New ole geezer with questions! Can anyone help answer

[Brewmaster54]

Hello, I am building a skooly for my final years on this earth. I been a maint. mechanic most of my life so I am a pretty much hands on everything, master of none. Electrical is one of my stronger suits but this solar stuff is kicking my butt. All of the reseach I've done and I have a few important questions I need answers on any help will be most appreciated. Even just a point to the answer would be most appreciated.

I purchased the following items..
A growatt 3000 all in one model spf 3000TL LVM 24Volt
Solar Inverter WiFi Module for Growatt Latest Upgrade SPF LVM 120V/240V Remote Monitoring Solar Inverter Build-in Storage
Soc 24 volt 100 amp hour battery with option for a second one if needed
2 of rich solar mega 200 max 200 watt solar panels 24v
1 - 24 volt - 12 volt converter
and all the various cables and fittings and fuse/breakers needed to run the bus.. I feel like I'm missing something to monitor the battery as It has the built in BOM and I have no control over this batteries condition. now it is all installed except the solar panels as I want to seal and paint the roof before mounting them. The system was configured like Will had suggested in one of his videos and everything appeared to be working wonderful. The mains were charging that big ole battery, the 110 volt system was working fine, I really thought this was it, Then I popped the extension cord main breaker while I was hunting and the bus system had to go on battery power. I have the frig running, and diesel heater running and a 1500 watt 110 volt quartz heater running. As you might guess, the battery went dead and the system shut down. The 24 volt battery is now too cold and too dead to even start the growatt 3000 on mains, It just will not start, If left setting for a bit, it will start up for about 10 - 15 seconds and then shut down dead. I'm thinking it is either too dead a battery, or a frozen battery, or both. Either way, This has raised questions I need answers to continue to make a reliable home.

1: with the present setup, is it big enough to live in once the2 / 200 watt solar panels are installed ?
2: just how much power will this SOK 24V battery give me in daily use? and would it be advisable to get another one or two?
3: Is 400 watts of solar typically enough for this small system or should I double it? It is only myself and a dog?
4: I feel like I am missing some sort of monitor I should be having to monitor the system, any suggestions?
5: Can or should you mix batteries, if you can, What would be compatible with my large 24v 100 amp hour SOK battery ?

oh, also the remote monitoring of the growatt is useless, The direct connect to laptop doesn't work and the remote to the android doesn't work, Growatt is of no help as they keep asking for a agency id and no one can tell me where or what it is.. I'm at an impass with them. so I'm going to find someone who has one working and try to pick their brain as to what I might be doing wrong.
I would like to get opinions and or ideas to finish this as I have a lot to do yet and not a lot of space, This is a micro bus 5 window so space is essential and I only want to do this one once. I appreciate any all advice.

 

[KITROBASKIN]

Welcome!
Hope you get answers.

 

[42OhmsPA]

I'd say you are way under paneled and short on batteries, especially if you are trying to run a space heater.

Your battery is ~2.5kwh in capacity.

For monitoring I'd look into SolarAssitant and/or a smart shunt.
I finally purchased solar assistant yesterday, wish I did it months ago. I'm using a won von shunt and am happy with it.

Welcome to the forum.

 

[OzSolar]

1: with the present setup, is it big enough to live in once the2 / 200 watt solar panels are installed ?

Sadly, you might not even be covering the tare losses of of your inverter.

2: just how much power will this SOK 24V battery give me in daily use? and would it be advisable to get another one or two?

It's better to learn sooner than later the difference between power (watts) vs energy (watt hours).
Batteries store energy. Inverters make power.

3: Is 400 watts of solar typically enough for this small system or should I double it? It is only myself and a dog?

A dog?!? Dogs and solar don't mix so it's got to go. (lol, my dog has been a on site for at a least hundred solar projects) Kidding aside you need to get your energy needs figured out before you do anything else. The dog can stay for now.

4: I feel like I am missing some sort of monitor I should be having to monitor the system, any suggestions?

The Victron Smart Shunt might be a good option for you.

