Inverter Wiring Sanity Check

[taylorbourne]

Looks like I'm almost ready to start my solar setup. I'm trying to post this schematic in a few places to verify my research has been correct. I've decided that since I have a brand new generator to recharge batteries (and a 160W suitcase setup) I should first add a new battery and set up my inverter. Note – inverter is extremely important to my wife in order to watch TV at night. Wondering if I can get a quick sanity check on my wiring diagram.

The plan is to mount all of this in the pass-through of my travel trailer, with the option to add a solar controller in the future. My unit is already prepped for solar/inverter, so I've already scoped out where the pos/neg from the panels on the roof route down near the pass-through, and I'll be able to pull them in with no problem. I think the hardest part here would be to drill the hole in the floor of the pass-through to run cables back to the POS/NEG battery bus up front behind the current batteries.

Note that the Romex coming from the load center is a loop in my pass-through currently – so I'll be cutting that and routing it through the transfer switch.

For wire size I'm thinking of 12AWG Romex style from the inverter to the transfer switch, then 1/0 for the rest. Is that overkill?

Thank you! (schematic attached to this thread)

 

[Zapper77]

Looks like I'm almost ready to start my solar setup. I'm trying to post this schematic in a few places to verify my research has been correct. I've decided that since I have a brand new generator to recharge batteries (and a 160W suitcase setup) I should first add a new battery and set up my inverter. Note – inverter is extremely important to my wife in order to watch TV at night. Wondering if I can get a quick sanity check on my wiring diagram.

The plan is to mount all of this in the pass-through of my travel trailer, with the option to add a solar controller in the future. My unit is already prepped for solar/inverter, so I've already scoped out where the pos/neg from the panels on the roof route down near the pass-through, and I'll be able to pull them in with no problem. I think the hardest part here would be to drill the hole in the floor of the pass-through to run cables back to the POS/NEG battery bus up front behind the current batteries.

Note that the Romex coming from the load center is a loop in my pass-through currently – so I'll be cutting that and routing it through the transfer switch.

For wire size I'm thinking of 12AWG Romex style from the inverter to the transfer switch, then 1/0 for the rest. Is that overkill?

Thank you! (schematic attached to this thread)

Where does the charger fit in to your diagram?

 

[taylorbourne]

So the "load center" is what comes from the WFCO distribution panel converter/charger (lithium compatible). When plugged into shore power that line is hot, so that's where the transfer switch comes into play. Let me know if that helps, thanks for the reply.

 

[Zapper77]

So the "load center" is what comes from the WFCO distribution panel converter/charger (lithium compatible). When plugged into shore power that line is hot, so that's where the transfer switch comes into play. Let me know if that helps, thanks for the reply.

Add on your critical load panel, your wfco distribution panel to your diagram.

 

[Rednecktek]

It says the bus bars are outside?? Is that right? Tell me that's inside a compartment or the like, right?

Other than that it looks simple enough. One thing to avoid is the shore power probably charges the battery through the panel, so what you want to avoid is the inverter (when switched over) feeding the charger that charges the battery that feeds the inverter that powers the charger that ... and the loop goes on.

 

[taylorbourne]

Add on your critical load panel, your wfco distribution panel to your diagram.

Thanks! I'll update the diagram, you're right that's an important component.

It says the bus bars are outside?? Is that right? Tell me that's inside a compartment or the like, right?

Other than that it looks simple enough. One thing to avoid is the shore power probably charges the battery through the panel, so what you want to avoid is the inverter (when switched over) feeding the charger that charges the battery that feeds the inverter that powers the charger that ... and the loop goes on.

Haha yes, the batteries right now live outside on the tongue of the trailer – and the bus bars are on the tongue behind them (semi-covered). Here's a picture. I think my long-term plan is to re-route those bus bars to also live in the pass-through. The positive wire in the top right of this photo comes from the batteries. The negative goes into the box on the right.

Do the wiring sizes sound right? 12AWG and 1/0?

 

[Zapper77]

Thanks! I'll update the diagram, you're right that's an important component.


Haha yes, the batteries right now live outside on the tongue of the trailer – and the bus bars are on the tongue behind them (semi-covered). Here's a picture. I think my long-term plan is to re-route those bus bars to also live in the pass-through. The positive wire in the top right of this photo comes from the batteries. The negative goes into the box on the right.

