Travel trailer Lithium & Solar upgrades Safety Check

Mkwirsch

New Member
I am a new member planning my first system and have been pouring through this site which I find to be incredibly helpful. I have a small travel trailer that I want to upgrade to Lithium batteries and solar for boondocking. The existing power center is a 30 amp WFCO 8735 which, based on research, is not an ideal charger for lithium batteries. I am tight on space so hoping to get by with a single 200ah lithium battery so need to get full charge. Given my basic power needs (lights, fan, furnace fan, rare microwave use) the calc's show this should work.

Given my current power center limitations I intend to install a new shore power battery charger and a new DC to DC charger to charge while driving. My goal is to leave the existing power center in place and use as an AC breaker and DC fuse distribution panel only. I will disconnect and leave the original charger in place. I have growing kids so in a few years will likely upgrade to a larger trailer and want to take these added components out and return trailer to original OEM set-up.

I have modified Will’s Classic 400 watt system to add the two chargers…I went this route over the Renogy DC-DC with MPPT because of the low solar voltage limit that unit has.

System components:
  • SOK 200 ah lithium battery (1)
  • Progressive Dynamics 12V 30-Amp Battery Charger
  • Renogy 20 amp DC to DC Charger
  • 60 amp MPPT solar charge controller
  • 2200 watt pure sine wave controller for laptops and occasional microwave use. Will manually plug in microwave here when needed. All else runs off DC or LP gas.
  • Two (2) 175 watt roof mounted solar panels
  • Possible future addition: 100 watt suitcase panel if needed.
System Diagram.PNG
Questions:
  1. Any concerns or recommendations on the system and connections shown? I want to be sure that I am not doing anything unsafe. My primary concern is that I have the chargers wired correctly with the system and 7-pin from truck.
  2. Should I up the charger to a 45 or 60 amp model for better future proofing? I assume this would still work with my 30 amp shore power connection?
  3. With solar on the roof to charge while driving is the DC to DC charging really needed/recommended?
Thanks in advance for any feedback! Looking forward to being a part of this community.
 

HRTKD

Boondocker
Are you going to wire the output of the inverter into the WFCO AC distribution panel? If so, you'll need some way to isolate the AC-DC converter. If you wire it to an existing outlet or wire it directly to the WFCO AC distribution panel then it will be trying to charge the batteries while the inverter is drawing from the batteries.

If you're not going to wire the AC output of the inverter into the WFCO then you're good to go. This is the approach I took. I ran a dedicated wire from the inverter to a single outlet that has a remote on/off switch (for the inverter) next to it.

I run a 55 amp AC-DC converter on my 30 amp system. Works fine.

Two 175 watt solar panels isn't much. A 60 amp solar charge controller is overkill for that wattage. More/bigger panels! I run a separate Victron 100/50 solar charge controller for my ground deployed solar panels (640 watts).
 

Mkwirsch

New Member
Are you going to wire the output of the inverter into the WFCO AC distribution panel? If so, you'll need some way to isolate the AC-DC converter. If you wire it to an existing outlet or wire it directly to the WFCO AC distribution panel then it will be trying to charge the batteries while the inverter is drawing from the batteries.

If you're not going to wire the AC output of the inverter into the WFCO then you're good to go. This is the approach I took. I ran a dedicated wire from the inverter to a single outlet that has a remote on/off switch (for the inverter) next to it.

I run a 55 amp AC-DC converter on my 30 amp system. Works fine.

Two 175 watt solar panels isn't much. A 60 amp solar charge controller is overkill for that wattage. More/bigger panels! I run a separate Victron 100/50 solar charge controller for my ground deployed solar panels (640 watts).
I do not intend to wire the invertor output AC into the WFCO panel at this time. My microwave plug will be inches from the invertor so I will just physically unplug from the AC outlet and into the invertor when boondocking. Beyond that the only AC appliances remaining is the air conditioner which I will go without while boondocking due to the high power draw.

I mistyped on the solar charge controller...I intend to use a 40 amp version. I hear you on the 2x 175 panels but my roof area is limited. Maybe I will go with a larger ground panel then originally planned. That will be a future add based on how things go.

Thanks for the feedback!

Camper2.jpg
 

williamsk913

New Member
Have you considered the renogy dc to dc charger with MPPT? If you are adding solar later might be an easy way to head that direction.
 

Mkwirsch

New Member
Have you considered the renogy dc to dc charger with MPPT? If you are adding solar later might be an easy way to head that direction.
I did but decided against due to the low voltage limit of that unit. It was close and I probably could have made that charger work but did not want to wire panels in parallel.
 

Rocketman

Solar Enthusiast
The only thing I would change is I would put a battery monitor on the system Victron smartshunt or BMV712 - or another really good one. You need to know the status of the lithium battery- how much charge is in it.

A 200ah battery and 350 watts of solar is a fair amount for a small system like yours. I would wait on the Dc-Dc charger until you use the system to see if you need it - my guess is you will not. I would think the suitcase panel would be more useful than the dc-dc charger - but I would wait on both.
 

Mkwirsch

New Member
The only thing I would change is I would put a battery monitor on the system Victron smartshunt or BMV712 - or another really good one. You need to know the status of the lithium battery- how much charge is in it.

A 200ah battery and 350 watts of solar is a fair amount for a small system like yours. I would wait on the Dc-Dc charger until you use the system to see if you need it - my guess is you will not. I would think the suitcase panel would be more useful than the dc-dc charger - but I would wait on both.
It's not shown in the above but I do have a battery monitor from SOK I ended up getting for free. I'm sure it's more basic than the Victron but for free will see how it goes for now. Good point on the DC-DC...probably will wait and see for now. My main concern is boondocking in the southeast often comes with a lot of tree cover. The suitcase can help to some extent.
 
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