My backup system ideas, will it work and be safe?

[jeepin95]

I'm looking to build a backup system for some of our home power that is at least partially PV based but trying to decide on the "best" route. While I generally like building, tinkering and DIYing as much as I can, I'm not sure I want to do that for this. I want it super simple for anyone in the house to operate. We live in the Pacific Northwest and don't lose power often, and generally not for long so I also don't want to invest to much.

Current setup:

• 3200w inverter dual fuel generator that we have only run on propane. We have three 20# cylinders with one usually on the grill as well as a 30# on the RV trailer that is almost always full since we don't use that propane there often. I believe this is a floating neutral.
• F-150 Powerboost with ProPower 7.2kw inverter that I know has bonded neutral and GFCI.
• Extension cords to run the fridge and freezer, so far only used them a couple times from the generator.

Primary Goals:

• Avoid the extension cords with input and a transfer switch. I do not need this to be automatic.
• Critical loads and options to manually prioritize those loads on the fly by turning off a transfer switch or breaker.
• Non-fixed solar panels to augment generator(s).

Loads:

• Small freezer in the garage.
• Fridge in the kitchen
• Cable modem, possibly a couple laptops and radios.
• A few LED lights.
• High efficiency gas furnace, no A/C.

Equipment Plan:

• EcoFlow DELTA Pro Ultra with a single 6kwh battery.
• Manual generator transfer switch.
• Portable solar panels, 400w initially. As I'm

My main panel is in the attached garage that got down to 41F during our record setting single digit temperatures earlier this month but we didn't lose power. My thought is to install the manual generator transfer switch in the garage where I could keep the DELTA Pro Ultra plugged in all the time so all it would take is turning it on and flipping the transfer switches to power circuits from the EcoFlow. I would have the PV panels available to put out in the yard when needed, but I don't have a place I can mount fixed panels at this time. I would also have the dual fuel generator and the ProPower on the truck available to charge the EcoFlow during an extended outage while the EcoFlow is powering the critical loads. I haven't specifically added up all the loads yet as they would be flexible depending on the situation. Everything has been run from the 3200w inverter on propane (which lowers it I believe to 2700w) with the exception of the furnace.

The main reason for looking at the DELTA Pro Ultra is for convenience not having to pull the generator out or hook the truck up to the transfer switch. It also might be interesting to run some of the circuits off of the EcoFlow + PV sometimes "just because".

Questions:

• I know for a fact that the 7.2kw truck inverter is a bonded neutral and would require a transfer switch that also transfers the neutral if I were to connect the truck directly to the transfer switch. While I haven't pulled it out to check, I believe the generator is a floating neutral. I also can't find documentation specifically for the Ultra to indicate if it is floating or not, but I suspect it is a floating neutral. It also isn't clear to me if a neutral bonding plug would work on the Ultra as some postings I was reading indicate it does not work on the other EcoFlow models. Does anyone know for sure if a bonding plug would work on the Ultra? If it does, then it seems like my best option is to use a transfer switch that also transfers the neutral. This would allow me to power those critical loads from the 3200w generator by utilizing a bonding plug. I could also power it from the EcoFlow DELTA Pro Ultra by using a bonding plug. And I could power it from the truck without anything special since it is already bonded. That way I have all three options available to directly power the circuits.
• If the Ultra is floating and there is no way to bond it then it seems like a transfer switch that also transfers the neutral is not an option. This would limit the ability to directly power the circuits from the truck. While I could still use the truck to keep the EcoFlow topped off, I would be dependent on the EcoFlow actually operating.
• If the weather turns bad and we are expecting grid failures, or even just fluctuations, could I flip the critical circuits over to the EcoFlow so they are operating off battery. Then have the EcoFlow also plugged into a non-critical load circuit in the garage so it would continue to charge while grid power is available? Effectively creating a UPS for the critical circuits? If the grid did go down for an extended period then I would connect the generator or the truck.
• While I understand this may be overkill for the amount we lose power, does it make sense?
• Does anyone have a similar setup with thoughts and experiences?
• What am I missing?

I have looked at some of the other options like EG4 and server rack LFP batteries. I understand that the features and KWH/$ is better on those "DIY" systems vs the PnP EcoFlow. For just me I would probably go that route, but for the household I don't think it is as good. I've seen the hand-truck setup, but I still think the slightly better portability of the EcoFlow is a little better. My primary concern is that I see the EcoFlow as more of an "Apple" product where I am more of a fan of open source generally.

Edit: I'll also note that this is just my initial setup. The longer term plan would be to add panels so that I could ideally run some of those circuits like the computers nearly exclusively on PV. My thought is the inverter/battery comes first, then augment with additional panels as space and funds allow.

Thanks for any input.

 

[deevee8]

I was considering a similar setup with the DPU connected to my transfer switch via the L14-30 for 240V 30A output. The issue is with AC passthrough. The DPU only supports 1800W AC (120V 15A) for AC passthrough. If you connected a 240V input, all AC output is disabled. This is stated in the DPU user manual and here in the FAQ.

AC passthrough (bypass) seems to support up to 12A output for > 3 hours (source).

It may be possible to charge using the x-stream AC charging port with 120V (say 120V 30A) and still have AC output but I have not seen any demonstration, reviews or comments indicating this works. I'd love to know.

 

[12VoltInstalls]

have looked at some of the other options like EG4 and server rack LFP batteries. I understand that the features and KWH/$ is better on those "DIY" systems vs the PnP EcoFlow. For just me I would probably go that route, but for the household I don't think it is as good.

What is your budget?

