dashdrum
New Member
Even though I don't have one of these units, I have enjoyed reading about everyone's efforts and trials. My still-on-paper plan for a garage setup with solar priority and grid backup could be served well by an LV2424 or similar.
MPP Solar LV2424 kicks butt!!!
- Thread starter erik.calco
- Start date
Not an electrician, but i assume this is a single pole breakers, so which wire, positive or negative, attaches to it? I have 4 - 100W panel in series each produce 6 amps, 4 x 6 = 24, so I'm assuming a 30a breaker, right?
sed6
Knows just enough to be dangerous...
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I spent just $150 more than individual components and it's got an AC charger, cool display and time shifting plus many other features! Plus mine arrived from the factory today, took just 1 week!!!
Not an electrician either, I broke both positive and negative with their own 20amp breaker. My idea was a complete PV disconnect without unscrewing any wires. You would want 30 amp like you said.
sed6
Knows just enough to be dangerous...
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Never mind, just needed a .rar unpacker.
Just a note on breakers being discussed - if your panels are in series you don't sum up amps per panel, only voltages. Four 6-amp panels in series will only give you a max of 6 amps.
A breaker should not be rated any higher than the thinnest gauge wire in that circuit can safely carry. Of course, if you have a component to which you want to limit the amps, then it's fine to downsize a breaker to protect that component.
A breaker should not be rated any higher than the thinnest gauge wire in that circuit can safely carry. Of course, if you have a component to which you want to limit the amps, then it's fine to downsize a breaker to protect that component.
I don’t have anything going into the unit what so ever. I have 8 solar panels and it gave me a reading of 80 volts when I had all of them plugged in. I was running two 400 watt arrays in parallel getting 80volts. I ended up unplugging two of the panels, leading me to have a total of two 300 watt arrays in parallel but now it is only reading 28volts so at this point I am royally confused. My voltage on my batteries is 26.8 currently
doctorcupcakes
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Are you sure you unplugged a panel from each array? Or did you unplug 2 panels from the same array? If you did, that would make one array half the voltage of the other, and combining different voltages in parallel is a big no no that can cause a funky voltage reading.
Sed linked to an ASI breaker on homedepot.com, but they sell directly, and have DC breakers rated at 125vdc/pole. Using a two-pole breaker on positive and negative, according to the datasheet, would give up to 250vdc. Here's an example, a two-pole 50A breaker at 250vdc:
Electronic Components & Supply Online Store | ASI
Need automation components and parts? Check out ASI's vast inventory of electronic components for automation and industrial applications.
www.asi-ez.com
Quite a difference between 250vdc and 400vdc, but 250vdc isn't nothing.
Last edited:
erik.calco
Solar Badger
Very nice find. Added to my breakers page.Sed linked to an ASI breaker on homedepot.com, but they sell directly, and have DC breakers rated at 125vdc/pole. Using a two-pole breaker on positive and negative, according to the datasheet, would give up to 250vdc. Here's an example, a two-pole 50A breaker at 250vdc:
Electronic Components & Supply Online Store | ASI
Need automation components and parts? Check out ASI's vast inventory of electronic components for automation and industrial applications.
Quite a difference between 250vdc and 400vdc, but 250vdc isn't nothing.
Sunny Days
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Anyone know about repair guides for
The LV2424?
Mine been working great for about 2 years, now its off, if switch it on the screen lights up with no data just blank and last for 3 seconds then its off, no beeps and no fans running.
Cant seem to find anything online.
The LV2424?
Mine been working great for about 2 years, now its off, if switch it on the screen lights up with no data just blank and last for 3 seconds then its off, no beeps and no fans running.
Cant seem to find anything online.
Hedges
I See Electromagnetic Fields!
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Sed linked to an ASI breaker on homedepot.com, but they sell directly, and have DC breakers rated at 125vdc/pole. Using a two-pole breaker on positive and negative, according to the datasheet, would give up to 250vdc. Here's an example, a two-pole 50A breaker at 250vdc:
Electronic Components & Supply Online Store | ASI
Need automation components and parts? Check out ASI's vast inventory of electronic components for automation and industrial applications.
Quite a difference between 250vdc and 400vdc, but 250vdc isn't nothing.
