Reply
 
Thread Tools Display Modes
 
Old 10-16-2020, 03:18 PM   #1
New Member
 
Join Date: Aug 2018
Posts: 4
Question My wiring diagram! How'd I do?

Hey guys, I just finished up my first version of my wiring diagram. I was wondering if I could get some feedback before purchasing some things. Let me know what you think!

Some concerns I'm unsure of:
1. Can the MPPT, bus bars and inverter all be connected to the same terminals on the battery? Is there an issue with charging the batteries and using them simultaneously?
2. Did I ground correctly?
3. Is it a good idea to have a fuse between the MPPT and battery? I'm concerned if it blows, then MPPT might ruin since there's will be no battery attached.

Please let me know how I did, I'm hoping to start this here soon! Thanks guys
Attached Images
File Type: jpg IMG_7413.jpg (221.4 KB, 59 views)
bradryannelson is offline   Reply With Quote
Old 10-17-2020, 12:33 AM   #2
Bus Nut
 
dzl_'s Avatar
 
Join Date: Jul 2019
Location: California, Bay Area
Posts: 668
Quote:
Originally Posted by bradryannelson View Post
1. Can the MPPT, bus bars and inverter all be connected to the same terminals on the battery? Is there an issue with charging the batteries and using them simultaneously?

Electrically Yes, but it would be best to make all or most of these connections off the battery (at the busbars) and just have one or two connections to the actual terminals. This isn't strictly necessary, more of a best practice (minimizing connections at the battery terminals, and also a bit tidier, there are other marginal benefits).



Quote:
Originally Posted by bradryannelson View Post
2. Did I ground correctly?

Grounding can be complicated, but in this case it looks fairly straightforward. Consult your inverter documentation, the inverter chassis is probably supposed to be grounded to the negative busbar or the vehicle-chassis ground point.



Quote:
Originally Posted by bradryannelson View Post
3. Is it a good idea to have a fuse between the MPPT and battery? I'm concerned if it blows, then MPPT might ruin since there's will be no battery attached.

From what I understand, this was more of a theoretical potential problem than a real issue, but your charge controller documentation would take precedence over my general understanding (which I know to be true of Victron, and I believe to be true of Epever, but not sure about others). Many controller manufacturers recommend a fuse or breaker.


I will look closer at the diagram in a bit. One thing that jumps out at me is some of your wiring is undersized relative to the fuse size (can also be thought of in reverse) which is not safe. In order to know if your wire is properly sized its necessary to know what insulation temperature rating the wire is.
dzl_ is online now   Reply With Quote
Old 10-17-2020, 02:05 PM   #3
New Member
 
Join Date: Aug 2018
Posts: 4
Quote:
Originally Posted by dzl_ View Post
Electrically Yes, but it would be best to make all or most of these connections off the battery (at the busbars) and just have one or two connections to the actual terminals. This isn't strictly necessary, more of a best practice (minimizing connections at the battery terminals, and also a bit tidier, there are other marginal benefits).






Grounding can be complicated, but in this case it looks fairly straightforward. Consult your inverter documentation, the inverter chassis is probably supposed to be grounded to the negative busbar or the vehicle-chassis ground point.






From what I understand, this was more of a theoretical potential problem than a real issue, but your charge controller documentation would take precedence over my general understanding (which I know to be true of Victron, and I believe to be true of Epever, but not sure about others). Many controller manufacturers recommend a fuse or breaker.


I will look closer at the diagram in a bit. One thing that jumps out at me is some of your wiring is undersized relative to the fuse size (can also be thought of in reverse) which is not safe. In order to know if your wire is properly sized its necessary to know what insulation temperature rating the wire is.
Multi-quote doesn't seem to work for me so I'm just gonna reply.

Originally, I opted against using the bus bars for all my connections because they are limited to 250A and I wanted to accommodate a worst-case scenario of a maxed out 12v system and maxed out 120v system. I realize now that's unrealistic lol. I'll move everything to the bus bars.

Based on some people feedback from reddit, it looks like I'll be grounding the negative bus bar. Good suggestion as well.

I'll have to do more digging to see what my documentation says but it seems like everyone puts a fuse anyways... hmm.

Also, I used this chart to pick my wire gauges. Are you referring to the size from the batteries to the bus bars? Now that my design changed a bit, I'm thinking I'll use 4/0 AWG.

Thanks for all the feedback, this has been super helpful!!
bradryannelson is offline   Reply With Quote
Old 10-18-2020, 02:11 AM   #4
Bus Geek
 
Join Date: Sep 2015
Posts: 3,554
Year: 2002
Coachwork: Thomas Built Bus
Chassis: Freightliner FS65
Engine: Caterpillar 3126E Diesel
Rated Cap: 71 Passenger- 30,000 lbs.
Another quick note: In your diagram you show you will use 6V 225aH batteries as a 12V 550aH bank. That should be a 12V 450aH bank.
Native is offline   Reply With Quote
Old 10-18-2020, 01:54 PM   #5
New Member
 
Join Date: Aug 2018
Posts: 4
Originally, I was trying to accommodate a worst-case scenario where the inverter was maxed out (4000W ~333A) and all my DC electronics on (119.5A). Those together would've been bigger than the 250A rating of a bus bar. Now I realize that scenario is extremely not probable lol. I'll use the bus bars.

