New trailer - 400w solar setup what are my best practices here?

[West1134-KEY]

Hello all, late last year we bought a 2024 Cougar 29RLI. It came with the 400w solar system, inverter, and I believe (haven't opened it to check) one Lithium Ion battery. It has a 12v fridge and a number of 12v outlets to power stuff off solar which is pretty cool. Considering we bought the trailer super late in the season I only had a few nights with it, and then winterized. We are about to de-winterize this weekend for our shakedown trip before camping season starts, and I'm getting back into thinking about better understanding a) solar in general, and b) some best practices for my particular setup.

We live in the PNW, so it isn't exactly sunny here all the time. Summer months sure we get a decent amount of days, but definitely not a year round thing.

When I winterized I turned off all three cut off switches for power in the trailer. I now wonder if I should've left the solar on to trickle charge the battery over winter, but again because we don't see many days of sunshine around here during winter I errored on the side of caution and just left everything off. It's my understanding the three cut off switches do the following (I may be wrong on this):
1) Cuts off solar to inverter
2) Cuts off inverter to battery
3) Cuts off battery from everything

So in theory if I opted to trickle charge the battery, I would leave switch 1 and 3 on to allow solar to feed battery since its in storage and inverter would only draw power and not be needed anyways.

So with the above "what I think I know" where should I start in learning more?

 

[NH_Bulldog]

Congratulations and welcome to the site.

A few things to first understand about the Keystone SolarFlex (Discover) system you have: First, it is 440w not 400w. Second is that the solar doesn't power anything, it simply charges the batteries. Third, it is very important that you find out what type of battery you have and how many. A single battery will not do a whole lot for you, and if it is lead-acid, it will do even less. In order to gauge your system capabilities, it is very important to know exactly what you have in the battery box.

As for operation principles:
When you are connected to shore power, the onboard converter supplies 12v DC power to run the 12v DC circuits in the camper (lights, slides, leveling system, charging ports, refrigerator, etc.) and is the primary charging source for the batteries, with solar as the secondary. All household 120v AC circuits are powered from the shore power connection (air conditioner, household outlets, microwave, television, etc.). When you are not on shore power, all the 12v DC loads draw from the batteries, and the solar replenishes the batteries (at what rate depends on a number of factors.

When you are not on shore power, the operation of all the 12v DC circuits is unchanged, they still draw from the batteries, but the battery replenishment comes from the solar charger, not the converter. All 120v AC circuits will not operate (no TV, household outlets, microwave, air conditioner, etc.) UNLESS your inverter is powered on and operating. When the inverter is on, it will provide 120v AC power only to 4 to 7 selected household outlets in the camper (each labeled with a yellow sticker that says "Inverted Outlet"). The location and number of those Inverted Outlets depends on your floorplan. On mine, I have 7 outlets that can run off the inverter; one on each side of the bed, one for the bedroom TV, one for the living room TV, one kitchen counter outlet, the mini fridge outlet in my outside kitchen, and one in the front passthrough compartment. The inverter does not, will not, and cannot power the air conditioner(s) or microwave. It is a best practice to only use the inverter if you want or need to run something on those 4 to 7 inverted outlets (watching TV at night, making coffee in the morning, etc.). Otherwise the inverter will unnecessarily accelerate the depletion of the batteries (again, it is important to know what type and how many batteries you have). I have two 100ah LiFePO4 batteries, and on a fully shaded site and no inverter usage, I can go 3 days before I need to either find sunshine or run a generator. I have found that even with sunshine and running the inverter, my range is still only about 3-4 days before I have to run the generator.

The SolarFlex Discover system is not endless power, it just extends the time before you need to run a generator or connect to a shore power source.

As for the disconnects:
For the winter (it gets pretty cold here), I turn all three disconnects to the disconnect positions, and remove the batteries and bring them into my shop.

If you have a lead-acid battery and left it in the camper over the winter without any kind of charging, the battery is very likely dead and ruined for life. Lithium is more tolerant, but Keystone and lithium battery manufacturers suggest that it is okay to leave them installed over the winter only if they are charged, and the battery cables disconnected (the ONLY way to truly disconnect your batteries). The battery disconnect, even when in the disconnect position will still have parasitic drains on the batteries for various loads that cannot/should not be eliminated (LP gas/co detector is one). So I leave my battery disconnect in the powered position unless I am storing for the winter.

