Jayco Seneca, how much solar?

[Roll'n Olaf]

I would like some input from you guys. I just upgraded to a Jayco Seneca 37k. I know the coach is pre wired to handle up to 400 watts of solar power. Do you recommend to go the max 4-100 watt panels, or go 2-170 watt panels? Does 60 watts make much of a difference? The rv will be stored , when not in use, at a storage facility. So the solar power will help keep the batteries charged and assist when I cool down the residential refrigerator.

[Rustynuts]

Originally Posted by Roll'n Olaf

I would like some input from you guys. I just upgraded to a Jayco Seneca 37k. I know the coach is pre wired to handle up to 400 watts of solar power. Do you recommend to go the max 4-100 watt panels, or go 2-170 watt panels? Does 60 watts make much of a difference? The rv will be stored , when not in use, at a storage facility. So the solar power will help keep the batteries charged and assist when I cool down the residential refrigerator.

I went with the Renogy 400 watt kit with the MPPT 40 amp Rover charger and couldn't be happier. We Boondock most of the time and only run the generator in in the mornings for the coffee maker and Microwave. Here is a link to my install. I want to also mention that first day home with the coach I switched it over to 4 - 105 Trojan 6 volts which are much better IMO.


https://www.jaycoowners.com/forums/f...all-58352.html

[Les7h]

We have 560 watts and the Trojan T-105 batteries
We could survive with less watts but it is nice not to have to conserve - if we upgrade to a residential refrigerator we may want more solar but we are very happy now Les

[LaMigra]

Great information, but I would like to know if you are using a residental refrigerator with your system.

[RetiredLEO]

I would check out Lithium batteries.Prices seem to be coming down some. Still very expensive to begin with but two of them will do what 4 AGM's will do, only weigh 59lbs for a pair instead of over 200 lbs for AGM's or wet cells, can be drawn down to 10% charge instead of 50% charge. Will charge faster than AGM's which could translate to smaller panels, can be charged 3,000-5,000 times, like AGM can even be in the Coach with you without venting, can be placed in any position.
People who have them, love them and would never go back to wet cells or AGM's

[Gizmopilot]

Originally Posted by Roll'n Olaf

I would like some input from you guys. I just upgraded to a Jayco Seneca 37k. I know the coach is pre wired to handle up to 400 watts of solar power. Do you recommend to go the max 4-100 watt panels, or go 2-170 watt panels? Does 60 watts make much of a difference? The rv will be stored , when not in use, at a storage facility. So the solar power will help keep the batteries charged and assist when I cool down the residential refrigerator.

You need to do a power need assessment - What do you want to run for how long and how much power does it use.

IE (my case) residential fridge - 75 watts per hour on average x 24 = 1800 consumed total for an hour.

A simple rule of thumb is expect 3 hours of good sunlight most places in the US (the further south is more/ winter is less and worse angle with the sun lower on the horizon)

So take 1800/3=600 watts needed

Keep in mind lithium batteries are nearly 100% efficient in both charging and discharging, If you go with lead acid it is much less efficient so you would need more (I went lithium) solar to get back to 100% charge on your batteries.

Solar panels as a rule don’t collect what they are rated at, it seems they get closer to 80% of their rating so 600 / .8 = 750 watts also during winter you get less available hours and to get the most you need to point the panels toward the sun otherwise you can lose upto another 40%.

Lastly your inverter is not 100% efficient either closer to 86% to 94%

Now for the good news the prewired for solar (at least on my 2018 Jayco) is rated at 30amps on the roof so as long as you don’t go over 30amps you can pretty much use any panels and wattage you want.

I plan on putting 960 watts of renogy 160 watt flexible panels or 6X160 wired with 3 in series (to keep the amps at about 9) and then duplicate that and wire the 2 groups in parallel bringing the amps up to 18 and the voltage would be closer to 69. Ideally you want to run power at higher voltage and less amperage otherwise the length of the wires will have a bigger impact and reduce the power made. I can add 2 more panels if needed before needing a second wiring run from the roof.

I already have a victron MPPT solar controller (100/50) that will convert this to as much as 50 amps at 14.4 volts to my lithium batteries (it also supports lead acid batteries) producing a max of 720 watts.

It is OK if the panels should produce more energy than the controller can put into the batteries (That is why you use a controller to manage that).

