Cheap 4-life
My body is 2.63 trillion volts, .07v per cell
Same here, nothing but good things I can say about them. Using for 4 years
Recommended vendors for GTIL inverters?
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If I can get 4-years out of my 2 GTILs, I’ll be more than happy.
One of the hidden gems of the DIY world
Are you driving yours directly off of solar or from a battery?
I’m charging a 24V LiFePO from an SCC during daylight hours and running the GTILs off of that stored energy late into the night to offset peak consumption long after sunset… (time-shift).
Cheap 4-life
My body is 2.63 trillion volts, .07v per cell
They are powered by 60v batteries. I run my inverters 24/7. They ofcourse use solar directly from cc when there’s day time loads, but when there’s clouds solar batteries and maybe a little grid power could be used if my loads are over the 3500w capacity of the inverters, if it’s night time the batteries are utilized and maybe a little grid power.If I can get 4-years out of my 2 GTILs, I’ll be more than happy.
One of the hidden gems of the DIY world
Are you driving yours directly off of solar or from a battery?
I’m charging a 24V LiFePO from an SCC during daylight hours and running the GTILs off of that stored energy late into the night to offset peak consumption long after sunset… (time-shift).
Electric bill is near zero every month other than the service fee
Nice. I’m guessing you’re getting much better efficiency operating off of 60V batteries than the ~80% efficiency I get operating at 24V.
But if you’ve gotten 4 years operating 24/7, that hopefully bodes well for the longevity I’ll get operating less than 12 hours per day
.
Cheap 4-life
My body is 2.63 trillion volts, .07v per cell
I’ve calculated 86% efficiencyNice. I’m guessing you’re getting much better efficiency operating off of 60V batteries than the ~80% efficiency I get operating at 24V.
But if you’ve gotten 4 years operating 24/7, that hopefully bodes well for the longevity I’ll get operating less than 12 hours per day
Cool - that’s not nearly enough of a gain to get me to ditch my 24V battery and 1S3P array for a 48V battery and 3S1P array (my little 1kW DC-coupled array suffers from severe shifting shade issues throughout morning, which have been very nicely mitigated by using half-cut panels in a parallel array…
If I went to a 3S1P array and a 48V battery, I’d probably lose more is reduced energy capture than the ~7.5% increased output I could get from the same stored battery energy.
Cheap 4-life
My body is 2.63 trillion volts, .07v per cell
Have you joined the GTIL2 Facebook group? Solar grid tie inverters with limiter USA users? I am the moderator there
There’s a lot of info regarding these inverters there.
Using a 24v battery forbthese inverters puts a lot of unneeded stress on them. I recommend a minimum of a 36v battery for the 22-65v version.
Sorry for not seeing this until now, it I’m not a fan of Facebook.
At this point, I’m stuck running my GTILs at 24V.
With smaller cables, a 24V battery can certainly be a challenge, but I used 2/0 welders cables and have had no issues (for one year now).
I may eventually go to 48V but only if I add Microinverters to my backup power array along with a proper hybrid inverter…
Cheap 4-life
My body is 2.63 trillion volts, .07v per cell
I only use Facebook to learn stuff and help others..
If you are limiting the inverters amps it can use in its settings then that slightly helps mitigate some of the concern of using such a low voltage..
I use the CT sensors and I’d been working great, but my offset level is typically low (25 to 250W).
What issues have others reported when running off of 24V batteries and are they using battery cables as large as mine (2/0)?
Cheap 4-life
My body is 2.63 trillion volts, .07v per cell
The size of the cables do not matter in regards to what I’m saying.. it’s how many amps your making the inverter use compared to the lower amps it would use if you were supplying it with a higher voltage.. if the load is 800w and your supplying the inverter with 48v then inverter only has to use 16amps. For that same 800w load and instead 24v battery the inverter has to use double the amps at 32amps.. more amps is more heat and more stress. Also 32amps is real close to the max the inverter can handle. 48v though is actually to high. That high of a voltage can stress the components because the voltage is at the inverters components max range.. this is why the best battery voltage is 36v for these cheapo 22-65v GTIL2s for longest life..
Issues reported are damage to these inverters/destroying them by over working them due to a 24v (to low voltage) battery.. the only way to get long life out of these inverters with a 24v battery is to set the amp limit to no more than 25amps in the settings.. still not good to use such a low voltage battery for these inverters but setting the amp limit will help..
Heat is related to power, not current. 16A x 48V = 768W = 32A x 24V…
These inverters are rated for 1000W of input power. That translates to 20.83A @ 48V or 41.67A @ 24V.