Depending on how cold it is where you are, keeping the batteries connected and the solar on may do nothing for you. For example, a lithium battery will not charge below 38-40 degrees (unless you have battery heaters, which using will only draw the batteries down faster and making it an uphill battle for the solar to even try to keep up). So if you are storing for the winter, my advice is simple, err on the side of caution and set all three disconnects to the disconnect positions and remove the batteries. You can always hook up a jumpstart/booster pack temporarily if you need lights or to operate any of the 12v DC systems in the meantime.

This is just a start, and my apologies if any of this is confusing, but reach out if you have any other questions on the system.

 

[workinonit]

This write up should be made a sticky somewhere. Nice explanation Rob. You could copy that and just paste it once or twice a week when this comes up.

 

[West1134-KEY]

Congratulations and welcome to the site. Thank you!

A few things to first understand about the Keystone SolarFlex (Discover) system you have: First, it is 440w not 400w. Second is that the solar doesn't power anything, it simply charges the batteries. Third, it is very important that you find out what type of battery you have and how many. A single battery will not do a whole lot for you, and if it is lead-acid, it will do even less. In order to gauge your system capabilities, it is very important to know exactly what you have in the battery box. Right, it was a 440w setup, thanks for the clarification. I recall there was two options offered, and the 440w was the larger of the two. I'm pulling my trailer out of storage tomorrow and will pull the battery box cover and take a look so I know for sure what I'm working with.

As for operation principles:
When you are connected to shore power, the onboard converter supplies 12v DC power to run the 12v DC circuits in the camper (lights, slides, leveling system, charging ports, refrigerator, etc.) and is the primary charging source for the batteries, with solar as the secondary. All household 120v AC circuits are powered from the shore power connection (air conditioner, household outlets, microwave, television, etc.). When you are not on shore power, all the 12v DC loads draw from the batteries, and the solar replenishes the batteries (at what rate depends on a number of factors. Makes perfect sense, thanks for the clear explanation.

When you are not on shore power, the operation of all the 12v DC circuits is unchanged, they still draw from the batteries, but the battery replenishment comes from the solar charger, not the converter. All 120v AC circuits will not operate (no TV, household outlets, microwave, air conditioner, etc.) UNLESS your inverter is powered on and operating. When the inverter is on, it will provide 120v AC power only to 4 to 7 selected household outlets in the camper (each labeled with a yellow sticker that says "Inverted Outlet"). The location and number of those Inverted Outlets depends on your floorplan. On mine, I have 7 outlets that can run off the inverter; one on each side of the bed, one for the bedroom TV, one for the living room TV, one kitchen counter outlet, the mini fridge outlet in my outside kitchen, and one in the front passthrough compartment. The inverter does not, will not, and cannot power the air conditioner(s) or microwave. It is a best practice to only use the inverter if you want or need to run something on those 4 to 7 inverted outlets (watching TV at night, making coffee in the morning, etc.). Otherwise the inverter will unnecessarily accelerate the depletion of the batteries (again, it is important to know what type and how many batteries you have). I have two 100ah LiFePO4 batteries, and on a fully shaded site and no inverter usage, I can go 3 days before I need to either find sunshine or run a generator. I have found that even with sunshine and running the inverter, my range is still only about 3-4 days before I have to run the generator. So it sounds like if we're boondocking for a few days and want to maximize the runtime of the batteries, best practice would be to leave the inverter off (physically switch the knob in the front bay) unless we need it for those specific outlets etc. This will limit the draw to the fridge, lights, slides, leveling system, and a few USB plugs etc. and hope there's enough sun to continue to trickle charge the batteries.

As for the disconnects:
For the winter (it gets pretty cold here), I turn all three disconnects to the disconnect positions, and remove the batteries and bring them into my shop.

If you have a lead-acid battery and left it in the camper over the winter without any kind of charging, the battery is very likely dead and ruined for life. Lithium is more tolerant, but Keystone and lithium battery manufacturers suggest that it is okay to leave them installed over the winter only if they are charged, and the battery cables disconnected (the ONLY way to truly disconnect your batteries). The battery disconnect, even when in the disconnect position will still have parasitic drains on the batteries for various loads that cannot/should not be eliminated (LP gas/co detector is one). So I leave my battery disconnect in the powered position unless I am storing for the winter. Good to know. I did leave the battery in and physically connected over this winter storage, just turning the disconnect knob. I'll find out tomorrow where that left me. We get temps mostly in the upper 30's-low 40's here with only a handful of cold snaps below freezing here and there typically in our winter cycle.

