What am I doing wrong? Conext SW4048 won't utilize 120V from my genny.

Hello, greetings from Hazel Green Alabama. I installed a Schneider Conext SW4048 with SCP panel to my Midnite Classic 250 and Big Battery 6KWh Lifepo4.
3KW of Trina pv panels.

Everything is working fine, making 240V split phase to my service panel and powering our 700sf tiny farm house. Very happy with everything.
However, I can't get the inverter to use the 120V that I'm sending to it from the generator. The supply is wired to the AC IN bus bars and grounded. The connections from the bus bars are feeding the AC IN connections into the Conext inverted. Multi meter shows 120-122 volts at both places. The AC IN/Generator support light on the inverter will not light up and power the house or charge the battery.

Is there a setting in the SCP that I'm missing? This should be a no-brainer but I can't get the Conext to use 120V supply from the genny.
Any help would be appreciated.

TIA!
Curtis

This may be a silly question, but... Is your generator 240V/120V split phase? I have the Conext SW4024 that works fine with my split-phase genny, connected to L1/L2 inputs and neutral.

Not an expert on the SW but its similar to the XW. I believe the input voltage has to be the same as the output voltage. This is typical of most inverter brands.

Your SW voltage/hertz parameters may be set too tight - get into the advanced menu & set the specs a bit 'looser'. Carefully read the owner's manual about generator settings in the advanced menu. I had a similar issue on my 12 year old XW6048 a few weeks ago, and resolved the generator/XW synchronization this way. Sorry, I don't remember exactly which change I made that corrected the problem.

Where did you get information that SW4048 supports 120vac only generator?

Some similar inverters support 120vac only input by feeding 120vac from L1 to N, but inverter must have software to accept that input. configuration.

I don't see anything in installation manual that says Conext SW4048 supports anything but 240/120vac split phase generator input.

You could always get a 120/240 isolation or autotransformer to create 240/120vac split phase from 120vac input.

XW inverter can run from 120vac but they are very careful of putting too many features in lower tier models that compete with their more expensive model.

Horsefly said:

This may be a silly question, but... Is your generator 240V/120V split phase? I have the Conext SW4024 that works fine with my split-phase genny, connected to L1/L2 inputs and neutral.

Click to expand...

Thank you for your response. My generator is a 3500W 120V Inverter generator. I specifically asked the supplier if it would accept 120V input and they said yes.

RCinFLA said:

Where did you get information that SW4048 supports 120vac only generator?

Some similar inverters support 120vac only input by feeding 120vac from L1 to N, but inverter must have software to accept that input. configuration.

I don't see anything in installation manual that says Conext SW4048 supports anything but 240/120vac split phase generator input.

Click to expand...

At the time I bought it (two years ago) the dealer said it would accept 120V single phase from a genny and convert it to 240 split phase.
I was too ignorant back then to ask if the AC in had to be 240 split phase as well.

Starfish Prime said:

Thank you for your response. My generator is a 3500W 120V Inverter generator. I specifically asked the supplier if it would accept 120V input and they said yes.

Click to expand...

I guess I'm not sure. I thought I remembered that the Conext SW inverters would take a single phase 120V in, but with some reduced power rating output. However, I can't find anything saying that in the installation or owner's manual (quick scan).

Duh. I just found my own reply to a similar issue back in October: https://diysolarforum.com/threads/b...ase-to-split-phase-inverter.49209/post-626032

So, according to me (who I wouldn't trust), you probably can put in single phase 120V using the L1 and Neutral input lines, and it should work.

Edit to add: This implies that the inverter does the magic to essentially convert the L1 input into a split phase L1/L2 output. In my case with a split-phase input, when I start the generator the transfer switch bypasses the inverter and connects L1 and L2 from the input to the output. Since I have a standard 240/120V main breaker panel, the loads on both legs continue to be powered.

RCinFLA said:

Where did you get information that SW4048 supports 120vac only generator?

Some similar inverters support 120vac only input by feeding 120vac from L1 to N, but inverter must have software to accept that input. configuration.

I don't see anything in installation manual that says Conext SW4048 supports anything but 240/120vac split phase generator input.

You could always get a 120/240 isolation or autotransformer to create 240/120vac split phase from 120vac input.

XW inverter can run from 120vac but they are very careful of putting too many features in lower tier models that compete with their more expensive model.

Click to expand...

Horsefly said:

Duh. I just found my own reply to a similar issue back in October: https://diysolarforum.com/threads/b...ase-to-split-phase-inverter.49209/post-626032

So, according to me (who I wouldn't trust), you probably can put in single phase 120V using the L1 and Neutral input lines, and it should work.

Edit to add: This implies that the inverter does the magic to essentially convert the L1 input into a split phase L1/L2 output. In my case with a split-phase input, when I start the generator the transfer switch bypasses the inverter and connects L1 and L2 from the input to the output. Since I have a standard 240/120V main breaker panel, the loads on both legs continue to be powered.

Click to expand...

Good info, thank you. I forgot to mention that I have the Midnite solar breaker panel. There are bus bars for AC in 1 and AC in 2, plus the ground bus bar. There *is* a neutral bus bar but it looks to be for the AC side. I am no electrician and this has been a struggle for me.

Starfish Prime said:

Good info, thank you. I forgot to mention that I have the Midnite solar breaker panel. There are bus bars for AC in 1 and AC in 2, plus the ground bus bar. There *is* a neutral bus bar but it looks to be for the AC side. I am no electrician and this has been a struggle for me.

Click to expand...

