What is 2nd breaker box for

[acoleman43]

The multiplus 2 is for a 50A two leg service (2 hot, neutral, ground). Can it be wired for just 30A one side (one hot, neutral, ground)? Having an unused open hot leg? if so it only has 3 wires in/ out for a 30A service, unless your upgrading to a 50A. You also don't show a connection from the batterys to the trailer buss bar powering the 12v side - should have a disconnect switch on that line too, 6 wag should work

Now what is the rated discharge capacity of your batterys. Most I have seen are only 100A continuous (with a few seconds surge) the Multiplus in inverter mode pulls between 250 and 300 amps when fully used, more on surge. Depending on your batterys you may need a 3rd to not exceed the discharge rating.

I have the Victron Multiplus 12/3000/120 and used 4/0 cabling, except for the batterys to my power in bar which I used 2/0.

Folks double check my thought here.

Keith

Multiplus II can have a single phase or split phase input. By using the Multiplus II you allow more flexibility for future upgrades in my opinion. When I installed my system, the Multiplus II was only available for 12v systems. Because I went with a 24v system I went with the Multiplus 24/3000/70. but NOW they have the Multiplus II for a 24v system :(

It looks like he is using Overkill BMS (missed this earlier....I do fully endorse Overkill BMS. They are excellent) on his batteries which limit continuous discharge to 120A. So max continuous discharge will be 240A (2 batteries), This may be his limiting factor in this system.

howson I was thinking the same thing. A Cerbo would be nice....but would add an additional $600-$700 because you would want the GX Touch as well (I paid the extra and got the GX Touch 70...much better and worth the extra $$).

[2by4]

Thanks for great info!

I was thinking about [maybe] to add CerboGX some time down the road, however did not put much emphasis on it. Maybe I don't understand the 'must have' of it.

CurrentConnectthat I am ordering MultiPlus from; will upgrade to latest firmware and do programing according to my specs. I understand that there is a 'cool' factor of looking at color diagrams and flow of power in and out of batteries, solar etc. but once it is setup; what is there to 'monitor' every day?

I am a techy, have built raspberry pi builds before, but I just don't get what is the need. Can someone set me straight how would this system would be beneficial to use on a daily basis?

Is screen essential or CerboGX setup with a phone is essentially the same thing?

[ncitro]

2by4 It's key if you want monitoring when away from the rig. The Cerbo (or PI) allow connecting the device to the VRM portal so you can access the system and view status, change settings, or update firmware remotely. Also that's where you set your shore power for power assist. They do make an inverter control if you are not getting a Cerbo for just setting your shore power, but I always felt it was a waste to spend that money if you were going to be getting a Cerbo at some point anyway.

https://battlebornbatteries.com/prod...caAvyAEALw_wcB



If you're familiar with pi already, I think my pi with touchscreen rubbing Venus OS I had just over $100 into.

[2by4]

2by4 It's key if you want monitoring when away from the rig. The Cerbo (or PI) allow connecting the device to the VRM portal so you can access the system and view status, change settings, or update firmware remotely. Also that's where you set your shore power for power assist.

Found couple of pi3's in storage; one of them still with Emby install on SD card, also a usb wifi and a spare 32GB card. It appears I need an mk3-usb to connect pi to MPII. Thank you for the great tip! I'll check it out once I am more or less done on this main project.

MPII is coming on Saturday; better start ordering wires.

Now what is the rated discharge capacity of your batterys. Most I have seen are only 100A continuous (with a few seconds surge) the Multiplus in inverter mode pulls between 250 and 300 amps when fully used, more on surge. Depending on your batterys you may need a 3rd to not exceed the discharge rating.

Each BMS is 120A continuous discharge with 130A surge - at max it can provide 240A / 2880W, MPII is max 2400W; that should be enough as BMS would be at 82% max when MPII is maxed out.