 

[HighDesertOffgrid]

The 24 volt battery is now too cold and too dead to even start the growatt 3000 on mains, It just will not start, If left setting for a bit, it will start up for about 10 - 15 seconds and then shut down dead

This is an issue with Growatt. Once the unit shuts down from low voltage, you must provide 24v from another source to re-fire the unit. It WILL NOT charge the batteries or function without this jumpstart.

As OzSolar said, you are way under-paneled and under-batteried to run a space heater.

 

[E. Cho]

From one Geezer to another.

Did you ever do an Energy Audit before thinking up your set up? Its just a list of all the appliances (including inverter) that you want to use and for how long and listing how many watts in total you will use. Then you need to add up enough solar panels to meet that list. Eg: I will use 1,875 watts from all my appliances for 3 hours per day. Therefore I will need at least enough solar panels to produce 1,875 watts for 3 hours per day and or a battery of that size or more to cover use when the sun isnt shining on the solar panels.

Read this and fill out the list. Do a Google or YouTube search for Energy Audit to figure it out. If I can do it, anyone can. However most people, even me, avoid the most simple math but you can't with solar and DIY. Do the math for: energy needed = energy production + storage and then decide what you can afford in equipment, to produce and or store the power you want / need.

System Energy Audit and Sizing Spread Sheet

To get the spreadsheet, click on the orange Button in the upper right of this page. This sheet is intended to help you plan your system. Fill it out down to the last decimal place, look at the results..... and then make your best guess;)...

diysolarforum.com

 

[Rocketman]

Just to give you some perspective…

We full-time in a Class A MotorHome. Everyone is different and your rig probably uses less power than ours.

I installed a Victron Multiplus 3000, and had 400Ah (at 12v) of agm batteries- I also installed 800w of solar. That worked fine on our trip to Alaska. I did use the generator sometimes when solar was not great. (My system has evolved since then - but that’s probably comparable to yours).

You NEED a battery monitor - like Victron BMV712 or Smartshunt. That can help you figure out how much power difference items are using for the power audit.

My guess is you will get a second battery (maybe a 3rd) and will have 800w to 1200w of solar. And a small generator for those times you need it.

Good Luck

 

[Brewmaster54]

Thank you so much for all of your information. I did get most of my questions answered now. The energy audit is unusable since I still on windoz xp and excel 2000 so the .xlsx spread sheet is unusable. I can only read .xls sheets. ( still in the dark ages, Like my bus ) I ordered a smart shunt so that should help me figure out what the battery is doing, Rocketman has answered and verified my thoughts on what I have been thinking, 400 watts of solar is most likely not enough so I'm going to order another 400 watts in panels, The second battery will most likely be purchased soon also as I already have the cables and location for it, We will see what happens next, Again Thnx to everyone who responded, I feel much better moving ahead as I feel I on the right track..

 

[Dona40]

My short answer is, Get as many panels that will fit and as much battery that you can afford. You can never have too much.

 

[42OhmsPA]

The energy audit is unusable since I still on windoz xp and excel 2000 so the .xlsx spread sheet is unusable. I can only read .xls sheets.

Check out open office, it's free and will open xlsx sheets.

 

[Geokilroy]

The thing one of my friends found hardest to understand was how little he was putting back into his battery with his 2 x 200 watt panels. He thought they would re-charge his battery in a couple of hours. I had it figured at about 300 watts total input in a good sun hour.
Count watts coming in vs watts going out. Simple math. When he turned on his space heater (1500w) it was more draw than he produced per hour. 300 watts in and 1500 watts out per hour. His batteries had about 2500 watt hours available when full charged. (less than 2 hours run time in battery).
He was never going to keep up. And that's just the heater. If your heater only runs for 15 minutes every hour, that's still 375 watts for that hour. Still more than he produces per hour.

More panels and more battery are needed.

 

[E. Cho]

The Resource link isn't the only website that has energy audit forms. There are others in doc, PDF, xls, website forms and so on. There are even websites that will convert an xlsx into an xls or whatever format you want. You would upload the Resource form and the website would convert it. Just use a search engine to find all this info for yourself. Or download the free OpenOffice as suggested.

Look to at other online solar retail websites, such as AltE, as most also have resources and learning guides and videos. Still using Windows XP will in no way stop you from finding information, though your browser may be very out of date and somewhat insecure but only if you visit wacko websites and or download just anything.