Solar panels also reduce capability over time, so I wanted more solar to make up this and for reduced sun angles, cloudy days, etc.

Hope this helps

[Mustang65]

Originally Posted by Gizmopilot

IE (my case) residential fridge - 75 watts per hour on average x 24 = 1800 consumed total for an hour.

Don't forget that when a residential fridge (at least the Frigidaire models) goes into defrost mode you can expect a 45 amp draw on your batteries (between the batteries and the inverter). Not sure what determines when the fridge will go into defrost mode (times door opened, humidity, temperature fluctuations...) as I have yet to see any concrete documentation on what triggers it. I do not remember as to how long the defrost cycle is, but 20 to 30 minutes rings a bell.

So, the number of times it will come on in a 24 hour period, well your guess is as good as mine. It would be GREAT if you could schedule the defrost mode to come on during peak sunlight, but the odds of that happening are pretty slim.

Don

My Registry

RVing with SOLAR

[Gizmopilot]

Originally Posted by Mustang65

Don't forget that when a residential fridge (at least the Frigidaire models) goes into defrost mode you can expect a 45 amp draw on your batteries (between the batteries and the inverter). Not sure what determines when the fridge will go into defrost mode (times door opened, humidity, temperature fluctuations...) as I have yet to see any concrete documentation on what triggers it. I do not remember as to how long the defrost cycle is, but 20 to 30 minutes rings a bell.

So, the number of times it will come on in a 24 hour period, well your guess is as good as mine. It would be GREAT if you could schedule the defrost mode to come on during peak sunlight, but the odds of that happening are pretty slim.

Don

My Registry

RVing with SOLAR

My numbers are from the Energy Star Sticker from my whirlpool that came with my Jayco and these are the average over a 24 period.

I have observed the defrost mode and it does increase the amp draw but it isn’t for more than maybe 15 minutes, and is taken into consideration in my calculations.

I have also tested this configuration by running from my batteries for over 12 hours repeatedly and observing the power draw via my bmv-712 and it is consistent.

Are you seeing a different 24 hour average power need for your refrigerator?

[Grumpy]

Originally Posted by Mustang65

. Not sure what determines when the fridge will go into defrost mode (times door opened, humidity, temperature fluctuations...) as I have yet to see any concrete documentation on what triggers it. I do not remember as to how long the defrost cycle is, but 20 to 30 minutes rings a bell.

Older domestic fridges had a defrost timer that usually cycled every 8 hours. Imports, such as SAMSUNG use a sensor that is on the coil that senses the ice/frost buildup and turns on the heater. With FRIGIDAIRE now being an import(owned by Electrolux, built in Mexico)it may operate either way.

I think Whirlpool has gone to the sensor system and they are still built in the US.

[LI-Camper]

GizmoPilot,
I think 80% of 600 watts is 480 watts , not 750 watts.

[Gizmopilot]

The goal is to get 600 watts, so if you start with 750 of rated capacity and only get %80 you would end up with 600 which is the need.

[Rick 17RB]

The 400 watt rating must be pointed absolutely correct and near the equator. Lol. But truly I've never got more than 85 watts out of my 100 watt panels. I'm sure that 100 is the maximum under nominal conditions. I'd go with 4 100's. It's quite unlikely they will output that but I'm quite sure there is a safety factor built in for that very senario.

[RetiredLEO]

Originally Posted by RetiredLEO

I would check out Lithium batteries.Prices seem to be coming down some. Still very expensive to begin with but two of them will do what 4 AGM's will do, only weigh 59lbs for a pair instead of over 200 lbs for AGM's or wet cells, can be drawn down to 10% charge instead of 50% charge. Will charge faster than AGM's which could translate to smaller panels, can be charged 3,000-5,000 times, like AGM can even be in the Coach with you without venting, can be placed in any position.
People who have them, love them and would never go back to wet cells or AGM's

When we finaly get our Coach I'm going to do 3-100's More coverage to soak in the solar.
This is the system that looks like a winner so far:
https://battlebornbatteries.com/shop...ithium-bundle/

[Gizmopilot]

Originally Posted by RetiredLEO

When we finaly get our Coach I'm going to do 3-100's More coverage to soak in the solar.
This is the system that looks like a winner so far:
https://battlebornbatteries.com/shop...ithium-bundle/

That kit - is very close to what I did, but keep in mind that if you drain those 2 batteries the included charge controller can only charge at MAX 30 amps at 14.4 volts or nearly 7 hours to charge the batteries from empty (if you are not also using 12 volt appliances which you normally are).

