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Schneider XW Pro system for home backup? (What parts do I need?)

armstrom

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Joined
Feb 26, 2022
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My post got kinda long. Here's the TL:DR questions.

1) Do I need to use the Schneider BCS device? Or can I just use the transfer switch in the XW Pro and a Mini PDP? (I'm using a critical loads panel, not full home backup)
2) I have no desire to sell power back to the grid and no solar, I've seen some reports of the XW Pro systems "leaking" back to the grid... is this still a problem if I configure the inverter to only act as a backup system? (Inverter should only power its output in the event of an outage, otherwise it will pass-through grid power)

Here's the full post.... Thanks for reading!

WIth the very low "clearance" prices on the Schneider XW 6.8kw inverter I'm very close to pulling the trigger on an inverter and EG4 280Ah battery to serve as a critical loads backup for my home. I suffer somewhat frequent power outages and would like to keep a handfull of circuits backed up without having to resort to a generator. I like that the schneider has very high surge capacity and also that I'm not paying for MPPT solar charger converters that I cannot use (I live in the woods, there is nowhere to put solar on my property).

I've been trying to decide exactly what equipment I need to buy in order to be code compliant (I'm going to DIY the heavy lifting, then pay a local electrician to do the final wiring/rework of my panel). Up until now I have assumed that I can get away with the XW Pro inverter, EG4 battery, a Mini PDP and the insight home interface. However, I now see there is a "BCS" unit that is apparently meant to be used for handling the changeover to battery backup in the event of an outage. This has me confused... I thought the inverter had a transfer switch built in and could be configured for backup use only... is that not the case?

Also, how serious is the problm I've been reading about where the XW pro is "leaking" power back out to the grid? All of the reports I've seen are from users who have solar and are trying to use the grid and battery/solar power simultaneously and still backfeeding the grid despite the inverter being configured for "no sell" mode. WIll I run into this issue if I use the inverter just to provide emergency backup to a subpanel?

Thanks for any advice you can give.
-Matt
 
My post got kinda long. Here's the TL:DR questions.

1) Do I need to use the Schneider BCS device? Or can I just use the transfer switch in the XW Pro and a Mini PDP? (I'm using a critical loads panel, not full home backup)
Not with a single inverter and a critical loads panel. That's exactly what I'm running. Even the mini PDP isn't "needed" but it sure does make connections easier and the breakers are all right there.
2) I have no desire to sell power back to the grid and no solar, I've seen some reports of the XW Pro systems "leaking" back to the grid... is this still a problem if I configure the inverter to only act as a backup system? (Inverter should only power its output in the event of an outage, otherwise it will pass-through grid power)
As long as it is set up properly to not invert when in grid, you should be fine. It won't try and balance the legs out through the grid or like all inverters take time (not quite instant) to adjust to large load changes when grid connected.
Here's the full post.... Thanks for reading!

WIth the very low "clearance" prices on the Schneider XW 6.8kw inverter I'm very close to pulling the trigger on an inverter and EG4 280Ah battery to serve as a critical loads backup for my home. I suffer somewhat frequent power outages
14kWh of back up with a 6.8 kW inverter doesn't sound like enough storage capacity. At 1000 watts, it might last overnight. I'd highly recommend a load calculation.

Battery communication may or may not help. I don't use it, but some swear it 100% vital
I'm sure your desired set up will work with voltage controls. Less confidant with how successful it will be using battery communication and SOC control.
and would like to keep a handfull of circuits backed up without having to resort to a generator. I like that the schneider has very high surge capacity and also that I'm not paying for MPPT solar charger converters that I cannot use (I live in the woods, there is nowhere to put solar on my property).

I've been trying to decide exactly what equipment I need to buy in order to be code compliant (I'm going to DIY the heavy lifting, then pay a local electrician to do the final wiring/rework of my panel). Up until now I have assumed that I can get away with the XW Pro inverter, EG4 battery, a Mini PDP and the insight home interface. However, I now see there is a "BCS" unit that is apparently meant to be used for handling the changeover to battery backup in the event of an outage. This has me confused... I thought the inverter had a transfer switch built in and could be configured for backup use only... is that not the case?

Also, how serious is the problm I've been reading about where the XW pro is "leaking" power back out to the grid? All of the reports I've seen are from users who have solar and are trying to use the grid and battery/solar power simultaneously and still backfeeding the grid despite the inverter being configured for "no sell" mode. WIll I run into this issue if I use the inverter just to provide emergency backup to a subpanel?

Thanks for any advice you can give.
-Matt
I'd say you are right, everyone complaining a out grid sell issues has solar and this has excess power to figure out what do with and use. If you are truly back up only, it shouldn't be an issue.

Once you have the components installed, take some time, review the manuals, ask questions and have patience. Settings can be counter intuitive and somewhat difficult to understand.

One issue you may run into is that sitting for weeks the inverter's 30ish watt idle draw will slowly drain down the battery capacity. Getting the settings right for where and how it will automatically recharge the battery may take time to dial in.

And because you are back up only, the XW's automatic charge cycle start when the grid returns will function exactly as you want.

Do you run a generator? Would you be recharging the battery when the gen is running?
 
One issue you may run into is that sitting for weeks the inverter's 30ish watt idle draw will slowly drain down the battery capacity. Getting the settings right for where and how it will automatically recharge the battery may take time to dial in.

That is something I didn't realize when first setting my system up. There doesn't appear to be anyway to just trickle charge the batteries. Even when there is grid power, the inverters do draw there idle current from the batteries. On mine I set it up to recharge at around 95%. I kicks off a charge cycle very 3-4 days. I have used both SOC and voltage to kick off charging cycles. SOC seems more precise. I did have some issues with charging cycles kicking off randomly. Eventually, I got some fault codes from one of the batteries. At the instruction of the company, I opened it up and tightened all the connections. No more problems and the batteries seem to stay more equal too.
 
