Lithium & Solar upgrade wiring question

[mfginc]

I am going to be using Victron Multiplus II with the Lynx distribution. I am basically following the wiring diagram from Explorist.life. My question is when wiring for the 12 volt system, I plan to connect the Lynx to my original busbar where the original battery connected but, I don't know if I need to run a negative line from the Lynx to the main fuse box or can I just run it to the nearby ground location where the original battery negative was located(on the chassis). The chassis location is also where I would attach the main negative for the Lynx Thanks in advance for any help

[Redapple63]

I am going to be using Victron Multiplus II with the Lynx distribution. I am basically following the wiring diagram from Explorist.life. My question is when wiring for the 12 volt system, I plan to connect the Lynx to my original busbar where the original battery connected but, I don't know if I need to run a negative line from the Lynx to the main fuse box or can I just run it to the nearby ground location where the original battery negative was located(on the chassis). The chassis location is also where I would attach the main negative for the Lynx Thanks in advance for any help

First, welcome to the forum!

Here is what I intend to do. Just connect the neg and pos that used to go directly to the batteries to your new pos and neg buss bars, then connect your new or relocated batteries to the next terminal on the same buss bars. Good to go.

Bill

[mfginc]

Thank you, Bill.
That is the same concept I was following. I'm just not 100% clear on grounding vs negative rules for a 5th wheel and the setup using the Lynx distribution. So do all negative & ground wires end up at the chassis? I will have battery/shunt negative, 12v fuse box negative, and equipment ground all routed to a negative busbar then to chassis. Does that sound right?

[Redapple63]

Thank you, Bill.
That is the same concept I was following. I'm just not 100% clear on grounding vs negative rules for a 5th wheel and the setup using the Lynx distribution. So do all negative & ground wires end up at the chassis? I will have battery/shunt negative, 12v fuse box negative, and equipment ground all routed to a negative busbar then to chassis. Does that sound right?

GM,

You already have ground to chassis in place.
When you connect the ground from “Loads” to your bus bar, it is already going to chassis ground, so your other negative wires just go to your new negative on your Lynx. You could run another, but it would be redundant. Both the pos and neg from your old batteries run to buss bars.

Good Luck!
Bill

[jproctor9]

Thank you, Bill.
That is the same concept I was following. I'm just not 100% clear on grounding vs negative rules for a 5th wheel and the setup using the Lynx distribution. So do all negative & ground wires end up at the chassis? I will have battery/shunt negative, 12v fuse box negative, and equipment ground all routed to a negative busbar then to chassis. Does that sound right?

I'm not 100% clear on your plan. A diagram might help. However in order for the shunt to work properly, it will need to be between the battery and all other connections.

Battery (-) -> Shunt -> Lynx Dist (-) ->

Attaching a picture of my Lynx Dist in case helpful. From left to right with wire sizes...

Battery (+/-) and Chassis (-) 4/0
Multiplus II (+/-) 4/0
Case Ground for Multiplus (-) 4/0
Smartsolar MPPT (+/-) 4awg
DC Loads (+/-) 4awg


Battery (+) comes from battery thru BlueSea disconnect switch.

Battery (-) comes from battery thru Victron shunt.

DC Loads (+) wire is routed thru OEM disconnect switch and to DC distribution center. This could probably be routed to chassis bus bar, but I wanted a clean path for DC loads. I did make sure that brake power comes off OEM switch (in addition to DC distribution center) with its own wire (which is already present because it was previously the OEM battery +).

DC Loads (-) is connected directly to the DC distribution center. This could probably be routed to chassis bus bar, but I wanted a clean path for DC loads.


I have noticed significant improvement in slide function with properly sized wires to the DC distribution center. It's my belief that the 8awg wires used in my rig created undesirable voltage drop impacting the slide motors.

Hope this helps a bit.

[Butcher]

Like all electrical systems, the higher the load [current] the shorter the leads I would want.

I look at the entire system and plan accordingly. My largest consumer is the 3k inverter and therefore, that inverter is as close to the buss bars as possible. That is the ground and the power bars. I have two 304ah batteries and those are fairly close to the buss bars. The rest of the 5th wheel is not as important since the loads are not that extreme.

The inverter cable is 4/0 and about 1 foot in length. Batteries are 2/0 that are maybe 2 feet at most. Converter, is 2ga and about 3 feet.

[Redapple63]

Thank you, Bill.
That is the same concept I was following. I'm just not 100% clear on grounding vs negative rules for a 5th wheel and the setup using the Lynx distribution. So do all negative & ground wires end up at the chassis? I will have battery/shunt negative, 12v fuse box negative, and equipment ground all routed to a negative busbar then to chassis. Does that sound right?

Hi mfginc,

Let me clarify a bit more. Your Lynx Distributor has both + and - built in. On the plus side there is the solar input, the inverter input, the battery input and finally, the dc loads. There are fuses and switches between those connections to protect the wiring.
On the negative side you have the shunt and then the negative buss bar. Same set of inputs to those connections.

Note specifically the positive and negative to your dc loads will go through what used to be the connections ton your batteries. It is those connections that go to the dc load (distribution center) and chassis ground via the disconnect switch.

You should be fine doing it that way.

Bill

[mfginc]

Thank you to everyone for the solid advice! I feel like I'm on the right track but let me explain in better detail what I hope to do...

I will have my shut placed first between the batteries and to the busbar. I plan to run 4/0 cable for negative/ground from the load side of the shut. As shown in this drawing:
This is a picture of my current battery location & busbar. The Blue circle was the location of my battery pos and the green was the location of the neg:


I plan to have a negative busbar (ground to the chassis) that will join the 4/0 cable from the top of the shunt(show above) along with the equipment ground from the multiplus II and the dc loads neg coming from the Lynx distribution. My assumption is that the remaining black wire shown in the green circle above is the current dc loads negative so I will attach my busbar at that location. Does this make sense?

Thanks again for the help.

[edontheroad]

I installed a VMP II in my old rig with three BattleBorn batteries and a distribution busbar. You are correct. One negative from the VMP II to the chassis and one negative from the busbar to the chassis. You should not need to run a negative to the RV's 12v distribution box.

[edontheroad]

While we are discussing Victron's MP Il, I also have an install question.

I am installing a Victron MultiPlus II and BattleBorn batteries in my 2022 Solitude 390RK. I have installed all the equipment (But t, I have not connected it to the rig's system yet). This rig has a separate OEM inverter/charge (it is not an all in one 120v/12v distribution/fuse panel/inverter).

The OEM inverter/charger has four 4/0 wires coming out of it. A negative going to the chassis and three positives; one going to the OEM 120v/12v distribution/fuse panel and two to unknown locations. I believe I have to connect Victron to the OEM 120v/12v distribution/fuse panel in order for the Victron to invert 12v to 120v when not in shore power

Can someone explain how/where I connect the Victron MP II besides the batteries? I do know one positive goes from the Lynx distribution busbar to OEM buss bar that runs to the 12v side of the OEM distribution/fuse panel.

Any guidance would be much appreciated.

Sorry if my description l/question is confusing.