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frankpaige
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# Posted: 10 Mar 2025 09:37pm
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What would be the results adding a chest freezer to this system?
2-100amp, Walmart Deep Cycle Marine Batteries
2-220 watt solar panels.
The freezer is 3.5 cu ft. Says it uses 193 KW a year.
Southern exposure is really great.
Would this be doable? Or do I? Need to add any panels? Add any batteries?
What am I missing.
Thanks
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Nobadays
Member
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# Posted: 10 Mar 2025 11:31pm
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What else are you running with this system?
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frankpaige
Member
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# Posted: 11 Mar 2025 08:50am
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Pretty much nothing.
I recharge the IPad, hearing aids at night.There is a rechargeable toothbrush every 5-6 days. There are a total of 3LED lights. Usually there is only one that is used. The rest. Microwave and coffee pot are handled with the Generator.
My hope is to turn the freezer down to what a refrigerator temps would be.
IDK
Just kicking thoughts around.
Thanks
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MtnDon
Member
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# Posted: 11 Mar 2025 08:54am
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Does that freezer run on DV or AC?
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frankpaige
Member
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# Posted: 11 Mar 2025 08:55am
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My plan is AC.
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paulz
Member
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# Posted: 11 Mar 2025 09:02am
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Can’t quote numbers but my little 1.5 cubic foot fridge has surprised me by freezing foods this winter. Temp difference between outside air and temp setting makes quite a difference. Mine is outside so frequently in the 50s in afternoon, down to high 30s overnight. So it doesn’t have to run that often and use much juice. That will change this summer, luckily the solar goes up then. Anyway the cooler you can make its location the better, I know you’re up in the mountains.
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Nobadays
Member
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# Posted: 11 Mar 2025 10:15am
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I'm assuming a 12v system...
193kwh/year = ~530wh/day
200ah @ 12v - 50% usable = ~1,200wh/day
2 x 220w panels - 440 x 5hr = 2,200wh/day but... I would not count on more than 80% so realistically - ~1,760wh
Theoretically yes, but with maybe two days without sun to dead batteries with your combined loads. This is maybe too tight if you plan to leave food in it when gone. I'd consider switching to 2 x lifepo4 100ah and maybe add a panel or two paired with a good MPPT SCC for better charging on mediocre sun days.
LiTime has 100ah lifepo4 with low temp protection and Bluetooth connectivity for ~$200 ea. The low temp protection works by not allowing charging below 32*F but does allow discharging down to -4*F.
If you do decide to move ahead, the best way to control a freezer (that I know of) is to use an Inkbird temp controller. Plug the Inkbird in the wall, the freezer into the Inkbird and the Inkbird temp probe in the freezer. This allows the controller to turn the freezer on and off as needed to hold the temperature you want. You can set a delay to protect the compressor and on/off temperature range. Best part is they are only about $35.
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gcrank1
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# Posted: 11 Mar 2025 10:16am
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Thoughts:
The chest freezer will hold the cold better than an upright fridge
Putting prev cold stuff in it (at least the inside temp) wont make it run harder to cool down something warm
Once it hits saturation cold inside it wont cycle much
Panels are cheap if you buy used, get matching panels and get min of 3, run MPPT solar control, you wont regret being a bit over paneled for todays use, and use always rises.
Lead acid batteries will last best if only the top 25-30% of amps are taken, if you go 50% or deeper it dramatically shortens the time. The bat-bank is what will carry you overnight AND through a period of poor overcast recharge. So 200ah of bats really only has 50 to 60ah usable on a regular basis or you murder the bats. You can wire multiples of 12v bats in parallel but dont go more than 3; that would be 75-100ah.
You might want to consider 24v, wish I had. You can use smaller gauge wires on 24v and/or go longer distances for the gauge than at 12v. Def do this from panels to charge control (must have a 24v compatible, common now). It can intake 24v and put out 12 or 24v. If you use those same bats wired in series each pair make 24v and you can use up to 3 banks of 2 wired series/parallel, thus start with 2 and be expandable.
The inverter must then be 24v and output 120vac. The bigger the inverter the more it sucks amps just running itself. I suggest an inverter that has about 25% more capacity than your start-up load from the freezer.
In a typical 'days use' I liked my system to be able to recover the bat-bank fully by noon from the bat drawdown of the prev late afternoon and overnight (when there was use but no charging).
Fwiw, ours was 600w array, 24v to acc, 12v to bat-bank orig 400+ah to 12v to 120vac 1000w inverter and a 60' run from 'bat-shack' to cabin. I consider this a min size unless all you want is very basic; ie, no fridge, electricity. Some others may disagree.
Note that right now LFP batteries are the cheapest they have ever been but that may quickly change with the China tariffs where all the bat cells come from. LFP was a game changer for us as each 100ah LFP has easily 2x the available power as a lead acid bat; so half the batteries to deal with and FAR longer lifespan.
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Nobadays
Member
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# Posted: 11 Mar 2025 10:37am
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Another thought... I was using a Giandel (cheap'ish Chinese) inverter in my shop for a couple of years and this lead to very shortened life of some batteries.
This inverter is considered one of the "better" cheap inverters but it leaves a lot to be desired.
First is Idle power consumption which is many times higher than a comparable Victron inverter.
