Beginner needs to buy components before going to Mexico

[San Felipe BC]

Short background: We have an off grid home in San Felipe BC my brothers and I are taking over expenses for. It seems like we’ve heard our dad fussing about power usage for 30 years and we want to put that to bed. The system is 12 volt with, I believe, 6 panels on the roof. My dad says we have 60 amps coming off the roof. During his last visit, July 2021, he purchased 8 new batteries, so they’re taken care of. The inverter is 1500 watts and is dying a slow death so I need to replace it, along with the charge controller, which is a 60 amp.

The kicker is I need to buy new components before traveling to Mexico from Virginia in late September. From the resources page, which is awesome by the way, I think I need about a 2500 watt inverter but I’d like to get one that’s 4000 watts. I’m also planning to add 2 more panels so the new charge controller needs to be 80 amp?

As you can tell this is an odd situation. My questions are:
1) Do my assumptions about the controller and inverter make sense?
2) I see inverters on line ranging from a few hundred bucks to a thousand. Please help
3) With a new inverter do I need a new breaker box?
4) Can I install these components myself?
5) Should I replace any of the wiring between the panels and the controller or inverter?
6) Should the controller and inverter be the same brand?

Can’t thank y’all enough
Steven

 

[FilterGuy]

The system is 12 volt with,

I think I need about a 2500 watt inverter but I’d like to get one that’s 4000 watts.

1) Do my assumptions about the controller and inverter make sense?

4000W is a lot for a 12 volt system. You would need to manage around 350 amps on the DC side.
Do you have 12V loads? If not, perhaps you should convert to a 24V or maybe even 48Volt

My dad says we have 60 amps coming off the roof.

That seems high. Even in parallel, that would be 10 amps. Do you have make/model of the panels?

I’m also planning to add 2 more panels so the new charge controller needs to be 80 amp?

Without knowing more about the panels, it will be very difficult to advise you on the controller.
Also, if your old and new panels arn't well matched, you may not get the gain in power production you hope for. You may want to put the new panels on a separate controller.

2) I see inverters on line ranging from a few hundred bucks to a thousand. Please help

You kinda get what you pay for. If this is the only power for your Dad, you really should stay away from the cheapo units....

3) With a new inverter do I need a new breaker box?

If the current breaker box is working and safe the only reason you would need a new one is if it is too small for the expected load. However, 6000W is only 50A so it would have to be a pretty small breaker box to be under-rated.

4) Can I install these components myself?

Yes..... if you know what you are doing.......

5) Should I replace any of the wiring between the panels and the controller or inverter?

Without knowing more about the panels and existing wiring, that is impossible to answer.

6) Should the controller and inverter be the same brand?

That is certainly not a requirement.... but sometimes there are advantages if the brand has the features to tie them together. (You typically only see this on the higher end systems.

Have you looked at any of the new 6K all-in-one units? They have the inverter, solar charge controller, generator input etc all tied together.

 

[John Frum]

4000W is a lot for a 12 volt system.

I think @FilterGuy has understated the scale and proportion.

2000 watts is a lot at 12 volts.
3000 watts is getting impractical at 12 volts.
4000 watts is cuckoo bananas at 12 volts.

 

[San Felipe BC]

Thank you both for the quick replies. I hope to help others once I learn too. I’m sorry I don’t have a lot of details about the panels. I believe they’re 150 and are in series. I’ll reach out to our neighbor down there to see if he knows what we have. How do you convert from 12 volt to 24? Do you need different batteries? My understanding about the inverter is that it doesn’t hurt to go bigger than you need or is 4K overkill? The house is about 3000 sq ft with about 16 110v outlets, a garage with a few more, 8 4 foot lights, 2 ceiling fans, a tv, and a refrigerator. No AC or heat.
I added up the wattage and got 2500 peak. I plan to change the lights to LED.
I’m not familiar with the all in one 6k units. Can you point me in the right direction?

 

[12VoltInstalls]

understanding about the inverter is that it doesn’t hurt to go bigger than you need or is 4K overkill?

