Reply
 
Thread Tools Display Modes
 
Old 04-12-2018, 02:06 PM   #1
Mini-Skoolie
 
Join Date: Oct 2017
Posts: 10
Question Solar/Electrical System Review For A Learning Newbie

First Off I am a bit of a lurker, but want to say thank you to everyone who contributes to this site. I have spent many a night here reading peoples post. I have been doing my electrical system research for my bus, but I know NOTHING about electrical systems. I have bought a book "Mobile Solar Power Made Easy" per someones suggestion here and it has helped a ton. I have also read many a blog posts about the electrical system in R.V's and Skoolies. I am ready to begin purchasing my equipment, but want to be sure that I know what I am getting into first. I would really appreciate a lookover by some people who have gone to electrical battle and have emerged victorious!!

Thank You to everyone who looks at this in advance

I have calculated my electrical needs as follow
*edit* my table did not get formatted how I wanted it. I hope its not too hard to read.

| Appliance | Hrs Used per day | Wattage | Voltage | Watt Hours per day |
----------------------------------------------------------------------------------
| Fridge | 4 Hours | 65W | 110V | 260 W |
|WaterPump| 1 Hour | 36 W | 12 V | 36 W |
| Lights | 4 Hours(6) | 8.5W | 120V | 204W |
| LED Strips | 4 Hours(20ft) | 2.6W(ft)| 12V | 208W |
| Chargers | 2 Hours | 60W | 120V | 120W |
| Fan | 6 Hours | 60W | 12V | 360W |

Total Watt Hours: 1188 W per day
Watt Hours *2*2 = 4752 for 2 days no sun and <50% discharge on batteries

QUESTION 1: Does this seems like a fair assumption on power consumption? Or have I over/underestimated something with wattage?

I have created a wiring diagram That I think will work, but am unsure if I am missing any critical components for my solar system. I am also unsure if I have the correct gauges for each component. I have labeled the parts that I think have correct and have marked where I am less sure with ?.#

QUESTION 2: Have I missed anything critical in my system
QUESTION 3: Could someone help me with the gauge wires I need for ?.1-4
QUESTION 4: Does my "power" selection of components make sense in my system?
Attached Images
File Type: png Screen Shot 2018-04-12 at 3.05.35 PM.png (125.1 KB, 50 views)
travelgravel is offline   Reply With Quote
Old 04-12-2018, 09:36 PM   #2
Mini-Skoolie
 
gzimmerman372's Avatar
 
Join Date: Feb 2017
Location: Blacksburg, VA
Posts: 48
Year: 2003
Coachwork: Thomas
Chassis: Ford E450
Engine: 7.3L (Navistar T444E)
I too am no expert but from what I've read I think your Charge Controller should be 40amp because your two panels being 19amp each combined would be 38amp exceeding a 35amp max. (Unless you were to wire the panels to bring in 24v which then you would have to step down to the 12v batteries which wouldn't have any benefit)

Also, dont both + and - from Controller go to the batteries? Your diagram shows + out of Controller to a 50amp fuse to a 250amp fuse.
gzimmerman372 is offline   Reply With Quote
Old 04-12-2018, 09:38 PM   #3
Mini-Skoolie
 
gzimmerman372's Avatar
 
Join Date: Feb 2017
Location: Blacksburg, VA
Posts: 48
Year: 2003
Coachwork: Thomas
Chassis: Ford E450
Engine: 7.3L (Navistar T444E)
Also the controller should have a load connection too which would be what leads to the 12v fuse block and the inverter.

Again, this is completely from what I think I've come to understand, someone else who knows better than I, correct anything that is wrong.
gzimmerman372 is offline   Reply With Quote
Old 04-13-2018, 04:59 AM   #4
Bus Nut
 
ComfortEagle's Avatar
 
Join Date: Dec 2017
Location: Southern Maryland
Posts: 346
Year: 1986
Coachwork: Gillig
Chassis: Phantom
Engine: Cat 3208/Allison MT643
Quote:
Originally Posted by travelgravel View Post
First Off I am a bit of a lurker, but want to say thank you to everyone who contributes to this site. I have spent many a night here reading peoples post. I have been doing my electrical system research for my bus, but I know NOTHING about electrical systems. I have bought a book "Mobile Solar Power Made Easy" per someones suggestion here and it has helped a ton. I have also read many a blog posts about the electrical system in R.V's and Skoolies. I am ready to begin purchasing my equipment, but want to be sure that I know what I am getting into first. I would really appreciate a lookover by some people who have gone to electrical battle and have emerged victorious!!
I am no solar SME (subject matter expert), and I look forward to seeing responses from our resident experts.