[Country Campers]

Another nice thing about the Cerbo GX and the Touch 50 is that it can be seen by anyone in the RV with out having to log into an App, easier for the wife to know what is going on or let me know what is going on if there is an issue. I do not have any wifi or such in our RV so that is not a help or even needed at this time. Also I do not even look at the Victron Connect app for any information, unless I am sitting outside the RV and am bored. You will like the ease of the Multiplus 2. I would double check the settings when you get it, just to make sure that it is exactly what you need for your system.

Brian

[acoleman43]

Thanks for great info!

I was thinking about [maybe] to add CerboGX some time down the road, however did not put much emphasis on it. Maybe I don't understand the 'must have' of it.

CurrentConnectthat I am ordering MultiPlus from; will upgrade to latest firmware and do programing according to my specs. I understand that there is a 'cool' factor of looking at color diagrams and flow of power in and out of batteries, solar etc. but once it is setup; what is there to 'monitor' every day?

I am a techy, have built raspberry pi builds before, but I just don't get what is the need. Can someone set me straight how would this system would be beneficial to use on a daily basis?

Is screen essential or CerboGX setup with a phone is essentially the same thing?

I wanted the Cerbo GX Touch so I can see a visual monitor while using the trailer, and so I have a place to tweak settings. I am also using the programmable relays of the Cerbo and wanted the VRM available to me. Future plans are to attach new tank sensors to the Cerbo (Via the GX Tank 140) for black, grey and fresh water, and for propane level sensors. That way I can have all my data in one location.

I also have a Lynx Shunt that I'm able to see/use via the Cerbo. And, if time/money permits, I will convert the trailer to a split phase 50A and add an additional Multiplus for split phase operation. The Cerbo makes setup easier in my opinion.

But, adding that to your system is an additional $600-$700. It's gotta be worth it to you to drop that kind of money.

[2by4]

For DC wiring from Multiplus to distribution panel I would go with 4 awg.

I had to spend some time digesting this info and I am a bit confused about this - Multiplus II does not have DC out to distribution panel, it is just AC 120V out to WFCO WF-8955PEC-GE
Am I missing something in between or do I just run directly 4 AWG cable from batteries to DC bus on WFCO bus bar?

For AC I would look at something different than romex. I used romex and it wasn't the easiest to use in my installation - something like the Southwire flexible SOOW. I would go with 12/2 or 10/2. The larger the wire, the less voltage loss and heat....

Thank you for recommendation; will get 10/2 SOOW wire at local hardware store by the foot.

[howson]

2by4
The Multiplus is an inverter/charger. Or you could say it's an inverter/converter. Since the Multiplus is connected to the battery bank those 12vDC connections serve as both as an input from the batteries (for inverting) and also an output (to charge batteries and/or provide 12vDC to the camper).

Does that help?

[2by4]

Thank yo howson it definitely helps; to confirm on converter disconnect and which wires to run.


1. Disconnect the converter for 120V side:
A:black wire from "Converter" circuit breaker
B: neutral (white)
C: ground.
2. Disconnect converter from DC fuse side:
A: white
B: red
3. Run from Multiplus/batteries 4AWG wire:
A: red
B: black
4. Should the other 2 wires be disconnected from DC fuse side:
A: black
B: red

[howson]

2by4

Disconnecting the OEM converter is easy. Turn off the breaker. Put a sticker over it (DO NOT TURN ON!) . Leave all the wires as they are so it will be easy to fire it back up upon the (slim!) chance the Multiplus fails or the trailer is sold (and you remove the Multiplus).

How the Multiplus is wired into the trailer depends on how you want it to power the system. Without an overall schematic showing how you intend to incorporate the Multiplus I'm hesitant to endorse the plan outlined in your previous post.

WondersAwait has an amazingly well done wiring diagram. See https://gdrvowners.com/forum/operati...lectrical-mods

If you want your mind blown, my rat's nest of a diagram is here: https://gdrvowners.com/forum/operati...lts-f-350-mods

Others have posted diagrams, too, but my mind is not firing on all cylinders rights now (tired).

