Stuart Pittaway
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Sonic01 said:
So you are using that to run things off-grid then?
Greetings from London, UK
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So you are using that to run things off-grid then?
Sonic01
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StuartPittaway said:
My intention is to build an off-grid, yes. Currently I'm still planning and preparing.
I have a large shed/smallworkshop with a lot of equipment in it, my idea is to mount the powerwall, inverter and solar there to reduce the energy consumption from that building.
I've still got a little bit of reading to do, but its my understanding that the AC mains input, solar and batteries are all connected to the inverter, then the inverter has an AC output. The inverters solar charger chargesthe batteries and then when full, it switches its energy source from AC mainsinput to battery input, then when the batteries discharge anddrop to a certain voltage, the inverterswitches back to AC input until they are charged again.
is my understanding correct?
There seems to be some confusion around the term "off grid", and your applying it to your project.
It means without ANY connection to the AC mains supply.
Whereas you are talking about a mains-connected (ie grid-tied) inverter project. Which is going to require professional hook up, and everything (mains side at least)being assessed for formalcompliance with The (wiring) "Regs".
There is a wealth of info on here about those "PIP" boxes. There are many versions though, with different feature sets quite apart from different DC voltages and inverter outputs.
But if your 297 cells came from salvage, then you'll be very lucky indeed if 200 are 'good'.
I'd strongly suggest that you don't go buying an inverter based on assuming all 297 areusable.
Unless those are known good brand new cells, your priority should be carefully evaluating just what you have!
Have you screened them for voltage yet? That can determine what charge regime you could safely apply. The Opus doesn't have the specially gentle charge facilty that is advised for over-discharged (low voltage) cells. Setups based on the 4096 chip seem very popular for charging with a gentle pre-charge until the voltage comes into the normal range. Oh, and capacity testing isn't a very quick process... But you should recycle asap any cells that are 0volts and test as open circuit.
You might wellwant to use the cell databaseto id your cells, as some may be of significantly low capacity (specification) that you might not want them for this project, and so even capacity testing those ones wouldn't be a priority.
Plenty to be doing before going shopping for an inverter!
It means without ANY connection to the AC mains supply.
Whereas you are talking about a mains-connected (ie grid-tied) inverter project. Which is going to require professional hook up, and everything (mains side at least)being assessed for formalcompliance with The (wiring) "Regs".
There is a wealth of info on here about those "PIP" boxes. There are many versions though, with different feature sets quite apart from different DC voltages and inverter outputs.
But if your 297 cells came from salvage, then you'll be very lucky indeed if 200 are 'good'.
I'd strongly suggest that you don't go buying an inverter based on assuming all 297 areusable.
Unless those are known good brand new cells, your priority should be carefully evaluating just what you have!
Have you screened them for voltage yet? That can determine what charge regime you could safely apply. The Opus doesn't have the specially gentle charge facilty that is advised for over-discharged (low voltage) cells. Setups based on the 4096 chip seem very popular for charging with a gentle pre-charge until the voltage comes into the normal range. Oh, and capacity testing isn't a very quick process... But you should recycle asap any cells that are 0volts and test as open circuit.
You might wellwant to use the cell databaseto id your cells, as some may be of significantly low capacity (specification) that you might not want them for this project, and so even capacity testing those ones wouldn't be a priority.
Plenty to be doing before going shopping for an inverter!
Sonic01
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Thanks Dougal,
Is it not possible to have an inverter which only draws from AC (as in, not feed back into the grid)? I could easily run a mains connection to it.
The cells are all LG and Samsung and have come from machines being retired due to replacements, not necessarily faults. They all come from 4 different types of HP laptop packs and from what I've read are all 2600 - 3000mah. Though I've only looked at half so far, the rest are still inside their casings.
Under-volted Li-Ions require low trickle charging to restore..? that seems the be the opposite of LiPo which if they go dead you pump them with a 1C charge until they are back over 3.7v then you can normally cycle them again. If they respond of course...
