Yet another new guy needing feedback on his system

[Munford]

So I'm looking to generate enough solar power to run two newer freezers and a newer fridge that are in my garage. I ran the Kill a watt on the first freezer and came out with 650 watt power consumption in 24 hours. Until I measure the other two I'm going to guess that 3 kilowatts of power a day should run all three.

Solar array.
At this time, all I have actually purchased is 10 Harbor Freight 100 watt solar panels. Their rated power is 18 V DC @ 5.56 amps. Maximum is 24 V DC @ 6.2 amps.
Looking at a series parallel configuration of the 10 panels I figure 90 V DC @ 11 amps best case. I get a solid 6 hours of sun at my location so again best case is 6000 watts per day. Probably around 5000 watts or less would be more realistic. Maybe.
Supposedly the solar array wattage at the rated output would be around 1000 watts but at the max rating it could be almost 1500 watts. Or higher if I understand how the cooler weather affects the panels.

Charge controller.
I've been looking at the 60 amp EPEVER Tracer AN series MPPT charge controller. At the 24V setting it is rated at 1500 watts on the input. I'm not sure if that is enough under the cooler weather conditions but I have read that you can over panel this controller. Since I'm just getting started I'm really not trying to push any sort of limits at this time.

Battery.
I was looking at the LiTime 24V 200Ah LiFePO4 Lithium Battery or possibly stepping up to the 24V 230Ah version if needed. To be truthful I'm not sure if my panels will charge the 200Ah let alone the 230Ah. Since this is the most expensive part I don't mind spending a little more if needed.


So if I may humbly ask the board a few questions, please keep in mind that I figure I know just about enough to get myself in trouble.

At 1500 watts input on the charge controller, is it large enough to handle my solar array output when the weather cools off?

Will my array supply enough wattage to fully charge the 200Ah battery?

Do you think if I get the batteries fully charged they can supply enough power for the 2 freezers and the fridge?

How big of a Pure Sine Wave Converter to power the 3 appliances?


A bit more background.
I want to mount the system in the garage close to the appliances.
I looked at the All In One Systems but figured I would learn more with a separate component system and it would be easier to repair if something went wrong.
I bought the 10 Thunderbolt 100 watt solar panels over an 8 month period when on sale and have less than $1000 dollars invested.
I have had 46 years of dependable power from TVA but that all ended last year as we were subjected to rolling blackouts for the first time.


I am open to any and all suggestions.
If you have a better way to meet the goal please feel free to let me know your ideas.
As always, I am grateful to anyone who provides feedback on my system
Thanks in advance.

​

 

[Rocketman]

I think you are about right for your three freezers/fridges for 1200 to 1500w of solar.

one item to consider is how you will be mounting the panels. Building a rack? On a roof?

You will need to connect those panels in a series-parallel string. My guess is 4s3p for 12 panels. The mppt can handle 150v (Voc). That will inform you of the max amount you can have in series.

As far as an inverter… you can get them cheaply that are just a Pure Sign Wave inverter. You could have all three compressors startup at once - so your inverter will need to be large enough to handle that. See if they give a Locked Rotor Amps LRA number on them. Then add them up - round up - and that’s the size of inverter you need.

You can also get an inverter/charger, they include a built in charger. (That may be nice - keep the grid power off of it - unless you get several days of bad weather - then plug it in).

A few other items you may want/need is a shunt based battery monitor. (Unless your batteries are able to give you that info).

The battery you picked will work - you may just need two of them(?) - it depends on the inverter. The battery can discharge 200a - which will probably be good at one - but needs verification. Note: it recommends a 40a charge rate - you are setup for a 60a charge rate. Also, the battery MUST be kept above 32F (if charged below that you can ruin it), - if that’s an issue? Also what’s the coldest temp EVER recorded in your area?
Also you may need a second battery if you want to go longer without good weather.

I would highly recommend that you draw out a system schematic- and let the people on this site review it. Include fuses, wire size and selected components (do this plan before buying any more stuff for this project).