Well from your description I’d guess at power needs but I’ll just guess without being sure.

six batteries: what kind, Ah rating?

If “deep cycle” that could be wildhat guessing like 360Ah usable. So again, wildhat guessing 1000W of solar might do it. If my guess is right 1500W would be better.

So how many amps at 120V do you need? A 1200W inverter does ~10A at 120VAC and a 1500W can deliver 12.5A at 120VAC
The biggest concerns are the fridge and TV watts. I see no conceivable purpose in buying a new 4000W pure sine wave inverter if all you need is 10A. I’d buy a 1500W for 10A. I bought a 1200W for my 8A max (shopvac) although 600W coffeemaker, 80W fridge, cellphones, laptops, etc all do fine on it. My TV hasn’t been on since 2018.

There’s really a lot to know to give not-guess answers.

 

[San Felipe BC]

Thanks @12VoltInstalls i know, it’s a mess trying to figure this out from 2500 miles away. Your list of things reminded me of the shop vac we use there. I’d also like to be able to run a swamp cooler on hot nights, a small microwave, and it’d tickle my wife pink if she could use her blow dryer for 2 minutes . I also have a 140 amp welder that I’ll use periodically. It runs on 120 but I can use my Miller welder/generator for that. I’ll work on getting more details about the panels today.

 

[Wellbuilt]

For a place that size I would just upgrade to 48v , 8 battery’s can work for 24v 48v system .
It sounds like you will need more solar power .
6 300 watt panels is 1800 watts it mite work depending on the AH rating of the battery’s .
my place is 2800 sf with a 3600 watt out back inverter , 430 hr battery 80 amp fm80 charge controler .
The system just works , I installed it myself in a few short weekends , I would do a little work then stop to order parts , then the next week end I would do some more work and order parts .
You are in the sunniest place on the planet so solor should work for you.
The all in one systems seam very easy to hook up and cheep to by but I stuck with tier 1 equipment .
The system below dose look interesting ? growatt 5000 watt.
I use this out back system , the price has gone i payed 2800$ 4 years ago ?
My neighbor has a outback system that has been running for 20 years .
I don’t know if growatt would pass inspection here , but I may of try one if they where when I was shopping .
I don’t know if the unit would start a heavy well pump?
I have plenty of power for my place and it is not solar friendly .
Heat wave today ?

 

[San Felipe BC]

Thanks @Wellbuilt I just spoke to my dad in California. Evidently we have 9 panels of varying ages ranging from 2 to 10 years old. He says each one is 9 amps. I’m not sure that’s right if we have a 60 amp charge controller. We go to Mexico 2-3 times a year so I don’t want to spend a ton on it. As mentioned the batteries are brand new deep cycle so I want to keep using them but want to remove the worry about one of the solar power components failing.

 

[12VoltInstalls]

It’s not a ‘rule’ but you can guess by saying 100W at 12V will make +/- 5.4A. So a 250W is like 12-13A, etc. For retailed commodity panels you could use that as a guess.

In your case, you suggest 9 150W panels. So ~7.5A * 9 is wildhat guessing 60 nominal amps total. If you went 3S3P (provided the charge controller will accept the volts) the amps would be ~30ish for your nominal 1450W; then you could add three more 150W panels for 3S4P for 1800W and assume if it’s been working you will be even better off.

The less stress on the batteries the longer they’ll go. Never let them get discharged below like 12.04V and you might get way over 5 years out of them. It matters how they are connected- should be X-randomized to each other.
(You should have someone check them and add distilled water if needed at least every four weeks for good life.)

