Solar for two refrigerators and a freezer chest.

[Greasyrick]

Hi, new here, I`m trying to come up with a decent package to run my Two refrigerators and a Freezer chest.
One of the refrigerators pretty new not even a year-old, runs at 5 amps 120v (that`s on the door decal), that gives about 600watts.
The other refrigerator is about 15 years old, NO STICKER, but I assume it pulls more power, being that old.
The freezer chest I assume it pulls half of what the refrigerator uses.
I know that start up watts are to be taken into consideration, so I`m going with at least 2500 watts for all 3, I`m I being too conservative or realistic about that number?
I purchased a Killawatt meter from Amazon to measure the equipment, it arrives tomorrow, but I was wondering if my estimates are somehow correct.
Planning to use a 3000-or 3500watt inverter with 4 12-volt 200ah LifePo4 plus batteries, (don`t know if it`s enough batteries) I was told in another forum to use a 48-volt setup which is better.
So, wiring the 4 batteries in series to get 48 volts will keep me at 200ah.
Question is, Is that enough to get those 3 fridges running all day and night in a 24 hour period, (of course it will be cooler and the doors will not be opening as much during the night, plus the freezer chest usually stays shut most of the time). I don`t know the exact number of surge watts all 3 consume, but I was wondering if someone has an idea of what to look into, plus I assume the solar panels will also be providing consumable power during the day on top of charging the batteries, also how many solar panels to charge those batteries in one day with about 5 hours of direct sunlight, plus some extra wattage to run the loads during the day, I`m planning to get t least 16 100 watt panels, (don`t know if enough) wired to supply the 48 volts with a MPPT Renogy 60 amp controller that can do 12V 24V 36V and 48V. I can put the controller pretty close to the batteries, about 4 feet.
The newer refrigerator will be about 45 feet from the inverter and the older refrigerator with the freezer chest will be next to each other no more than 25 feet from the inverter. This is already the 120v ac side, don`t know if I loose too much with the loads too far from the inverter using extension cords.
Also, there are not many choices for a 48volt dc to 120v ac 3500 inverters out there, planning to NOT hook it to a generator or to the power grid, just plug the refrigerators and chest cooler with extension cords from the inverter, unless I can wire a little breaker box to the inverter with 3 breakers for the 3 loads, then hook extension to them.
What inverter you guys recommend?

Thanks for your responses in advance.

 

[sunshine_eggo]

You're a little ahead of yourself, but it looks like you've considered most things.

At a guess, you're looking at about 4-5kWh/day assuming full size appliances.

4 * 12.8 * 200Ah = 10.24kWh - about 2 days of backup power.

You don't necessarily have to get an inverter rated at max continuous for startup of all 3 components. Bigger inverters have bigger idle consumption meaning more consumed power even if you don't power loads. It might make sense to get a smaller inverter with legit surge capability. There are 1000W inverters with true 2000-3000W surge capability.

Run the kill-a-watt on each for a few days making sure you open and close them several times simulating use. That will give you a good idea of the total energy usage as well as actual power consumption.

Once you have your energy needed, you'll be able to size everything.

Concerns with 120VAC losses through extension cords can be addressed by higher quality extension cords, but given the currents/distances involved, I doubt you'll need anything more than standard duty cords.

"5 hours of direct sunlight" this is a concern. This implies you may have some shading. If that's the case, it complicates things.

You can get your exact solar insulation via https://pvwatts.nrel.gov/, which factors in weather. You can even download the HOURLY performance of a simulated array and estimate what you'll lose due to shading as well as info you can use to plan for different seasons.

If you get 5 hours of insolation, you'll likely only need about 1000W.

 

[WYtreasure]

Hello Greasyrick, welcome to the party.

My home runs on about 3k a day while running 2 freezers, 2 fridges, lights, microwave, televisions, computers. The clothes dryer, hot tub and water heater can double or triple consumption by doing lots of laundry, refilling the hot tub or lots of showers.

The meter you have coming will help you complete an energy audit, so will looking at your electric meter for a few days. There's a link in my signature for the energy audit.

Extension cords are not a great idea but adding an off grid sub panel, wiring and outlets can get expensive. If you must use an extension cord, up the quality to 12 gauge wire. Your appliances will not like you if you use 14 or 16 gauge wire. Test what I say by using 16 or 14 gauge wire and feel how warm they get towards the end of a run cycle on a fridge.

Sunshine has good advice and there is much more to consider after you know your load requirements.

Enjoy the show.

 

[Greasyrick]

You're a little ahead of yourself, but it looks like you've considered most things.

At a guess, you're looking at about 4-5kWh/day assuming full size appliances.

