Safe Start Procedures for Hybrid Inverters?

[Lighthouse Beacon]

Is this correct?

Inverter Safe Start

Step 1: Turn on the circuit breaker of the battery

Step 2: Turn on the battery BMS (button). Intelligent BMS will automatically precharge inverter.

Step 3: Turn on the inverter, the screen and indicators light up to indicate that the inverter has been activated

Step 4: Turn on the circuit breakers for PV Solar

Step 5: Turn on the circuit breaker for AC input into inverter

Step 6: Turn on AC output from inverter

Step 7: In breaker box, start the loads one by one in order of power from small to large


To safe shut down inverter, repeat these steps in reverse.

 

[Crowz]

Is this correct?

Inverter Safe Start

Step 1: Turn on the circuit breaker of the battery

Step 2: Turn on the battery BMS (button). Intelligent BMS will automatically precharge inverter.

Step 3: Turn on the inverter, the screen and indicators light up to indicate that the inverter has been activated

Step 4: Turn on the circuit breakers for PV Solar

Step 5: Turn on the circuit breaker for AC input into inverter

Step 6: Turn on AC output from inverter

Step 7: In breaker box, start the loads one by one in order of power from small to large


To safe shut down inverter, repeat these steps in reverse.

1 and 2 look ok.

step 3 isn't the next one for me.

After battery is going I would turn on ac then pv.

Then turn on the inverter itself.

 

[Lighthouse Beacon]

1 and 2 look ok.

step 3 isn't the next one for me.

After battery is going I would turn on ac then pv.

Then turn on the inverter itself.

I thought the same thing, but it looks like SRNE ASF 10k and rebrand SG SPH10K48SP 10k hybrid inverter manual states:

Does it really matter you think?
@42OhmsPA

 

[Crowz]

I thought the same thing, but it looks like SRNE ASF 10k and rebrand SG SPH10K48SP 10k hybrid inverter manual states:
View attachment 183010
Does it really matter we think?

If its required or even helps that you start your loads in a certain order I wouldn't own the thing.

What are we supposed to do as the inverter is in use daily? Run around and make sure family members check to see whats running already to see if they can turn something on or not to make sure its a larger load than the last thing that was turned on?

Sounds like step 4 wasn't thought thru.

 

[jeremyee]

How would you start 3x inverters for parallel configuration? I really wish there was a D/C disconnect switch with a button to activate a resister to charge the inverter caps. I tried following this process starting two 6k inverters at the same time and it tripped the battery's BMS, all 5 of them.

 

[Crowz]

Also can that inverter run without a battery? That might mess up the startup sequence

 

[timselectric]

I really wish there was a D/C disconnect switch with a button to activate a resister to charge the inverter caps.

This is something that you have to make, yourself.
Or just have enough BMS capacity.

 

[Crowz]

How would you start 3x inverters for parallel configuration? I really wish there was a D/C disconnect switch with a button to activate a resister to charge the inverter caps. I tried following this process starting two 6k inverters at the same time and it tripped the battery's BMS, all 5 of them.

You just need a setup like this :

My Push Button Pre-Charger Install for the SW 4024 Inverter

Up until Last week I had never heard of pre-charging a larger inverter before connecting the battery cables. I just lived with the spark. But I was watching a "Will" video about a DIY LFP build and saw that he used a resistor before connecting the Positive Terminal. This peaked my...

diysolarforum.com

The only part I would wonder about is the reaction of a few inverters being precharged at once.

 

[timselectric]

The only part I would wonder about is the reaction of a few inverters being precharged at once.

One for each inverter.

 

[Crowz]

One for each inverter.

Makes sense but wiring that is a bit more complicated than the diagram I linked

 

[timselectric]

Makes sense but wiring that is a bit more complicated than the diagram I linked

It's the same. Every inverter should have a breaker. Just add the precharge circuit to each one.

 

[Crowz]

It's the same. Every inverter should have a breaker. Just add the precharge circuit to each one.

Yep that would work great.

 

[timselectric]

If you have a Chargeverter connected to the bus.
It will take care of the precharge for you.
Another good reason to have a Chargeverter.

