Renogy inverter not changing voltage

[ckelly3415]

Hi all. Having an issue with my 3000watt renogy inverter and looking for some help. My inverter is running my 120v appliances but does not seem to be actually changing the voltage from 12v to 120v. For example, I have a water heater that pulls 1800 watts. The inverter powers the water heater for a moment or two and then shuts itself off. While the water heater is running, my BMS reads that I am pulling 150amps and 1800 watts, which would mean that the voltage was still 12…. The heater is rated for 15 amps at 120v. All my “120v loads” show that I’m pulling extremely high amperage and usually calculate back down to a 12 volt draw, with the watts being right as advertised. Anyone have any insight as to what is going on here and how to fix it?? Thanks

 

[sunshine_eggo]

Hi all. Having an issue with my 3000watt renogy inverter and looking for some help. My inverter is running my 120v appliances but does not seem to be actually changing the voltage from 12v to 120v. For example, I have a water heater that pulls 1800 watts. The inverter powers the water heater for a moment or two and then shuts itself off. While the water heater is running, my BMS reads that I am pulling 150amps and 1800 watts, which would mean that the voltage was still 12…. The heater is rated for 15 amps at 120v. All my “120v loads” show that I’m pulling extremely high amperage and usually calculate back down to a 12 volt draw, with the watts being right as advertised. Anyone have any insight as to what is going on here and how to fix it?? Thanks

First, the relationship you are describing is very normal and proper. Your perception of the problem is wrong.

Your inverter is a device that takes DC input and converts it to AC output.

Your 12VDC battery will always be a 12V DC battery.

Approximately speaking the AC voltage is 10X the DC voltage and the DC current is 10X the AC current.

1800W:

12V * 150A = 1800W (input)
120V * 15A = 1800W (output)

Additionally, there are losses, so you consume 10-15% more DC power than you get out as AC power.

Likely issues (approximate order of likelihood):

1. Cables between battery and inverter are too thin.
2. Improperly torqued connection(s).
3. Pulling more current than the battery BMS allows.
4. High resistance item like a cheap breaker or fuse holder between battery and inverter.
5. Inverter is malfunctioning.

 

[JWLV]

Your BMS is (or should be) inside the battery. Since your battery is 12V, the BMS will report all data based on 12V.
If your BMS is reporting 150amps, that means 150 amps x 12 volts = 1800 watts. This is correct.

Your inverter's job is to convert the 12 volts DC from your battery to 120 volts AC to be used by typical household appliances. 1800 watts is a lot of power if it's coming from only one battery. You did not mention the type of battery you have. Let's just assume you have a typical 12V 100A LiFePo4 battery that usually sells for about $350 on Amazon. These batteries usually have a maximum current of 50A to 100A. At 50A, you could power something as much as 600 watts. At 100A, you can do 1200 watts. If this is indeed the type of battery you have, you will not be able to power something as much as 1800 watts. The BMS will shut down immediately when that happens. And this seems to be exactly what is happening based on your description of events above.

How do you fix it? You need a bigger battery with more capacity and a higher current limit. Some 12V 300A batteries have a BMS that can handle 200A of current. Some of the cheaper ones may still be limited to 100A.

 

[mikefitz]

To discuss further details of the battery and its BMS are needed, also circuit details, cable, breakers, fuses.
12v systems running loads at around 2000 watts and over, need best practice and quality parts to avoid poor performance.

 

[hyxsungold]

Hi there,

It sounds like you're encountering a puzzling issue with your 3000-watt Renogy inverter. It appears to be running your 120V appliances, but you're noticing that the voltage isn't actually changing from 12V to 120V as expected. For instance, your water heater, which requires 1800 watts, is initially powered by the inverter but then shuts off after a brief period. While the water heater is operational, your BMS indicates a draw of 150 amps and 1800 watts, suggesting that the voltage remains at 12V.

It's concerning that your "120V loads" are displaying high amperage values that ultimately seem to calculate back down to a 12-volt draw, while the wattage remains accurate as specified. This situation indeed poses a challenge to your setup.

To troubleshoot this, you might want to consider a few potential causes:

1. Inverter Settings: Double-check the settings on your inverter to ensure they're configured correctly for your intended output voltage (120V). Sometimes, incorrect settings can lead to unexpected behavior.
2. Inverter Capacity: Ensure that your inverter's capacity aligns with the demands of the appliances you're trying to power. The sudden shutdown you're experiencing could be due to the inverter being overloaded.
3. Wiring and Connections: Faulty or inadequate wiring could lead to voltage drops and incorrect readings. Inspect your connections, especially those related to the power input and output.
4. BMS and Voltage Sensing: Your Battery Management System (BMS) might be causing complications. If it's inaccurately sensing the voltage, it could result in improper inverter behavior.
5. Battery State: Monitor the state of your battery bank. Low voltage or battery issues could impact the inverter's ability to maintain the desired output.
6. Inverter Health: Consider the overall health of your inverter. If it's malfunctioning, it might not be converting the voltage properly.