4 * 12.8 * 200Ah = 10.24kWh - about 2 days of backup power.

You don't necessarily have to get an inverter rated at max continuous for startup of all 3 components. Bigger inverters have bigger idle consumption meaning more consumed power even if you don't power loads. It might make sense to get a smaller inverter with legit surge capability. There are 1000W inverters with true 2000-3000W surge capability.

Run the kill-a-watt on each for a few days making sure you open and close them several times simulating use. That will give you a good idea of the total energy usage as well as actual power consumption.

Once you have your energy needed, you'll be able to size everything.

Concerns with 120VAC losses through extension cords can be addressed by higher quality extension cords, but given the currents/distances involved, I doubt you'll need anything more than standard duty cords.

"5 hours of direct sunlight" this is a concern. This implies you may have some shading. If that's the case, it complicates things.

You can get your exact solar insulation via https://pvwatts.nrel.gov/, which factors in weather. You can even download the HOURLY performance of a simulated array and estimate what you'll lose due to shading as well as info you can use to plan for different seasons.

If you get 5 hours of insolation, you'll likely only need about 1000W.

Ok, I used the link you gave me, my house faces North, I have a nice direct sunlight on the East side of the house for the morning and the same in the afternoon on the west side, no trees or buildings

I don`t remember where I saw that about 6 hours of direct sunlight, I might have been confused.
I calculated 20 panels of 12v 100 watts each giving me 2000 watts DC system size into the data.
I input 1% shading (since there are no trees or buildings) giving me an estimated system loss of 12.30%.
Here are the results:

3,136 kWh/Year*

RESULTS​

System output may range from 3,002 to 3,271 kWh per year near this location.

Month	Solar Radiation ( kWh / m2 / day )	AC Energy ( kWh )	Value ( $ )
January	4.79	235	27
February	5.22	230	26
March	6.30	306	35
April	6.73	301	34
May	6.77	312	36
June	6.03	269	31
July	5.61	256	29
August	5.45	250	29
September	5.44	246	28
October	5.79	274	31
November	5.15	240	27
December	4.34	215	25
Annual	5.64	3,134	$ 358

DC System Size	2 kW
Module Type	Standard
Array Type	Fixed (open rack)
Array Tilt	20°
Array Azimuth	180°
System Losses	12.30%
Inverter Efficiency	96%
DC to AC Size Ratio	1.2

Modify the parameters below to change the overall System Losses percentage for your system.

 

[sunshine_eggo]

"5 hours of direct sunlight" implies you only have 5 hours of exposure per day.

"5 solar hours" is a more accurate way to express the intent.

You modeled the array @ due South and 20° tilt.

If that's the case, than 2kW is more than you need. Assuming 5kWh:

5kWh/4.43h = 1.13kW of solar - in December. All other months will outperform it.

You'll likely still have overcast days that will throw a wrench into things, but that's what a generator is for. With a couple days of battery, you'll likely rarely need the generator.

 

[Greasyrick]

"5 hours of direct sunlight" implies you only have 5 hours of exposure per day.

"5 solar hours" is a more accurate way to express the intent.

You modeled the array @ due South and 20° tilt.

If that's the case, than 2kW is more than you need. Assuming 5kWh:

5kWh/4.43h = 1.13kW of solar - in December. All other months will outperform it.

You'll likely still have overcast days that will throw a wrench into things, but that's what a generator is for. With a couple days of battery, you'll likely rarely need the generator.

So, providing the average estimated of 4-5kw/h for the total combined of the 3 appliances, (I`m I right)? you think that the 4 200ah batteries at 48 volts and the 20 panels hooked to do the 48 volts will be sufficient to run those 3 appliances every day without running out of battery power, correct?
Again, I`m going to wait for the Killawatt meter to get more accurate readings.

 

[Bvillebob]

Should be more than enough, assuming your panels make near rated output. One of my systems is 3.5kw of panels, with 800 ah of 24v lead/acid batteries and a 2 kw Samlex Evo inverter. It runs my shop, which include 3 freezers, of 13, 18 and 22 cf capacity. Two are fairly new, one is old. That system has no problem running them and the other needs of my shop, even in the Oregon winter with lots of cloudy days.

The freezers take 400-500 watts when they start up, but the the consumption drops into the 150 watt range, and they only run a fairly small portion of the day, at least here in a cool climate, so they don't consumer nearly as much power as the sticker might make you think.

 

[WYtreasure]

I don`t know the exact number of surge watts all 3 consume, but I was wondering if someone has an idea of what to look into, plus I assume the solar panels will also be providing consumable power during the day on top of charging the batteries, also how many solar panels to charge those batteries in one day with about 5 hours of direct sunlight, plus some extra wattage to run the loads during the day, I`m planning to get t least 16 100 watt panels, (don`t know if enough) wired to supply the 48 volts with a MPPT Renogy 60 amp controller that can do 12V 24V 36V and 48V.