Secondly, and more importantly, there is no way to adjust the low battery cut-off point, it is preset. For a 12v inverter this is set at 9.5v!! This means the first time you hit a week of rain/snow your batteries will be drained to less than just dead!
These two issues are why we switched to Victron. Yes they are roughly twice the cost but not if you consider the cost of replacing the batteries ruined by the cheap inverter.
The Victron SCC is just heads above most other MPPT Controllers especially on marginal sun days.
My two cents! Hope it helps!
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frankpaige
Member
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# Posted: 28 Mar 2025 06:57pm - Edited by: frankpaige
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Nobadays
Purchased the Ink Bird temp controller. Used it in conjunction with my Jackery for the men time. Works like a champ! Printed directions are not the greatest. But, thanks to YouTube all is well.
I purchased (2) 200 watt panels to combine with the other 2.
Got those up today, connecting tonight.
If nothing else, the Jackery will power the freezer.
Tired of hauling ice in, and worse, hauling melted water out from the cooler.
That suggestion for the ink bird was a lotto winner. Thanks
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Nobadays
Member
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# Posted: 28 Mar 2025 11:43pm
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Glad it's working for you!
BTW, we also use a 3.5cuft freezer - as a freezer at our cabin. One thing we noticed, no surprise really, is that it is very efficient when full but very inefficient when partially empty. We saw a noticeable energy usage uptick our first year using it towards the end of the season when we were getting ready to leave for the year. Took a bit to figure out that as my wife began emptying the freezer so we could shut it off, the power we were using each day was climbing. Finally two and two together and filled the bottom of the freezer full of water jugs, stacking them up to keep it full, adding another jug when there was room. The power consumption went down shortly after those jugs all froze.
This to say maybe there is a way to add water jugs in your refrigerator/ freezer so you are not trying to chill air. I think it will help lower the power consumption. A thought would be a layer of jugs then maybe a piece of 2" foam on top of them allowing you to have your foods closer to the top.
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gcrank1
Member
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# Posted: 29 Mar 2025 09:18am
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I do similar with my old chest freezer at home, the 'cold sink' sure cant hurt and we always have ice jugs to take to cabin for our Yeti-Clone 'ice' chest.
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travellerw
Member
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# Posted: 29 Mar 2025 08:30pm
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We run a stand up freezer as a fridge using an Inkbird. Nowadays you can simply buy a freezer at Costco that is capable of fridge temps. Both stand-up or chest.
Anyway, ours is fantastic and just sips power.
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paulz
Member
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# Posted: 29 Mar 2025 11:02pm
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Quoting: travellerw buy a freezer at Costco that is capable of fridge temps.
Do these not have thermostats? What do the inkbirds do different?
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travellerw
Member
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# Posted: 29 Mar 2025 11:47pm - Edited by: travellerw
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Quoting: paulz Do these not have thermostats? What do the inkbirds do different?
Up until a couple of years ago all freezers had thermostats that didn't adjust to a temperature warm enough to be used as a fridge. The warmest you could adjust them was like -7C.
For those freezers if you want to use them as a fridge you needed to install an inkbird to replace the internal thermostat.
Some manufacturers caught on that some people want to use them as fridges and started putting wider thermostats in them recently.
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paulz
Member
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# Posted: 30 Mar 2025 09:15am
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Ah ok thanks. Never had a stand alone freezer, just regular old household combos.
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Nobadays
Member
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# Posted: 30 Mar 2025 10:47am
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Quoting: travellerw Up until a couple of years ago all freezers had thermostats that didn't adjust to a temperature warm enough to be used as a fridge. The warmest you could adjust them was like -7C.
Also, often times freezers have a several degree temperature differential..... between coming on and going off. Their whole function is to keep food frozen. The Inkbird allows you to set that differential to keep a more constant temperature.
A side note.... I found in my beer kegerator that I can keep an even - contents - temperature by inserting the Inkbird probe in a gallon of water. This way it is monitoring the temperature of the contents not the air temperature.
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paulz
Member
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# Posted: 30 Mar 2025 12:03pm
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Quoting: Nobadays Also, often times freezers have a several degree temperature differential..... between coming on and going off. Their whole function is to keep food frozen. The Inkbird allows you to set that differential to keep a more constant temperature.
Wouldn’t that result in more on off times, increasing start voltages, coil heat up and energy use?
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Nobadays
Member
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# Posted: 30 Mar 2025 08:13pm
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I usually set 3 degrees differential and there is the ability add a delay between off/on so you don't try to cycle the compressor that Jay still be under pressure.
It would seem it could have more energy usage but my experience is no, it doesn't. But, again I keep my temp probe in a gallon of water, this way you aren't measuring air temperature but rather the temperature of the items you are trying to keep cool. I know my kegerator does not cycle on and off too many times a day.
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paulz
Member
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# Posted: 31 Mar 2025 07:08am - Edited by: paulz
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Ok well the proof is in the pudding. Obviously they don't have to run as long. How do you add the sensor?
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Nobadays
Member
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# Posted: 31 Mar 2025 09:43am
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Quoting: paulz How do you add the sensor?
There is a "sensor" with about 3' of wire coming off the control head.
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gcrank1
Member
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# Posted: 31 Mar 2025 10:25am
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Looks Like 'plug & play'
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