Solar Newbee

[KDube]

Hi all, pretty ignorant on the subject, but taking delivery of our first RV latter this month. It's a 2021 Landmark Daytona 365 and says it's wired for 300 watts of solar. I'm reading that these panels only put out approximately 50% of their stated output. Would like to put as much solar up top as is feasible and connect to 2 208 WH LiFe 04 batteries. Not sure if a system like that makes sense and what type of inverter and controllers i would need and how it should all be configured. Pretty big ask, I know, but any help would be appreciated.

Thanks,
Kevin and Laura

 

[danemayer]

I believe the 300 watt factory option can be expanded by adding a 2nd 300 watt panel. But aside from battery choices, to go any larger, you'll need to consider the inverter as well as the wiring to AC outlets. My recollection is that the factory option feeds the entertainment center, residential refrigerator, and bedside outlets. To cover more outlets and appliances, you'll have to rearrange the coach wiring and add some components.

Page 36 of our Electrical User Guide describes the factory option as of 2020 models. It may have changed since then.

 

[carl.swoyer]

If you have a factory installed 300 watt panel I would try to get the same one so the panels are matched

Sent from my SM-A526U using Tapatalk

 

[Stew116]

Hi, you should be getting more than 50% of the rated output, should be closer to 80%. That is at off solar noon, at solar noon should be about 90% with your batteries you can used it till the inverter stops running. LiPo unlike my AGM can be run to 100% of their capacity. My AGM only 50%. Used 10 year old panels are in the 80% range like mine at solar noon. My 500W panels at pre solar noon (Sun directly over panel ) will get just over 50%. this was taken early am sun around 830ish I believe at around 44% starting to charge my system.

 

[taskswap]

Yeah my experience is the same as Stew's with new/recent panels. Maybe the 50% was referring to daily output? Your peak output is going to be full sun on a cloudless day at whatever time the sun hits those panels just right. You're not going to see that at 10am or 5pm although the panels will still have some output. Every system and situation is going to be different (especially based on location) but it wouldn't be a bad rule of thumb to take "an hour after sunrise to an hour before sunset" as your "solar day", multiply that number of hours by your panel's max rating to get watt-hours, and then knock it back 50% to get a more realistic "ideal charging day".

I think it's super helpful to pair a system with some type of monitor that has logging functionality. Stew's post above looks like the EPEver MT50, which is what I use as well (I have an EPEver Tracer-AN 40). That unit can connect to a data logger EPEver sells called the Elog01, or you can add an aftermarket system. I'm not shilling for them, but I'm a fan of the RVWhisper system with the Thermowave power module. With it, I can see what my panels are putting out and chart it over time. It can really help you understand how solar performs.

One common gotcha a lot of folks don't realize is a concept called "panel shading". Depending on how your panel is wired, even a small amount of shading like from a tree branch or power pole can knock out a significant percentage of your output. There are some good videos on Youtube that talk through this if you want more explanation.