Efficiency is supposedly higher at higher voltage, presumably meaning that you will get more maximum power output from 20.83A@48V than you will than the ~800W I am getting from 41.67A @ 24V (~80% efficiency).
That 20% in lost efficiency translates to
energy lost as heat internally, so operating at a higher voltage delivering higher efficiency will result in less ‘stress’ / heat on interval components, as you are suggesting.
But I’m hearing from other GTIL owners operating at 48V that they are getting efficiencies of ~85%, and for 25% less internal heat generation, I’m not sure the change is worth it…
36V is a difficult voltage to manage, but I am interested to know whether you have any efficiency data from GTIL owners operating at 36V…. If 90% or higher that could represent a significant drop in internal energy loss and heat geberation.
I’m not expecting to get very long life from these very cheap inverters (I paid $275 for mine) but I am interested if you have any details from those who experienced failures @ 24V.
As I wrote earlier, my average load is very modest (25W to 250W) in case operating near maximum output levels was a contributing factor to those component failures @ 24V.
The only time my GTILs max out is on those rare times we use the electric oven and even then, it’s typically under 25% duty cycle after the oven has heated up to temp…
We’ll I suppose I’ll be a reality check on your hypothesis then.
One of my GTILs runs at 25W most all of the time (except when the electric oven is being used).
The other has a typical load of 250W.
So if the GTIL I have running at 250W fails long before the unit running at 25W, you can use my experience as further evidence to support your theory.
What lifetime do you believe I can expect from my GTIL running at 250W @ 24V?
And on the question of 36V batteries, I’d be better off increasing my battery from 24V to 36V than I would be increasing to 48V, so I’m interested to understand what BMS and charger you are using for your 36V battery.
I’ve got severe moving shade issues that give me much higher morning output at 1S than 2S. Charging @ 28.8V is no problem at 1S but charging @ 57.6V would force me to go to 2S.
Charging @ 43.2V isn’t a showstopper.
Vmp with newer panels just keeps getting higher and higher and the new 450W panels I am considering have a Vmp of 38.0V and a Voc of 48.43V.
At a full 43.2V, output power is only 70% of max, but it rises quickly at lower charging voltages and the voltage levels are only going to increase further with further panel advances.
Also, once you decide to go ‘non-standard’, there is nothing dictating a 12S / 43.2V battery (other than losing any possibility of finding a cheap AC charger).
An 11S battery charged at 39.6V and will be pretty much depleted at 35.2V (and completely spent by 34.1V) while a 10S battery will charge at 36V and be largely depleted by 32.0V.
So going 36V / nonstandard might eventually be an option for me and if you’ve already headed down that path, I’m interested to learn more…
On 36V LiFePO4 batteries, the standard 36V LiFePO4 chargers are had-coded for 43.8V: https://www.amazon.com/gp/aw/d/B0B5...d2lkZ2V0TmFtZT1zcF9waG9uZV9kZXRhaWwp13NParams
So there is some value to targeting a 12S 36V battery (39.6V).
The new 156-cell half cut panels that have started showing up have a Vmp of 45.33V: https://drive.google.com/file/d/1FhWM577Ay0XBghfxEeTAeMEenHPDUVId/preview
It’ll be a while before panels of this class become widely available and more reasonably priced, but this could be a match made in heaven (1S charging of 12S / 36V LiFePO4 batteries).
So there is some value to targeting a 12S 36V battery (39.6V).
The new 156-cell half cut panels that have started showing up have a Vmp of 45.33V: https://drive.google.com/file/d/1FhWM577Ay0XBghfxEeTAeMEenHPDUVId/preview
It’ll be a while before panels of this class become widely available and more reasonably priced, but this could be a match made in heaven (1S charging of 12S / 36V LiFePO4 batteries).
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Cheap 4-life
My body is 2.63 trillion volts, .07v per cell
less amps means less heat to make the same power. For example this is part of the reason why electric companies send out power at 17k volts. Smaller wires less amps less heat etc etc
This stuff isn’t up for debate.. I know what these inverters are rated for lol.. you can continue to use whichever battery voltage you choose.. even Rogel (creator) has said its best to use a higher voltage than 24v for these inverters..
Efficiency is also better due to less heat in the inverter due to higher voltage.. heat is wasted power..
For efficiency alone, no it’s not worth the change to a higher voltage.. to not waste your money and not work your inverters so hard to make them have an early demise, it’s definitely worth changing to a higher voltage from the start.. the voltage of a battery bank should be what’s best for the inverters. Sounds to me that you had your battery before the inverter..