Good Luck - you are at the beginning of the process- don’t rush it…

 

[rodrick]

With over paneling on your Epever on a 24 volt system 2000 watts is possible with the right panel layout keeping your voltage at a safe range

I would get 2 batteries just for the extra power and redundancy also you need to see how many amps your inverter will need at maximum load and make sure your bms can handle it you may be stuck needing 2 batteries

 

[pollenface]

For a 24v system, I suggest looking at a Victron 100/30 Smartsolar, it will provide a max of 880w changing power at 24v. Configure 10x100w panels to 2s5p for a VOC of 48v.

The price you pay for the extra tech over the Epever Tracer is worth it. Native bluetooth connectivity to your smartphone for programming/monitoring, 30 days historical data storage. Ability to synchronise up to 20 other Victron Smartsolar MPPTs using the Battery Sense module, low temp charging disconnect (when using Battery Sense or Smart Shunt). Extremely fast MPPT processing, Epever are agricultural in comparison.

But what I like most and the reason I switched to Victron was I don't get voltage spikes (over 31v) causing my inverter to momentarily shut-down during cloud edge effects and after having a large load switched off while strong sunlight is available. The Epever cannot react quick enough to maintain safe system voltage. I could rant all day about it.

For inverter, I use a Xijia Cnswipower 6000w high-frequency-type which I find to be very robust. It will run anything (including stick welder and 2.5hp air compressor). It costs about $1050aud. They are available in various input/output voltages. I think you need to consider the surge capacity needed should all 3x fridge/freezers start their compressors at the same time. If you like redundancy, possibly use 3x smaller inverters; 2000-3000w each.

Running my 265L 15yr old fridge freezer (in my shed) will consume about 1kwh/24hrs in summer. I think you would just scrape by with a single 24v 200ah lifepo4 battery (4kwh safe usable capacity). A bigger battery would be good in case you get a few rainy days in a row, or some backup charging from grid-power.

 

[Rednecktek]

Since you bought HF panels (I'm sorry) when they were on sale, I'm guessing that budget is a concern. The HQST 60a SCC is going to give you all the features of the Victron and cost about half or less. EPEver has some software issues that have made me stop recommending or using them anymore. Look into the HQST and compare it pricewise to the EPEver.

The battery should be fine for a couple days at least, you can always add another in the future if you want.

The HF panels have been known to have issues in parallel, and are way over priced for what they offer.

 

[Rocketman]

Figuring out the brands and quality of equipment you want/need can be difficult/ especially with what you can afford.

I am a Victron fan! I used all Victron for my MotorHome- we full-time and boondock a lot so great equipment is worth it to me. I realize your needs may be different.

One item I have been very grateful for is the Victron app. The history it has and the voltage reporting have helped me track down issues and problems with my system.

Good Luck

 

[NCislander]

I am in agreement on known Brands out here. But also, Budget is a concern for many of us. Myself included.

I started my solar experiments using an EPever 4215BN (40amp, 12vdc-24vdc) MPPT Charge Controller, EPever has served me well.

I believe in is using larger watt/per panel units if at all possible. Made it much simpler in my opinion. Rather than many 100 watt units, try (2) 200 watt panels, or (1) 400 watt panels. More solar power for space to mount them.
Larger panels. @250-350-400 watts. Fit them to your budget and charge controller needs.

On my EPever 4215BN I used (4) 350 watt panels (1400 watts total) 2S2P. I could have easily over paneled additional units.
For inverters many good units, again budget always a thought. I like Samlex brand stand alone units. (Until I decided to go with All-In-One units)

Battery wise, specs look like it will work for your scenario. I would recommend having additional battery capacity as budget allows. Refrigerated foods need to be chilled/frozen no matter the solar conditions with charging.

 

[Tomthumb62]

EPEver has some software issues that have made me stop recommending or using them anymore.

I’ve heard the Epever can be hard to program, is this what you’re referring to here? Or some other software problem?

