Advice on possibilities for upgrade to my tiny system please?

[Mountainmama]

Good morning from a mountain in sunny Spain
I currently have a small system of 2 x 85w panels and 200ah batteries 12v. And a broken Trace inverter. I use 12v lights and a generator for 220v.

Some neighbours have recently upgraded their large system and are giving (!!!) me their 2v x 12 battery bank and a 5kw inverter system (comprising of 2 inverters, a slave and a master)


So here come the rookie questions,
My system is 12v and I want to remain 12v because of the 12v lighting already in place in my house which I love.
1...Will I be able to configure the batteries I'm being given in 2 groups of 6 to give 12v?
2...Their system is 24v, will I be able to use the inverter(s)? and still keep my 12v lights?
Thanks for reading, any pointers gratefully received whilst I get my head round this exciting possibility ?

 

[Mountainmama]

I realise I need much stronger panels, this was already on my to-do list before the neighbours said they would give me their existing batteries and inverter

 

[12VoltInstalls]

Will I be able to configure the batteries I'm being given in 2 groups of 6 to give 12v?
2...Their system is 24v, will I be able to use the inverter(s)? and still keep my 12v lights?

You can probably do 12V like that just fine

Their inverters won’t work, but they can sell to get a néw 12V inverter…

To use their 24V inverters and still do 12V you’ll have to add a 12V supply to the system.

 

[Don B. Cilly]

I don't know about 12V... for 5 KW of inverters, they're definitely "weak".
If the problem is just the lights, double them up :·)
I mean, for each bulb, add another one in series with it. Shouldn't be much work. You get better lighting, and use 24V.
Or, if they're low-power (like LED) just use a 24 to 12 PWM converter. Cheap and quite efficient.

Now, panels are reasonably cheap, good inverters, and above all good batteries, are not.
What sort of batteries are you getting?
And the inverters, hopefully they are pure sine wave?

 

[Porch]

Good morning from a mountain in sunny Spain
I currently have a small system of 2 x 85w panels and 200ah batteries 12v. And a broken Trace inverter. I use 12v lights and a generator for 220v.

Some neighbours have recently upgraded their large system and are giving (!!!) me their 2v x 12 battery bank and a 5kw inverter system (comprising of 2 inverters, a slave and a master)


So here come the rookie questions,
My system is 12v and I want to remain 12v because of the 12v lighting already in place in my house which I love.
1...Will I be able to configure the batteries I'm being given in 2 groups of 6 to give 12v?
2...Their system is 24v, will I be able to use the inverter(s)? and still keep my 12v lights?
Thanks for reading, any pointers gratefully received whilst I get my head round this exciting possibility ?

Go with 24v battery system to make use of the free equipment you got. Newer panels will be cheaper too as all the big and cheap ones are 24v.
Use a DC-DC buck converter to drop the 24v down to 12v for your lights.

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[MichaelK]

I recently had the same conversation with a neighbor I was trying to switch from 12V to 24V. He was just too focused on his 12V lighting. I gave him four strategies, most of which are already mentioned above

1) simply replace the 12V bulbs with 24V bulbs, and continue to use the same wiring
2) wire two 12V fixtures in series to make 24V pairs.
3) buy a 24V to 12V converter that you wire in for your 12V lights.
4) just throw away your 12V lights and go with AC lights.

I think it's foolish to give up a free inverter just because you want to save some light bulbs.

BTW, will they also be giving you some panels? Since the batteries are 2V, I assume they are very high amphour batteries, in the range of 900Ah to 1200Ah, is that correct?

This needs an order of magnitude more power that what you are producing right now. Use this formula to determine how many watts you need. Base your decision on your rate of capacity charging rate. I'll give you some examples

1/20 C: marginally adequate. Might not fully charge a battery every day.
1/10 C: good charging rate. Most likely the battery will be fully charged most days.
1/8 C: maximal charging rate recommended by many battery manufacturers. Batteries will almost never be undercharged.

