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please help! New panels putting out very little energy

Gracie8

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Sep 4, 2021
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I may have really goofed.
I bought 4 Longi 355w panels that were rated for 12, 24 or 36v and a combo inverter/controller. I hooked them together in series parallel with multiple 2 foot y cables with mc4 connectors. I didn't have any combiner connectors. So some of the connectors are partially empty. I measured the volts coming off the main wires where they would connect to the controller around 1700 watts on a smoky day where we had no sky/sun showing due to heavy smoke cover.

I then put ring connectors on the pos and negative and attached them to the combined controller/inverter. I didn't hook any batteries up yet. I didn't plug the combined unit into any electrical outlet. I switched it to on and nothing happened.
A day or two, later I went down to finish hooking everything up to the batteries. I checked on the volt meter the watts coming in off the panels and it was around 85. I went out and checked for loose wires and found some were not tight and tightened them. Still the meter reading was fluctuating around 85. I cut the rings off and checked the output on the end of the wire. Still fluctuating roughly around 85. If I disconnect the mc4's after covering up the panels, can I measure the watts somehow with the MC4's on the wires?

We had a clear and sunny day in between there. Did the output exceed the all in one unit? Did I fry everything? Is there a way to repair?

Here's the info on the all in one controller/inverter:
3500W_all_in_one.jpg
All-in-one Inverter(3000W 24V Inverter+80A controller)
Build-in 80A Controller Part
Solar Charge Mode: PWM
Solar Panel Wattage: up to 2800W
Rated Input Voltage: 24V DC
Open Circuit Voltage: 70V
Pure Sine Wave Inverter Part
Rated Output Power: 3000W
Dc Input Voltage: 24V
Frequency: 110V-60Hz/220V-50Hz
Rated Input Current: 125A
Rated Output Voltage: 110V/220V

And info on the panels:
DC/Charger Volt Compatible 12v, 24v, 48v
Rated Power Output355
Voltage (VOC)40.6V
 
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That thing says it's rated for 24 volts input, but by wiring your panels in series, you gave them more than 2x the allowed voltage. I think you may have indeed goofed.
 
That thing says it's rated for 24 volts input, but by wiring your panels in series, you gave them more than 2x the allowed voltage. I think you may have indeed goofed.
I followed the diagram in the instructions for the all in one but didn't take into account the panels were rated for 12, 24 or 48 volts. So did I kill just the controller inverter or the panels?
 
I followed the diagram in the instructions for the all in one but didn't take into account the panels were rated for 12, 24 or 48 volts. So did I kill just the controller inverter or the panels?
It sounds like you may have killed the inverter (like someone else already said. Not sure what circus means by battery. maybe he's saying you battered your inverter.
 
You did not kill the panels. The other items may be ok (may have over-voltage protection). Just rewire everything for the proper voltage and try again.
Rewire in parallel and see if i get any watts off wire?
 
You did not kill the panels. The other items may be ok (may have over-voltage protection). Just rewire everything for the proper voltage and try again.
product description on combo controller inverter says: The protection of under voltage, over-voltage, overheat, overload, over current and short-circuit.
 
There are no batteries connected to the system and never have been.
Could be why circus said batteries. the inverter probably has to be powered by battery before it will process the solar feed. hopefully the over voltage hasn't damaged it. What's the open circuit voltage of your panels? How were the panels initially wired? Sounds like you need to do 2s2p. Anyone else have thoughts on this?

I had it in my head they were 12 v panels if they could be wired 12/24/48v. If indeed they're 24v panels, put them all in parallel for that unit.
 
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What's the open circuit voltage of your panels? How were the panels initially wired? Sounds like you need to do 2s2p. Anyone else have thoughts on this?

Yeah, we need to know exactly what the panels are rated for. I'm guessing they are 24V panels. If so, they should all be in parallel for that unit.
And it is likely he does need at least one 24 battery.
 
There are no batteries connected to the system and never have been.
Not familiar with your UPS device, so I didn't want to assume, but the battery is hooked up first on every charge controller I've encountered. In fact it voids the warranty if it isn't.
 
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Yeah, if the charge controller is not "powered up" by a battery, it most likely will do nothing with just panels connected. The controller will have no "reference voltage" or any clue as to how much current to regulate with basically an open circuit on the output. Plus an inverter without batteries is not going to work well if at all.
 
