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  1. #11
    Site Team Redapple63's Avatar
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    Quote Originally Posted by Petrovsky View Post
    Interesting how everyone is focusing on only the fridge draw down. Will you not be using lights, water pump, and if cold, heater. I have a 120 VAC/propane 8 cuft fridge from Dometic. I will eventually change to the 12volt system but not before I do a complete analysis of my power requirements. For me, it looks like 2 Battleborn, 2 160 watt solar panels or higher (ideal would be 400), invertor, and most importantly, a honda generator. I agree with the post above concerning the effects on the fridge except that the sun hitting the fridge side has more effect on my fridge than the 12volt due to the efficiency of the system.

    A full analysis of your utilization is in order and that includes everything you use on a daily basis for a week divided by 7 and then multiplied by 15%. Note that you are unlikely to hit 7 full days of sun a peak intensity in all your camping excursions.

    In the fall and the spring the amount of sunlight and inclination depending where you camp will be a factor to consider. Luckily the Li batteries charge fast, and are much lighter than wet cell or AGM's.

    Like I said....I am just starting to analyze my own requirements but I know that I will have to monitor at least a weeks camping this summer in order to estimate my needs. One way I intend doing this is right in my driveway. Plugged in, all power off, batteries disconnected (isolated as I don't want to add converter voltage). Amp meter on incoming line and use each appliance, fan, light, etcetera. I know this will be a/c amps but at least it is a start.

    Good luck and don't forget recharging your usb devices.....
    If you look at post number 8 , I did that at least a rudimentary level.
    2019 GMC 3500 SRW Sierra Denali Duramax
    2020 Reflection 315RLTS

  2. #12
    Site Sponsor SolarPoweredRV's Avatar
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    Quote Originally Posted by Soundsailor View Post
    We're interested in the drawdown from the Furrion 12 volt refrigerator when used "off-grid". The Furrion manual describes the power use in "off-grid mode" as 5.3 Ah (Amp-hours) when the external temperature is 77 degrees F. That would suggest a battery budget of 127.2 Ah (5.3 x 24) per day. The question is: Does the refrigerator use that much? For instance, the manual suggests that there is an "Off-Grid Vacation mode" which they suggest helps to conserve power usage when disconnected from the grid. But they're not clear if the lower draw is the 5.3 Ah or some other amount. And is the 5.3 Ah an average figure accounting for the time the refrigerator compressor is not working or is it the draw when the compressor is on? This is important in deciding on the size of our battery bank. A lot of our camping is done off the grid. And while we will have solar to recharge the batteries, many of the campgrounds we like the best are heavily wooded minimizing the amount of solar we will get.

    So how to size the battery bank? If we assume 127.2 Ah per day, then to go for an off-grid excursion of five days without any recharge from the sun would take 636 Ah of battery (for reference the battery that comes with the 260RD is 100 Ah but since it is a lead-acid battery it should not be discharged more than 50% leaving an effective budget of 50 Ah, not even enough to run the refrigerator for 12 hours leaving out any other draws on the battery.) Currently, we're planning on 3 200 Ah LifePO4 batteries but are considering adding a 4th. Lithium batteries theoretically can be discharged to 0%, but in practice, they last longer when discharge to no more than 30%. So the 3 batteries we have now would give a battery budget of 3 x 200 Ah x 70% (100% - 30%) or 420 Ah. That might be enough for a little over three days assuming the 127 Ah draw is correct and we don't run too much else off the battery.

    Have any of you done any real-world observations on what the Furrion refrigerator actually uses? Any suggestions on how to size the battery bank? I'm already leaning towards a 4th battery. While we will get some solar recharge even from the shadiest of sites (I'm going to deploy two 100 W portable arrays that can be moved around to be in the sun, plus a 100 W panel in addition to the 160 W panel already on the roof), right now I'm planning on worst-case numbers. We also have a generator (rather not use it due to the noise) and will be employing a 40 A DC to DC charger to allow the TV to charge the batteries when driving.
    You have received some good suggestions. However, the bottom line is you can't know until you are out camping in your rig, doing the things you and your family do.

    I have a friend, who knows a guy...

    Anyway, this guy spent months calculating all of his electrical needs, figuring out all the variables for his Solar and battery system. He knew exactly how much energy he would use on any given day and how long his batteries would last. Well, you guessed it, he fell horribly short on his calculations during his first week of camping at Yellowstone NP.

    Myself, I figured out my biggest usage would be our furnace. I knew from past experience that we could get by for one night on a pair of 6v batteries, about 100ah +/-. So, I designed my system with a whole lot of batteries (400ah) and a whole lot of Solar (1200 Watts) and then we spent a month in a campground without hooking up to shore power. The main reason for the month's stay was to test the new electrical system. Since it was December we experienced several cold nights. What we found out is that we needed to double our battery bank. While we were able to get through the entire month without any issues, we found that the reserves we expected just weren't there.

    Once we doubled the size of our battery bank we were much more relaxed about our system and could relax about monitoring the system. This also allowed us to be comfortable using the Air Conditioner when we stop for lunch on hot days and not be concerned the battery could not keep the furnace running through the night.

    Bottom line: make your best guess as to how much Solar and battery storage you are going to need and then just live with it for a while. You will soon know if you need more batteries or a larger Solar array.
    David and Peggy
    2019 Ford F350 Lariat, 6.7L Diesel, Dually, Long Bed
    Running with 20k Reese Goosebox (Love It) and Ford Factory "Puck" system.
    Stopping with 8,000 lb Disc Brakes and Titan Hydraulic over Electric Brakes system.
    Powering all this fun with 1200 Watts of Solar, two Tesla, Model S, battery modules, 24 volt Victron Inverter.
    2018 Solitude 310 GK

  3. #13
    Seasoned Camper chemist308's Avatar
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    I would recommend wiring in a Victron shunt. That would tell you exactly how much DC power your rig is using and how much life is left. That said, if I had a fridge that ran DC only, I'd want an extra battery at the least.
    2018 Grand Design Reflection 337RLS
    2020 Ram 3500 SRW
    https://c2.staticflickr.com/8/7803/4...56f2161a_m.jpg

  4. #14
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    We recently purchased a 2500Rl with 12 v furion frig, 165 w solar and two lead acid batteries. Our first Dry camping experiment was three days of sunny to partial sun. We were very easy on the power needed but the last night it did dip into the high 30 degree temps. Heat was set to around 58 so it did turn several times in the evening. I had no way to monitor the power being used but I did monitor the battery level. Around 3 AM the batteries went off. We dry camp about 50% of the time many times around 5 days at a time. I do have a 3000 w generator but prefer not using it much.
    I have decided to bite the bullet and install two additional 175W solar panels for a total of 515W, 3000w inverter/charger and three 100ah lithium batteries. This might be a little overkill for our size of trailer and use demands but rather be more need than less. A side note. We are in norther California and a lot of our dry camping is along the ocean and mountains so foggy and/or tree canopy can hinder solar power.
    I would highly advise you upgrade to a minimum AGM or 6 volt batteries. I don’t have personal experience withAGM but our past TT I had good experience with the 6 volt batteries used in conjunction with generator.

  5. #15
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    Your comments are good. After having gone three days dry camping with nice daytime temps but cold evenings wit heater set to 58 batteries ran dry on third night. I have standard 165 w solar with two lead acid. Want to try and eliminate generator use as much as possible. I’m installing two additional 175 watt panels, three 100 watt lithium batteries and 3000w charger/inverter. Not sure the third battery is needed but why not have it. For reference I live in northern cal with 2500rl with 12v fridge

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