Sizing Wires & Breakers/Fuses

[jsmit209]

Hmmmm ?

I think yo are talkng about “parallel“ & “parallel” affects amps not volts.

They're 40a 12v chargers. I want to connect them in series to supply 40a at 24v, if that's possible and if it won't nuke my 180a standard alternator. Just not sure if it's possible or how to set up the connection.

 

[RV8R]

They're 40a 12v chargers. I want to connect them in series to supply 40a at 24v, if that's possible and if it won't nuke my 180a standard alternator. Just not sure if it's possible or how to set up the connection.

Sounds like a Promaster?

Victron has a 12v to 24v DC2DC

 

[jsmit209]

Sounds like a Promaster?

That's correct - 2015 Promaster 2500, Kansas City area

 

[RV8R]

I have built out 2 Promasters (2018) & (2021) models.

Sent you a PM “Conversation”

 

[RV8R]

FYI;

on your Solar array to Charge Controller - wired in 2s3p configuration


I would wire it for low voltage (biggest wire), but I would hook it up on the roof 3s2p or in a rough way of looking at it 60v @ 10a. Then if you have issues with shadowing you can alter the panel configuration on the roof.

Your Victron 100 | 50 ,,, 100v input max & 50a charge current max

 

[John Frum]

FYI;

on your Solar array to Charge Controller - wired in 2s3p configuration


I would wire it for low voltage (biggest wire), but I would hook it up on the roof 3s2p or in a rough way of looking at it 60v @ 10a

Your Victron 100 | 50 ,,, 100v input max & 50a charge current max

If the scc can accommodate the voltage 3s2p doesn't require fusing or a combiner box.
I don't think we've seen the panel details though.

 

[jsmit209]

If the scc can accommodate the voltage 3s2p doesn't require fusing or a combiner box.
I don't think we've seen the panel details though.

Solar Panels - In 3s2p, my only concern would be shading issues. If I understand correctly, I would essentially be creating two large panels from 6 small ones. If any part of the small panel is shaded, it would reduce the charge from the whole "large" panel.

 

[John Frum]

Solar Panels - In 3s2p, my only concern would be shading issues. If I understand correctly, I would essentially be creating two large panels from 6 small ones. If any part of the small panel is shaded, it would reduce the charge from the whole "large" panel.

Your are correct.

 

[Hedges]

• 3000w 12v inverter
• 
  
• Battery Bank to Inverter - 4/0 AWG & 250a breaker?

I believe you'll need a 300A fuse. If you're using a Victron MultiPlus II, I think Victron recommends a 400A fuse.

3000W / 12V minimum battery / 90% efficiency = 278A mean current

278A x 1.25 headroom = 347A fuse normally recommended
347A x 1.12 ripple factor = 389A fuse my recommendation --> 400A fuse

Maybe 500 MCM 90 degree wire for 400A?

Cerrowire Resources - Ampacity Charts

Ampacity is the maximum current that a conductor can carry continuously under the conditions of use without exceeding its temperature rating. Cerrowire's ampacity chart helps calculate the load requirement for a circuit.

www.cerrowire.com

The 1.25x factor is to avoid nuisance blowing, including hot environment and heating from cables.
The 1.12x factor I recommend is because battery current is not steady, will look like a rectified sine wave. Fuse is heated by RMS current, not mean current.

Battery ripple current

After reading of someone tripping battery breakers at well below rating, I realized that could be due to pulses of current drawn by the inverter. Ideally capacitors would smooth out current draw so high frequency switching pulses and 60 Hz draw all came from the caps, and current from batteries...

diysolarforum.com

Although, 3000W continuous isn't very realistic for a 12V system.
Your battery is enough to deliver that for 3 hours, so things would heat up a fair amount.
600W of PV might deliver 450W, with 6 effective sun hours will take 4 days to charge batteries back up.

24V or 48V system would be more reasonable for your loads.

I am planning to put a 2500W MSW inverter on a pickup, but it is for occasional tool use, like pipe threader.

 

[RV8R]

Solar Panels - In 3s2p, my only concern would be shading issues. If I understand correctly, I would essentially be creating two large panels from 6 small ones. If any part of the small panel is shaded, it would reduce the charge from the whole "large" panel.

Ya, but you can change it on the roof if it isn’t working to your liking.

Here is my “perfect” event on my 3s2p. 600W from 600W ?



North of the 49th Parallel ,,, Canada

 

[OffGridForGood]

Maybe 500 MCM 90 degree wire for 400A?

Or twin up smaller wire, easier to source, and work with, and find ring terminals to fit?