Again it’s not about efficiency. It’s about destroying these cheap inverters by overworking them. At 24v they are basically screaming for higher voltage. It doesn’t make sense to work cheap inverters as hard as you can by supplying them with the lowest voltage they can possibly use.
I am expecting to get a long life out of mine and many others have and I’m explaining to you how to do it. The details are on the Facebook forum of which I have had many extensive conversations with many of our members regarding using a 24v battery with these inverters. It is in the announcements not to use a 24v battery for these inverters. Rogel has his own Facebook group for these inverters, mostly foreign language.. if you have never read anything on any of these groups (mine or Rogels) then you probably shouldn’t be questioning my advice so much. There’s a plethora of information to help users use these inverters correctly on those forums.. I myself have read days and days of issues problems advice etc etc.. and have helped many figure out their problems as a lot of these inverters are installed DIY by people who do not know what they are doing. I’m a licensed electrician and have installed many solar setups..
If your loads are only 250w then that’s why your inverter has made it as long as it has at 24v.. the inverter simply isn’t using many amps with load that low. But when the ovens on it does and that’s why you need to set an amp limit to 25amps in the settings...
Hypothesis it is not. Everything I’m saying has been proven many times over..
I am using a 60v battery and using two of the 2kw inverters in the USA. for a 36v battery most bms and charge controllers can be used..
Many users of these inverters are using a 36v battery. I use the 45-90v inverters so I use a 60v battery for the same reasons a 36v battery should be used for the 22-65v inverter.. higher voltage is easier on the inverters..
I am typing all this for like the millionth time so some of it might sound a bit like an attitude... is all in the announcements on the Facebook group... search solar grid tie inverters with limiters USA users
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you may not think it’s up for debate, but that doesn’t mean you understand the underlying physics.
Current and amps don’t generate hear, power and watts do.
In the case of heat generated in wires, the power generating heat is Isquared-R losses.
If you are using the same wire size for twice as many amps at half as much voltage, current is double, resistance us the same, and so heat generated and power lost in wiring will be 4 times higher.
Use wires that have 1/4 the resistance for that double-current / half voltage scenario and heat generated / power lost will be identical.
I’m using 2/0 battery cables for exactly that reason - 2/0AWG has less than 20% the resistance per foot of 6AWG wire, so anyone powering their GTIL @ 48V using 6AWG wires will be losing 25% more power than I am powering my GTILs @ 24V using 2/0 wires (assuming equal battery cable lengths).
I’m not arguing that lower voltage is better. My point is that if you plan for it appropriately (by using much lower-resistance battery cables), he difference in performance between 24V operation and 48V operation is less than you are suggesting it is.
Internal to the inverter, I agree. Those wires are all remaining the same size, so wire-related loses internal to the inverter should be 300% higher when powered at 24V compared to when powered at 48V..
If the ~80% efficiency I’m getting @ 24V was primarily caused by increase interval wiring losses, efficiency @ 48V should be ~95%.
The fact that others have reported efficiency of only ~85% @ 48V suggests that only ~2% of list efficiency is due to internal wiring loses and ~13% is due to other factors which are relatively independent of supply voltage. My internal wiring losses @ 24V will be 4 times higher @ ~8% but that represents only ~40% of my overall list efficiency @ 24V.
And operating at 36V, currents would be 133% if what they are at 48V and internal wiring losses would be 178%, meaning ~3.56%.
So assuming identical wiring losses in the battery cables due to appropriate and equivalent cable sizing, I’d expect interval efficiencies of:
85% @ 48V
83.7% @ 36V
80% @ 24V
As I said from the outset, I’ve been constrained to a 24V battery because of my need to charge with a 1S solar array (severe shading).
I had to look long and hard to find an inverter that could operate at 24V and the GTILs fit the bill (with a bit of attention to wiring).
Once again, I’m driving my GTILs with relatively modest loads of 25W on one and 250W on the other, not ‘as hard as I can.’
Yes, I know that. And yet, with testing, you can discover exactly how these GTIL inverters perform powered by a 24V battery.
Long lifetime from these $275 GTIL inverters has never been an expectation or a priority for me. I’ve already generated 1400kWh through them over their first year, so I’m already a satisfied customer.
I’m not questioning your advice, I’m explaining the reasons I don’t believe it necessarily applies to my situation:
-I have reasons I need to operate at 24V (shading).
-My average load level is very modest.
-I understand the challenges of operating at lower voltage with higher currents and how to compensate for that through proper cable sizing.
-I don’t really care that much about maximum lifetime of these GTIL inverters.