This is just a start, and my apologies if any of this is confusing, but reach out if you have any other questions on the system. This was fantastic. Thank you for taking the time to respond, and with such detail. This was exactly what I was looking for to learn more about this system, what I can do to proactively take care of it, etc. Much appreciated.

I will post up with more details tomorrow once I get the trailer out of storage and set up at camp re: battery type, how many, etc. Thanks again!

 

[West1134-KEY]

OK, well my plans to post up the next day were delayed, but here is how the weekend went and what I've learned.

1) My batteries were dead upon picking up my trailer from storage. Which made hooking up a bit more challenging since I couldn't raise the landing gear without power, and when connected to my truck it still wasn't feeding enough power to do so. I recently purchased a portable jump starter big enough to jump my diesel, which I leave in my truck. But of course, I took it out to charge it right before leaving to grab the trailer, so I didn't have it with me. So I got creative, and was able to connect to the trailer, then use my airbags to inflate the ride height up enough to take the weight off the landing gear, and telescope them up. Thankfully when I drop the trailer for storage, I telescope landing gear out manually nearly to the ground so the motors barely lower to ground and lift weight off truck.
So first item for next year is making sure I remove the physical connector to the batteries to keep a parasitic drain from occurring, or pulling them and keeping them on a trickle charger at home for the winter.

2) I found I have two batteries installed. But they are lead acid vs lithium. Considering boondocking is rare for me, I'll probably ride these out until they need to be replaced at which time I'll go lithium...unless they're cooked already from running dead over the winter. I'll know more on that after they sat this week before our next camping trip.

Other than that start, the rest of the weekend went well with de-winterizing, testing things out etc. Thanks again @NH_Bulldog for your responses, it was very helpful/educational.

 

[NH_Bulldog]

Happy to help! I had those Interstate batteries on my last trailer. They are very good and lasted me over 5 years and were still going strong when I sold the camper. The downside is that they are not true deep cycle batteries since they list CCA (cold cranking amps). True deep cycle batteries will not identify cranking amps (motor starting amps) and only list reserve capacity. Either way, if they were dead and the temps dropped to or stayed below freezing for any length of time, they might not come back from the dead, at least not like they were. I would suggest charging them up and stopping by an auto parts store to have them load tested. That will tell you if they will hold enough charge long enough to operate your slides or leveling system.

Good luck with everything! I started some spring prep work on ours this weekend, but it is snowing again today so I am trying not to get too far ahead of myself. We have our first 10-day trip planned in 4 weeks, so I still have time!

 

[West1134-KEY]

Happy to help! I had those Interstate batteries on my last trailer. They are very good and lasted me over 5 years and were still going strong when I sold the camper. The downside is that they are not true deep cycle batteries since they list CCA (cold cranking amps). True deep cycle batteries will not identify cranking amps (motor starting amps) and only list reserve capacity. Either way, if they were dead and the temps dropped to or stayed below freezing for any length of time, they might not come back from the dead, at least not like they were. I would suggest charging them up and stopping by an auto parts store to have them load tested. That will tell you if they will hold enough charge long enough to operate your slides or leveling system.

Good luck with everything! I started some spring prep work on ours this weekend, but it is snowing again today so I am trying not to get too far ahead of myself. We have our first 10-day trip planned in 4 weeks, so I still have time!

I'm hoping they weren't completely toast. They had enough juice to power lights etc. but not enough to turn the electric motors for the landing gear. We'll see though, having them load tested is a good plan though. We've got three nights scheduled next week for kids spring break, then awhile before our next 4 night trip. Since buying this trailer late last yea we're itching to go use it! I've got 25 nights booked thus far this summer, which for us having young kids, and both working full time is probably the most we'll be able to swing. Excited though! Safe travels.

