Cheapest and easiest way to keep panels working during a power outage

[Siamac]

I have some experience with solaredge, enphase and tesla systems in the past. I don't really see any major enough differences between them, so for my latest system a chose to go with the cheapest, which was Hoymiles grid tied in my case.

I want to be prepared when the terrorists attack the grid. The power outage could last only a few hours, but I want to be prepared for at least a few days of the grid being down. But I'm working on a very tight budget so I am not going to pay for something like a Powerwall.

My generator will last only a day or two before the propane runs out and it wouldn't be enough to charge the EV anyway, so my only option is to figure out a way to keep the solar panels working during an outage. It doesn't seem like there's any new easy ways to do it, but maybe there is that I'm missing?

All I need is some kind of 240V AC coupled small battery system that's cheap and easy. Is that too much to ask for?

Ecoflow has the Delta Pro x 2 on sale right now for about $4000 but it's still kind of expensive and I don't know how I can get the panels working with it.

Anyone know of an easy cheap solution?

I can use the generator at night, but need the power of the panels in the daytime to charge the EV. I think my panels will reach 7-8kw mid day so I can get a good 10-20% charge if I can get it working.

 

[1201]

What's your budget for battery and backup inverter?

 

[solar8484]

I have some experience with solaredge, enphase and tesla systems in the past. I don't really see any major enough differences between them, so for my latest system a chose to go with the cheapest, which was Hoymiles grid tied in my case.

The Enphase iQ8 Sunlight backup is different from the other grid-tied inverter in its ability to produce power during grid outages without batteries.

Anyone know of an easy cheap solution?

Define cheap and how much power.

 

[Siamac]

Cheap would be under $3000 total. I don't need much power, just enough to get the panels online. I can add more if I need later, but it's mostly to prepare for the terrorist attack, so it's not going to be used daily

 

[Samsonite801]

I have some experience with solaredge, enphase and tesla systems in the past. I don't really see any major enough differences between them, so for my latest system a chose to go with the cheapest, which was Hoymiles grid tied in my case.

I want to be prepared when the terrorists attack the grid. The power outage could last only a few hours, but I want to be prepared for at least a few days of the grid being down. But I'm working on a very tight budget so I am not going to pay for something like a Powerwall.

My generator will last only a day or two before the propane runs out and it wouldn't be enough to charge the EV anyway, so my only option is to figure out a way to keep the solar panels working during an outage. It doesn't seem like there's any new easy ways to do it, but maybe there is that I'm missing?

All I need is some kind of 240V AC coupled small battery system that's cheap and easy. Is that too much to ask for?

Ecoflow has the Delta Pro x 2 on sale right now for about $4000 but it's still kind of expensive and I don't know how I can get the panels working with it.

Anyone know of an easy cheap solution?

I can use the generator at night, but need the power of the panels in the daytime to charge the EV. I think my panels will reach 7-8kw mid day so I can get a good 10-20% charge if I can get it working.

How many watts do you need? Do you need batteries? Batteries is the biggest expense in a solution. There are all-in-one inverters that can run batteryless to at least provide daytime power if cheap is what you want. Although not required, I might still at least run like 4 car batteries in series as opposed to batteryless since it gives more surge handling. Not enough battery to run on for a period of time, but just to help with surge load.

Once batteries are involved where you want significant capacity, then the price goes up fast.

The EG4 6000EX or the MPP Solar LVX6048 are an example of an all-in-one model that can run batteryless, but can still add even a tiny bank of lead acid batteries on it for better surge handling (for motor loads startup). Then you can add more batteries later or switch to lithium if you decide later.

All-in-ones are also usually capable of scaling-out up to 8 or so inverters wide, so leaves room for future expansion.

Example of batteryless operation:

 

[solar8484]

Cheap would be under $3000 total. I don't need much power, just enough to get the panels online.

There is no one size fits all solution that is "just enough to get the panels online" without knowing the total power capacity (AC) of the panels . AC coupling generally requires 1:1 power capacity ratio between the independent power source (e.g. the grid) and the AC coupled solar. So, a 2kW max independent power source can only be paired with 2kW max of AC coupled solar. Depending on how much AC coupled solar power capacity you want during outages, you will need to scale the power capacity and cost of the independent power source accordingly. For $3k, what's the minimum power capacity you would accept?

 

[chrisski]

Cheap would be under $3000 total. I don't need much power, just enough to get the panels online. I can add more if I need later, but it's mostly to prepare for the terrorist attack, so it's not going to be used daily

I don't have much hope of finding anything to run a lot of power for a $3k budget.

Perhaps getting an EG4 48 VDC 6 kw inverter and a 48 volt 10 ah lithium battery, but that would likely bust the budget.

Battery-less is an option, but you of course would need to work around the nights and clouds. Depending on your needs, battery-less could be the only option for your price tag.

 

[Siamac]

Good info about batteryless. My solar is around 11kw system. So I would need 11kw inverter?

 

[1201]

Imo since you don't have a DC string you have to ac couple and the cheapest solution just for one will run at least $3500

 

[Siamac]

How many watts do you need? Do you need batteries? Batteries is the biggest expense in a solution. There are all-in-one inverters that can run batteryless to at least provide daytime power if cheap is what you want. Although not required, I might still at least run like 4 car batteries in series as opposed to batteryless since it gives more surge handling. Not enough battery to run on for a period of time, but just to help with surge load.