With the above you could go 24V with those 8 batteries… My opinion is, however, I’d consider staying 12V and using a 1500- or 2000W pure sine inverter. A good one - or just buy two Giandel inverters and keep a spare. Either will potentially do two minutes of hair dryer without much risk if you don’t exceed 12.5A total with the 1500. Forget about the welder LOL

All of this is speculation, though, without being sure of what you’ve got and what the tv and fridge consumption is. Wild guesses. But you should have a good idea now with filterguy’s info and my inapt guessing. (I didn’t proofread myself either)

btw your picture kills me

 

[Wellbuilt]

O ya that is a good pic , a lot more friendly then mine.
You mite be ok with the panels you have , and the growatt 5000watt inverter looks supper tempting .
I don’t think you could complain about dropping 850 bucks on a all new system .
There are a lot of guys on this form that use them , so I’m sure there will be lots of help.
A 48 volt inverter will help with larger loads and uping the voltage means your wiring would be smaller .
I see no reason to go 12/24 volt .
If you have 8 battery’s 6volt or 12 volt they can made into a 48 volt bank .
The cheep Chinese inverters / ‘ charge controllers really aren very reliable.
A mppt charge controller gives you more power for longer time and on cloudy days .
I started out with a 200 $ charge controler and a 400 dollar inverter and they both died days after the warranty
Was up .
Really unless you are buying Tier 1 equipment you run the risk of sitting in the dark .
But it seams like the all in one system would work for you .

 

[San Felipe BC]

It’s not a ‘rule’ but you can guess by saying 100W at 12V will make +/- 5.4A. So a 250W is like 12-13A, etc. For retailed commodity panels you could use that as a guess.

In your case, you suggest 9 150W panels. So ~7.5A * 9 is wildhat guessing 60 nominal amps total. If you went 3S3P (provided the charge controller will accept the volts) the amps would be ~30ish for your nominal 1450W; then you could add three more 150W panels for 3S4P for 1800W and assume if it’s been working you will be even better off.

The less stress on the batteries the longer they’ll go. Never let them get discharged below like 12.04V and you might get way over 5 years out of them. It matters how they are connected- should be X-randomized to each other.
(You should have someone check them and add distilled water if needed at least every four weeks for good life.)

With the above you could go 24V with those 8 batteries… My opinion is, however, I’d consider staying 12V and using a 1500- or 2000W pure sine inverter. A good one - or just buy two Giandel inverters and keep a spare. Either will potentially do two minutes of hair dryer without much risk if you don’t exceed 12.5A total with the 1500. Forget about the welder LOL

All of this is speculation, though, without being sure of what you’ve got and what the tv and fridge consumption is. Wild guesses. But you should have a good idea now with filterguy’s info and my inapt guessing. (I didn’t proofread myself either)

btw your picture kills me

 

[San Felipe BC]

The picture kills me too when I’m in Virginia. So here’s where I get lost (doesn’t take much) If I stay at 12v and a 4000 watt inverter is overkill, would the growatt 5k unit be too much? The ones I see listed say for 48 volts? I’m all for it if it’s ok, especially at $850 for an inverter and charge controller in one. Being so new with this stuff I’d like to make the upgrades as simple as possible. With that setup adding 2 more 150 watt panels shouldn’t be an issue, right? I’ll need to check how the panels are strung together when I get there. I do know that a few years ago the old batteries were boiling so the guy that adds water when we’re gone disconnected them. More drama…… Also found out today that the solar guy in Mexico wants $2500 to replace the current inverter, which is a Trace 1500.

 

[Wellbuilt]

Ok , the difference between 12v and 48 volt is x4 soooooo 4000watts @ 12v needs a huge wire and breaker to be able to use it .
Plus you can use 4 times the solar panels on the charge controller
My out back charge controller and take 1000watts of solar panels @12 volt .
2000watts at 24 volts. And 4000 watts at 48 volts
you wire at 12volts would need to be 4x the size , then it would be at 48 volt .
Battery’s can only put out so much power
12 volt should stop at 1000 watts 24volts 2000watts 48 volt is the rest now .
You really just can’t string the panels together ? you need to look at the size and voltage
you need at least 68 volts per string in order to equalize a 48 volt battery .
so your 9 panels need to be close in voltage and watts .
I’m guessing your panels are 22 volts so you could string 4 of them together for 88 volts minimum or 5 110 volts .
maybe 6 panels for 132 volts , I think that inverter can receive up to 150 volts.
So I think you will need to add one more panel or 3 more so there is seven number .

