Electrical System Questions - 2021 Keystone Ultra Lite 221UMD

[EKH0ar]

Hello all. I am a newbie. Just purchased a used 2021 Ultra Lite 221UMD. I am a total novice when it comes to understanding the electrical systems on this used RV. It has a lithium battery, but I do not know the make and model. The dealer is installing a 400W solar system. I do not have a generator yet. I need your help with a very basic understanding of how I will turn on the lights, tv, refrigerator, microwave, and make all the DC/AC and USB outlets work. I barely understand the difference between DC and AC!!! I will probably need to charge the lithium battery if the solar doesn't work well enough on cloudy/rainy days. HELP!

[govols380]

RV electric is pretty intuitive, in that basically everything but the outlets run on 12V, gas, or both. If the camper is plugged into AC, the AC to DC converter is charging the battery and powering the DC systems like lighting, furnace controls, etc. If not plugged in, almost all but the outlets will run from the battery or/and propane.

You'll get more answers from others, and you'll figure it out pretty quickly.

[govols380]

Also, spend some time with the various instructions. Basically all of the appliances have make/model tags,and most manuals are ready available for download if they didn't come with the camper.

[EKH0ar]

I will be primarily boondocking without hookups. Does the solar charge the battery? Or do both the in-house converter and solar charge the lithium battery? Do I need to get a generator?

[govols380]

You have some learning to do. You must know the battery amp hours. You'll need to figure out what solar "system" the dealer is installing. Will it include an inverter? Is the inverter also a charge controller? You'll get there, but you have homework.

My 23 221umd has a DC only fridge, 400W solar. The solar will mostly keep up with the batteries while running the fridge, water pump sparingly, good sun. I have 200 Ah worth of lithium and can tolerate some cloud cover for a day or two, but were I camping without hookups I'm taking the generator.

[EKH0ar]

Thank you for this advice. Are you aware of any companies that make an inverter generator that can also intake and control solar power so I don't overcharge my existing lithium batter installed on the RV tongue? I found in some of my research some comments that solar arrays and generators don't work well together.

[chuckster57]

Originally Posted by EKH0ar

I found in some of my research some comments that solar arrays and generators don't work well together.

Where did you find that? I haven’t heard any customers complain about that. I doubt you will find a generator with a built in solar charge controller. If you’re worried, I would buy an inverter/charger. Start the gen, plug the shore cord into the gen and let the inverter/charger do its job.

[EKH0ar]

Thank you. I am getting my information from random searches on the internet and YouTube videos and RV forums like this one. I don't exactly know enough the ask the right questions. The dealer is installing a 400W solar panel array on the top of my 2021 Keystone Ultra Lite 221UMD trailer, but has not explained how the solar will integrate with the existing on-board generator or a portable inverter generator. I think I will need a solar controller installed with a separate kill switch. So far, the dealer has not given me the ability to talk to the technician who will be installing the solar array. So I have developed the following question to send to the tech. Do any of you have any thoughts on the quality of my questions below?

Here are the questions I have for the tech:

1 -- Are the solar panels being installed*mounted to the roof or glued on?2 -- Can (and will) the 400W solar array being installed be integrated with*the generator already installed on the RV to create a hybrid power solution that*automatically switches the power source from inverter generator to solar power?
2 -- Does the*400W solar array being installed come with its own lithium battery, or will it only power the existing lithium battery?
3 -- Will the 400W solar array being installed come with its own inverter, or do I need to purchase*one separately?
4 -- Can I use the solar battery when I am using the inverter generator I will purchase?* (I am looking at the Cummins Onan P4500I 4500W Inverter Portable Generator.)
5 -- Are there any inverter generators on the market that will accept and control the voltage generated by the solar power?
6 -- Will the electrical panel in the RV now need to be modified in any way now that we are installing solar panels?* Will a solar charge controller be installed?
7 -- Will a solar breaker be installed so I can turn off the solar power when I want to use the inverter generator so I don't damage electronics?

[chuckster57]

With the proper solar controller, you don’t need to “integrate” solar and gen charging. The solar controller will adjust the input based on the charge of the batteries. Any and all batteries should be linked together.

[govols380]

I pecked around a bit to see what I could learn about your 21 v my 23. It looks like you have solar prep with no inverter prep. I could be wrong. If solar prepped, that's wiring from roof ports the panels will plug into, direct to batteries. Installing a system will definitionally require accessing that wire run, cutting the "direct to batteries" and putting a solar charge controller into that circuit between the panels and the battery. Verify that with installer.

Without prewiring for an inverter, you'll have a big job to add one. For any AC power you'll need a generator or shore power. If you buy a generator make sure it's enough to run your air conditioning.

You'll want to ensure the shore power AC to DC converter was upgraded to properly charge lithium batteries; maybe the previous owner did that, given the money spent to upgrade the battery?

Your lights are all DC, I think your fridge is DC only (pretty large battery drain), your furnace and water heater are DC controlled and propane fueled, though your water heater might also be 120V AC, I can't tell from what I've found.

A solar system with a proper charge controller doesn't care about your generator or shore power. The solar charge controller puts as much power into the batteries as the panels can feed it, but only according to what it detects that the batteries require. A decent modern solar charge controller will not over charge the batteries, but instead note they're at a fully charged condition and go into a float mode that won't overcharge. You are responsible for making sure the charger controller is correctly set up for lithium given the default settings for many or most is for AGM rather than lithium. Don't trust that the dealer technician set it up correctly.

MAKE SURE you get the instructions/manuals for any of the solar components so you can better understand the system and verify that it's set up correctly.

That's about all I can offer. Hopefully somebody can come along and confirm or correct me if I'm leading you astray. Mostly I'm not, but...you get what you pay for?

[EKH0ar]

Thank you! This helps tremendously!!! I sincerely appreciate your time and effort looking into this. Now I know exactly what to ask the technician! I am very grateful.

[govols380]

I forgot to mention above that the furnace is also a pretty big battery drain because the blower is 12V. All but the microwave and AC outlets are designed to function without generator/shore power, so when running on batteries and gas, lights, stove, fridge, furnace...all of that stuff runs without plugging in. Still, my old camper could easily run down by 80 amp hours per day in cold conditions.

If you plug in each morning, and the on-board converter is properly configured for lithium, a couple of hours on the generator plus the solar should be enough to have you topped up. The solar alone ought to be enough under ideal conditions...but those rarely exist.

Good luck and happy camping.