I have seen that renogy is not getting good reviews these days. I've heard good things about Epever, like the Tracer 6410AN, 6415AN and the xtra series.

 

[timselectric]

So, providing the average estimated of 4-5kw/h for the total combined of the 3 appliances, (I`m I right)? you think that the 4 200ah batteries at 48 volts and the 20 panels hooked to do the 48 volts will be sufficient to run those 3 appliances every day without running out of battery power, correct?
Again, I`m going to wait for the Killawatt meter to get more accurate readings.

If you are planning to go with 48v. You should get 48v batteries. Assuming that you haven't already bought them.

 

[WYtreasure]

@timselectric has an excellent point.
The first item you purchase limits everything else you buy. The best thing to do is build the system on paper, then buy.

 

[Greasyrick]

I have seen that renogy is not getting good reviews these days. I've heard good things about Epever, like the Tracer 6410AN, 6415AN and the xtra series.

If you are planning to go with 48v. You should get 48v batteries. Assuming that you haven't already bought them.

Haven’t bought anything yet, but the price is up there for the 48 volt batteries, for less of the price of one 48 volt 10am I can get 2 12 volt 200ah batteries,

If you are planning to go with 48v. You should get 48v batteries. Assuming that you haven't already bought them.

 

[Greasyrick]

If you are planning to go with 48v. You should get 48v batteries. Assuming that you haven't already bought them.

Yes but those 48 volt batteries are up there on price, for less than the price of one 48 volt 100ah battery, I can get 2 12 volt 200ah batteries. Correct me if I’m wrong but, what’s the benefit? And how many should I get.

 

[timselectric]

Yes but those 48 volt batteries are up there on price, for less than the price of one 48 volt 100ah battery, I can get 2 12 volt 200ah batteries. Correct me if I’m wrong but, what’s the benefit? And how many should I get.

If 200ah is your goal, you will need 2x 100ah.
I'm not even sure if you can put 4 12v batteries in series. It depends on the BMS, in the battery.

 

[Greasyrick]

If 200ah is your goal, you will need 2x 100ah.
I'm not even sure if you can put 4 12v batteries in series. It depends on the BMS, in the battery.

It’s a 200amp bms it’s a 12 volt LifePo4 Plus. The non plus is a 100 amp bms , I’m looking into the plus

 

[timselectric]

It’s a 200amp bms it’s a 12 volt LifePo4 Plus. The non plus is a 100 amp bms , I’m looking into the plus

Still need to check how many can be put into series.
Some are only rated for 2 in series.

 

[Greasyrick]

Still need to check how many can be put into series.
Some are only rated for 2 in series.

• From the description
• 【Capacity Expansion & Wild Application】Ampere Time LiFePO4 Battery can be connected in parallels and in series for larger capacity (Max 800Ah ) and higher voltage (24V, 36V, 48V). Max Connection in series: Up to 4 identical batteries for up to 48V and a load of 10240W. Connection in parallels: Up to 4 identical batteries for up to 800Ah capacity. Various combinations make it perfect for RV, caravan, solar, marine, home storage and off-grid application.

 

[rcrracer]

Current sensing switches to make sure appliances don't run simultaneously? https://www.amazon.com/Hyuduo-Adjus...011&rnid=1249156011&rps=1&s=industrial&sr=1-1

 

[WYtreasure]

My 200Ah 12 volt Lifepo4 batteries are "off the shelf batteries". The BMS limits them to 100 Amps, in or out.
They are limited to 4 in series. They are also limited to 10 in parallel.

 

[timselectric]

My 200Ah 12 volt Lifepo4 batteries are "off the shelf batteries". The BMS limits them to 100 Amps, in or out.
They are limited to 4 in series. They are also limited to 10 in parallel.

Not completely sure. But I've always assumed that the parallel limit is based on what the BMS can safely hold back, if the cells become shorted.

 

[Greasyrick]

My 200Ah 12 volt Lifepo4 batteries are "off the shelf batteries". The BMS limits them to 100 Amps, in or out.
They are limited to 4 in series. They are also limited to 10 in parallel.

This is the description of the ones I’m looking at,

Ampere Time 12V 200Ah Plus Lithium LiFePO4 Battery, Built-in 200A BMS, 4000+ Deep Cycles, Max 2560W Power Output, FCC&UL Certificates, 10-Year Lifetime, Perfect for RV, Solar, Marine, Off-Grid, etc.​