Let's say you have an 1100Ah battery at 24V. You want to use the maximal 1/8C rate. 1/8 can also be written as 0.125C The math is 1100Ah X 0.125C X 25V charging X 1.175 efficiency fudgefactor = 4040W. Two 85W panels ain't gonna do it! Will they also be giving you a charge controller? You might need two 80A controllers to handle that much current. Use the formula to scale your system to the size of battery you eventually make.

 

[Mountainmama]

You can probably do 12V like that just fine

Their inverters won’t work, but they can sell to get a néw 12V inverter…

To use their 24V inverters and still do 12V you’ll have to add a 12V supply to the system.

Thankyou for your reply?

 

[Mountainmama]

You can probably do 12V like that just fine

Their inverters won’t work, but they can sell to get a néw 12V inverter…

To use their 24V inverters and still do 12V you’ll have to add a 12V supply to the system.

Thankyou for your reply

I don't know about 12V... for 5 KW of inverters, they're definitely "weak".
If the problem is just the lights, double them up :·)
I mean, for each bulb, add another one in series with it. Shouldn't be much work. You get better lighting, and use 24V.
Or, if they're low-power (like LED) just use a 24 to 12 PWM converter. Cheap and quite efficient.

Now, panels are reasonably cheap, good inverters, and above all good batteries, are not.
What sort of batteries are you getting?
And the inverters, hopefully they are pure sine wave?

 

[Mountainmama]

Batterir

Thankyou for your reply

View attachment 70722

Batteries are Enersys OpzS 1200. 8 yes old and at 50% capacity..

 

[Mountainmama]

I recently had the same conversation with a neighbor I was trying to switch from 12V to 24V. He was just too focused on his 12V lighting. I gave him four strategies, most of which are already mentioned above

1) simply replace the 12V bulbs with 24V bulbs, and continue to use the same wiring
2) wire two 12V fixtures in series to make 24V pairs.
3) buy a 24V to 12V converter that you wire in for your 12V lights.
4) just throw away your 12V lights and go with AC lights.

I think it's foolish to give up a free inverter just because you want to save some light bulbs.

BTW, will they also be giving you some panels? Since the batteries are 2V, I assume they are very high amphour batteries, in the range of 900Ah to 1200Ah, is that correct?

This needs an order of magnitude more power that what you are producing right now. Use this formula to determine how many watts you need. Base your decision on your rate of capacity charging rate. I'll give you some examples

1/20 C: marginally adequate. Might not fully charge a battery every day.
1/10 C: good charging rate. Most likely the battery will be fully charged most days.
1/8 C: maximal charging rate recommended by many battery manufacturers. Batteries will almost never be undercharged.

Let's say you have an 1100Ah battery at 24V. You want to use the maximal 1/8C rate. 1/8 can also be written as 0.125C The math is 1100Ah X 0.125C X 25V charging X 1.175 efficiency fudgefactor = 4040W. Two 85W panels ain't gonna do it! Will they also be giving you a charge controller? You might need two 80A controllers to handle that much current. Use the formula to scale your system to the size of battery you eventually make.

The batteries are Enersys OpzS 1200?
New panels were already on my to buy list cos I know 2x 85w is not going to do anything. They are keeping their panels. I believe they are giving me a charge controller, I will find the manual

 

[Don B. Cilly]

That Victron is top-of-the-line, Masters-I'm'ard-BruceLee gear.
They must really like you if they're giving that to you for free :·)

Hombre, just get a 24V panel or two - they're cheap enough - and forget about 12V. How to deal with 24V has been explained well enough.

Now, the problem is... getting your batteries to do 24V, right? The solar controller is easy/cheap enough.
Are they 2V elements? So you have 6? But from what I see, those are not 200 Ah, they're 1200Ah. Big. Huge. Expensive too.

So, you're "on the verge" of having a tip-top system. You have to work out how much battery storage you want, and a way to make it 24V.
Which comes down to - as usual - batteries. How much are you prepared to spend on them?

 

[houseofancients]

Thankyou for your reply

View attachment 70722

victron are top of the line inverters that should keep you going a long time, especially since you have 2 of them
i would swap out the 12v and go for AC.
AC is safer, and more importantly , appliances at normal 220/230v are much much cheaper to get, and available everywhere.

you better thank you neighbor, couse they are give you a truely nice gift !

