Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×


Reply
 
Thread Tools Display Modes
 
Old 01-22-2020, 09:59 PM   #1
Bus Nut
 
jjhwick119's Avatar
 
Join Date: Dec 2017
Location: Frisco, Texas
Posts: 829
Year: 1998
Coachwork: Thomas
Chassis: International 3800
Engine: Dt466e
Rated Cap: 71
Need help with fuse / circuit breaker sizing

I've got most of my solar and electrical setup all hooked up, and I'll be finishing it this weekend once I get the proper fuses / breakers and make the last connections. This part gets confusing pretty easily so I was hoping somebody might be able to help me figure out what I need for my setup.

Here's what I got.
4x 245 watt solar panels. 2 in series, 2 in series, then paralleled together. (imp: Current at Max Power (7.6A))
40A mppt charge controller
9x nissan leaf battery modules (3 groups of 3 in series for 24v, wired in parallel for 24v battery bank)
24v 3000w inverter / charger
24 volt to 12 volt converter
30A shore plug
6 bay load center
24volt LED lights
12volt roof vent/fan
12volt water pump

I know I'll need a 30A breaker between shore power and inverter/charger
I have my breakers in the load center already wired up (20a and 15a, depending on circuit, not all of them being used but may add later)
I'll have a 12v fuse box for those 2 loads
Planned on wiring 24v LED right to the batteries with a small fuse (switches inline up front) as it's my only thing needing 24v, but I'm not sure if I should just wire those to the output of the charge controller


What i need help figuring out is the proper size fuses/breakers to put in between -
solar panels - charge controller (20A circuit breaker with disconnect option?)
charge controller - battery bank (unsure)
inverter / charger - load center (unsure)
battery bank - inverter charger (charging output current of inv/ch is 50a, so 60amp fuse/breaker?
battery bank - 24v/12v converter (converter is rated 40A, so i assumed 40a fuse/breaker)


Also, am I missing anything or is that everything I'll need?
attached is a rough sketch of my setup, and the couple pictures i took of some of the stuff

in advance. Any help is much appreciated.
Attached Thumbnails
20200122_164046.jpg   20200120_000604.jpg   20200120_202008.jpg  

__________________
https://www.skoolie.net/forums/f11/n...tml#post256987
My build thread - Started 3.2.18
jjhwick119 is offline   Reply With Quote
Old 03-06-2020, 08:37 PM   #2
Bus Nut
 
dzl_'s Avatar
 
Join Date: Jul 2019
Location: California, Bay Area
Posts: 896
As a general rule of thumb size your fuses to protect your wiring, and aim for roughly =>125% of the device/circuit max load.


The manuals for your components will often give a fuse recommendation, look there first.



Once you understand the theory of fuses/protection devices, its easier to figure out the specifics.


This thread, these links, and this video is a good place to start
dzl_ is offline   Reply With Quote
Old 03-06-2020, 09:00 PM   #3
Bus Nut
 
dzl_'s Avatar
 
Join Date: Jul 2019
Location: California, Bay Area
Posts: 896
As for specifics (with the caveat that I'm still learning too, and that my advice should be take with a grain of salt or two, and that the recommendations in your manuals are better than any advice you'll get on the internet):



solar panels - charge controller - There is disagreement on how useful a fuse is here, but a breaker or switch is advisable.

charge controller - battery bank - Check your controller documentation, for a 40a controller a 50-60a breaker sounds about right
inverter / charger - load center - Check your documentation
battery bank - inverter charger (charging output current of inv/ch is 50a, so 60amp fuse/breaker? - check your inverter/charger documentation. I suspect you would need a much larger breaker, 60-75a would work for the 50a charger but what about the inverter? My guess is that the inverter draws at least 80a maybe upto 160. Best bet here is to read the manual and follow manufacturer recommendations.
battery bank - 24v/12v converter (converter is rated 40A, so i assumed 40a fuse/breaker) - 40a fuse would be okay as long as you don't intend to ever use all 40a (which is probably smart).
dzl_ is offline   Reply With Quote
Old 03-07-2020, 06:18 AM   #4
Member
 
Join Date: Jan 2020
Posts: 60
Sent you a pm.
UnicornWizard is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 06:58 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2024, vBulletin Solutions, Inc.