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Also, how serious is the problm I've been reading about where the XW pro is "leaking" power back out to the grid? All of the reports I've seen are from users who have solar and are trying to use the grid and battery/solar power simultaneously and still backfeeding the grid despite the inverter being configured for "no sell" mode. WIll I run into this issue if I use the inverter just to provide emergency backup to a subpanel?

You just want to turn off the "Grid Interactive" mode. In this configuration the inverters are only activated when you lose power. The "No Sell" option is part of the grid interactive configuration. It is designed to generate just enough power locally to zero out your consumption from the grid. Not something you need to worry about.

Schneiders power management functions do leave a lot to be desired. If you wanted to charge your batteries up during cheap rates and sell back at high rates, this does not work well with Schneider.

I have micro inverters that export straight to the grid. I added the Schneiders in later to provide backup. When the grid is down the Schneiders disconnect from the grid using the internal relays and supply power from the batteries. They are also able to recharge the batteries using the AC power from the microinverters. This is the AC coupled mode. Again, not some thing you will need.

For your application, it should work well and the setup should be pretty simple. For a single inverter, you will have a 60 amp pass through limit.
 
Thank you everyone for the replies. Very helpful!
Regarding a load calculation. My current plan is to only provide about 8-12 hours of backup power for a small number of circuits. I doubt I will hit 1kW average/continuous (though peaks will be higher for sure). My plan is to move a handfull of breakers to a subpanel. Keep some lights on, allow me to run my pellet stove to heat my house, keep the fridge cold and the internet up.. that's about it. Most of my power outages last 4-8hrs at most. If I find I'm running low on battery power I can always buy a second EG4 battery. I don't think I'm in any danger of running out of load capacity from the 6.8kW Schneider with the circuits I'm planning to power. Especially considering the huge surge capacity it has.

As for the standby power draw, is there any sort of deeper standby mode that keeps the inverter turned off until needed (perhaps at the expense of response time?) If not, then it sounds like some of the solutions proposed will work fine for me. I may also consider buying a 48V trickle charger to offset the standby drain... I could probably even drop in one or two 450W bifacial panels and a cheap MPPT to try to offset the draw. As I mentioned in my initial post, my lot is heavily treed/shaded so large solar array would be a waste of money, but dropping a couple hundred bucks on a couple of panels might be enough (800W of panels should be able to get me enough power on average if I'm careful about where I position them. Either way, it sounds like I have options.

thanks again for the replies. It sounds like I'm good to go with just getting the inverter, mini-PDP and battery (along with a home depot run for wire, conduit and the critical loads panel). Time to start searching for a good local electrician who will work with me.
-Matt
 
One other thing to think about is if one 14kWh battery can support the 250 amp draw the inverter specs require. Otherwise, you may trip out the battery when starting a motor. From the sound of the initial post, that sounded important. But in the next post, you may not have large loads connected.

The inverter needs to be on to keep the transfer relays closed. It does have a sleep mode, but I'm not sure on the requirements or function when on grid. It is designed to stop the inverter from producing if the AC loads are low (in off grid use). Your entire subpanel is the AC loads...
 
 
One other thing to think about is if one 14kWh battery can support the 250 amp draw the inverter specs require. Otherwise, you may trip out the battery when starting a motor. From the sound of the initial post, that sounded important. But in the next post, you may not have large loads connected.
I have a dual inverter setup with three 100 amp batteries. The batteries trip before the inverters. I've never had that happen other than when I was deliberately loading the system up. Like running my dryer, my electric oven and then having the AC start. I have a soft start on the AC now, but in real use I won't try to run everything in my house at the same time.

Still, you want to make sure that the single battery can actually supply enough current to handle your projected loads. Remember this is a 50 volt system so 100 amps = 5000 watts. In theory my batteries can supply 15,000 watts and the inverter should max out at 12,800. In practice, the inverter will apparently surge higher for at least short spikes without tripping. The BMS seems to trip almost instantaneously, even on a short spike.
 
I have a XW Pro 6848 and two 48 volt 100ah batteries to be installed in the barn on my off grid 40 as soon as the snow melts so I can drive in. I know Schneider recommends 460ah of batteries. I can't afford more now. With only 200ah of batteries will the system work for small loads like lights, drills, and a skill saw? I don't want to damage the Schneider by under powering it.
 
I'm pretty sure that 460Ah rating is based on the capability and voltage sag of lead acid batteries. As long as your chosen battery can support 250 amps that the Schneider might pull, you don't need to be concerned about their old capacity recommendation.
 
I think you will be ok. They recommend the higher amount to keep up with it's potential. don't think you will hurt the xw pro, it will just stop working if it runs out of power. Hope fully you will be charging the batteries with some solar panels at the same time. Try not to power to much, the skill saw is probably the biggest load you want to run until you have more capacity. Keep your batteries charged up.
 
I finally got off my butt and called Schneider customer support. The 460ah battery recommendation is for lead acid batteries. For lifepo4 batteries they must put out 250ah for the XW to put out 12000 watts. The specs on my 2 batteries say the BMS can put out 100ah continuous and 200ah for a short time each. The two I have should be enough. I'll let you know when I get the system hooked up.

Also asked about needing to register the XW to get the full 10 year warranty. Support says you get the 10 year warranty even if you don't register it.

I asked about running the XW at lower than the recommended temperature. They sat don't run the XW below the recommended temps but the main reason is because the lifepo4 battery's voltage goes up at low temps and may cause the XW to go into high voltage shut down. Probably won't damage the XW.
 

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