Adding Lithium and Inverter/Charger to Forest River 2618VS

[Rocket1Point0]

I've beat my head on the wall on the following. New to RV electrical upgrades and new to the forum. I have designed and wired data center server racks for a living and have done some household electrical. However, I'm having a heck of a time deciding on a location and configuration for the batteries and inverter on my Forest River Ultra-V 2618VS. Floor plan and specs can be found, here. Storage space is extremely limited and there is no exterior storage compartments except on the bedroom slide:

2017 Forest River Rockwood Ultra V 2618VS specs and literature guide

www.rvusa.com

I am not planning on adding solar at this time. We like to camp in state and federal parks and have discovered a couple in my area that do not have electrical hookups. So, I'm looking to add enough power to cover a 2-3 day campout without connecting to generator or electrical. In testing, 200 ah appears to be sufficient when the heater needs to run at night for two days. 300 ah would be ideal for 3 days, but 200 ah would be sufficient for 2 days and when the heater is not needed.

The power center is a WFCO 8955 under the fridge that does not support lithium. There is only room for one Group 31 battery on the tongue. I'm planning on replacing the WFCO 8955 with a WFCO 8930/50 distribution panel that supports two 120v legs (e.g 50 amp service) and use the first leg for 30a non-critical service and the second leg for inverter distribution. Shore power inlet is at the back of the trailer.

There is limited storage in this trailer and limited places I can find that "might" work. I was hoping to obtain some input from the members to determine the ideal location and any concerns or issues I may not have considered:

1. In front of the sink for the batteries and behind the power distribution panel under the fridge for the inverter (deck mounted). My only concern with this area is possible leaks with the water lines or plumbing that might cause problems. Custom battery storage will need to be fabricated to cover and protect the terminals. Also, since this is under counter storage for the kitchen, I'll have to find a solution to protect the DC wiring path to the inverter. Most of the area is taken up by the propane tanks outside, but there is 30"w x 9"d x 20"h available space that will still allow access to the plumbing for maintenance. The door opening is 11"w x 27" h.
2. Under the dinette seating near the front entry door. The water heater is located in this area and could be a problem if a water line breaks. 20"w x 18.5"d x 16"h. Additional 14"+ of space is available on the left sidel for mounting the inverter. Being on the opposite side of the trailer will be a challenge and if used, I'm considering running flex conduit through the closed underbelly to the other side for the AC and minimum 6 awg for the DC circuits. Challenge would be removing the underbelly covers (screwed and stapled), and working around the existing front grey tank.
3. Under the opposite dinette seating area. About the same space without the extra space to the left. Heater is located there so isolating into two compartments to reduce heat will be critical. There is also a cheap subwoofer that would need to be removed or relocated. Same issues with power routing, just longer runs.

I'm also considering starting small with a single lithium battery on the tongue and using small inverters to run the TV / CPAP. It would also allow me to easily power the brake emergency break away circuit. However, when upgrading to a larger battery bank I'm struggling with how to separate this battery from the inverter batteries while still allowing both to power the DC loads in the trailer. I'm not finding an easy solution for this other than a two bank battery switch...nothing automatic to allow charging of this single battery from the inverter/charger and preventing overloading the smaller wiring from the distribution panel.

If all batteries are relocated inside, the longer brake emergency break away circuit would be a long run to the batteries. Would you recommend a small 10 ah tongue battery for this or is the long run not an issue? This is typically an unfused wire and could become an issue with more chances for damage / shorts along the path.

I'm looking to minimize cost and balance this with automation / ease of use. I may only have this trailer for another 3-5 years and we plan to purchase a 5th wheel when we retire.

Ultimate configuration would allow powering the microwave and outlets in the trailer. A Xantrex XC 2000 appears to be the most economical solution and I would welcome other suggestions. Though I like the power assist features of the Victron products to allow running on a smaller generator for AC use, the Victron Multiplus line is probably more than I want to spend on this trailer.

For batteries, I'm seriously considering Enjoybot's line with their new low-temp protection and SOK batteries if I need a smaller package.

Thanks in advance for your assistance and suggestions!

 

[time2roll]

If you can give up the MW the whole project becomes so much easier. Maybe save the 2000w inverter for the next trailer.