Personally, I would have purchased the $20-$40 Kil-a-Watt type meter first to measure and list your 110 volt appliance loads to figure our your needs, which would be MUCH easier than than your method, which is kind of ass backwards. Your just guessing and hoping vs figuring out the actual numbers. The shunt method is not as easy as you think. There is more to it than just connecting a couple of wires to the battery. But hey, we tried to make it easier for you .... so, Good Luck.

 

[EastTexCowboy]

Thank you so much for all of your information. I did get most of my questions answered now. The energy audit is unusable since I still on windoz xp and excel 2000 so the .xlsx spread sheet is unusable. I can only read .xls sheets. ( still in the dark ages, Like my bus ) I ordered a smart shunt so that should help me figure out what the battery is doing, Rocketman has answered and verified my thoughts on what I have been thinking, 400 watts of solar is most likely not enough so I'm going to order another 400 watts in panels, The second battery will most likely be purchased soon also as I already have the cables and location for it, We will see what happens next, Again Thnx to everyone who responded, I feel much better moving ahead as I feel I on the right track..

If you want a copy of the energy audit spreadsheet from @FilterGuy I can save it in the older format and upload it or send it to you. I don't think he would mind. Or anyone you know with a new version of Excel can do the same thing for you. They can just download it, File > Save As > change the file type to Excel 97-2003 > Save.

 

[FilterGuy]

If you want a copy of the energy audit spreadsheet from @FilterGuy I can save it in the older format and upload it or send it to you. I don't think he would mind. Or anyone you know with a new version of Excel can do the same thing for you. They can just download it, File > Save As > change the file type to Excel 97-2003 > Save.

I have no problem with people using it any way they want. In fact, I kinda expect people to customize it to match their needs.

Also, I believe Google Sheets can open it.... and that is free.

 

[Brewmaster54]

Once again, Thanx for all the information. It is all valuable to me. I did order a kill a watt meter as suggested. I think where I seem to get lost is the 24V system. In reading all I can about a 24v system, I understand it to be pretty much double everything ( watts and amphrs ) once converted to 12 volt. The part not really understood is the 120volt side. That seems to be where I'm getting mixed up. The solar panels are 200 watt for a 24volt system so I should be getting a total of 400 watts at 24 volt in ideal sun. Either way, I'm learning more and more about this solar system. Thanx again to all.

 

[Brewmaster54]

Another question with this system, Using the growatt 3000 all in one unit, in a 12 volt chevrolet chassis, is it advisable to chassis ground all the systems? That would mean having the factory bus ground, the 12volt solar system grounded, the 24 volt grounded and the 120 volt ac from the inverter grounded and the mains should I use them grounded also ? Any thoughts on that ?

 

[FilterGuy]

Another question with this system, Using the growatt 3000 all in one unit, in a 12 volt chevrolet chassis, is it advisable to chassis ground all the systems? That would mean having the factory bus ground, the 12volt solar system grounded, the 24 volt grounded and the 120 volt ac from the inverter grounded and the mains should I use them grounded also ? Any thoughts on that ?

It is hard for me to follow the description of the system so a diagram would be good.

Here are some general guidelines:

* The solar panel metal frames should be grounded to the chassis.
* DO NOT ground either the positive or the negative wires of the solar panels
* The AC Equipment Grounding conductor (The green wire) Should be grounded to the chassis.
* Grounding the 24V negative is optional, but I would do it.
* Grounding the 12V negative is optional, but I would do it.

Warning: I have seen buck converters that have a common positive and control the negative. I would avoid these like the plague, but if you do use one, the 12V negative must be totally isolated from the chassis.​

 

[Rocketman]

Once again, Thanx for all the information. It is all valuable to me. I did order a kill a watt meter as suggested. I think where I seem to get lost is the 24V system. In reading all I can about a 24v system, I understand it to be pretty much double everything ( watts and amphrs ) once converted to 12 volt. The part not really understood is the 120volt side. That seems to be where I'm getting mixed up. The solar panels are 200 watt for a 24volt system so I should be getting a total of 400 watts at 24 volt in ideal sun. Either way, I'm learning more and more about this solar system. Thanx again to all.