I'll also take a look at the inverter documentation. But as of now, with your help and the help of others, I'll ground the negative bus bar.

Thanks for your reply! Its been helpful
bradryannelson is offline   Reply With Quote
Old 10-18-2020, 01:55 PM   #6
New Member
 
Join Date: Aug 2018
Posts: 4
Talking Oops

Quote:
Originally Posted by Native View Post
Another quick note: In your diagram you show you will use 6V 225aH batteries as a 12V 550aH bank. That should be a 12V 450aH bank.
Lol classic. Noted, thank you
bradryannelson is offline   Reply With Quote
Old 10-18-2020, 05:02 PM   #7
Bus Nut
 
dzl_'s Avatar
 
Join Date: Jul 2019
Location: California, Bay Area
Posts: 668
Quote:
Originally Posted by bradryannelson View Post
Originally, I was trying to accommodate a worst-case scenario where the inverter was maxed out (4000W ~333A) and all my DC electronics on (119.5A). Those together would've been bigger than the 250A rating of a bus bar. Now I realize that scenario is extremely not probable lol. I'll use the bus bars.
This is a reasonable consideration. I generally try to plan for worst case scenarios as well, or at least realistically plausible worst cases.

In this case you could either (1) get a higher amperage busbar (busbars are just fancy bars of copper, they can definitely exceed 250A if you find the right one (they can get pricey though unless you DIY), or (2) Connect everything other than the inverter to the busbar but have the inverter connected directly to the busbar.


Quote:
I'll also take a look at the inverter documentation. But as of now, with your help and the help of others, I'll ground the negative bus bar.
If this is in response to my recommendation to consult the inverter documentation re: grounding guidance, bear in mind that there are two aspects of grounding here, 'system grounding' and 'equipment grounding'.

System ground (in this context) = the point at which DC negative and 'ground' (in this case the "chassis-ground" connection).

Equipment grounding = connecting the (not normally energized) metal chassis' of electrical components to a common point, usually the negative busbar and/or a dedicated grounding busbar that is tied to the negative battery terminal and chassis-ground

Below is an image from Victron depicting a somewhat typical, simple, off-grid system, which shows both the equipment and system grounding connections (teal and pink text/lines are mine, everything else is original schematic):


Attached Images
File Type: png Screenshot_2020-10-18 Wiring-Unlimited-EN pdf.png (247.7 KB, 46 views)
dzl_ is online now   Reply With Quote
Old 10-23-2020, 07:17 PM   #8
Bus Nut
 
dzl_'s Avatar
 
Join Date: Jul 2019
Location: California, Bay Area
Posts: 668
Took me a while to get around to reviewing the schematic. A couple things that jump out at me:


Green: Your Inverter Documentation Most likely requires or suggest that the designated grounding lug be connected to DC negative and/or the Chassis Ground point. (Green is just an example of what may be the recommended grounding method)


Yellow: I think you are cutting it kinda close using 6 AWG for 100A fuse blocks with 100A breakers. Depending on several factors (ambient temp, insulation rating of the wire, if conduit is used) 6 AWG can handle just above or just below 100A. If it were me I would either bump it up to 4 AWG, or use smaller 80A breakers.


Red: You cannot use a 250A fuse with 6 AWG (well you can but it won't provide protection) and you cannot use 6 AWG for a circuit expected to carry up to 120A.


If you are sure 120A is the max for the DC main circuit, you could use a 150A or 200A fuse but you want to use larger gauge wire, at least 90*C 2 AWG with a 150A fuse, maybe 90*C 1/0 AWG with a 200A fuse.


dzl_ is online now   Reply With Quote
Old 10-23-2020, 07:33 PM   #9
Bus Nut
 
dzl_'s Avatar
 
Join Date: Jul 2019
Location: California, Bay Area
Posts: 668
One more thing I just noticed, the fuse between the charge controller and PV panels is unnecessary.


HOWEVER


You don't detail what your array looks like, but based on the numbers I suspect it is at least 3 panels in parallel. If this is the case, it is likely you need to fuse each parallel panel individually. This is only the case when three or more panels are put in parallel.


If you have an even number of panels it is also worth considering putting panels in series pairs, and then putting the pairs in parallel. MPPT controllers do a bit better with some amount of positive voltage difference between PV array and Battery.




Also, could you explain how the Dual Switch is being utilized. I think I understand what you are doing there, but don't want to make assumptions.
dzl_ is online now   Reply With Quote
Old 10-24-2020, 10:17 AM   #10
Bus Nut
 
Join Date: Apr 2018
Location: NorCal
Posts: 386
Year: 1995
Coachwork: Girardin
Chassis: E-350
Engine: 7.3L Powerstroke
Are you planning on having a battery monitor system? If so, this requires a shunt, which typically goes along the negative line right off the battery. I'm not saying I have done it the right way, but what I did was connect the positive post of my battery pack directly to a 60 amp ANL inline fuse, and then the other side of that fuse connects directly to the inverter/charger and MPPT (which then has an output for the DC load). The negative post of my battery pack is connected directly to the shunt, and the other side of the shunt is connected directly to the inverter/charger and MPPT. The shunt's positive line is powered from the ANL fuse (with a smaller automotive fuse for protection). Just something to consider.
TheArgobus is offline   Reply With Quote
Reply

Tags
diagram, electricity, inverter, 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 05:51 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
×