In the meantime I too have been working to get smarter for my pending install, and I may be able to help a little...

You may want to consider a fuse or circuit breaker in between your panels and the charge controller. Along those lines, using circuit breakers in lieu of fuses could give you on/off switches as well as over current protection.

Will you be building in capability for generator and/or shore power?

A couple of inexpensive displays like these: for AC, for DC could provide some visual peace of mind as to the state of your system.

As for wiring sizes, once you choose your inverter, the inverter manual should provide recommendations for fusing and wire size for battery to inverter (?.2 and ?.3).

The below tables are from the Magnum MS series inverter/charger manual.




Quote:
Originally Posted by gzimmerman372 View Post
I too am no expert but from what I've read I think your Charge Controller should be 40amp because your two panels being 19amp each combined would be 38amp exceeding a 35amp max. (Unless you were to wire the panels to bring in 24v which then you would have to step down to the 12v batteries which wouldn't have any benefit)
I may be mistaken but I believe the 19A the OP is referencing is the combined open circuit current (Isc) for his panels.
__________________
Rick <>< - Comfort Eagle (Bird Strike) - Solar/Batteries - Seat - Door - Dash - Mini Split - Fuse Box - Wood Stove
ComfortEagle is offline   Reply With Quote
Old 04-13-2018, 06:31 AM   #5
Bus Crazy
 
joeblack5's Avatar
 
Join Date: Dec 2015
Location: pa
Posts: 1,419
Year: 98
Coachwork: 1. Corbeil & 2. Thomas
Chassis: 1 ford e350 2 mercedes
Engine: 7.3 powerstroke & MBE906
It looks good enough, For the fuse between the panels and charge controller I use normal automotive fuses , they are a lot cheaper. If you expand with more strings then each string should have it own fuse.

For me the most important thing missing is a proper battery gauge with shunt resistor like a trimetric or other brand.

That is the only instrument that can tell you if you battery is full or what SOC it has. Next to that you might want to get a acid density tester that also will tell you how your battery health and charge is doing.

Good luck
later J
joeblack5 is offline   Reply With Quote
Old 04-13-2018, 08:21 AM   #6
Site Team
 
JDOnTheGo's Avatar
 
Join Date: Feb 2017
Location: The West
Posts: 977
Year: 1998
Coachwork: MCI
Chassis: 102 EL3
Engine: DD 60
Quote:
Originally Posted by travelgravel View Post
I have spent many a night here reading peoples post. I have been doing my electrical system research for my bus, but I know NOTHING about electrical systems.
It appears that your efforts are paying off! Good work!!

It appears you are wiring your solar panels in series. Is this on purpose? I would think that parallel would be a better option.

I agree with the other comments about cleaning up the fuse connections and wire gauge info. There are a bunch of 12VDC voltage drop charts online (calculators as well).

Quote:
Originally Posted by travelgravel View Post
QUESTION 1: Does this seems like a fair assumption on power consumption? Or have I over/underestimated something with wattage?
Its difficult to know without specifics but nothing appears grossly underestimated. The refrigerator is usually the most difficult is very dependent on the make/model/size/conditions.

Quote:
Originally Posted by travelgravel View Post
QUESTION 2: Have I missed anything critical in my system
Agree with what the others have said (good battery monitor and shore power). Once you add shore power (transfer switch of some sort or get an inverter with the switch built in) you may want to add a charger/converter. This somewhat confusing title is simply a battery charger that runs off 120VAC shore power and keeps your batteries charged while also supplying whatever 12VDC needs exist. It is certainly NOT mandatory. I don't have one as my solar keeps my batteries charged just fine.

Quote:
Originally Posted by travelgravel View Post
QUESTION 4: Does my "power" selection of components make sense in my system?
I'm not exactly sure what you are asking here. Nothing looks crazy, if that's what you mean.
__________________
JD - Full timer out west
Missy - 1998 MCI 102-EL3 - 1.7kW Solar - 10kWh Lithium
My Adventures & Build
JDOnTheGo is offline   Reply With Quote
Reply

Tags
electrical, solar, wiring

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 08:50 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2019, vBulletin Solutions, Inc.