Mega plus board with ESP 32

@dastardlydoug The arduino etc don't use enough to be of concern. Your total is 55.2W, but what is missing is the duty cycle. I doubt all that equipment runs 24/7. Now it's part art, part science to determine the avg and the peak. A safe peak is of course 55.2W, I think that is covered, it's the duty cycle. Let's try some thought experients.

1. AT 10% duty cycle, 55.2W x 2.4H is 132.48WH. I think 6 minutes on 54 off is too low.

2. AT 50% duty cycle it is 662.4WH. That number is of interest since a single battery contains ((100AHX12)/2) 600WH BUT you will also get some solar. The battery however will be dead in a day or two without an external charger.

Depending on your local weather, you may get NO solar for 3 days. Sorry, but you will need a much bigger battery bank. At 50% duty cycle 55.2x72hrs is 3,974.4WH and that represents 6.6 batteries.

Since you are running an extension anyway, use that to power an intelligent 4 stage charger. On a 20A circuit will 5A for the charger and 15A for the circulation fans work? (I say 20 since it must be a GFI and they are mostly 20A outlets)

Posted by: @zander

@dastardlydoug The arduino etc don't use enough to be of concern. Your total is 55.2W, but what is missing is the duty cycle. I doubt all that equipment runs 24/7. Now it's part art, part science to determine the avg and the peak. A safe peak is of course 55.2W, I think that is covered, it's the duty cycle. Let's try some thought experients.

1. AT 10% duty cycle, 55.2W x 2.4H is 132.48WH. I think 6 minutes on 54 off is too low.

2. AT 50% duty cycle it is 662.4WH. That number is of interest since a single battery contains ((100AHX12)/2) 600WH BUT you will also get some solar. The battery however will be dead in a day or two without an external charger.

Depending on your local weather, you may get NO solar for 3 days. Sorry, but you will need a much bigger battery bank. At 50% duty cycle 55.2x72hrs is 3,974.4WH and that represents 6.6 batteries.

Since you are running an extension anyway, use that to power an intelligent 4 stage charger. On a 20A circuit will 5A for the charger and 15A for the circulation fans work? (I say 20 since it must be a GFI and they are mostly 20A outlets)

Thanks @zander

Since I'm not a wealthy man, the latter will have to do. These solar batteries (as you already know) are super expensive. I'll just have to hope for the best. Just have to see how much one of those 4-stage chargers are. 🤔 

@dastardlydoug Good luck

@zander

Forgot to mention that I decided to go with the Arduino MKR WiFi 1010

I gain a battery port, operation LED and an extra output. I don't need an accelerometer anyway. Plus, it has DuPont connections on the top for easier breadboarding.

@dastardlydoug Actually they are inexpensive compared to Lithium. You could add some Trojan T-105's, but they are 6V so you would still need about 6 (they are 2x more powerful) A pair (need 2x6V to get 12V) are 225AH so slightly more than double your AGM. This means you only need 3 pairs more and they are 1/2 the price of AGM's.

It's science and physics, if your loads are as you state and you don't have more battery and solar the batteries will be quickly destroyed. So far I see no mention of a battery monitor. I strongly recommend the Bogart Trimetric along with the matching PWM solar controller. But don't even bother without a lot more solar and battery. Your best bet is to use that extension cord and a decent charger. You don't need to connect it to the battery, you just need a 12V source. Good luck.

@zander

What's your thoughts on this 'inexpensive' battery monitor?

"https://www.amazon.com/Multifunction-Battery-Monitor-Multimeter-Voltmeter/dp/B07T8GN61Z/ref=asc_df_B07T8GN61Z/?tag=&linkCode=df0&hvadid=344004303287&hvpos=&hvnetw=g&hvrand=10821093206779382395&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9032995&hvtargid=pla-781089579504&ref=&adgrpid=70731225313&th=1"

@dastardlydoug The wiring is weird but as long as it has a shunt it will work as a 'gas guage' I know you don't want to spend the money but there is a HUGE difference between that and a Bogart especially with the solar charger, you could sell the wanderer.

I don't know how to deal with you Doug. Going back to the beginning of this, you seemed intent on having a remote controlled system that would NEVER fail. The parts you have assembled so far is soooooooo far short of that objective it's not even funny. If money is now the key driver, just get a good plug in 3 or 4 stage charger and this battery monitor.

@dastardlydoug Here is an ok charger Charger

Any 12V 5A or more will do, the 4 stages are Bulk, Absorb, Float and Equalize. 

