I'm new - question LV6548 120VAC input to 240VAC output

[thebeavesknees]

There's two things you can do:
1. You can figure out how to program the units easily so you cab run one inverter normally to limit your standby consumption, then if you need the second to come online, you set the first one to parallel mode and power on the second and you should be in business.

2. I was in a similar situation with my dual 3048LV-MKs. They would output split phase with a 120V input, but, they would not utility charge in that configuration. So, I bought a victron autotransformer and with that splitting the 120V input into 240V, I get all the functionality I was expecting, and, honestly, a more versatile configuration.

You'll also need to make sure that your surge capacity from only two batteries will handle your surge loads, especially from your welder. Welders are notified for very high inrush currents, and two batteries might not be enough to supply the inverters with the juice to start an arc. Some batteries are better than others at this, obviously, but I figured I'd point that out on case you didn't know.

 

[OffGridForGood]

I think you might be better served with something like the Victron MultiPlus-II 2 x120V. Read the description here, (not promoting you purchase from this vendor) this inverter was designed for RV applications.

Low idle consumption will help stretch the batteries before charging is needed.

RV=Limited space for PV = low idle becomes high priority.

 

[Nimrod5]

I am going to set up a solar system this spring on my off grid property. I have gone deep into the weeds researching some of these inverter chargers. These are not charge controller all in ones, just inverters and built in battery chargers from shore power or a genny. A single Schneider SW or XW inverter charger will put out it's rated 220 volt power from a fully charged battery bank. If you input 110 volt power from a genny or shore power it will add half the input to each leg and output 220 volt power greater than the inverter alone. It sounds like this is what you want to do. The news tonight says I didn't win the Mega Millions jackpot. I still have hope for tonight's Powerball. I may win and afford the Schneider yet.

 

[RaiderRC]

RV=Limited space for PV = low idle becomes high priority.

Idle is killing me but I do have 40+ feet or roof space. almost worried about the weight

 

[RaiderRC]

There's two things you can do:
1. You can figure out how to program the units easily so you cab run one inverter normally to limit your standby consumption, then if you need the second to come online, you set the first one to parallel mode and power on the second and you should be in business.

2. I was in a similar situation with my dual 3048LV-MKs. They would output split phase with a 120V input, but, they would not utility charge in that configuration. So, I bought a victron autotransformer and with that splitting the 120V input into 240V, I get all the functionality I was expecting, and, honestly, a more versatile configuration.

You'll also need to make sure that your surge capacity from only two batteries will handle your surge loads, especially from your welder. Welders are notified for very high inrush currents, and two batteries might not be enough to supply the inverters with the juice to start an arc. Some batteries are better than others at this, obviously, but I figured I'd point that out on case you didn't know.

1. biggest challenge will be the split system is 240 kind of stuck with running both.

2. That autotransformer looks intresting I would have to see how big the load will be on the mini split to see if it will stay under the 6500 watt rating.

I just looked into the surge capacity. I believe most of the rack mount 48v batteries are ~100amp.
I think the miller matic 211 might be a probem please correct me if I'm wrong. https://www.millerwelds.com/equipment/welders/mig-gmaw/millermatic-211-mig-welder-m30024

Amp draw says 30A to 230A

So 3 batteries would be needed in parallel (3x 100A) to be safe and not push limits?

 

[RaiderRC]

One can stack the LV6548's in parallel and not 240V, thus just one 120V leg with 13Kw capacity. On a 50A pedastal, one would need to determine if legs on in 240V split phase, most likely the pedastal would be just 2 120V legs in the same phase.

I see you have not purchased any units yet. I would not use the latest LV6548V versions in an RV due to the high idle consumption. Limited PV space on a RV combined with high idle consumption is not a great idea. Much of what the panels generate will be used to idle the inverters. You can install switches to turn the inverters off, I have one to switch off my Growatt in the truck camper but much of the truck camper runs off 12V. The LV6548V has been reported to use 130W at idle, take that times 2 comes to 250-260W. 10 hours is 2600W, 20 hours is 5200W and 24 hours is 6200W. If you have 2000W of panels on the roof, it takes 3 hours of peak sun just to cover that overhead. Watch TV for 3 hours and it takes 1/2 hour of peak sun for just the inverter, the loads are on top of that.

I think you might be better served with something like the Victron MultiPlus-II 2 x120V. Read the description here, (not promoting you purchase from this vendor) this inverter was designed for RV applications. https://invertersrus.com/product/vi...bpb2hYGKUZ1zBW-Amaaq-99p4f15Qhn0aAl5REALw_wcB Prices have come down and there is plenty of guidance on how to incorporate a Multiplus into an RV. Low idle consumption will help stretch the batteries before charging is needed.

I will be moving up to a 48V system. The MultiPlus-II are super sexy though.

I am kind of sad to hear the 130W idle.

Looking to get the most wattage per square foot up top. I believe I can fit 10 of these on the roof RV 8' x 43'

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That would be 5500 watts of solar.

 

[OffGridForGood]

almost worried about the weight

Solar panels are not very heavy really - per sq foot. On an RV I would be more concerned about securing them down for the 70mph wind they will endure on the Interstate.

 

[Quattrohead]

Idle is killing me but I do have 40+ feet or roof space. almost worried about the weight

Consider the heat output and fan noise from these units too, especially in tight quarters where you might mount this in an RV.

 

[Zwy]

Consider the heat output and fan noise from these units too, especially in tight quarters where you might mount this in an RV.

Yep, the LV6548's are not quiet when the sun is shining or heavy loads.

 

[thebeavesknees]

1. biggest challenge will be the split system is 240 kind of stuck with running both.

Yes. But it's doable

2. That autotransformer looks intresting I would have to see how big the load will be on the mini split to see if it will stay under the 6500 watt rating.

You don't need to use the transformer post AIO. You just need it pre-AIO in order to get charging.

No minisplit should draw anywhere near that much juice. You should be focusing only on inverter compressor minisplits that slowly ramp up the compressor.

I just looked into the surge capacity. I believe most of the rack mount 48v batteries are ~100amp.

Not exactly. That's 100A max steady state current draw. Instantaneous draw can be significantly higher depending on the BMS used. Many will do short spikes of 3C. You need to dig in to the capabilities of the BMS to be sure that it can handle the loads from welding.

I think the miller matic 211 might be a probem please correct me if I'm wrong. https://www.millerwelds.com/equipment/welders/mig-gmaw/millermatic-211-mig-welder-m30024

Amp draw says 30A to 230A

So 3 batteries would be needed in parallel (3x 100A) to be safe and not push limits?

If you are doing sustained welding, then 3 is the bare minimum. You also won't be able to utilize the full rating of the batteries if you have very high C draws on the system. I don't know what you'll be welding or how much welding you'll be able to do.

Edit: if you will be doing significant amounts of welding, you really should be running a generator. That's just the simplest, most robust way to do that.