 

[Rednecktek]

I’ve heard the Epever can be hard to program, is this what you’re referring to here? Or some other software problem?

My particular issue with them, and the reason I've retired 2 of them and stopped buying, is how slow they are to react. Every time a cloud, even a thin one way up there, passed by, the unit would stop charging, wait a couple minutes, then start the tracking process all over again from scratch. After my 200w array only put 172Wh into my battery after 6 hours of pretty clear skies from the constant restarting, I just gave up.

 

[Hogheavenfarm]

I am currently running two chest freezers, 1 large and one medium size with no issues at all. I have an EpEver 6415 as well, (get the remote with it for easier programming). For paneling I run 2,500 watts through it to charge 4 12v AGM batteries in series parallel for 24v. Panels are a mix of 2S3P (185w panels) and 4s2P (100w panels). Inverter is a 3500w Educoa. Batteries (when running freezers alone 225w) only dips to 25.5v overnight and recharges by 10am. I am adding another 150w load and have been experimenting with that, but the smoke and storms have been interrupting my tests.

 

[EastTexCowboy]

I know you said you didn't want to do an AIO but if it were me I'd hang one of the EG4 3k units on the wall, hook up the PV and batteries, and be done with it. It's going to easily handle your load and give you some room to grow.

 

[Munford]

So I would like to thank everyone who has taken the time to reply. Right now advice I received from Rocketman telling me not to rush it made a big impression on me. Thanks for that.

Pollenface, I've looked at the Victron equipment and love it but going through the documentation always gives me a headache. It seems to be aimed at the experienced solar DIYer or the professional installer. Not the new guy like me. I will keep it in mind tho.

Rednecktek, thank you for the heads up on the Harbor Freight panels. If you remember where you saw the info on parallel problems I'd like to know the background on that. Budget was less of a concern for me then the cost of shipping and the damage that happens in shipping. There are a couple of good videos with the panels hooked up in series with good results. I guess I'll find out.

NCislander, if I build the system any larger I will be sure to go with the larger panels.

Hogheavenfarm, I appreciate the info on the loads you're running. If I stick to the 1000 watts of PV it will probably take a lot longer to charge my battery or batteries but at least I have some idea now.

EastTexCowboy, I went out into my garage and looked at the corner where I want to put my system and realized that your advice would probably be the easiest way for me to go. I'm going to do some more research and thinking and see what I come up with. So thank you for that.

Thank you again to everyone.

I hope y'all all have a great, safe 4th of July

 

[Tomthumb62]

Pollenface, I've looked at the Victron equipment and love it but going through the documentation always gives me a headache. It seems to be aimed at the experienced solar DIYer or the professional installer. Not the new guy like me. I will keep it in mind tho.

I can relate to being the new guy. We originally bought a lot of Renogy gear, because they are marketed towards beginners and the products look pretty, too (the whole "blue Victron" theme is kinda silly imo). But long story short, having realized now how some of our Renogy equipment is rather subpar in performance, we have replaced the Renogy inverter with a Victron one and also added a Victron AC charger. Cheaper than going with a combo device like the Multiplus, but some functionality is lost as well. Anyways, I agree that the Victron ecosystem might seem a little daunting at first since they assume you already know certain things like what a "charge profile" is, but dang! their programmability and real-time data is excellent and very handy. Sure, you can spend $$$ getting their touch screen device to view and interact with the system, but they also have a very good free phone app called Victron Connect. You can download it to your phone and use the DEMO mode to choose a device you're considering and it will function like the real thing so you can see what it looks like and what settings can be changed for that particular device.

Not saying that Victron is the best choice for your use case, but I'm yet another convert to their products. Top notch, albeit expensive but should you ever want to sell it, you will likely have no problem getting a good price for it. If you do buy Victron, I recommend InvertersRus.com, they are an authorized Victron dealer and they sell so much Victron equipment that they have a deals page of open-box/scuffed/used gear that is ALL Victron: https://invertersrus.com/victron-energy-b-stock-sale/ I've bought from them twice now and their customer service has been top notch when I had a problem with one of the orders. I saved 15-30% buying from their b-stock list, free shipping and includes the standard warranty (I think 5 years) and products were in like-new condition.