Thanks to everyone who helped. I dont have enough cords to hook everything in parallel and I am rethinking if I need to replace the combo inverter/controller to a larger size. And how to maximize these panels that are able to do 12v, 24v, or 48v. I'll go on over to another chat room and posts some questions on optimizing what I have. Thanks again for giving me hope to keep on trying and answering all my questions.
 
Not familiar with your UPS device, so I didn't want to assume, but the battery is hooked up first on every charge controller I've encountered. In fact it voids the warranty if it isn't.
Obviously, I have no idea what I am doing. Thanks for that tidbit. Im waiting on batteries to arrive and got eager to start.
 
And how to maximize these panels that are able to do 12v, 24v, or 48v.
Not sure what you mean by this. Typically a panel is either 12V (~20V with no load called VOC on the specs) or 24V panels that are close to 40V with no load. The specs you posted earlier show these to be 24V panels. You match the panels with the type of controller you have. The controller you listed earlier calls for 24V input. Since this is a PWM controller, you would run all of the 24V panels in parallel. If you had a MPPT controller then you typically can go higher on the input (i.e. two in series). But right now the bigger issue is not having a battery. You will need some combination of batteries to give you 24V.
 
Not sure what you mean by this. Typically a panel is either 12V (~20V with no load called VOC on the specs) or 24V panels that are close to 40V with no load. The specs you posted earlier show these to be 24V panels. You match the panels with the type of controller you have. The controller you listed earlier calls for 24V input. Since this is a PWM controller, you would run all of the 24V panels in parallel. If you had a MPPT controller then you typically can go higher on the input (i.e. two in series). But right now the bigger issue is not having a battery. You will need some combination of batteries to give you 24V.
I appreciate your reply. I wish I could hire someone to do this and optimize what I can afford. The panels I bought were listed as DC/Charger Volt Compatible for 12v, 24v, 48v. I am realizing if I had bought the inverter/controller combo that was for a 48 volt system I would be able to power more than with the 24 volt combo unit. I have two batteries and ordered 2 more. I wanted to wait to wire batteries till the other two came. I have 5 panels in total and wiring in parallel will allow me to use the 5th panel that wiring in series left out. nd I think I need to buy some in line fuses for the postive and negative lines coming in from the solar panels. I do have a fuse for after the batteries with a switch. Am I right in thinking with the panels wired in parallel I will get twice the watts because the all in one unit is a 24v system and if I had bought the 48v system Id have roughly 4 times the wattage? Or does that only happen when you wire in series? Obviously I am in way over my head and need to figure a bunch of stuff out while I wait for batteries.
 
OP post #1: "I checked on the volt meter the watts coming in off the panels and it was around 85. I went out and checked for loose wires and found some were not tight and tightened them. Still the meter reading was fluctuating around 85"

That does not make any sense, Volt meter does not read and or show reading Watt, it sound like you are reading the panel Voltage of 85V.

Your charge controller has PV rated input of 70V.
'Open Circuit Voltage: 70V'
 
I appreciate your reply. I wish I could hire someone to do this and optimize what I can afford. The panels I bought were listed as DC/Charger Volt Compatible for 12v, 24v, 48v. I am realizing if I had bought the inverter/controller combo that was for a 48 volt system I would be able to power more than with the 24 volt combo unit. I have two batteries and ordered 2 more. I wanted to wait to wire batteries till the other two came. I have 5 panels in total and wiring in parallel will allow me to use the 5th panel that wiring in series left out. nd I think I need to buy some in line fuses for the postive and negative lines coming in from the solar panels. I do have a fuse for after the batteries with a switch. Am I right in thinking with the panels wired in parallel I will get twice the watts because the all in one unit is a 24v system and if I had bought the 48v system Id have roughly 4 times the wattage? Or does that only happen when you wire in series? Obviously I am in way over my head and need to figure a bunch of stuff out while I wait for batteries.
Ok, solar panels aren’t rated that way.
Please post the specs on your panels…
 
Am I right in thinking with the panels wired in parallel I will get twice the watts because the all in one unit is a 24v system and if I had bought the 48v system Id have roughly 4 times the wattage?

Total watts are the same regardless of how they are wired (4 x 355w). The reason you typically want to go higher on the voltage (i.e. 24V vice 12V, or 48V vice 24V) is the lower current (amps) at the higher voltages. This allows you to use smaller gauge wire and has some other advantages.
 
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