Stay with the existing WFCO panel and mount a small 400 watt inverter behind the panel. Small transfer switch on one or two branch circuits. Use the main battery feed to get 12v for the inverter. Drop an LFP battery into the battery spot on the tongue. Done.

https://gopowersolar.com/products/400-watt-industrial-pure-sine-wave-inverter/

https://www.donrowe.com/KISAE-TS15A-Automatic-Transfer-Switch-p/ts15a.htm

https://www.us.sokbattery.com/product-page/marine-grade-12v-206ah-lifepo4-battery-sealed-plastic-box

 

[Rocket1Point0]

This does sound like a good interim, low-cost solution and I appreciate the help back out of the rabbit hole of possibilities. If we are longer term on upgrading to a 5th wheel, I would like to enable use of the microwave and coffee pot IF we find dry camping to our liking. However, there were ways to cook before coffee makers and microwaves were developed.

Even if the existing WFCO panel is used, the converter will need to be upgraded at a minimum to support lithium.

I have considered the 200ah marine Sok battery on the tongue and wish it would fit into a Group 31 box. There is a mere 10" from the jack to the tip of the trailer. As far as width, a Group 31 box barely fits with 1" hangover at the front left and right of the box. And, I have yet to find a battery box that will fit and doesn't take on some water as we travel, which probably rules out the metal version of this battery without building a custom sealed box (not beyond my abilities).

In your suggested configuration, is the output of the ATS wired to the 30a main in the WFCO panel or a sub panel feeding the branch circuits supplied by the inverter? In this trailer, all outlets are on a single 15a branch circuit.

Thanks!

 

[Rocketman]

For smaller lithium batteries look at Li-ion batteries, I remember seeing one person put three of those into the space of two battle-born batteries. Costco sometimes has those on sale.

If possible put the batteries inside (not on the tongue). Many times spring and fall camping temps can drop below zero - if inside saves lots of issues.

For now add the 400-ish watt inverter -c-pap, electric blanket, phone chargers work great on that.

 

[time2roll]

Nothing terribly wrong with the WFCO for this use. Profile is 14.4 Boost, 13.6 Normal, 13.2 Float that is very compatible with LFP. The real issue is getting 14.4 boost mode to charge a lead-acid battery. This is not necessary with LFP.

Box is not needed except to prevent theft. Simple tray and a strap to hold it down is fine. When not camping I would remove the battery unless stored in a private locked garage. If the box collects water, drill a couple holes in the bottom.

In my configuration the transfer switch is plugged direct into the inverter. Only the selected branch circuit is powered. The romex to that branch circuit is removed from the panel (H-N-G) and connected to the transfer switch OUT terminals. A new section of romex is connected between the breaker-panel (H-N-G) and the transfer switch IN terminals. Essentially powering the single branch circuit. This keeps the A/C and W/H off the inverter. Do need to verify if the converter or the fridge is powered by this branch circuit. If they are connected, the converter needs to be moved to a different breaker and the fridge can be set to propane only.

 

[Rocket1Point0]

For smaller lithium batteries look at Li-ion batteries, I remember seeing one person put three of those into the space of two battle-born batteries. Costco sometimes has those on sale.

I'm assuming you are referring to Lion Energy Batteries, like the UT1300?

Of course, we're back to my original reason for this post, recommendations for placement inside the coach.

In my configuration the transfer switch is plugged direct into the inverter. Only the selected branch circuit is powered. The romex to that branch circuit is removed from the panel (H-N-G) and connected to the transfer switch OUT terminals. A new section of romex is connected between the breaker-panel (H-N-G) and the transfer switch IN terminals. Essentially powering the single branch circuit. This keeps the A/C and W/H off the inverter. Do need to verify if the converter or the fridge is powered by this branch circuit. If they are connected, the converter needs to be moved to a different breaker and the fridge can be set to propane only.

Fridge is indeed on the same circuit as outlets, so thanks. Original plan was a sub panel and fridge would have ended up on its own circuit. More to think about.

So, no breaker or fuse on the inverter output? How are you protecting the wiring when it switches over to the inverter. I didn't see that the Go Power inverters contained their own breaker (though it may not be needed with such a low wattage).