Also the 3 100 watt panels even at max (equator aimed perpendicular to the sun) will only provide 20.8 amps which would mean it would take 10 hours to charge the batteries from empty. More likely the 3 panels will only provide about 16 amps to the batteries.

So in essence if your goal was to not run your generator, you probably will still need to daily for an hour or two.

I originally bought the same charge controller and returned it for the 100/50.

What is really nice about these charge controllers is that it allows you to go much higher voltage and get much more solar capacity then the default jayco kit advertised.

They also allow you to put more solar than it can output, with out issue you just need to stay within the open voltage/amp input ratings - so even if it was the perfect solar day it won’t hurt the controller, batteries, etc.

The reason I went with the larger controller is - it allows you to add more panels down the road with out losing the cost of the controller when it is maxxed out ie price sweet spot. $225 vs $325 for over 50% more charge ability.

[RetiredLEO]

Originally Posted by Gizmopilot

That kit - is very close to what I did, but keep in mind that if you drain those 2 batteries the included charge controller can only charge at MAX 30 amps at 14.4 volts or nearly 7 hours to charge the batteries from empty (if you are not also using 12 volt appliances which you normally are).

Also the 3 100 watt panels even at max (equator aimed perpendicular to the sun) will only provide 20.8 amps which would mean it would take 10 hours to charge the batteries from empty. More likely the 3 panels will only provide about 16 amps to the batteries.

So in essence if your goal was to not run your generator, you probably will still need to daily for an hour or two.

I originally bought the same charge controller and returned it for the 100/50.

What is really nice about these charge controllers is that it allows you to go much higher voltage and get much more solar capacity then the default jayco kit advertised.

They also allow you to put more solar than it can output, with out issue you just need to stay within the open voltage/amp input ratings - so even if it was the perfect solar day it won’t hurt the controller, batteries, etc.

The reason I went with the larger controller is - it allows you to add more panels down the road with out losing the cost of the controller when it is maxxed out ie price sweet spot. $225 vs $325 for over 50% more charge ability.

Good advice as usual The difference in price between the 100/30 and 100/50 is minimal. Sounds like I might be way ahead of the game to go to three 160's.
Also intend to add a auto gen start set for gen start at 10% remaining charge in the Li's. Also a need for the auto start of the gen when we would be connected to power and if shore power got lost to run the AC for our Golden Retriever if we're away from the Coach.

[Gizmopilot]

Originally Posted by RetiredLEO

Good advice as usual Sounds like I might be way ahead of the game to go to three 160's.
Also intend to add a auto gen start set for gen start at 10% remaining charge in the Li's. Also a need for the auto start of the gen when we would be connected to power and if shore power got lost to run the AC for our Golden Retriever if we're away from the Coach.

This message puts me at 100!

If you get all of that victron energy equipment the only piece you are missing is the color console that has all of that advanced management and conects all of it to the internet (assuming you have internet access) this would give you the extra piece of mind that you can check remotely on your systems and know your extended family is safe ( I could show you how to even setup 2 way video so you can see and speak to them from your smart phone)

Link

[Mustang65]

Originally Posted by Gizmopilot

My numbers are from the Energy Star Sticker from my whirlpool that came with my Jayco and these are the average over a 24 period.

I have observed the defrost mode and it does increase the amp draw but it isn’t for more than maybe 15 minutes, and is taken into consideration in my calculations.

I have also tested this configuration by running from my batteries for over 12 hours repeatedly and observing the power draw via my bmv-712 and it is consistent.

Are you seeing a different 24 hour average power need for your refrigerator?

What is the battery voltage and lowest voltage, while the defrost mode is in operation for those 15 - 20 minutes?
Don
My Registry

RVing with SOLAR

[Gizmopilot]

Originally Posted by Mustang65

What is the battery voltage and lowest voltage, while the defrost mode is in operation for those 15 - 20 minutes?
Don
My Registry

RVing with SOLAR

I have 2 lithium iron phosphate battle born batteries, the voltage doesn’t typically drop very much.

From memory I would say it was around 13.3 volts, currently it is winterized.