 

[houseofancients]

and panels, especially second hand , can be had very cheap, in the range of 50 euro for 250w.

800 euro would buy you 16 panels, which is 4 kw an hour generation.

if you are in the mid to south of spain that would give you 5,5 sun hours in winter and a staggering 8-9 in summer.

in winter that would yield you 15 kwh a day ( 4 x 5,5 x 0,70 )

you would be set to go

 

[Mountainmama]

That Victron is top-of-the-line, Masters-I'm'ard-BruceLee gear.
They must really like you if they're giving that to you for free :·)

Hombre, just get a 24V panel or two - they're cheap enough - and forget about 12V. How to deal with 24V has been explained well enough.

Now, the problem is... getting your batteries to do 24V, right? The solar controller is easy/cheap enough.
Are they 2V elements? So you have 6? But from what I see, those are not 200 Ah, they're 1200Ah. Big. Huge. Expensive too.

So, you're "on the verge" of having a tip-top system. You have to work out how much battery storage you want, and a way to make it 24V.
Which comes down to - as usual - batteries. How much are you prepared to spend on them?

Hi there? I'm really excited about it all, it's a huge improvement on what I have.
So to clarify, my existing batteries are 12v.
They are 3yrs old and 200ah.

I am being given 2v X 12 batteries , ie 24v
I think they are 1200ah , although they are now at 50% capacity after 8yrs of use, (hence the neighbours upgrading as they need more )
??

 

[Mountainmama]

and panels, especially second hand , can be had very cheap, in the range of 50 euro for 250w.

800 euro would buy you 16 panels, which is 4 kw an hour generation.

if you are in the mid to south of spain that would give you 5,5 sun hours in winter and a staggering 8-9 in summer.

in winter that would yield you 15 kwh a day ( 4 x 5,5 x 0,70 )

you would be set to go

Wow, that all sounds great? like I say, panels where already on my list but now I will get some kick ass 24v ones!

 

[Mountainmama]

victron are top of the line inverters that should keep you going a long time, especially since you have 2 of them
i would swap out the 12v and go for AC.
AC is safer, and more importantly , appliances at normal 220/230v are much much cheaper to get, and available everywhere.

you better thank you neighbor, couse they are give you a truely nice gift !

Thankyou ? I am so grateful to them, I realise it's some top kit and I want to do it justice

 

[Don B. Cilly]

I bought a 24V one at Bricomart (Palma). 340W (nominal), 140€.

I also bought a battery there... LFP, much more expensive, but a total game-changer.

 

[Mountainmama]

I bought a 24V one at Bricomart (Palma). 340W (nominal), 140€.

I also bought a battery there... LFP, much more expensive, but a total game-changer.

Thanks, I hear good things about bricomat and that sounds like a good price!
This is all really helpful, I'm starting to get my head around it all ??

 

[MichaelK]

I am being given 2v X 12 batteries , ie 24v
I think they are 1200ah , although they are now at 50% capacity after 8yrs of use, (hence the neighbours upgrading as they need more )
??

You can go back to the formula I gave you in post #6 and recalculate how many watts you need. I would say 4400W. In Spain, do you have a local website similar to the US's "Craigslist"? That's a site where random people can post their items for sale to the general public. What you might find is that standard grid-tie panels are FAR more economical than mail-order panels (especially 12V) if you don't have to pay for shipping. Buy locally with local pickup instead of shipping.

What you might find is that you'll still need to replace these gifted batteries in a few years because they are really showing their age, I I still think you will need at least a couple of thousand watts of panels to do a new battery bank justice. Might as well start now, so you can have the new panels in place.

Do you know much about the history of these batteries? How many amps were the original owners putting into them? Have they be routinely equalized? With proper care and equalization, some of the lost capacity might be restored if the batteries are quickly brought to full charge and kept that way after equalization. Most lead-acid batteries die from under-charging.

Keep in mind that most charge controllers max out at about 80-100A capacity, so if you need 150A to charge this battery bank, you'd need two controllers to reach that level. We can help you do the math.