Do the wiring sizes sound right? 12AWG and 1/0?

 

[taylorbourne]

View attachment 148978

This is great, thanks. Looks like 12AWG will be fine to wire up the transfer switch since it’s 110V 15A, but I think I’ll use 10AWG instead.

I think for the rest I should be using 2/0AWG since the battery discharge is 200A max. Thanks for posting that, I had seen this chart the other day but now that I’ve finished the Prowse book and circled back to my old research it makes more sense.

 

[JK14]

One thing to avoid is the shore power probably charges the battery through the panel, so what you want to avoid is the inverter (when switched over) feeding the charger that charges the battery that feeds the inverter that powers the charger that ... and the loop goes on.

@Rednecktek I am planning a similar upgrade with a battery powered inverter and manual transfer switch and thinking about this possible loop. I was planning to just turn off the AC breaker that feeds the converter when the Tx Sw is in "inverter" position and turn it back on for "shore".
Is there a way to wire the Tx Switch to do this more automatically? Or is the manual 2-switch method good enough?

 

[taylorbourne]

Okay – here’s what I have so far. I haven’t secured the disconnect switch yet as I’m contemplating moving the switch to the other side of the fuse.

So the top of the photo is the 110v AC output from the inverter, and the positive wire goes to the battery after the switch.

Not pictured here as I’m going to run them when I secure the board in the trailer is the pos/neg wires going to the trailers existing bus bars.

My only concern now is that fuse size.. it’s 200A which is correct for the inverter. That’s also the batteries max discharge rate. I’m worried that if I’m running something off the inverter then also run the DC heater this fuse will blow.. but that’s not possible since I can’t draw more than 200a out of the battery, right?

Thanks for all the help so far, glad I’m using the board method as I know I’ll eventually want to move things around. Right now the plan is to add the solar charge controller directly across from the inverter next to the bus bars.

 

[Rednecktek]

My only concern now is that fuse size.. it’s 200A which is correct for the inverter. That’s also the batteries max discharge rate. I’m worried that if I’m running something off the inverter then also run the DC heater this fuse will blow.. but that’s not possible since I can’t draw more than 200a out of the battery, right?

Yes and yes. Your battery will limit you to what it can do regardless of the fuse size, but if you parallel in more batteries later then your fuse becomes relevant again. Remember, the fuse is there to protect the wires, not the equipment. In your case it'll be a race between the fuse and the BMS if you start to overload it. You'll have to be pulling a LOT of load to do that though maxing out that inverter AND still sending 35a to the DC devices.

As for the DC heater, you should probably have another fused line off the battery to the fuse block for all the 12v stuff that's independent of the inverter fuse.

Tl;Dr: It looks fine, don't panic and leave the switch and fuse where they are.

 

[taylorbourne]

As for the DC heater, you should probably have another fused line off the battery to the fuse block for all the 12v stuff that's independent of the inverter fuse.

Tl;Dr: It looks fine, don't panic and leave the switch and fuse where they are.

Cool! Just want to make sure things are safe for the family, really appreciate it. So in the future if (when) I add another battery I should go straight off the battery terminal to the DC stuff? But for now I should be good to just go from my positive bus pictured here to the trailers positive bus (which feeds the load center, the tongue jack, etc.) Just a note, right now the way my batteries are wired there is no fusing, it goes straight back to the load center. My guess it’s properly fused on that end.

 

[Rednecktek]

So in the future if (when) I add another battery I should go straight off the battery terminal to the DC stuff?

No, take the additional batteries right to the main switch, I'm saying the positive bus bar should be fused off to the load center which sounds like how it is. You're good to go.

 

[taylorbourne]

Thanks! Glad I found this site!

 

[taylorbourne]

No, take the additional batteries right to the main switch, I'm saying the positive bus bar should be fused off to the load center which sounds like how it is. You're good to go.

By the way, what I’ve been referring to as the trailers “bus bars” are actually just the ground the frame from the neg side of my current batteries, and the positive side goes to one of those self resetting circuit breakers. So there’s my answer, it’s protected there as well. Anyway, thanks again – board went into the trailer this morning, battery is in (holy shit it’s huge) and later on I’ll drill holes and get the battery hooked up.