2800bh battery, inverter, & solar upgrade

[mchinnas]

Hi All,

I’m a fairly new member here as I recently purchased a new to us 2022 Imagine travel trailer that I intend to upgrade for solar and inverter. I’ve read through many posts and learned a ton from everyone’s comments so far – much of which are incorporated into my work below. Rather than post questions and ask for feedback in many other existing threads, I hope you don’t mind if I cover all my aspects in this new thread. My intent is to do an electrical upgrade to my trailer to make it usable for a fairly specific need (extended boon docking). I've tried to organize everything in a logical manner but apologize in advance for how lengthy this has made things.

My knowledge and abilities:
• Was a mechanical engineer with early career in factory automation systems. So, I understand electrical and communications but get less confident when it comes to things like inductive vs. resistive power, grounding and ground loops, system energy losses, and wire connections.
• I have most of the tools needed but expect to purchase a high-quality thick gauge wire cutter and a crimper (suggestions appreciated!)
• This is our third RV with a Class C and a Class A unit owned previously.

My Trailer and Needs:
• Our new to us trailer is a 2800bh with the basic 165W solar package, 25amp charge controller, single lead acid battery, and standard WFCO charge converter. The unit does have two A/C’s and is set up for 50A shore power but does not have an inverter.
• We will be placing the trailer on some land we own in Virginia (no utilities) for the foreseeable future. We want to place the trailer in a shady area but have a clearing close by with sunlight most of the day.
• I have a 3200W generator but want to limit how much I run it. Perhaps 1-2 hrs a day to do high energy things like vacuum, run the A/C before bedtime, and recharge batteries (not all at once).
• My energy audit says that I need 2800-3000 watts a day.

The Plan:
• I want to convert to lithium, add an inverter, and utilize portable ground placed solar panels. The panels can be placed in the clearing and I can adjust their angle and azimuth to optimize solar collection.
• I haven’t yet decided on the panels but have been looking at Renogy 200W and HQST 190W ones that I would place in a 2S2P arrangement for 800W total.
• Most of the equipment would be Victron and the batteries would be either Epoch or SOK (see ? below).
• I’ve created some as-is and proposed layouts in the attached. Some things like disconnects, fuses, and comms are not included to keep it readable. All wires will be sized based on length and current flows to minimize losses and heating.
• Note that I plan to keep the existing PV, charge controller, and battery to power the tongue jack and break away switch. So anything currently connected directly to the existing battery will be maintained and anything that is fed from the panel will be switched over to the new system.

System Questions:
• It's hard to tell how my panel is wired. There are too many wires to be sure of things. I’ve attached a pic of the electrical schematic on the back of the panel cover. For those familiar with these systems and electrical details, I'm hoping you can clarify something: It looks like my charge converter feeds directly to the 12V panel and then a wire goes from the panel to the battery. I don't see a wire from charge converter directly to the battery. I assume this isn't necessary as current can flow either way through the panel; i.e. panel to battery to charge battery when on shore power and battery to panel when off-grid?
• My schematic shows a negative line from the battery to the 12V negative bus bar (top left in attached schematic) as well as a negative line from the battery to the 12V ground bus bar (middle right). But it also seems to indicate a jumper between the negative and ground bus bars. All this is the same for the charge converter. I’m trying to figure out why this is or perhaps I am mis-interpreting the schematic?
• Hard to tell where all my existing chassis grounds are. What is best practice here? Should I just connect new grounds to the frame where close and convenient to the component or should I try to consolidate into an existing ground point?
• One battery option is Epoch 12v - 460ah battery with built in Victron comms. I’m assuming this will negate the need for a shunt and it looks like the battery will ‘tell’ the Multiplus its status. The alternative is two SOK 280ah batteries with a Victron 1000amp shunt. Other than the additional 100ah, some thinner wiring, and the option to go 24v with the SOK’s, are there any other pros and cons?
• Can/should I repurpose the 12v wire from batteries to the charge converter over to feed the 12v panel from the new inverter or should I install new 6AWG lines?
• I don’t see a lot of comment or pictures on running the lines from storage bay to electrical panel. Is it simply a matter of dropping the Coroplast and zip tying the new lines (in a flexible split sleeve) up against some existing ones?
• I don’t have an idea of who makes quality wiring and lugs. Any recommendations? When crimping lugs onto wires, is it best practice to use some sort of wire treatment to improve the connection prior to crimping?

I’m sure I’ll have many other questions as I embark on this project. Would really appreciate answers to my questions along with any comments on my plan that you may have.

Thanks in advance!!!
MHC

[Soundsailor]

First off, it looks like you're pretty new here, welcome to the forum. It sounds like you have a pretty good grasp of what you're doing. I'd suggest leaving the existing solar on its own and using a separate solar charge controller for your proposed array (look at residential panels, way cheaper for the output). And while you might get by on the 250 Ah you cite as your energy budget, once you get started you'll be glad you went with more, The two SOC 24-volt batteries you cite should do quite nicely.

[mchinnas]

First off, it looks like you're pretty new here, welcome to the forum. It sounds like you have a pretty good grasp of what you're doing. I'd suggest leaving the existing solar on its own and using a separate solar charge controller for your proposed array (look at residential panels, way cheaper for the output). And while you might get by on the 250 Ah you cite as your energy budget, once you get started you'll be glad you went with more, The two SOC 24-volt batteries you cite should do quite nicely.

Thank you!

I did notice a design flaw in my system. I need to connect the shore power directly to the inverter via a bus bar in the panel and a new (6/4) line running up to the inverter in the storage bay. Then I need to run another line (6/4) back from the inverter to the panel. With my old design, I would end up with a hot 50A shore power plug. Not a good thing if I had the inverter on when I connected up to shore power!!!