2021 T@b 320 CS-S solar addition

maccorsr

I just bought a 2021 320 cs-s (not a BD, no solar, wet battery with WFCO power center).  I want to switch to Li batteries and a portable solar panel.  I understand that the pre-2022 WFCO doesn't work for Li batteries.  So i'd appreciate any expert advice on designing my full system needs.  Here's what I'm thinking so far:  2 Li Time 100AH bluetooth batteries in parallel, portable solar panel (at least 200W, maybe 400?).  I was looking at an MPPT charge controller for the incoming solar, but  do I need to replace the WFCO with a Li compatible converter/charge controller to manage shore power and the solar panel?  I'm struggling to understand exactly the components needed for a system with no existing Li/solar setup.  (also, I do have the BD tongue rack so I have a lot of room up front).  Thanks

pthomas745

The WFCO works for charging lithium batteries.  The issue is: the WFCO will "only" charge them to about 85 percent.  Many owners have added lithium batteries, made sure their solar controllers will charge a lithium, and never looked back.  There are many lithium chargers on the market that you can add for the trailer (either installed or just stand alone) that will work when you absolutely "need" to charge on shore power.

The rest of your setup is just fine.  The amount of solar wattage depends on what you think your day to day usage of the battery will be.  What fridge do you have?  2 way or 3 way (propane?).  Any other items that you "must have?'  Computers, CPAPs?  Appliances like a small coffee maker would require a decently sized inverter, if you want to wire that sort of thing up with thatt 200 AH capacity in the lithiums.

So: the lithiums are virtually drop in and go, as long as you understand that if you are on shore power, you "might" only get an 85 percent charge.  Solar can charge them "completely" with the appropriate solar controller.

The other item to consider strongly is some sort of "shunt", the device that will count your amp hour use and provide the most useful battery monitoring.  The Victron shunts, because of their bluetooth capability, are the go-to devices for this monitoring capability.  (There are other less expensive kinds that work just fine, but no bluetooth, etc.)

Welcome to the Forums!

maccorsr

pthomas745 Thanks for the quick response!  I realize I can get to 80% with the pre-2022 WFCO but I was concerned that NuCamp said it could affect the life of the Li battery.
https://nucamprv.freshdesk.com/support/solutions/articles/44002010684-lithium-pre-2022-model-year

It looks like I can get a new WFCO with auto-detect for Li batteries for about $200.  Thought it would be worth it to get full charge of the batteries from shore power when that is available (?).  I'm figuring our boondocking will just be to have the flexibility of staying a couple days at a time in a primitive campsite since they are often all that is available.  I have a 2way fridge and will want to keep it powered up.  Otherwise just the fan, a few lights and hot water with the alde on propane is what I was thinking of needing.

A couple other questions while I've got you-  there is a plug on the side of the front box with leads running to my battery, which i assume is for a solar connection.  Would I run those leads to a charge controller then to the battery? Or would the controller be before the box?  

Thanks so much for your help!

pthomas745

The "port" on the side of the trailer would be the connection from the controller to the port.  (The port is an ordinary "SAE" port.)  The setup would be: solar panel to solar controller, solar controller to the port, and then on to the battery.  There are endless ways to connect the solar controller to the battery, and the SAE port is just one.  There are many threads here from "back in the day" where owners installed their controllers in the front tub next to the battery in different ways.  The SAE port makes wiring a separate panel very easy.  It just takes a little thinking to get the wiring correct. (Add an "autoranging multimeter" to your shopping list.)

It has always been difficult for me to determine what any of the battery manufacturers mean by "decrease in performance and lifespan" if not using a specific lithium charger.  We know that a non-lithium charger will only charge to 85 percent (performance) but how does this affect the "lifespan" of a battery that is supposed to last for more than "3000 cycles?".  My lithium, with only charging on solar, is working just fine.

Your 200 amp hour setup is more than enough to get you through a couple of days boondocking, even without solar.

maccorsr

Thanks for the updates!

Yoshi_TAB

Hi, 

Do you have any interest in moving your batteries inside either in front of the Air 8 (where I put mine) or others have placed them under the passenger side bench.  This frees up a lot of space in your tub for other storage.  I used the space next to the Air 8 as that space was used very little by us.  You can do this w/o cutting any holes in your TAB.  The "left over" wiring going out to the front tub can be used for your external solar port connection (which I did) to an inside solar   controller then to your inside battery .  If so, here is  how it's done.  The #6 wire coming from the WFCO is the  wire the goes out to the trailer junction box, then to the front tub (shown in the top drawing).  If you bring your batteries inside, you just splice them in (using a bus bar) to the #6 wire coming from  the WFCO.  The left over wire that is going from inside your TAB  to the front tub can now be used solar for the port connection.  If this is fuzzy, please ask more questions.

Slackers

In our case we've merely added an SAE connector (our '19 CSS didn't come "solar-ready) and an unused NOCO X connector at the battery terminals in the tub. The former allows us to attach a 200 Watt solar suitcase (w/ PWM controller), while the latter accommodates a NOCO charger. Both devices have Lithium charging profiles. We haven't disconnected or upgraded the TAB's built-in WFCO charger. For our more common style of camping at State Parks w/ (and w/o) electric power there's little need to charge from either external device as our stays are 4 days or less (no refrigerator when off shore power). We have recently returned from an epic cross-country trip with only 1 of 42 nights on shore power. Our solar suitcase covered all of our charging needs. Our LiFEPO4 battery mounted in the front tub weathered temps dipping below the 40s and peaking over 100 without issue. We don't have a shunt but it sure would have been nice. Instead we paid careful attention to the voltage reported at the battery terminals. I should note we moved the solar controller from the solar suitcase to inside the tub for better performance.
I guess I'm saying start with small changes/additions and see how that works for your camping style(s).

maccorsr

Wow, great information, I really appreciate this forum!

morey000

the stock battery is usually about 75Ahr, which really gives you only about 35-40Ahr of usable power storage.  With a 100Ahr lithium you'll get 3 times the battery storage, (check out the LiTime mini, it's a good one for cheap. https://www.litime.com/products/12v-100ah-mini-lifepo4-battery?

and yes, you'll need a solar panel and controller.  something like this is a good MPPT one:  https://www.amazon.com/dp/B075NQH3QW. which is the one I just got when my Renogy Rover controller got fried.  as you noted- correct, don't get a cheap PWM one.  they'll work, but sub-optimally.  this Victron is a good brand, comes with bluetooth built in and a nice app for tracking. you don't need to get a shunt to track actual power usage, unless you're fastidious about it.  otherwise, just watching your battery voltage is often good enough.

Unless you're a heavy power user, add a 100w solar panel (or 2 if running a fridge) and you should have plenty of power for your needs.  you could get an external one that faces towards the sun, but sticking a thin one to your roof is really slick and simple.  

it's been a while, so the links may not be current, but here is my setup (until I replaced the controller)
https://tab-rv.vanillacommunity.com/discussion/8869/my-solar-install-clean-and-simple#latest