 

[Lighthouse Beacon]

If its required or even helps that you start your loads in a certain order I wouldn't own the thing.

What are we supposed to do as the inverter is in use daily? Run around and make sure family members check to see whats running already to see if they can turn something on or not to make sure its a larger load than the last thing that was turned on?

Sounds like step 4 wasn't thought thru.

I assume they mean flip individual breakers in your panel, so all the breakers are off then turn on lights, bedroom outlets, then the hot water heater, etc.

 

[Crowz]

I assume they mean flip individual breakers in your panel, so all the breakers are off then turn on lights, bedroom outlets, then the hot water heater, etc.

I just flip the main load panel breaker on and off not individual breakers.

Its just surge and my LF inverter loves surges

 

[Lighthouse Beacon]

I just flip the main load panel breaker on and off not individual breakers.

Its just surge and my LF inverter loves surges

Lmao

 

[ksmithaz1]

I've seen numerous discussions about 'pre-charge' for inverters. It would seem to me that if this is necessary it would be handled trivially in the inverter with a relay, and a ballast resistor in front of the 48v caps. As soon as the caps hit the proper voltage level, the relay kicks on bypassing the ballast resistor. Same principle as a "Power Good" circuit on most electronics boards, only with a relay instead of an IC. I would consider this a design flaw if this was necessary to prevent damage or creating a fault, to a battery/ on a BMS. Having to manually "pre-charge" an inverter sounds pathetic.

I'm pretty sure my units do something similar, as there is a short delay from the time you flip the battery breakers until things click on.

If I had to build it I would drop a simple voltage detection circuit on the inverter side of the connection and tie it to an IC that trips a relay with the appropriate current capacity. Ought to be able to find something close off the shelf at Jameco or Digikey. The 18P/12L doesn't even have a power switch.

As far as turning it on in a special order or something blows up, that seems somewhat arcane. What if you have a fault condition that creates the same effect? Oops, fried my inverter? Any device like this should be engineered in a "fail-open" condition, where nothing is working unless the core logic unit is running and explicitly turns it on. Any fault should immediately put the unit in fail-open. If we have a devices that behave otherwise we should re-examine everything we are doing from a safety standpoint.

 

[ksmithaz1]

I assume they mean flip individual breakers in your panel, so all the breakers are off then turn on lights, bedroom outlets, then the hot water heater, etc.

I ripped out and returned a system for this very reason. I should be able to turn on my system at close to 100% of it's rated load and have it work. If the system needs things to turn on in some special order then it needs to take care of that itself, if it needs me to gradually put a load on it, it's garbage. I am not always around when there is a minor issue to make sure everything comes up in some special order that doesn't set my house on fire, or shuts down if it gets loaded down too fast.

 

[Lighthouse Beacon]

I ripped out and returned a system for this very reason. I should be able to turn on my system at close to 100% of it's rated load and have it work. If the system needs things to turn on in some special order then it needs to take care of that itself, if it needs me to gradually put a load on it, it's garbage. I am not always around when there is a minor issue to make sure everything comes up in some special order that doesn't set my house on fire, or shuts down if it gets loaded down too fast.

Well yeah but these are 1500 dollar Chinese inverters we’re talkin here…lol

 

[jeremyee]

I ripped out and returned a system for this very reason. I should be able to turn on my system at close to 100% of it's rated load and have it work. If the system needs things to turn on in some special order then it needs to take care of that itself, if it needs me to gradually put a load on it, it's garbage. I am not always around when there is a minor issue to make sure everything comes up in some special order that doesn't set my house on fire, or shuts down if it gets loaded down too fast.

it's not the A/C load it's the massive surge used to charge the caps in the inverter. This happens with all Growatt, Victron and EG4 6000XP inverters. I always used a resistor to charge the caps but on this new install i tried just powering the device on. The first inverter is not an issue because of the caps in the battery but the issue is the second / third inverters. 25 kw of battery's won't start the 2nd inverter even with no A/C load on the first inverter. Since the EG4 6000XP has a D/C breaker I hate to install another cutoff switch with a precharge resistor on each one but I may have to.

I wish the inverter company's started putting in a precharge state on powering on the device.