have a high enough AIC... That's the fuse purpose. He also has an oops having breakers between packs and not rack batteries. The rack batteries are each packs of batteries just like the battery packs. Add fuse for best safety.