I'm not too sure what you are saying. The neutral bus bar *IS* - by definition - on AC rather than DC. If you are talking about the Midnite E-Panel (I use one of those), there is one Neutral bus bar, and the Neutral on both AC-in and AC-out connect to it.

Horsefly said:

I'm not too sure what you are saying. The neutral bus bar *IS* - by definition - on AC rather than DC. If you are talking about the Midnite E-Panel (I use one of those), there is one Neutral bus bar, and the Neutral on both AC-in and AC-out connect to it.

Click to expand...

Yes you are correct WTH was I thinking...

I have the Conext SW4048 as well and initially tried using a 4000w peak/3500w run 240 v gas generator for backup. Even though the conext would qualify the AC input, it kept kicking it off and reverting to invert power. That size generator just wasn't enough for the battery charging requirements of the Conext SW4048. I now use a 5500 peak watt generator (running watts 4275 on propane). This is mostly adequate EXCEPT when the well pump kicks in. I can't allow the pump to run until the generator has been running for at least 20 minutes. I don't know if this is because the generator needs to warm up or if the batteries need to get up to a certain state of charge before the system can handle the pump load in addition to the charging load. Sadly, the conext manual has zero information to assist a DIYer in selecting the proper generator for your system.

Overall, for price and performance I've been happy with my Duromax XP5500EH dual fuel, electric start generator, but if I had to do it again, I would buy the next size up. https://generatorbible.com/generators/duromax/xp5500eh/
Even though this is not an inverter generator, I've been pleased with how clean the power output is and have not had any issues with computers or sound equipment.

I would add that if you ever want to add the AGS (Automatic Generator Start) module to your Conext you will need a propane generator as they do not require choking when burning propane. Only when you get into the multi-thousand dollar generators do have have such features as automatic choke.

Finding the proper size generator with the features you want at the price you can afford is very difficult. the web link above to the generatorbible.com is really useful in comparing every generator currently on the market.

Although I haven’t tried it with my SW4048 I understand it will output 240V from a 120V generator input with a 2700W limitation.

Here is some discussion on the topic :


Although I don’t fully understand this feature I wonder if the OP has a battery connected and also may need to enable some load sharing setting ?

And the reason for the 2700W limitation may be best explained in post #15 here :


Block diagram rough illustration courtesy of @RCinFLA who has probably forgotten more of this stuff than I ever knew ?.

Starfish Prime said:

At the time I bought it (two years ago) the dealer said it would accept 120V single phase from a genny and convert it to 240 split phase.
I was too ignorant back then to ask if the AC in had to be 240 split phase as well.

Click to expand...

Your dealer is right, I have an SW4048 in a 30amp RV and am feeding only one side of it with a generator and it works fine.

Jennifer said:

Your dealer is right, I have an SW4048 in a 30amp RV and am feeding only one side of it with a generator and it works fine.

Click to expand...

I am preparing to do the same in my rv. It is an Onan 4000w. Do you have the same setup and issues with inverter noise?
Thanks

Skip said:

I have the Conext SW4048 as well and initially tried using a 4000w peak/3500w run 240 v gas generator for backup. Even though the conext would qualify the AC input, it kept kicking it off and reverting to invert power. That size generator just wasn't enough for the battery charging requirements of the Conext SW4048. I now use a 5500 peak watt generator (running watts 4275 on propane). This is mostly adequate EXCEPT when the well pump kicks in. I can't allow the pump to run until the generator has been running for at least 20 minutes.

Click to expand...

I'm familar with this issue. The problem is that your generator is not capable of CLEANLY supplying the power the inverter wants, and the SW is rejecting it for poor waveform/voltage/Hz.

What you should do is go into the charge settings on your SCP, and reduce the charging rate. Most likely it is set at the maximum of 45A. So, 100% on the SCP will equal 45A. Ratchet down the charge rate to some very low initial number, say 10%, then start your generator. As the incoming power gets qualified, the blinking green light will switch to solid green, and then you'll hear the load on the generator go up.

Once the generator has been running for a few minutes to warm up and stabilize, start ratcheting back up the charging rate a percent or two at a time. You will finally reach a point at which the generator can't meet the demand, and the generator's output will be rejected again. Play with the settings for a while to find the sweet-spot for your generator. Trial and error will tell you at what charge settings to leave the inverter at for long-term stability of the system.

Once you've zeroed in on an appropriate charging rate, you'll have to determine whether or not this rate works on the generator while cold, right at startup. Most likely for the very best charge rate, you'll have to start out low, and ratchet up every time, if you want to acheave your max rate.

Starfish Prime said:

Hello, greetings from Hazel Green Alabama. I installed a Schneider Conext SW4048 with SCP panel to my Midnite Classic 250 and Big Battery 6KWh Lifepo4.
3KW of Trina pv panels.

Everything is working fine, making 240V split phase to my service panel and powering our 700sf tiny farm house. Very happy with everything.
However, I can't get the inverter to use the 120V that I'm sending to it from the generator. The supply is wired to the AC IN bus bars and grounded. The connections from the bus bars are feeding the AC IN connections into the Conext inverted. Multi meter shows 120-122 volts at both places. The AC IN/Generator support light on the inverter will not light up and power the house or charge the battery.

Is there a setting in the SCP that I'm missing? This should be a no-brainer but I can't get the Conext to use 120V supply from the genny.
Any help would be appreciated.

TIA!
Curtis

Click to expand...

Would love to see how you wired everything up to your SW4048... we need power on our remote property and I cannot get anyone out there to install. I just need the basics and a way to install a sub panel to supply power to our 50 Amp RV to get off the ground. Reading all you messages here to glean the most information I am able to. Thank you.