Is it not possible to have an inverter which only draws from AC (as in, not feed back into the grid)? I could easily run a mains connection to it.
The cells are all LG and Samsung and have come from machines being retired due to replacements, not necessarily faults. They all come from 4 different types of HP laptop packs and from what I've read are all 2600 - 3000mah. Though I've only looked at half so far, the rest are still inside their casings.
Under-volted Li-Ions require low trickle charging to restore..? that seems the be the opposite of LiPo which if they go dead you pump them with a 1C charge until they are back over 3.7v then you can normally cycle them again. If they respond of course...
There is no such thing as an inverter that runs on AC. Well, there is actually, it is usually called a power supply. When we speak of inverters this usually is a device that runs on DC (12/24/48V) and puts out AC (110/115/220/230V) like your mains voltage.
Among them there are off-grid and grid-tied variants. Off-grid inverters are standalone, grid-tied inverters have a connection to the grid to loop through mains voltage if there is no battery power available (UPS function in reverse) or to feed back power to the grid (and possibly get paid for it by your local power company).
Low voltage lithium cells, LiIon and LiPo alike, should be charged with a smal current until they are back up. Sure, you can push 1C through them, but that's the brute force method. If I want you to move forward I can either push you a bit from behind or can give you a kick in the back. What would you prefer?
Among them there are off-grid and grid-tied variants. Off-grid inverters are standalone, grid-tied inverters have a connection to the grid to loop through mains voltage if there is no battery power available (UPS function in reverse) or to feed back power to the grid (and possibly get paid for it by your local power company).
Low voltage lithium cells, LiIon and LiPo alike, should be charged with a smal current until they are back up. Sure, you can push 1C through them, but that's the brute force method. If I want you to move forward I can either push you a bit from behind or can give you a kick in the back. What would you prefer?
Sonic01
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forgive me, but isnt grid power AC? I'm not aware of any inverter that changes my mains supply from DC on the grid to AC in my house?
interesting, everyone in the Airsoft forums says use a 1C kick on flat lipo's, and I've tried and tested it works well too... when i tried with lower currents it had no effect, though maybe i just just impatient.
EDIT: quoting from daromer in the first page in this thread:
A simple inverter only runs from the battery and supplies AC. Nothing smart in it at all that can do witching
Off-grid inverter generally have solar charger, ac charge, can relay AC to loud and can alsy supply to load from battery bank
Hybrid is like the offgrid but it can also deliver excess energy to the grid. ie sell the energy.
he states that it can charge off AC?
interesting, everyone in the Airsoft forums says use a 1C kick on flat lipo's, and I've tried and tested it works well too... when i tried with lower currents it had no effect, though maybe i just just impatient.
EDIT: quoting from daromer in the first page in this thread:
A simple inverter only runs from the battery and supplies AC. Nothing smart in it at all that can do witching
Off-grid inverter generally have solar charger, ac charge, can relay AC to loud and can alsy supply to load from battery bank
Hybrid is like the offgrid but it can also deliver excess energy to the grid. ie sell the energy.
he states that it can charge off AC?
Yes sure, AC is used on the grid. There is obviously some kind of misunderstanding. Not sure what daromer is referring to, but I guess it refers to the inverter also having a battery charger so the inverter can do DC -> AC which is always the inverters main function, that's where its name comes from. But it then can also do AC -> DC which is the other way. That is probably possible with some models but that doesn't mean that the inverter runs on AC. And that's what I've read when you said "Is it not possible to have an inverter which only draws from AC (as in, not feed back into the grid)?". That question made no sense for me as it would defeat the whole point of an inverter.
Maybe a mistake on my part or still some unclear definition of off-grid and on-grid/grid-tied.
Maybe a mistake on my part or still some unclear definition of off-grid and on-grid/grid-tied.
Sonic01 said:
The simple answer is no.
The inverter's fundamental role is to make AC from DC.
And where grid power is available, people use inverter systems to augment their AC mains system, reducing the power drawn from the grid and sometimes feeding power back to the grid, rather than running extra house wiring for an alternate non-mains-linkedset of ring mains.