Perhaps the diagrams below may help (or may just confuse you). The intent is to convey how my trailer was changed from the OEM configuration to what it is today (focused just on the +DC side).

The 120vAC side is an entirely different conversation.

[2by4]

Disconnecting the OEM converter is easy. Turn off the breaker. Put a sticker over it (DO NOT TURN ON!) . Leave all the wires as they are so it will be easy to fire it back up upon the (slim!) chance the Multiplus fails or the trailer is sold (and you remove the Multiplus).

How the Multiplus is wired into the trailer depends on how you want it to power the system. Without an overall schematic showing how you intend to incorporate the Multiplus I'm hesitant to endorse the plan outlined in your previous post.

My plan was to disconnect WFCO converter and leave it in place; that's why I was planning to use 3A and 3B directly from batteries. I was just not sure about what are 4A and 4B (too much snow to get to RV now).


As for chassis power, I am not modifying anything there - from lithium positive 6AWG will go exactly to same spot on a bus bar where it was before.



Updated diagram.

[acoleman43]

I had to spend some time digesting this info and I am a bit confused about this - Multiplus II does not have DC out to distribution panel, it is just AC 120V out to WFCO WF-8955PEC-GE
Am I missing something in between or do I just run directly 4 AWG cable from batteries to DC bus on WFCO bus bar?




Thank you for recommendation; will get 10/2 SOOW wire at local hardware store by the foot.

Sorry about the misinformation. Howard is correct. Batteries go directly to distribution panel (through a fused connection). I think I got ahead of myself

[acoleman43]

Thank yo howson it definitely helps; to confirm on converter disconnect and which wires to run.


1. Disconnect the converter for 120V side:
A:black wire from "Converter" circuit breaker
B: neutral (white)
C: ground.
2. Disconnect converter from DC fuse side:
A: white
B: red
3. Run from Multiplus/batteries 4AWG wire:
A: red
B: black
4. Should the other 2 wires be disconnected from DC fuse side:
A: black
B: red

4a and 4b should be +/- from batteries. No need to do anything with those.

For converter/charger, howson is correct, you can just flip the breaker. Knowing me (or my wife) I would flip is back on at some point not realizing what I did. I would disconnect either AC or DC side just to be safe. But that's up to you.

[acoleman43]

My plan was to disconnect WFCO converter and leave it in place; that's why I was planning to use 3A and 3B directly from batteries. I was just not sure about what are 4A and 4B (too much snow to get to RV now).


As for chassis power, I am not modifying anything there - from lithium positive 6AWG will go exactly to same spot on a bus bar where it was before.



Updated diagram.

This is how I would do it.

[Yoda]

Thank yo howson it definitely helps; to confirm on converter disconnect and which wires to run.


1. Disconnect the converter for 120V side:
A:black wire from "Converter" circuit breaker
B: neutral (white)
C: ground.
2. Disconnect converter from DC fuse side:
A: white
B: red
3. Run from Multiplus/batteries 4AWG wire:
A: red
B: black
4. Should the other 2 wires be disconnected from DC fuse side:
A: black
B: red

UGGGGGGGGG

Your converter is wired the same as mine was. . Take a look at this thread where I disconnected mine and trace the wires back. https://gdrvowners.com/forum/solar/5...-don-t-mess-up Sorry for the long read..
Do not touch 2a and 2b. You can leave them without any issue. There are two black (hot) wires connected to the breaker (wire nut). I left one attached (not the one from the converter) as I could not determine where it went. Then disconnected the ground (green) and negative return (white) and leave the rest in place just in case of failure. Be sure to wire nut and tape the wires you disconnected. Doing this would make it easy to reconnect if needed. No issues so far.
Hope this helps

Try and remember Murphy and the Kiss law.... Kip it simple.......Stu... I have learned this lesson many times here Mostly due to Howard, Jim, and Rob

Hoping to help
Keith