Watts = volts * amps

To me that simply formula allows me to figure most of the conversion stuff out.

Watts is a power measurement of work. It doesn’t matter if the watts are in a 12v, 24v, or 120v system (or a 1000v Tesla)

A microwave uses 1200w of 120v at 10 amps.
(assuming 100% efficiency)
A 12v inverter powering that microwave will use 12v at 100amps.
If it was a 24v inverter it would be 50amps.
The work (watts) are the same.

On a solar panel…
A 200w panel @ 12v will have 16.6amps of charging.
A 200w panel @ 24v will have 8.3amps of charging.


If you have two 100amp/hr (Battle Born) batteries.
In parallel they are 12v 200a/hr
In series they are 24v 100a/hr.

From empty to full on the battery, that one 200w panel will take:
12v - 200a/hrs divided 16.6 amps = 12 hrs
24v - 100a/hrs divided 8.3 amps = 12 hrs

The microwave will drain both batteries in 2hrs…
12v system: 100a/hrs divided by 200a = 2hrs
24v system: 50a/hrs divided by 100a = 2 hrs

hopefully my simple examples will help - (normally inverters are not 100% efficient- 85% is a good estimate)

 

[Wakintx]

Hello, I am building a skooly for my final years on this earth. I been a maint. mechanic most of my life so I am a pretty much hands on everything, master of none. Electrical is one of my stronger suits but this solar stuff is kicking my butt. All of the reseach I've done and I have a few important questions I need answers on any help will be most appreciated. Even just a point to the answer would be most appreciated.

I purchased the following items..
A growatt 3000 all in one model spf 3000TL LVM 24Volt
Solar Inverter WiFi Module for Growatt Latest Upgrade SPF LVM 120V/240V Remote Monitoring Solar Inverter Build-in Storage
Soc 24 volt 100 amp hour battery with option for a second one if needed
2 of rich solar mega 200 max 200 watt solar panels 24v
1 - 24 volt - 12 volt converter
and all the various cables and fittings and fuse/breakers needed to run the bus.. I feel like I'm missing something to monitor the battery as It has the built in BOM and I have no control over this batteries condition. now it is all installed except the solar panels as I want to seal and paint the roof before mounting them. The system was configured like Will had suggested in one of his videos and everything appeared to be working wonderful. The mains were charging that big ole battery, the 110 volt system was working fine, I really thought this was it, Then I popped the extension cord main breaker while I was hunting and the bus system had to go on battery power. I have the frig running, and diesel heater running and a 1500 watt 110 volt quartz heater running. As you might guess, the battery went dead and the system shut down. The 24 volt battery is now too cold and too dead to even start the growatt 3000 on mains, It just will not start, If left setting for a bit, it will start up for about 10 - 15 seconds and then shut down dead. I'm thinking it is either too dead a battery, or a frozen battery, or both. Either way, This has raised questions I need answers to continue to make a reliable home.

1: with the present setup, is it big enough to live in once the2 / 200 watt solar panels are installed ?
2: just how much power will this SOK 24V battery give me in daily use? and would it be advisable to get another one or two?
3: Is 400 watts of solar typically enough for this small system or should I double it? It is only myself and a dog?
4: I feel like I am missing some sort of monitor I should be having to monitor the system, any suggestions?
5: Can or should you mix batteries, if you can, What would be compatible with my large 24v 100 amp hour SOK battery ?

oh, also the remote monitoring of the growatt is useless, The direct connect to laptop doesn't work and the remote to the android doesn't work, Growatt is of no help as they keep asking for a agency id and no one can tell me where or what it is.. I'm at an impass with them. so I'm going to find someone who has one working and try to pick their brain as to what I might be doing wrong.
I would like to get opinions and or ideas to finish this as I have a lot to do yet and not a lot of space, This is a micro bus 5 window so space is essential and I only want to do this one once. I appreciate any all advice.

Sounds like you need a good 24v lifepo4 charger and I say a lot more panels. On overcast days I add a couple panels and remove them as sunny days arrive.

You need to know the wattage or amperage of the fridge and that heater will suck that battery dry in a very short time