Budsy
New Member
This is my first system and I need to know what fusing is nessisary for a 4 x 100w panels with 4 100 ah agm batteries and 30 amp charge controller and a 1500 watt pure sine wave 24 volt inverter. Thanks
75a to inverter
Need more specs for panels (voltage, series/parallel config, if you plan on an inspection)
So am I correct in my calculation that with75a to inverter
Need more specs for panels (voltage, series/parallel config, if you plan on an inspection)
No just 2 batteries in each of the series packs and I won’t be needing any DC fuse block as this system is for my shopThere really are several power systems running in parallel in a system like this.
Battery pack A ---- breaker ---- main bus bar
Battery pack B ---- breaker - main bus bar
Inverter ---------------------main bus bar ( some like to put a T fuse or breaker on this line )
Fuse block ----- breaker ----main bus bar
If you wanted, you could use an 80 or 90 amp breaker in each location for commonality and do the bulk of the wiring with 2 awg.
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Most fuse blocks can handle 30 amp loads and chargers per fuse position, so you can just run the solar charge controller into the fuse block
For the solar charge controller fuse, ( 400 watts of solar ) / (nominal 28 volts charging conditions ) ~ 14 amps under perfect conditions.
Most likely you will use 10 awg wire for this and it is rated for 30 amps, so you can fuse at 20 or 30 amps and be just fine.
If you do the bulk of your wiring with 10 awg, then many of the fuses can be 20 amp or 30 amp ( you can pick a common size for spares vs having a bunch of sizes )
I have built a number of setups like this - very straightforward and reliable.
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Your 2 Series , 2 parallel setup from 4 each, 100 amp-hr batteries
Battery pack A is ( 100 amps - hrs ) x ( 24 volt ) ~ 2400 watt-hrs
Same for pack B
Sorry. I get it now. Do you know where I can find a wiring diagram that allows you to plug in the values of your components and it will give you fusing and wire gauge’s nessisary?No just 2 batteries in each of the series packs and I won’t be needing any DC fuse block as this system is for my shop
No just 2 batteries in each of the series packs and I won’t be needing any DC fuse block as this system is for my shop
Sorry. I get it now. Do you know where I can find a wiring diagram that allows you to plug in the values of your components and it will give you fusing and wire gauge’s nessisary?
I was thinking of getting a Victron battery protect for between the battery and inverter. Would the 100 amp model work for that? And would it go before or after the positive buss bar? ThanksThe next step is to select a breaker for the wires that go from battery pack A to the bus bar.
A common breaker for this is this one from bus
187-Series - Blue Sea Systems
Thermal circuit breakers provide heavy duty circuit protection for 25 to 200 Amp loads when switching and circuit protection are both required.www.bluesea.com
It is a thermal breaker, so you can think about it like a fuse that trips when it gets hot from too much current flowing through it, but has a re-set handle so that you don't need to get the tools out to change it.
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Since there are two parallel battery packs, then each one would need to carry ~ 50% of the load.
( 50% ) x ( 100 amps ) ~ 50 amps
The wire ampacity from the chart is ~ 100 amps
So now you have the option to choose a breaker really anywhere between 50 and 100 amps to make it all work and to some extent, it does not really matter.
There is a small amount of resistance in the breaker and that is what is determining the amps trip point, so going to the bare minimum can result in the breaker running a bit warm, so I would pick at least 1/2 way in between - so ~ 75 - 80 amps minimum.
If you plan to put a breaker in between the bus bar and the inverter and use 2 awg, then the right size would be to go 100 amps as that is the max load.
I like to buy common sizes and ratings for things, as this provides a way to just buy one size and have things as self spares, so as common as possible.
The breaker and fuse are to protect the wire in case it comes loose and does a dead short basically - that sets the absolute max rating.
The end device might not be capable of handling the current that the wire can, for instance a fan might only use 1 amp and require it to be fused at 5 amps.
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I am still drinking morning levels of coffee, so hopefully others will check my work and suggest edits.
Thank you so much. Very helpful. I’m actually building two systems, one the 4 agm 100ah’s 4x 100w panels and my little trailer build with 2 100ah lithium iron and 1 395 w panel. Both 24 voltThe next step is to select a breaker for the wires that go from battery pack A to the bus bar.
A common breaker for this is this one from bus
187-Series - Blue Sea Systems
Thermal circuit breakers provide heavy duty circuit protection for 25 to 200 Amp loads when switching and circuit protection are both required.www.bluesea.com
It is a thermal breaker, so you can think about it like a fuse that trips when it gets hot from too much current flowing through it, but has a re-set handle so that you don't need to get the tools out to change it.
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Since there are two parallel battery packs, then each one would need to carry ~ 50% of the load.
( 50% ) x ( 100 amps ) ~ 50 amps
The wire ampacity from the chart is ~ 100 amps
So now you have the option to choose a breaker really anywhere between 50 and 100 amps to make it all work and to some extent, it does not really matter.
There is a small amount of resistance in the breaker and that is what is determining the amps trip point, so going to the bare minimum can result in the breaker running a bit warm, so I would pick at least 1/2 way in between - so ~ 75 - 80 amps minimum.
If you plan to put a breaker in between the bus bar and the inverter and use 2 awg, then the right size would be to go 100 amps as that is the max load.
I like to buy common sizes and ratings for things, as this provides a way to just buy one size and have things as self spares, so as common as possible.
The breaker and fuse are to protect the wire in case it comes loose and does a dead short basically - that sets the absolute max rating.
The end device might not be capable of handling the current that the wire can, for instance a fan might only use 1 amp and require it to be fused at 5 amps.
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I am still drinking morning levels of coffee, so hopefully others will check my work and suggest edits.