You could have an off-grid system (solar, batteries, inverter and its own 'private' load circuit/s). And then add a mains-connected battery charger, so you could have the option to charge the batteries (in winter perhaps), even with a timerto usecheaper off-peak Economy7, mains power.
I doubt you will find a single product combining an off-grid inverter and a mains-powered battery charger. But you could create a system with those two modules.
Would thatget you where you were aiming for?
daromer
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Offgrid inverters is most likely what you are looking for. They can forward from grid to your load when battery or solar is low.
Sonic01
An inverter is just an inverter. It goes from 1 type of voltage/type to another. Generally this is from low voltage DC to normal grid based AC that you use in your home appliance.
And Off-grid Inverter for solar is a combination of several "tools" in 1 box.
It firstly have the inverter function where it can supply a AC load from a DC source.
It has a solar charger where it can charge this DC source from solar.
It also generally has an AC charger that you can charge your battery bank from normal AC grid
With all this most of them also have transfer switch in that sense that it can for instance bypass AC incomming to AC output.
All above except solar part is what most UPS system does. (I left out the hot-UPS systems and all those but they work a bit different)
I hope that this answers the question a bit more in detail.
Sonic01
An inverter is just an inverter. It goes from 1 type of voltage/type to another. Generally this is from low voltage DC to normal grid based AC that you use in your home appliance.
And Off-grid Inverter for solar is a combination of several "tools" in 1 box.
It firstly have the inverter function where it can supply a AC load from a DC source.
It has a solar charger where it can charge this DC source from solar.
It also generally has an AC charger that you can charge your battery bank from normal AC grid
With all this most of them also have transfer switch in that sense that it can for instance bypass AC incomming to AC output.
All above except solar part is what most UPS system does. (I left out the hot-UPS systems and all those but they work a bit different)
I hope that this answers the question a bit more in detail.
daromer said:
??? :huh:???
Errr... I think there may be a translation difficulty here, which is going to cause terrible confusion!
"Off grid" is taken to mean without grid connection.
"Grid-tied" inverters are connected to the grid and some are capable of drawingfrom the grid as well as their primary function of adding their generated product to the mains grid (which apart from anything else requires them to synchronise with the mains AC waveform).
I think Daromer's thoughtful advice makes more sense if those terms are swapped over.
In the UK, a grid-connected installation is going to require certificated professional involvement, whereas an off-grid shed shouldn't require a formal sign-off (though it might be a good idea!)
I continue to be impressed and astonished by the command of technical english displayed by posters from around the world. It puts my own linguistic efforts to shame.
daromer
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No m8.
Grid-tied = can send and take from grid.
Off-grid cannot send back to grid but they can switch the load to grid use.
Off-grid does not need grid to function meanwhile grid-tied need grid-connection to work. thats the reason behind the name
Note that this is the most common synonym for it meanwhile there have started to pop up versions that are in middle and all.
Hybrid is a grid-tied version but with battery bank and can work without grid
Grid-tied = can send and take from grid.
Off-grid cannot send back to grid but they can switch the load to grid use.
Off-grid does not need grid to function meanwhile grid-tied need grid-connection to work. thats the reason behind the name
Note that this is the most common synonym for it meanwhile there have started to pop up versions that are in middle and all.
Hybrid is a grid-tied version but with battery bank and can work without grid
I probably wouldn't call a device an off-grid inverter if it can loop mains voltage through to its output as well. It is not off-grid but isn't tied to the grid either, it just has a mains connection.
Let's try it this way and see what kinds of inverters there are:
1. DC -> AC
2. DC -> AC with UPS function, maybe with solar charge controller and AC battery charger as well
3. Same as 2 but with the option to put out AC back into the grid
I'd say:
1. Off-grid
2. Hybrid
3. Grid-tied
Let's try it this way and see what kinds of inverters there are:
1. DC -> AC
2. DC -> AC with UPS function, maybe with solar charge controller and AC battery charger as well
3. Same as 2 but with the option to put out AC back into the grid
I'd say:
1. Off-grid
2. Hybrid
3. Grid-tied
daromer said:
We are just going to have to agree to disagree!