O boy you really can’t Disconnect the batteries and leave them .
In the winter I can turn off my system when charged up and walk away for 5 month and when I come back
My battery’s are still charge .
In Mexico it’s hot , depending on the type of battery’s they will discharge in the heat very fast , they really need to be charge every month Or they will die. Your Thoughts ?
Tracer made good stuff .
I think this will work for you .
If you could get some pics of the system wiring battery’s solar panel front and back .
We could help more .

 

[Wellbuilt]

Another thought you need to make sure what type of power the place runs on now.
The inverter posted has 220 volt my place just runs on 120 volt
I use a small 120v generator to charge my battery’s when I’m covered in snow .
a 220 volt system would need a generator with 220 volt plug to use both lugs on the inverter it would be a larger generator and burn more fuel .
One other thing , I use out back equipment for a reason ?

 

[San Felipe BC]

I’ve been trying to get some pictures from Mexico but it’s proven to be a problem texting pictures. The system is 120 volt. If we need to plug in something 240 we use the Miller welder/generator.

 

[San Felipe BC]

Ok , the difference between 12v and 48 volt is x4 soooooo 4000watts @ 12v needs a huge wire and breaker to be able to use it .
Plus you can use 4 times the solar panels on the charge controller
My out back charge controller and take 1000watts of solar panels @12 volt .
2000watts at 24 volts. And 4000 watts at 48 volts
you wire at 12volts would need to be 4x the size , then it would be at 48 volt .
Battery’s can only put out so much power
12 volt should stop at 1000 watts 24volts 2000watts 48 volt is the rest now .
You really just can’t string the panels together ? you need to look at the size and voltage
you need at least 68 volts per string in order to equalize a 48 volt battery .
so your 9 panels need to be close in voltage and watts .
I’m guessing your panels are 22 volts so you could string 4 of them together for 88 volts minimum or 5 110 volts .
maybe 6 panels for 132 volts , I think that inverter can receive up to 150 volts.
So I think you will need to add one more panel or 3 more so there is seven number .

O boy you really can’t Disconnect the batteries and leave them .
In the winter I can turn off my system when charged up and walk away for 5 month and when I come back
My battery’s are still charge .
In Mexico it’s hot , depending on the type of battery’s they will discharge in the heat very fast , they really need to be charge every month Or they will die. Your Thoughts ?
Tracer made good stuff .
I think this will work for you .
If you could get some pics of the system wiring battery’s solar panel front and back .
We could help more .

I guess where I’m lost is how to convert to 48v from 12v. Do I need new wire, breakers, or cables? I’m starting to understand the benefits of 48v I just don’t know what switching entails equipment wise. Agreed on them charging monthly. We don’t usually disconnect them and I’m guessing the charge controller failed if the batteries were boiling.

 

[Wellbuilt]

That’s easy 12 volt uses low volts hi amps.
but a 4000watt inverter would work better on 2g from inverter to battery . I have a shut off on my inverter
so I use a simple fuse on my battery lug .
The square block is the fuse . Buy a extra fuse so you have it .
If the inverter has no on off switch it nice to have so you can turn off the system .
Most lead acid batteries don’t like to float for ever , more likely the battery’s got a little older and started using more water and ran out so they where bubbling like crazy .
Really we should pick a unit then study the manual , most of the answers will be in there .
You should try to find a supply house before you go down so you can pick up small things .

 

[Wellbuilt]

this seams like what you are looking for 120 vac power 48 volt battery 80 amp charge controller
It’s a little cheaper .

 

[Wellbuilt]

One other thought , I would buy this thru Amazon with pay pal and a Credit card in case you have some type of problem

 

[Wellbuilt]

These all in one units have a hi idol load just being turned on they use 100w of power every hour .
my out back uses 35 watts