My initial system 15 years ago had 24, 12V panels in series with and Outback box that had 6 or seven 15A 150V breakers. Those segmented the 600V string to groups less than 100V each. That was before MC connectors that let me safely mate a high voltage string.
Later I used unfused 30A 600V "heavy duty" visible blade disconnects.
Now I have touch-safe fuse holders for multiple 600V strings, and the inverter has a DC disconnect attached.
I finally got around to testing my system running 240 split phase. (my pool pump) It wouldn't start when I flipped it on - then 1-2 minutes later the pump would spin up and run for a while and then stop after a couple of minutes, then spin up again and stop. Something was not right. To recap my set up I have each inverter feeding one leg of my Reliance transfer switch and both of them feeding one 30amp double pole breaker. Everything was running fine with the single pole breakers. This was the first test of the double pole breaker and my pool pump.
I checked voltage at each breaker point and I was seeing 248 when running and then when the pump stopped the voltage would go to essentially zero - That was weird as it meant the inverters themselves were not providing voltage to this circuit.
I re-read the (Poor) manual on Parallel split phase set up. Mind you reading this manual means looking at the pictures. I found my issue. It was the Grid input feed.
When I originally installed this I had one inverter with plans for expansion. I leveraged what I had in place already for my Grid input side which was on 30Amp circuit. That circuit was feeding a duplex outlet. I was plugging both inverters into that outlet (one 120Volt circuit). Everything was working fine and while charging (30amps to the battery from each inverter) it was never pulling more than 10amps or so on the AC input side.
The inverters however always have awareness of the grid when it's connected as they need to know if the load is too or battery too low they need to be able to pull that power from grid. What was happening was when I flipped on the pump, the inductive load was enough to call for grid power. I found this out by shutting off the grid and forcing it to pull from my batteries and the pump started and ran fine. When it went to pull from the grid it only saw a single 120volt circuit and couldn't figure out to feed a split phase 240Volt circuit with that input. I rewired the grid feed to use a double pole 30AMP breaker in my main panel, and now have two hots feeding the duplex outlet by my inverters. Each inverter is plugged into a different hot. I also now have more input capacity for each inverter- Problem solved
So to summarize, if you're using split phase 240 on the inverter output side, you need two circuits feeding the Grid input side
I checked voltage at each breaker point and I was seeing 248 when running and then when the pump stopped the voltage would go to essentially zero - That was weird as it meant the inverters themselves were not providing voltage to this circuit.
I re-read the (Poor) manual on Parallel split phase set up. Mind you reading this manual means looking at the pictures. I found my issue. It was the Grid input feed.
When I originally installed this I had one inverter with plans for expansion. I leveraged what I had in place already for my Grid input side which was on 30Amp circuit. That circuit was feeding a duplex outlet. I was plugging both inverters into that outlet (one 120Volt circuit). Everything was working fine and while charging (30amps to the battery from each inverter) it was never pulling more than 10amps or so on the AC input side.
The inverters however always have awareness of the grid when it's connected as they need to know if the load is too or battery too low they need to be able to pull that power from grid. What was happening was when I flipped on the pump, the inductive load was enough to call for grid power. I found this out by shutting off the grid and forcing it to pull from my batteries and the pump started and ran fine. When it went to pull from the grid it only saw a single 120volt circuit and couldn't figure out to feed a split phase 240Volt circuit with that input. I rewired the grid feed to use a double pole 30AMP breaker in my main panel, and now have two hots feeding the duplex outlet by my inverters. Each inverter is plugged into a different hot. I also now have more input capacity for each inverter- Problem solved
So to summarize, if you're using split phase 240 on the inverter output side, you need two circuits feeding the Grid input side
Hedges
I See Electromagnetic Fields!
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With the second inverter connecting a grid wire that was 180 degrees out of phase with what it expected, you're lucky it didn't blow itself up. Is it designed to combine inverter output with what comes from the grid, or does the inverter turn completely off and use the grid instead?
My SMA Sunny Island can be programmed for how many amps to pull from the grid (e.g. 15A or 53A max) and if the load is higher it will draw from batteries to supply balance of power needed by the load without tripping a breaker. If it is disconnected from the grid (e.g. due to grid failure), before reconnecting it monitors grid for voltage & frequency within limits, then alters inverter frequency to align phase before connecting grid. If we have a transfer switch between generator and grid on the input, we are supposed to have both disconnected for 5 seconds before connecting the second one. If the switch snaps directly to a source that is out of phase, the wrong FET transistors might be turned on presenting a short across the grid.
