Battery and buss bar settings

[Joehebbo]

I have 4 battery lifepo4 youth power 4x 100 ah in parallel 48v on an inverter deye 8kw and pv of 6500w system … my question is i am using buss bar i want to know if it s correct, my buss bar is copper 40 cm x2.5 cm and thickness or 0.5 cm i have a 125 amps breaker for the battery even they have beakers on each one … as long i am new in solar and i want to see how much i can go max charge and discharge and stay safe
Some pics for more clearness

 

[Luxpower_Gilbert]

you need a thicker busbar.

 

[Joehebbo]

you need a thicker busbar.

How much thicker should be… and anything else is ok?

 

[Luxpower_Gilbert]

If you run high load, at least 5 mm thick. The thicker the better to prevent heat..

 

[Joehebbo]

If you run high load, at least 5 mm thick. The thicker the better to prevent heat..

My batteries max max reach 22-23 cells temp but in lithium it s normal in charging reach 25 what do u think about charge discharge how far i can go and stay in safe side

 

[John Frum]

my buss bar is copper 40 cm x2.5 cm and thickness or 0.5 mm

I hope you don't actually mean .5mm

25 mm * .5 mm = 12.5mm2
which is good for 80 to 100 fault amps
80 fault amps * .8 fuse headroom = 64 service amps

 

[Joehebbo]

I hope you don't actually mean .5mm

25 mm * .5 mm = 12.5mm2
which is good for 80 to 100 fault amps
80 fault amps * .8 fuse headroom = 64 service amps

Yes 25mm and thickness 0.5mm sorry im not a technical i’ am a rookie who made his own system can you explain more about fault amps 0.8 fuse headroom = 64 ??

 

[John Frum]

Yes 25mm and thickness 0.5mm sorry im not a technical i’ am a rookie who made his own system can you explain more about fault amps 0.8 fuse headroom = 64 ??

.5 mm is approximately as thick as aluminum foil.
But that is what you have affirmed.

I estimate that the maximum fault ampacity for your busbar is 80 amps.
80 amps * .8 fuse headroom = 64 continuous amps.

That means the largest continuous current you should plan to put through the busbar is 64 amps.
That gives 16 amps of safe margin before the fuse blows.
In practice its a bit more but that is the logic.
Put another way, those 16 amps of saftey margin are factored so that your fuse doesn't incur nuisance trips.

 

[Joehebbo]

.5 mm is approximately as thick as aluminum foil.
But that is what you have affirmed.

I estimate that the maximum fault ampacity for your busbar is 80 amps.
80 amps * .8 fuse headroom = 64 continuous amps.

That means the largest continuous current you should plan to put through the busbar is 64 amps.
That gives 16 amps of safe margin before the fuse blows.
In practice its a bit more but that is the logic.
Put another way, those 16 amps of saftey margin are factored so that your fuse doesn't incur nuisance trips.

0.5 thickness true

.5 mm is approximately as thick as aluminum foil.
But that is what you have affirmed.

I estimate that the maximum fault ampacity for your busbar is 80 amps.
80 amps * .8 fuse headroom = 64 continuous amps.

That means the largest continuous current you should plan to put through the busbar is 64 amps.
That gives 16 amps of safe margin before the fuse blows.
In practice its a bit more but that is the logic.
Put another way, those 16 amps of saftey margin are factored so that your fuse doesn't incur nuisance trips.

I neer to put max charge 50 amps to 100 and discharge 60-100 amps that s why i am asking if i should go for thicker buss bar and i am not using fuses i am using 125 breaker on the bus bar

 

[John Frum]

0.5 thickness true

I neer to put max charge 50 amps to 100 and discharge 60-100 amps that s why i am asking if i should go for thicker buss bar

Yes you should go to a thicker busbar.

 

[John Frum]

My vision is bad but those busbars look ~3mm thick.
If they are 3mm by 25mm then you are good for 300 amps.

 

[Joehebbo]

Yes you should go to a thicker busbar.

10 mm or 20 mm copper is better

 

[John Frum]

10 mm or 20 mm copper is better

20 mm, studs can be up to 13mm diameter.

 

[Joehebbo]

My vision is bad but those busbars look ~3mm thick.
If they are 3mm by 25mm then you are good for 300 amps.

0.5mm x 25 mm and length 400 mm i just check it by the tape

 

[John Frum]

0.5mm x 25 mm and length 400 mm i just check it by the tape

the length doesn't really matter to the ampacity, the product of the other 2 dimensions determine the ampacity.
.5 mm copper may deform when the fasteners are torqued down.

 

[John Frum]

Could you please post a close up shot of the busbars with a measuring device for scale.

 

[Joehebbo]

the length doesn't really matter to the ampacity, the product of the other 2 dimensions determine the ampacity.
.5 mm copper may deform when the fasteners are torqued down.

I have my my solar system 6500w and my battery size 400 ah im using them for home and my work shop so i might use high current so that s why it s better to purchase another bussbar 20 mmm thickness or i ll buy another 15 mm copper and adding to my available copper

 

[Joehebbo]

Could you please post a close up shot of the busbars with a measuring device for scale.

I will tomorrow because we are in different time zone im +3 and its night here so tomorrow i ll post it

 

[Joehebbo]

Could you please post a close up shot of the busbars with a measuring device for scale.

Sorry sorry my mistake im confusing between cm and mm ohhh it s the fatigue i use here cm and m in my country so i didn t convert well sorry 2.5cm x 0.5 cm = 25 mm x 5 mm copper sorry again = 125 mm2

 

[John Frum]

Sorry sorry my mistake im confusing between cm and mm ohhh it s the fatigue i use here cm and m in my country so i didn t convert well sorry 2.5cm x 0.5 cm = 25 mm x 5 mm copper sorry again = 125 mm2

That busbar is good for ~450 fault amps.
Make sure that the joinery is properly flat and clean with alchohol.