 

[Rednecktek]

Rednecktek, thank you for the heads up on the Harbor Freight panels. If you remember where you saw the info on parallel problems I'd like to know the background on that. Budget was less of a concern for me then the cost of shipping and the damage that happens in shipping. There are a couple of good videos with the panels hooked up in series with good results. I guess I'll find out.

I'll dig up the youtube videos when I get home for ya. Yeah, in series they punch above their weight class on a regular basis, but when you take a 500w string and parallel it with another 500w string and get less than 600w there's problems. Not being an EE it boggles my mind on how that can happen.

 

[pollenface]

I can relate to being the new guy.

Funny story. Back in the day I didn't know any better, bought a Victron 75/15 Bluesolar for a little 26ah AGM. Connected it to the solar panel first, it charged the battery to 17v ... I didn't know one had to connect the battery first.

 

[Rednecktek]

Rednecktek, thank you for the heads up on the Harbor Freight panels. If you remember where you saw the info on parallel problems I'd like to know the background on that. Budget was less of a concern for me then the cost of shipping and the damage that happens in shipping. There are a couple of good videos with the panels hooked up in series with good results. I guess I'll find out.

OK, so the best videos, as far as redneck engineering and troubleshooting go, are here:

Part 2 he spends a lot of time doing one panel at a time and calculating. For some reason when they start paralleling up the performance just flops.

 

[Munford]

Rednecktek, thank you for taking the time and digging up the videos. I will take a deep dive into it and see what I can find out. I have the MC4 solar connectors already and I'll check the wire gauge on it this week and see if wires need to be swapped out or not. Worst case I can get a dual PV imput charge controller and run two strings of 5. Thank you again.

Tomthumb62, I spent the afternoon looking through the Victron documentation and I'm feeling better about it. The price difference is really too small to worry about. Probably $50, which is nothing when you're spending $2500 to $3000 on a system. I appreciate you and pollenface speaking up on it.

I will have more questions as the week goes on. Thank y'all again.

 

[Munford]

So I picked up a battery this week, I went with one of the clone brands that Will reviewed. I got the Vestwood 24V 220Ah Lithium since all I'm trying to power is my garage appliances. I guess we'll see if there is enough power in there to run everything, if not I'll see about adding another one. I admit that I don't understand that if I drop another battery in parallel with the one I already have, will the array have enough power to charge them both? Physics says I need more solar panels to charge another battery?

I'm studying the charge controller now, I'm leaning towards the Victron 150/45.
Will's video states that the 1000 watts of panels divided by the 24V battery voltage should give me the amps for the charge controller and that comes out to about 42. The Vestwood battery can handle that much easily.

When figuring the charge controller size I connected 5 of my panels in series and got a reading of 98.1V open circuit. My plan is to run two 5 panel series branches in parallel. I'm trying to keep it simple since there is some question how the Harbor Freight panels will act when all 10 are connected to the charge controller in series/parallel. In theory, the PV should be around 100V and the amperage should be 12.4 amps. As far as I can see the Victron should be able to handle that even in the winter. Does this sound correct?

In the meantime, I called the Harbor Freight tech number and talked to a extremely polite young women who was obviously reading out of a book but gave me a couple of good insights on the 100 watt Thunderbolt panels.

First, she gave me the ISC which is 5.778A. I have not seem this anywhere on the interwebs yet.

I then asked her why they don't want you to connect solar panels in series and she said that the information states that "the regulator lacks the capacity to handle more than one panel". I take that to mean that the Harbor Freight charge controllers can't handle the power. I have heard this on other sites on the internet but I guess I will find out when I wire up my system.

Shout-out to Harbor Freight for having such a wonderful young employee and also to her family for doing such a good job of raising her up, it's not such a simple thing anymore.

As always, I appreciate any and all advice and assistance with my system.