So your inverter is able to start the pool pump induction motor without grid present, but that is an overload so it uses the grid if available?
You said the pump stopped after a couple minutes. Is that too heavy a draw, and the battery got low or inverter overheated? No reason to run the pool pump off this circuit unless it can run a reasonable time from battery and PV.
erik.calco
Solar Badger
My understanding of what he was saying was that there was no second grid wire connected. Once he connected it, the LV2424 was able to correctly sync to split phase.
When you have grid in, it syncs to the grid. When you don't it produces its own phases. So, it can't sync to split phase if you only have single phase coming in.
From everything we've seen so far, the LV2424 is very smart and does a great job of syncing to grid input and, as we learned from Mac, does a decent job handling human error in configuration. This is also good to know because, in theory, there are other reasons this could happen, such as one of the grid inputs later becoming disconnected (e.g., mouse chewed it?)
What Erik Said. The induction load wanted to pull from grid for support. It was looking for Split phase from the grid to power that load. There was only one circuit attached. Per Hedges post it would be nice to be able to tell it to pull from my Lifepo4's instead as it seems they can support it but I haven't found a configuration that will do that.
One of the biggest challenges with these MPP Solar units is determining expected behaviors due to the poor manuals. It requires testing different configuration settings and combinations to see how they affect things.
Hedges
I See Electromagnetic Fields!
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Driving induction motors can be a problem for a couple reasons. They draw massive current when first starting. Depending on load, current drawn is out of phase with voltage and higher than necessary for the power produced. Current is also pushed back into the source. For the grid that gets consumed by other loads and there is just some excess IR drop. For an inverter the current needs to go somewhere, ideally back into capacitors on the DC side, but could do nasty things to the semiconductors instead.
An amplifier or power supply can be anything from "one quadrant" (I drive voltage and current, delivering power only) to "four quadrant" (I source or sink current in or out of phase with voltage, both polarities, delivering or receiving power.)
Here's an article on large AC motors:
www.ecmweb.com
And a graph from that article:
The graph shows several large motors loaded to about 50% of capacity, and power factor ranges from 62% to 90%. 100% would mean current is in phase with voltage, just like a resistive load. Less than 100% means the motor is shoving current back into the source during part of the AC cycle.
Your inverter only running the motor for a few minutes sounds like a problem. Did the battery voltage drop too low in that short a time and so the inverter switched back to grid? If not, could be a more serious issue like overheating. Could be reactive power due to power factor shoving out of phase current through the transistors. Or just excessive current due to power factor. Better figure out what's going on before something gets damaged.
An amplifier or power supply can be anything from "one quadrant" (I drive voltage and current, delivering power only) to "four quadrant" (I source or sink current in or out of phase with voltage, both polarities, delivering or receiving power.)
Here's an article on large AC motors:
Motor Efficiency, Power Factor, and Load
How to improve system performance and generate cost savings on the plant floor
www.ecmweb.com
And a graph from that article:
The graph shows several large motors loaded to about 50% of capacity, and power factor ranges from 62% to 90%. 100% would mean current is in phase with voltage, just like a resistive load. Less than 100% means the motor is shoving current back into the source during part of the AC cycle.
Your inverter only running the motor for a few minutes sounds like a problem. Did the battery voltage drop too low in that short a time and so the inverter switched back to grid? If not, could be a more serious issue like overheating. Could be reactive power due to power factor shoving out of phase current through the transistors. Or just excessive current due to power factor. Better figure out what's going on before something gets damaged.
erik.calco
Solar Badger
@Hedges I was measuring my loads which included Power Factor (PF) before I brought my LV2424 online. My computers and their UPS (all computers run on a UPS) ran well into 90s, typically near 94. But, what ran low, often in the 60s, were things using AC to DC adapters, like my networking gear. Fortunately, they only represent a small % of my load, as they are relatively low power devices. But, I found that interesting as I've never heard anyone mention that.
Hedges
I See Electromagnetic Fields!
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Yea, it is something only an EE would think about. I don't even deal with motors professionally, but I'm aware of power/utility issues.