I’ve read enough of the horror/failure stories from various places to know you are correct about that, and those un knowledgeable DIYers are lucky to have you helping them, but I am not one of them.
At least on this point, we seem to agree…
If you know of anyone else who has powered their GTIL from a 24V battery using short 2/0 battery cables, I’m all ears.
I’d love to what lifetime anyone who used a similar setup to mine got out of their GTIL and how it failed.
And from that vast number of failures you are aware of at 24V, I’d also love to know how quickly you believe my more heavily-loaded GTIL running 12 hours out of 24 @ 250W should be expected to last before it conks out.
I’m at exactly 1 year of constant operation so far with nothing but good things to report.
If it does fail before I upgrade the entire rig to a proper hybrid inverter, I’ll either spend another $275 on a replacement or start believing your advice applies more to my case than I’m currently feeling.
Ah, so you are using the 2kW model. What BMS and charger are you using for your 60V battery? How many LiFePO4 cells make up that battery?
I’ve seen that some BMSes allow you to just not use some of the leads, but my biggest concern is with mainstream hybrid inverters.
It’s pretty much impossible to find mainstream hybrids supporting 36V and even 24V options are becoming rarer and rarer…
So I’m aware of the fact that when I move from this little ‘learner/experimental’ rig the a higher-quality / more permanent setup, I’m likely going to have to change battery voltage (probably to 48V).
That’s a lot of work I’d prefer to avoid until I select the hybrid I’m going to use for the long-term setup, so I plan to let my 24V rig ride for another year or two.
If you believe my more heavily loaded GTIL is likely to conk out before a year from now, you will have been right and I will have been wrong, but spending another $275 is the better alternative than diving into reconfiguring my battery at this stage…
I certainly agree that it’ll be easier to get these GTILs performing correctly with 36V or 48V batteries than with 24V batteries.
Subject to what hybrid I end up with, I also explained that the new class of 155-cell solar panels means I may be able to charge a 12-cell LiFePO4 battery with a 1S array, so you’ve helped me to add another option to the list of architectures I am considering for the future (and thanks for that).
I appreciate the advice but a Facegroup forum full of unknowledgeable DIYers is just not my cup of tea.
I’m not having any problems with my GTILs - they are exceeding the expectations I had when I spent $550 on the pair of them.
I’m more comfortable on this Forum where the level of knowledge and quality of exchange is much higher…
Cheap 4-life
My body is 2.63 trillion volts, .07v per cell
You may be misunderstanding what I’m saying.. 24v 32amps creates more heat inside the inverter (not in wires outside the inverter) than 48v 16amps .. that’s why these inverters (the 22-65v version) using a 36v battery causes less heat because the inverter is using less amps.. the more amps an inverter uses, the harder it’s being used the more stress it is going thru
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Cheap 4-life
My body is 2.63 trillion volts, .07v per cell
The wires you are using to feed the inverter are not in question. Of course use appropriate size wire for that...
you can’t change the size of the internals.. lower voltage make the inside ofbthese inverters use more amps and creating more heat wear and tear in the process
Cheap 4-life
My body is 2.63 trillion volts, .07v per cell
Again efficiency is irrelevant... it’s about over working the inverter with the lowest voltage it can use.. nearer to the higher end of the voltage the inverter can use is ALOT easier on the inverter than the lower end.. come on now this isn’t debatable..
Well unfortunately you are wrong because these inverters should not be used with a 24v battery to prolong their life.. if you don’t care about longevity or your loads are always extremely low then of course using a 24v battery would be ok but you would be barely using the inverter so of course it would last long. Yeah they say you can use a 24v battery because 22v is the low end but they also say you can plug these inverters into an outlet which should absolutely be avoided as anyone who knows what they are talking about would do..
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Cheap 4-life
My body is 2.63 trillion volts, .07v per cell
Again your not getting it. Of course dont use 10awg to feed and inverter with 24v... that’s before the inverter.. I’m talking about inside the inverter and what makes the inverter itself last the longest without issues. These are cheap inverters and the last thing anyone should do is operate a cheap inverter at its lowest operating voltage. I figured you would know better if “you are not one of them” but maybe you didn’t have any other option... idk or maybe you knew your loads are low enough to barely use the inverter anyways.. still set amp limit though in inverters settings
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Cheap 4-life
My body is 2.63 trillion volts, .07v per cell
At 250w the inverter is barely on.. I mean it’s barely doing anything and will last a long time. Just make sure you set an amp limit (25amps) for those occasional high loads or you will pop the inverter..
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