 

[DustyRoads]

Hello - and good luck with the new trailer.
I have a 2023 Keystone Cougar 23MLE. It came with the Solarflex 400i. For this model year it came with 2x200 watt solar panels, Inverter and 2 Dragonfly 100aph Lithium batteries. If your trailer didn't come with a Victron Smart Shunt I highly recommend installing one, especially if dry camp a lot. Install the Victron App on your phone, this way you can monitor your Solar Panels and Monitor your batteries more accurately. Keystone didn't properly connect our Smart Shunt and the dealer after repeated trips didn't notice. Since I am new to solar and monitoring, I thought the Solar app was providing me that info and I was getting frustrated. Connected the power wire and now I know the state of charge always. Don't rely on the lights or the iN-Command information. For the inverter I installed the remote pad in the trailer so I can turn it on and off from inside the 5th Wheel. I use the inverter primarily to power my CPAP at night. As stated, the solar doesn't fully power the batteries. I do carry a generator to charge them when needed. There are some parasitic draws even though the battery disconnect is set.
When charging in the winter, I live in the northeast, even the trickle charge of Lithium batteries requires the batteries be heated somehow. I have to turn on a heater switch inside my trailer to make this happen.
Good Luck!!

 

[Bellabrie]

Congratulations and welcome to the site.

A few things to first understand about the Keystone SolarFlex (Discover) system you have: First, it is 440w not 400w. Second is that the solar doesn't power anything, it simply charges the batteries. Third, it is very important that you find out what type of battery you have and how many. A single battery will not do a whole lot for you, and if it is lead-acid, it will do even less. In order to gauge your system capabilities, it is very important to know exactly what you have in the battery box.

As for operation principles:
When you are connected to shore power, the onboard converter supplies 12v DC power to run the 12v DC circuits in the camper (lights, slides, leveling system, charging ports, refrigerator, etc.) and is the primary charging source for the batteries, with solar as the secondary. All household 120v AC circuits are powered from the shore power connection (air conditioner, household outlets, microwave, television, etc.). When you are not on shore power, all the 12v DC loads draw from the batteries, and the solar replenishes the batteries (at what rate depends on a number of factors.

When you are not on shore power, the operation of all the 12v DC circuits is unchanged, they still draw from the batteries, but the battery replenishment comes from the solar charger, not the converter. All 120v AC circuits will not operate (no TV, household outlets, microwave, air conditioner, etc.) UNLESS your inverter is powered on and operating. When the inverter is on, it will provide 120v AC power only to 4 to 7 selected household outlets in the camper (each labeled with a yellow sticker that says "Inverted Outlet"). The location and number of those Inverted Outlets depends on your floorplan. On mine, I have 7 outlets that can run off the inverter; one on each side of the bed, one for the bedroom TV, one for the living room TV, one kitchen counter outlet, the mini fridge outlet in my outside kitchen, and one in the front passthrough compartment. The inverter does not, will not, and cannot power the air conditioner(s) or microwave. It is a best practice to only use the inverter if you want or need to run something on those 4 to 7 inverted outlets (watching TV at night, making coffee in the morning, etc.). Otherwise the inverter will unnecessarily accelerate the depletion of the batteries (again, it is important to know what type and how many batteries you have). I have two 100ah LiFePO4 batteries, and on a fully shaded site and no inverter usage, I can go 3 days before I need to either find sunshine or run a generator. I have found that even with sunshine and running the inverter, my range is still only about 3-4 days before I have to run the generator.

The SolarFlex Discover system is not endless power, it just extends the time before you need to run a generator or connect to a shore power source.

As for the disconnects:
For the winter (it gets pretty cold here), I turn all three disconnects to the disconnect positions, and remove the batteries and bring them into my shop.

If you have a lead-acid battery and left it in the camper over the winter without any kind of charging, the battery is very likely dead and ruined for life. Lithium is more tolerant, but Keystone and lithium battery manufacturers suggest that it is okay to leave them installed over the winter only if they are charged, and the battery cables disconnected (the ONLY way to truly disconnect your batteries). The battery disconnect, even when in the disconnect position will still have parasitic drains on the batteries for various loads that cannot/should not be eliminated (LP gas/co detector is one). So I leave my battery disconnect in the powered position unless I am storing for the winter.

Depending on how cold it is where you are, keeping the batteries connected and the solar on may do nothing for you. For example, a lithium battery will not charge below 38-40 degrees (unless you have battery heaters, which using will only draw the batteries down faster and making it an uphill battle for the solar to even try to keep up). So if you are storing for the winter, my advice is simple, err on the side of caution and set all three disconnects to the disconnect positions and remove the batteries. You can always hook up a jumpstart/booster pack temporarily if you need lights or to operate any of the 12v DC systems in the meantime.

This is just a start, and my apologies if any of this is confusing, but reach out if you have any other questions on the system.

Well said! I have the same system and this was a perfect explanation of the system. Thank you.