Cheap AC adapters are nasty. Instead of simulating a purely resistive load (like high end models might), they just use diodes to charge a capacitor, which only draws current during the peak of a sine wave. I visited a factory in Guadalajara where X-Box was being manufactured. With many of them plugged in for testing, the AC line voltage had peaks of the sine wave flattened.
UPS can be on-line or off-line. If off-line and just passing through, then you were seeing the computer supplies, however they behave.
Can you measure power factor of a 1 or 2 horse induction motor to represent Mac6792's pool pump? If you have something like an air compressor you could see the change in PF from light to heavy load as pressure rises. Only representative if you have one with an induction motor. The cheaper ones I've bought from Harbor Freight may be brush-type, I'm not sure.
I'm about to get all my cables to connect my Hybrid LV2424 this weekend. I did notice I don't have a disconnect between the MPP and the PV. I saw some talk earlier in the threads about how to disconnect. I'll be using (2) Sunpower T5-SPR-318E 318w panels to start and added another 6 panels later.
If these are my specs what should I be doing for a disconnect and can someone share links.
If these are my specs what should I be doing for a disconnect and can someone share links.
| Vmp: Voltage at Max Power (V) | 54.7 |
| Imp: Current at Max Power (A) | 5.82 |
| Voc: Open Circuit Voltage (V) | 64.7 |
| Isc: Short Circuit Current (A) | 6.2 |
Hedges
I See Electromagnetic Fields!
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You could use a combiner box like one of these, or roll-your-own enclosure, and DC breakers:
outbackpower.com
https://www.altestore.com/store/enc...akers/din-rail-mount-circuit-breakers-p40906/
Up to two strings it could be a switch and no fuses, or a breaker of about 20A with both strings going to it.
Above two strings you could have a breaker per string (something 10A to 20A each depending on what the label on the PV panel says). Or, one switch or breaker sized for all strings, and separate fuses for each string. Those fuses could be DIN use holders in the box, or MC-4 fuse holders.
www.mcmaster.com
https://www.amazon.com/Renogy-30-Waterproof-Line-Holder/dp/B00YG2IAQ4
Here is a switch I use (but I didn't pay this Granger price!)
Each pole is good for 30A, 600VDC. My strings are just under 600V for a grid-tie inverter, but yours are much lower (< 150V).
One pole would be enough to disconnect all four of your proposed strings.
You probably only need to fuse & disconnect the positive lead. (Some of my grid-tie equipment needs both positive & negative protected.)
If you go with a box and DIN rails, that'll give you the flexibility to reconfigure different number of strings and different number of inverters. I see many pre-configured on eBay. Here's one that could work for you, 4 strings and ganged 15A breakers:
FLEXware PV - OutBack Power Inc
OutBack's FLEXware PV Combiner Series sets the new standard for PV balance-of-system hardware. Ideal for both small or large systems, the FLEXware PV8 and FLEXware PV12 accommodates the overcurrent protection requirements of your application.
outbackpower.com
https://www.altestore.com/store/enc...akers/din-rail-mount-circuit-breakers-p40906/
Up to two strings it could be a switch and no fuses, or a breaker of about 20A with both strings going to it.
Above two strings you could have a breaker per string (something 10A to 20A each depending on what the label on the PV panel says). Or, one switch or breaker sized for all strings, and separate fuses for each string. Those fuses could be DIN use holders in the box, or MC-4 fuse holders.
McMaster-Carr
McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.
https://www.amazon.com/Renogy-30-Waterproof-Line-Holder/dp/B00YG2IAQ4
Here is a switch I use (but I didn't pay this Granger price!)
Each pole is good for 30A, 600VDC. My strings are just under 600V for a grid-tie inverter, but yours are much lower (< 150V).
One pole would be enough to disconnect all four of your proposed strings.
You probably only need to fuse & disconnect the positive lead. (Some of my grid-tie equipment needs both positive & negative protected.)
If you go with a box and DIN rails, that'll give you the flexibility to reconfigure different number of strings and different number of inverters. I see many pre-configured on eBay. Here's one that could work for you, 4 strings and ganged 15A breakers:
Solar Combiner Box with Circuit Breakers - 4-String PV Combiner - 15A Breakers | eBay
Find many great new & used options and get the best deals for Solar Combiner Box with Circuit Breakers - 4-String PV Combiner - 15A Breakers at the best online prices at eBay! Free shipping for many products!
www.ebay.com
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