 

[time2roll]

The linked inverter at 400 watts will never ever get the #14 wire even warm. Inverter self limits to less than 4 amps and will shut down for overload.

 

[Rocket1Point0]

Thanks @time2roll and @Rocketman for your suggestions and advice!

Since we really like camping in state and federal parks, I'd like to explore all options. Back to my original question, does anyone see any issues with any of the three location options if a larger battery or more than one is preferred that will not fit on the tongue? Does one stand out as a preferred location over the others (and why)?

So far, I haven't been able to find any clear direction for the emergency breakaway and rv manufacturers are hesitant to provide recommendations. Some recommendations from the community suggest wiring directly to the lithium battery, some prefer a separate breakaway battery when upgrading to lithium, and many are concerned with an unfused circuit. There were some reports of states that inspect for an unfused circuit during a safety traffic stop. My inclination due to the distance to the batteries when moved would be to mount a separate battery for this circuit on the tongue.

Regarding combining two battery banks and allowing both to power DC loads while allowing only one to contribute to inverter loads is probably a discussion for a separate thread and was more for my education on the realm of possibilities.

 

[time2roll]

Nothing wrong with going big. I recommend right at 2000w to run a MW. Battery and inverter under the dinette bench is fine. Best to have these close as the wire needs to be fat and short. Then figure out how to pull wire from the inverter to the distribution panel. A small battery up front is fine for the brake system as needed. The battery should be capable of 200 amps output.

Can get two of the transfer switches to feed the two branch circuits or a 30a switch and feed the whole panel. I would still stay with the existing panel but that is your call and a lot of tedious work to swap in a 50 amp.

If the battery-inverter can be shoe horned under the sink near the electric panel that would solve pulling wire and eliminate that difficulty. I would not worry too much about water unless there is already an issue to fix.

 

[Rocketman]

We got these water leak detectors years ago - they have been great - if you are concerned about water leaks. - we have at least four in our MotorHome. Search Amazon for:

Zircon Leak Alert Water Leak Detector & Flood Sensor​

 

[Rocket1Point0]

if you are concerned about water leaks.

More like water spraying into or pouring onto inverter or other electronics from a leak. The leak detectors looks interesting, though. Thanks for the info.

Can get two of the transfer switches to feed the two branch circuits or a 30a switch and feed the whole panel. I would still stay with the existing panel but that is your call and a lot of tedious work to swap in a 50 amp.

I have no intention of upgrading to 50 amp service. The WFCO 8930/50 supports both 30 amp and 50 amp service and fits into the existing space. In my proposed configuration, one side of a WFCO 8930/50-NPB would use a 30a main for shore and non-critical loads and 20a branch to the inverter. The other side would contain an 20 amp QP breaker as the main with two 15a branch for the GFCI and microwave circuits. This would eliminate the need for a subpanel to feed the two branch circuits. And, the hold downs for the DC distribution board has cracked on the existing panel and the board won't stay in place. Easy enough to fix, but this would eliminate that requirement.

A small marine subpanel would fit the bill as well like the Blue Sea 8058. A little expensive though for this application, but would fit in the space available to the right of the existing panel. I would probably consider this option if installing the batteries and converter on the other side of the trailer under the dinette seating as I'd have to put a breaker in that location to protect the AC wiring back to the distribution panel. However, not really ideal if inverter/charger is mounted behind the existing panel.

This all assumes bumping up to a 200W inverter. The Go Power option is over $700, so the Xantrex XC 2000 seems to be the most economical and contains the transfer switch and charger for about $100 more (unless going with a cheap Chinese inverter/charger).

If the battery-inverter can be shoe horned under the sink near the electric panel that would solve pulling wire and eliminate that difficulty.

I still like this option, but with the inverter behind the electrical panel. A little longer run from the batteries, but only about 3-5 feet max, depending on how I have to route the cables to keep them out of the way. The inverter would fit to the left of the sink, but that is also the location of the drain cleanout and the trap. I'll just need to put on my thinking cap for a little ingenuity on how to secure the batteries in the 9" deep area in that cabinet.

Baffles me why one would need a drain cleanout just 3 inches from a removable drain trap.