Given the complexity of the situation, it might be a good idea to reach out to Renogy's customer support or consult an expert in electrical systems to diagnose and resolve the issue accurately. They can guide you through troubleshooting steps or offer insights based on their expertise.

Remember to prioritize safety while troubleshooting, especially when dealing with electrical components. Good luck, and I hope you're able to resolve the issue and get your inverter working smoothly again.

 

[sunshine_eggo]

@hyxsungold

Did you read any of the OP's post? Your response suggests you did not. It almost seems like you are copy/pasting from brochure material.

 

[ckelly3415]

I have 1awg wire spanning about 2 feet from the batteries to the inverter. I have a 600ah battery bank consisting of (3) 206ah SOK batteries wired up together. The specs on these batteries shows a max continuous discharge current of 100amps… peak discharge of 200 amps. Is this my problem??

I’ve got 8awg triplex wire going from the inverter to my breaker box with a 15amp breaker, then the water heater hardwired to the 15amp breaker. The 15amp breaker seems low upon revisiting this, but the breaker is not tripping, the inverter is just shutting off and re-setting. The fuse between the batteries and inverter may be low quality, but I believe it’s a 300amp fuse (installed it a long time ago and it doesn’t say the size on it) also BMS is the Victron smartshunt.

 

[ckelly3415]

Also my BMS is the Victron smartshunt

 

[mikefitz]

have a 600ah battery bank

Is this lead acid, what battery type?

 

[ckelly3415]

Is this lead acid, what battery type?

lifepo4

 

[sunshine_eggo]

1awg may only be rated for 110A

Victron smartshunt is a battery monitor, not a BMS.

The LFP battery has an internal BMS. What is the battery brand, model and maximum continuous discharge current?

 

[ckelly3415]

1awg may only be rated for 110A

Victron smartshunt is a battery monitor, not a BMS.

The LFP battery has an internal BMS. What is the battery brand, model and maximum continuous discharge current?

It’s an SOK 206ah, 3 of those wired together for 618ah. Max discharge of 1 is 100amps. Thinking now that could be the problem? Or does wiring them up together increase max discharge?

 

[Tomthumb62]

It’s an SOK 206ah, 3 of those wired together for 618ah. Max discharge of 1 is 100amps. Thinking now that could be the problem? Or does wiring them up together increase max discharge?

Most likely you have a wiring problem. Post photos of your battery wires. They’re either of unequal lengths or too thin of gauge or both, most likely. Or loose connections as sunshine_eggo mentioned.

And photos of your inverter wiring.

 

[sunshine_eggo]

How are the main (+) and (-) leads connected?

 

[ckelly3415]

Most likely you have a wiring problem. Post photos of your battery wires. They’re either of unequal lengths or too thin of gauge or both, most likely. Or loose connections as sunshine_eggo mentioned.

And photos of your inverter wiring.

All of the wire connecting batteries and inverter is 1awg

 

[ckelly3415]

How are the main (+) and (-) leads connected?

 

[sunshine_eggo]

All of the wire connecting batteries and inverter is 1awg

The primary battery cables do appear to be installed correctly. One on battery #1 and the other on battery #3 ("across" the battery).

Again, 1awg is not necessarily rated for 150A.

You need to check each and every connection on every battery terminal and everything in between including the inverter terminals.

This includes the connections to the lynx and smartshunt and especially the fuse holders in the lynx. Torque to spec. Do not over-torque.

 

[ckelly3415]

The primary battery cables do appear to be installed correctly. One on battery #1 and the other on battery #3 ("across" the battery).

Again, 1awg is not necessarily rated for 150A.

You need to check each and every connection on every battery terminal and everything in between including the inverter terminals.

This includes the connections to the lynx and smartshunt and especially the fuse holders in the lynx. Torque to spec. Do not over-torque.

Thanks. Is it possible that it’s the batteries themselves that’s the issue? Connections all are looking solid. Being that the batteries each have a max continuous load rating of only 100 amps? Or does wiring them up in parallel increase the continuous load rating?

 

[sunshine_eggo]

Thanks. Is it possible that it’s the batteries themselves that’s the issue?

Anything is possible.

Connections all are looking solid.

So you have used a torque wrench on each and every connection?

Being that the batteries each have a max continuous load rating of only 100 amps? Or does wiring them up in parallel increase the continuous load rating?

They add. You can't count on 300A since they won't share the loads perfectly equal, but I would expect at least 250A.

 

[ckelly3415]

Anything is possible.



So you have used a torque wrench on each and every connection?



They add. You can't count on 300A since they won't share the loads perfectly equal, but I would expect at least 250A.

No I have not hit each connection with a torque wrench as I don’t own one. Would over / under torquing connections really potentially cause this malfunction? If so, why?