The ability to "take from the grid" (for use outside the inverter itself,eg for battery charging) does not seem to bea necessary facility for something to be called "agrid-tiedinverter".
Also the ability to "switch theload to grid use" is hardlya necessaryfeature for a product to be fairly described as an "off-grid inverter".
If there was some specific product that had the feature-set that you were suggesting for Sonic01, I'm sure he'd be grateful for a pointer in that direction without holding you responsible for a specific recommendation!
daromer
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Check for instance sma website and how they group. Above is also known accronym in sweden
Note that grid tie inverter has no battery. They are generally only for selling electricity. Atleast if you check the group or search for them
And yes we dont have to agree
A rather bad example though still an example is MPP solar: https://www.mppsolar.com/v3/ They arrange it in off-grid, grid-tie and hybrid versions
Same is on several swedish sites actually
But as i said it have started to glide away a bit from this acronym where grid-tie systems in some extent can hook up battery system with external gear.
Darkraven
Off-grid means that it can be used off-grid. But most off-grid Solar inverter can handle and redirect grid connection to outpu. (Im not talking about a pure inverter)
grid-tie generally need the grid to even startup and doesnt have battery functionaly per defaul. Just google grid-tie and most of them are in this case.
Hybrid is combination of above
1. DC -> AC
2. DC -> AC with UPS function, maybe with solar charge controller and AC battery charger as well
3. Same as 2 but with the option to put out AC back into the grid
You say:
1. Off-grid
2. Hybrid
3. Grid-tied
Based on how its sold here above would be:
1. Off-grid or just a pure inverter itself. Though its sold as a pure inverter
2. Off-grid. Since it can work off grid.
3. That is Hybrid version. it doesnt need grid to function and you can run it as an offgrid inverter but you can also run it grid-tie and sell back energy
Above is not something that I have made up This is how they are labeled in Sweden among many websites selling Solar systems.
Note that grid tie inverter has no battery. They are generally only for selling electricity. Atleast if you check the group or search for them
And yes we dont have to agree
A rather bad example though still an example is MPP solar: https://www.mppsolar.com/v3/ They arrange it in off-grid, grid-tie and hybrid versions
Same is on several swedish sites actually
But as i said it have started to glide away a bit from this acronym where grid-tie systems in some extent can hook up battery system with external gear.
Darkraven
Off-grid means that it can be used off-grid. But most off-grid Solar inverter can handle and redirect grid connection to outpu. (Im not talking about a pure inverter)
grid-tie generally need the grid to even startup and doesnt have battery functionaly per defaul. Just google grid-tie and most of them are in this case.
Hybrid is combination of above
1. DC -> AC
2. DC -> AC with UPS function, maybe with solar charge controller and AC battery charger as well
3. Same as 2 but with the option to put out AC back into the grid
You say:
1. Off-grid
2. Hybrid
3. Grid-tied
Based on how its sold here above would be:
1. Off-grid or just a pure inverter itself. Though its sold as a pure inverter
2. Off-grid. Since it can work off grid.
3. That is Hybrid version. it doesnt need grid to function and you can run it as an offgrid inverter but you can also run it grid-tie and sell back energy
Above is not something that I have made up
This is how they are labeled in Sweden among many websites selling Solar systems.
DarkRaven said:
It is up to us to be clear what we are talking about.
SMA refer to "battery inverters"... for anything equipped to handle a battery. Which is helpful.
MPP's term forthose Daromer was referring to is "grid-optional". Which is also nice and clear.
But then they mess up with
https://www.mppsolar.com/v3/news2/
...which doesn't make sense to me. Running off backup batteries and feeding the grid at the same time...? Or at other times?
I think it is better to reserve the grid-tied and off-grid terms for their specific narrow meanings, in the interest of clarity alone.