Once batteries are involved where you want significant capacity, then the price goes up fast.

The EG4 6000EX or the MPP Solar LVX6048 are an example of an all-in-one model that can run batteryless, but can still add even a tiny bank of lead acid batteries on it for better surge handling (for motor loads startup). Then you can add more batteries later or switch to lithium if you decide later.

All-in-ones are also usually capable of scaling-out up to 8 or so inverters wide, so leaves room for future expansion.

Example of batteryless operation:

The MPP Solar LVX6048 seems like a good option. It's under $1000. Can it run with AC coupled? I have microinverters so it's already AC at the source I will be using to connect

 

[solar8484]

Battery-less inverters can't AC couple just by themselves since there is no place to sink excess solar power.

 

[solar8484]

For $3k, Victron Multiplus 3kVa and 4kWH battery could be doable for pairing with ~2kW of AC coupled solar.

 

[Samsonite801]

The MPP Solar LVX6048 seems like a good option. It's under $1000. Can it run with AC coupled? I have microinverters so it's already AC at the source I will be using to connect

Is it possible to remove the microinverters from the solar panels and just use the raw DC power off the panels themselves?

 

[1201]

The MPP Solar LVX6048 seems like a good option. It's under $1000. Can it run with AC coupled? I have microinverters so it's already AC at the source I will be using to connect

At this point it might be cheaper to buy a cheap inverter, add some solar panels and a battery and do a backup system

 

[Siamac]

Is it possible to remove the microinverters from the solar panels and just use the raw DC power off the panels themselves?

Can't do that, would cost too much

 

[Siamac]

At this point it might be cheaper to buy a cheap inverter, add some solar panels and a battery and do a backup system

Not a bad idea, but at that point, would just go with a generator. Would be cheaper

 

[1201]

Not a bad idea, but at that point, would just go with a generator. Would be cheaper

Probably

 

[Siamac]

How about an AC coupled inverter with frequency shifting? That way I can easily add more batteries down the line and solar would work when needed.

Is there an inverter that can be AC coupled that does frequency shifting, so that it turns off the panels when the load is lower than the panel output?

 

[Siamac]

I would also like to add that my EV charger has the capability to adjust the charge based on solar production, so I probably can get by with just a small battery backup. But I would still need an AC coupled inverter that can do frequency shifting

 

[1201]

How about an AC coupled inverter with frequency shifting? That way I can easily add more batteries down the line and solar would work when needed.

Is there an inverter that can be AC coupled that does frequency shifting, so that it turns off the panels when the load is lower than the panel output?

Yes, this is the correct way to do it. But those inverters start at $3k and go up from there

 

[Siamac]

Yes, this is the correct way to do it. But those inverters start at $3k and go up from there

Do you know of any?

Would a Ecoflow smart panel work?

 

[Hedges]

These should do it.
Sunny Island is 120V, so you either need two for 120/240V, or one and an auto-transformer.
msrp is around $5750, retail street price $4750, but there are liquidation bargains due to DC Solar bankruptcy, also used ones.

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But your cheapest option would be to buy a low-cost AIO ($500 to $1500) and rewire PV panels in series to feed them.

 

[1201]

These should do it.
Sunny Island is 120V, so you either need two for 120/240V, or one and an auto-transformer.
msrp is around $5750, retail street price $4750, but there are liquidation bargains due to DC Solar bankruptcy, also used ones.

SMA Sunny Island SI 5048U 5kW Inverter 60 Hz | eBay

Find many great new & used options and get the best deals for SMA Sunny Island SI 5048U 5kW Inverter 60 Hz at the best online prices at eBay! Free shipping for many products!

www.ebay.com

SMA Sunny Island SI 5048U 5kW Inverter 60 Hz | eBay

<p>SMA Sunny Island SI 5048U 5kW Inverter 60 Hz. </p><br /><p>Used but works well.</p><br /><p>Warehouse overstock.</p>

www.ebay.com

But your cheapest option would be to buy a low-cost AIO ($500 to $1500) and rewire PV panels in series to feed them.

I think the sunny island would not be a lot more expensive but would have a lot more flexibility

 

[solar8484]

What about the cost of required batteries?

 

[wattmatters]

Anyone know of an easy cheap solution?

AC coupling is not cheap.

Neither are batteries.

The power outage could last only a few hours, but I want to be prepared for at least a few days of the grid being down. But I'm working on a very tight budget so I am not going to pay for something like a Powerwall.

My generator will last only a day or two before the propane runs out and it wouldn't be enough to charge the EV anyway, so my only option is to figure out a way to keep the solar panels working during an outage. It doesn't seem like there's any new easy ways to do it, but maybe there is that I'm missing?

The cheapest option as far as I can tell to have several days of grid backup is a generator with sufficient fuel on hand to last for whatever duration you need, with propane being easiest to store for long periods without spoiling.

If your concern is outage coverage (rather than running from off-grid PV), then I would look into storing more propane. Don't know what propane costs there but where I am 1 x 45kg tank of propane would cost US$24/year bottle rental and ~ US$150 for the gas.

1 x 45kg tank of propane running a generator should provide roughly 100 kWh of electrical energy.

While I have a home outage backup system (PV & battery) to complement our grid-tied PV, our EV is actually part of the backup solution. It has vehicle to load capability so is itself a source of emergency backup power.