Questions on configuration (1 Viewer)

[mbennett22]

Good Morning, I posted a version of this question in the 200 thread but think it would be better suited here.

A few months ago we sold our off-road trailer that had the redarc manager 30, 2x100watt obsidian solar panels and 200amp hour battle born batteries. I just mention this because we never had to worry LOL.

We now want to just use the 200 for camping so my goal is to keep my fridge running without worrying or having to plug it in. I currently have a dual battery setup with Slee's aux battery tray (need recommendations for a good AGM group 31). I have a Redarc BCDC 1225D installed which has an MPPT controller built in. The fridge is an ICECO VL75 ProD, and my roof rack is completely covered by a RTT.

link for fridge specs

78qt VL75Pro Dual Zone 12V Refrigerator, Portable Freezer, Overland Fridge with 5-year Warranty Compressor

Buy ICECO VLPRO 12V Fridge Portable Freezer at the Lowest Price. vl75pro overland fridge has two reversible lids for multi-directional opening. 12V DC power port on both side. Sized for outdoor living. LA local tech support.

icecofreezer.com

Upgrade my current aux battery (group 35) and add in a 100-watt Lensun hood mounted solar panel. I also plan on getting a solar suitcase later for when I want to park in the shade. I drive to work Monday - Friday, 35-40 min trip, so about 1h10 min round trip each day. Would I be able to run a fridge 24/7 with this option?

The second part of this would be the ability to monitor the system. I have been looking at the Victron BMV-712, which looks great but I have read reviews that it won't take into account the + power coming in from solar, does that mean I would have to forgo the Redarc bcdc 1225 and get a Victron solar controller?

Thanks for the help

 

[e9999]

it's impossible to answer your question about enough power or not since that depends entirely on the level of insolation you would be getting. Now, that out of the way, in general I think a 100W panel is enough for a typical fridge, with good insolation as in the Southwest of the country most of the year, if exposed much of the day. Not dramatically overkill but OK. So my guess would be that if you expose the panel for 1h only a day, it would not be enough in the long run. Just run the numbers.

 

[mbennett22]

it's impossible to answer your question about enough power or not since that depends entirely on the level of insolation you would be getting. Now, that out of the way, in general I think a 100W panel is enough for a typical fridge, with good insolation as in the Southwest of the country most of the year, if exposed much of the day. Not dramatically overkill but OK. So my guess would be that if you expose the panel for 1h only a day, it would not be enough in the long run. Just run the numbers.

Insulation, meaning for the fridge? I did buy the insulation cover for the fridge as well just from reading a lot of comments on here and reviews that it really does help quite a bit.

 

[e9999]

^
no, insolation, how much sunlight you are getting. (Yes, fridge insulation matters too, but much less.)

 

[mbennett22]

^
no, insolation, how much sunlight you are getting. (Yes, fridge insulation matters too, but much less.)

I thought that was a typo, yea in south Texas we get plenty of sun.

 

[mbennett22]

it's impossible to answer your question about enough power or not since that depends entirely on the level of insolation you would be getting. Now, that out of the way, in general I think a 100W panel is enough for a typical fridge, with good insolation as in the Southwest of the country most of the year, if exposed much of the day. Not dramatically overkill but OK. So my guess would be that if you expose the panel for 1h only a day, it would not be enough in the long run. Just run the numbers.

Dang, I just noticed I made an error on the aux battery, I meant group 35. Do you think that your comment would still hold true for a group 35.

 

[e9999]

It makes no difference what battery you have in the long-term as far as sizing the panel. You need to produce more power with the panel than you use with the battery or the battery level of charge will decrease with time. Of course, if you have a larger battery it will be charged "enough" longer than a smaller one, but still, you want your panel to produce at least as much as you are using. In my experience a 100Ah battery with no power input would last about 2 days with a typical fridge and temps, not much more than that.
Your 100W panel might give you close to 100W at best maybe under a scorching South TX sun at noon in the summer, but for one hour that is only about 0.1 kWh or about 8Ah for a 12V system. Basically, that might give you a couple of hours of fridge compressor running if well insulated with a ventilated cabin, not enough for a day's worth of fridge.
Now, the above is about what sounded like a question about the driving time being enough. Maybe I misunderstood what you wrote. Of course, if you leave the truck in the sun when not driving it or when camping, then it gets better from a PV power perspective (not from a fridge one) and you might get enough power generated. On a side note, keep also in mind that a hood-mounted panel will not be as efficient as a panel mounted on the roof with an air space. Hood-mounted is really not great for a PV panel, it gets very hot and that's bad for PV power.

 

[LandLocked93]

Also maximizing the amount of current you can store while the engine is running helps leverage the fuel burned in that process.
It boils down to current storage and current use.

 

[lx200inAR]

Think he mentioned drive time because he will be getting 25 amps from the alternator/RedArc while driving.

ultimately you just need to do some math, ideally with some tested numbers. Your fridge will use a lot more power in August than it will in January.

whatever group 35 battery you put under the hood will be minuscule compared to your 200ah lithium battery.

If you drive 1hr dropping in 25amps (300w or so) and your fridge uses 60w while running (it’s probably a little more, but keeping math clean) then that buys you 5 hours (300w/60w) of runtime. your fridge doesn’t run constantl, so in jan that probably buys you 10-15hr of cool time, in Aug probably 7-8.

if you only have a 50AH (600Whr) house battery with about 40 (480WHr) usable, then your battery can only hold 8Hr of runtime on your fridge.
if you have a 100w panel, then you might have 3-4 hr a day in warm months of + production, but not much, the rest of daylight hours you will be hoping to break even.

point is, no one knows your habits but you, and there are a lot of variables. I tried to highlight the key ones and give you some examples, but you will have to solve for your own variables.

 

[LandLocked93]

Hey @mbennett22 how's this going?
If you've had some time in the scenario, curious your real-world results.

 

[mbennett22]

Hey @mbennett22 how's this going?
If you've had some time in the scenario, curious your real-world results.

LOL the "vehicle battery/solar" is overwhelming to me haha. I think eventually I will will swap the starting battery to the smaller aux battery I have now and get a bigger the Slee battery tray and have a bigger house battery. However until then we just ordered a Bluetti EB70S with the 200 watt solar panel. We can take that with us and definitely power what we need or I can just take the solar panel and hook it up to the BCDC.