Here are the facts from the Gold Standard battery for Deep Cycle

https://www.trojanbattery.com › pdf" target="_blank" rel="noopener"> U.S. Battery Charge Profile (Full) https://www.trojanbattery.com › pdf

Posted by: @dastardlydoug

@zander

What's your thoughts on this 'inexpensive' battery monitor?

"https://www.amazon.com/Multifunction-Battery-Monitor-Multimeter-Voltmeter/dp/B07T8GN61Z/ref=asc_df_B07T8GN61Z/?tag=&linkCode=df0&hvadid=344004303287&hvpos=&hvnetw=g&hvrand=10821093206779382395&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9032995&hvtargid=pla-781089579504&ref=&adgrpid=70731225313&th=1"

@dasterlydoug..althought your post was directed to @zander, I would like to make a comment or two on this device..

If you are using Lithium batteries, the SOC function isn't going to work, it's made for Lead/Acid types..

Wiring the shunt on the low side can cause ground loop issues..but over all, for $20, it seems to be a simple system for what you intend it for. However, I would recommend that you revisit the URL and read all the reviews o that you can make a more informed decision..As you said, most of us aren't wealthy, so $20 is $20 ...lol

best of luck with your project..

LouisR

@inst-tech Sorry to disagree, but a shunt MUST be attached DIRECTLY to the negative battery post with as short a wire and extra large as possible. Typically after that a bus bar is used for ALL other negative wires. We want every coulomb going to and from the battery measured. Given the critical importance of this device, in my case protectig $6,000 worth of batteries I would buy the best shunt and meter available. IIRC it's far less than 10% of the batteries.

@dastardlydoug Remember when you calculated your solar input? Your summer numbers weren't bad, about 500WH/day and at 50% duty cycle you need 600WH. That means the batteries will last for 5 to 6 days (-100WH/day) before reaching the stage of destruction. However in the winter you only get 167WH so if we started with full batteries, a 24 hr day of use leaves them empty and we only put back 167 which means the batteries will enter the destruction zone by the 2nd day.

I am getting tired of being the 'bad guy' here, but this is simple math. You have 600WH in the full battery, you consume 52W X 24Hrs x duty cycle(ratio of on to off) at 50% on you consume the battery. I do NOT know your system well enough to estimate duty cycle, but for sure in the winter time the system can only be on 3.2 hours out of 24 in order to re-charge  the batteries. (167WH from your solar irradiation chart / 52W is 3.2H)

Do you understand the math?

@dastardlydoug You said you have an extension cord for the fans, how much power do they use, you have 1,800W at least 2,400 with a 20A GFI available, you only need about 1/2A out of the 15 or 20 to power the 12V charger at 5A which gives you 60W going in and 52 coming out. Now the battery is a 11 hr UPS. That is a decent setup. AND cheap.

Posted by: @zander

@dastardlydoug Remember when you calculated your solar input? Your summer numbers weren't bad, about 500WH/day and at 50% duty cycle you need 600WH. That means the batteries will last for 5 to 6 days (-100WH/day) before reaching the stage of destruction. However in the winter you only get 167WH so if we started with full batteries, a 24 hr day of use leaves them empty and we only put back 167 which means the batteries will enter the destruction zone by the 2nd day.

I am getting tired of being the 'bad guy' here, but this is simple math. You have 600WH in the full battery, you consume 52W X 24Hrs x duty cycle(ratio of on to off) at 50% on you consume the battery. I do NOT know your system well enough to estimate duty cycle, but for sure in the winter time the system can only be on 3.2 hours out of 24 in order to re-charge  the batteries. (167WH from your solar irradiation chart / 52W is 3.2H)

Do you understand the math?

I'm not an actuary, but I understand what you're saying. 😉 

That being said, I'm not planning on using the system during the winter.

Even if I do, The plants will only get watered once per day if that.

@zander 

The fans are 15W 25A according to the box. Which doesn't sound right. They are only 6" clip-on fans 🤔 

Maybe it has a minuscule decimal I can't see, and it's actually .25A 🙄 

The math says the fans are .125A (120v/15w)

@inst-tech I am mystified by your statement that the SOC will not work for Li. Perhaps you are unaware of how these devices work, I have one so allow me to explain.

1 Fill the battery by charging until the specified voltage is reached, somewhere between 14.2 and 14.6. I like 14.4.

2. Set the capacity at in my case 600AH and press tha reset switch.

From that point forward every coulomb going in and out of the battery is counted and the SOC is simply the ratio of 600 to current state. 

Ex If after I press the switch I turn on a toaster and it uses 1AH then the SOC is (599/600) x 100 %.

There is NO place in the SOC calculation for Li it's simply a measure of 'fullness'.