Can I run multiple fused 24-12 step-downs from a single 24v distribution panel?

slipperysam

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Joined
Feb 2, 2021
Messages
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This setup seems intuitive to me, but there are areas where my understanding is lacking (e.g. isolation?), so I want to verify my plan makes sense. I have a 24V battery bank and plan to run mostly 12V appliances, but some 24V as well. I'd like to have a single Lynx Distributor fuse going to a 24V distribution panel. From there, I'd like to have fused circuits running 24-12 stepdowns to their own 12V distribution panels. I've attempted (keyword!) to draw this and have it attached.

The drawing is horrible, so I'm also including an example:
Code:
Lynx fused at 100A
  -> BlueSea fuse blade
    -> 10A fuse to 24v fridge
    -> 25A fuse to 24-12 50A output
      -> BlueSea fuse blade
        -> 10A fuse to 12v fan
        -> 10A fuse to 12v fan
        -> 5A fuse to 12v lights
    -> 10A fuse to 24-12 20A output
      -> BlueSea fuse blade
        -> 15A fuse to 12v water pump
        -> 5A fuse to 12v lights

Does this make sense? Or, is there some reason why the 24-12 converters would need to be wired directly back to the Lynx?
 

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FilterGuy

What, me worry?
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It should work but do you really need 100A of 12V?

Looking at your text description, it looks like you only need 50A Converter.

-> 10A fuse to 12v fan
-> 10A fuse to 12v fan
-> 5A fuse to 12v lights
-> 15A fuse to 12v water pump
-> 5A fuse to 12v lights
------------------------------------
45A Total....Assuming each fuse is run at 100% of its rating. If each item is fused correctly, the total current will be 45A x .8 = 36A.
My guess is the above items will use 30A or less in real life.
 

rmaddy

Full-time Solar-powered Trailer Life
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Interesting thought. In my 24V system I connected my 24V-12V converter directly to the bus bars (with a proper fuse), not the 24V fuse panel. So that would be equivalent to your 24-12 converter going through your Lynx, not the 24V fuse box.

I think the downside of going through the 24V fuse box is you need more fuses in the 24V fuse box and you need a bigger fuse in the Lynx for the 24V fuse box since it will also be handling all of the 12V loads in addition to all of the 24V loads.

Of course if you connect the 24-12 converter to the Lynx you need another available slot in the Lynx.

In the end it will work either way.
 

slipperysam

New Member
Joined
Feb 2, 2021
Messages
22
It should work but do you really need 100A of 12V?

Looking at your text description, it looks like you only need 50A Converter.

-> 10A fuse to 12v fan
-> 10A fuse to 12v fan
-> 5A fuse to 12v lights
-> 15A fuse to 12v water pump
-> 5A fuse to 12v lights
------------------------------------
45A Total....Assuming each fuse is run at 100% of its rating. If each item is fused correctly, the total current will be 45A x .8 = 36A.
My guess is the above items will use 30A or less in real life.
Sorry yeah the examples were a bit arbitrary in terms of amperage, mainly my question was just does the overall structure make sense. In reality, it will probably be something like a 30A converter and a 20A converter, etc.
 

slipperysam

New Member
Joined
Feb 2, 2021
Messages
22
Interesting thought. In my 24V system I connected my 24V-12V converter directly to the bus bars (with a proper fuse), not the 24V fuse panel. So that would be equivalent to your 24-12 converter going through your Lynx, not the 24V fuse box.

I think the downside of going through the 24V fuse box is you need more fuses in the 24V fuse box and you need a bigger fuse in the Lynx for the 24V fuse box since it will also be handling all of the 12V loads in addition to all of the 24V loads.

Of course if you connect the 24-12 converter to the Lynx you need another available slot in the Lynx.

In the end it will work either way.
True, but small ~ 25A fuses are extremely cheap, and if this lets me get away with only using one Lynx distributor, it's a big cost savings!
 
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