Because you can buy a lot for $6-$7k including panels, aio ‘inverter-charger,’ and some battery bank these days.
It would be just as simple as a suitcase battery it would seem- but actually way simpler (without the cords other than your generator) because it will always be up and running behind the scenes seamlessly. And the $7k system will:

also note that this is just my initial setup. The longer term plan would be to add panels so that I could ideally run some of those circuits like the computers nearly exclusively on PV

…start paying you back. $7k will be enough power to “save” more than $0.20/day.

The ecleflo is way too limited imho. It’s less convenient and it surely doesn’t scale well on a budget. At its sub-$3k price point marketing you’ll spend half the cost of a decent smaller system you can actually use before you even buy panels.
Further it’s barely 3000 useable Wh.

YMMV

 

[jeepin95]

I was considering a similar setup with the DPU connected to my transfer switch via the L14-30 for 240V 30A output. The issue is with AC passthrough. The DPU only supports 1800W AC (120V 15A) for AC passthrough. If you connected a 240V input, all AC output is disabled. This is stated in the DPU user manual and here in the FAQ.

AC passthrough (bypass) seems to support up to 12A output for > 3 hours (source).

It may be possible to charge using the x-stream AC charging port with 120V (say 120V 30A) and still have AC output but I have not seen any demonstration, reviews or comments indicating this works. I'd love to know.

Thank you for the reply. All of my critical loads are 120v so I don't think I need to worry about the 240v limitation. The truck has 2x20A 120V receptacles and 1x30A 240V receptacle. So I would be limited in the output from the truck for charging to just one of the 20A receptacles right?

If I have 120V AC plugged into the generator or the truck does that mean that the inverter has a hard limited of 1800W out from the inverter total and is only passing through the AC? Or is 1800W passed through and anything additional would be augmented by the batteries? So if my load was 3600W and was able to supply 1800W through other AC the battery would basically last twice as long? Or would I be fully limited to 1800W while plugged in to AC? If my load was only 1000W would it then be able to put the extra 800W to charging the batteries if I had run them down prior to turning on gas?

My understanding from the manual is that solar charging can be done in addition to AC charging. So if I had 400 or 800W of available that would be on top of the 1800W correct?

Thanks

 

[jeepin95]

What is your budget?

I probably wouldn't want to go over $8k. My wife saw the DELTA Pro Ultra for $5799 and thought we should prepare better and that didn't seem to bad to her

Because you can buy a lot for $6-$7k including panels, aio ‘inverter-charger,’ and some battery bank these days.
It would be just as simple as a suitcase battery it would seem- but actually way simpler (without the cords other than your generator) because it will always be up and running behind the scenes seamlessly. And the $7k system will:

Part of the draw to the DPU is the semi-portability. Either being able to take it with the RV for some situations, or take it to the park other things would be nice. The hand truck with server rack batteries just doesn't seem quite as user friendly. So we don't want something mounted to the wall (aside from the obvious need for some sort of panel/transfer switch).

Plugging a cord in or throwing a transfer switch isn't something we need to avoid. Pulling the generator out, hooking up propane, running extension cords in the wind and rain is what we want to avoid.

I personally would lean more towards the DIY for the experience of building it and the options to improve it later but she would rather have it delivered ready to go.

If I had room for enough PV panels to get mostly off the grid I would probably go the DIY route with aio and battery banks. When we decide to move to a new house that will be in the criteria as we search.

…start paying you back. $7k will be enough power to “save” more than $0.20/day.

The ecleflo is way too limited imho. It’s less convenient and it surely doesn’t scale well on a budget. At its sub-$3k price point marketing you’ll spend half the cost of a decent smaller system you can actually use before you even buy panels.
Further it’s barely 3000 useable Wh.

YMMV

The DPU claims to be 6KWh, is that not actually the usable power? My F-150 has a 1KWH battery but it is forced to between 40-70% SOC and will run on battery generally for ~20-30 minutes before it needs to start the ICE for a minute to bring that back to 70% SOC. I thought I had read somewhere that the DPU could go as far down as 10% SOC before it shuts off.

I'm really not worried with saving $$ on energy during the day. I'm more interested in having the backup power. The novelty of being able to say I worked all day on solar power is more interesting to me than the $$ savings.

 

[12VoltInstalls]

The DPU claims to be 6KWh, is that not actually the usable power?

Sorry. Was referring to the $3k edition. Yikes. Pricey thing, there.
Their addon battery is $3300?!! That’s like double the cost of a server rack battery Wh-to-Wh

The novelty of being able to say I worked all day on solar power is more interesting to me than the $$ savings.

That’s interesting for sure. I budget differently I guess. But of course I don’t actually have an electric bill.

 

[jeepin95]

Sorry. Was referring to the $3k edition. Yikes. Pricey thing, there.
Their addon battery is $3300?!! That’s like double the cost of a server rack battery Wh-to-Wh

Yes, their batteries do seem to be way overpriced.

That’s interesting for sure. I budget differently I guess. But of course I don’t actually have an electric bill.

The idea here was more of a backup since I know that we won't be able to produce enough to fully replace our electric bill. For my situation even if we were to be able to fully replace our electric bill with solar it would be >20 years to pay for itself, and we will likely not be in this house that long. Our next house I would like to be capable of 100% off-grid. In my particular case I'm not going into it thinking about potential savings.



I did ask EcoFlow support a few questions and one was about the limits when plugged in to AC for charging.

"Yes, the power will be limited to 1800W in bypass mode. If the load is greater than 1800W, EcoFlow DELTA Pro Ultra will use battery power to make up for the excess power."

I think this means if I had a 3600W load 1800W would be passed through from the generator and 1800W would be coming from the batteries so they would last twice as long at night (to not account for any PV).

They did not answer what the idle consumption is and I couldn't find that in the manual either.