Backup to a generator for prolonged grid down scenario

justgary

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Deep conservation mode... A+ We try to do the same, but I have to try to see what the new Bluetti will do with a small mini split HVAC as it gets way hot and humid here in Florida. I currently do without AC now when power is out. Fans become my friend.
We are in Florida as well, and I understand what it means to do without air conditioning. That is exactly why I would like it on its own solar system. It is a geothermal system that also heats water and is very efficient, so I don't really want to supplement it with a mini split.

I know how to keep my food cold with a bit of time on a small generator.
 

robby

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I think the OP has a problem in that 1.5KW of panels is not going to produce enough voltage to even run most Inverters MPPT's in the power category he is looking at. So really he needs to Grid Charge the batteries.
I have not looked at this in detail but I think the MPP LV6048 Inverter might be the ticket.
It's Split Phase and can produce 6000W of power plus it's only about $1200. From what i have read it can charge the batteries from his Generator or from the Grid.
That leaves you enough money to buy 3 to 4 SOK 48V 5KW Rack mount batteries or EG4 Batteries. So that gives you 20KWh of battery backup. You would have a system that can be moved to your next house and then hook up a proper amount of solar panels later on.
 

Browse

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I think the OP has a problem in that 1.5KW of panels is not going to produce enough voltage to even run most Inverters MPPT's in the power category he is looking at. So really he needs to Grid Charge the batteries.
I have not looked at this in detail but I think the MPP LV6048 Inverter might be the ticket.
It's Split Phase and can produce 6000W of power plus it's only about $1200. From what i have read it can charge the batteries from his Generator or from the Grid.
That leaves you enough money to buy 3 to 4 SOK 48V 5KW Rack mount batteries or EG4 Batteries. So that gives you 20KWh of battery backup. You would have a system that can be moved to your next house and then hook up a proper amount of solar panels later on.

The LV6048 looks like it might work with a few rack mount batteries. Would you recommend SOK over EG4 Lifepower4? Will this unit and batteries handle a large surge for a second or two? I've read that the hybrid inverters with large transformers can handle surges well. AIMS had a few that could handle surges of triple their rated continuous output. It would be nice to be able to start the main HVAC and run it for an hour or two to cool down the house for a short time. I think if there was a prolonged outage, we'd be sleeping in the basement to keep cool.
 

Browse

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Browse

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This one looks like it can handle solar as well for a few hundred more:
 

robby

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This one looks like it can handle solar as well for a few hundred more:
If you need the surge current then it would be a better choice but your going to pay the price with it's much lower efficiency. Are you planning on using a Well Pump or something of that level of importance? I would not build an emergency Grid down system based around AC units. I would head for whats going to power the basics the longest.
If length of time is important then get the LV6048.
 
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robby

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The LV6048 looks like it might work with a few rack mount batteries. Would you recommend SOK over EG4 Lifepower4? Will this unit and batteries handle a large surge for a second or two? I've read that the hybrid inverters with large transformers can handle surges well. AIMS had a few that could handle surges of triple their rated continuous output. It would be nice to be able to start the main HVAC and run it for an hour or two to cool down the house for a short time. I think if there was a prolonged outage, we'd be sleeping in the basement to keep cool.
Yes because SOK cells have a longer history of reliability than EG4 and secondly I am not thrilled with Signature Solars response to Warranty issues and customer service. On the flip side Currentconnected seems to put CS First and I suspect if you have an issue they will fix or exchange the battery ASAP.
 

Browse

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I just can't decide. The more I look into Sungoldpower, Sigineer, AIMS and Growatt, the more uncomfortable I get with the complaints and potential quality issues. If I was rich, I'd get a Sol-Ark 12kw and four SOK 48V 100ah rack mount batteries and call it done for backup power, but I can't justify the expense. Even looking at the simple 2xEcoflow Delta Pro package brings me to people complaining that buttons stop working and they can't charge while two are in use via the double voltage hub.

I need a simple, high quality, low cost solution but it evades me.
 

timselectric

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Just take your time. And weigh all of the options.
Decide what work that you are willing to do yourself.
You'll figure it out, I'm sure.
 

42OhmsPA

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I was leaning towards sungold initially... The more technical questions I ask, the less I am interested...
TP6048 - 135 watts idle consumption (was my first choice) didn't ask about THD
8Kw UL certified - 88 watts idle consumption 10% +/-5% THD 😔 I wouldn't want to feed my well pump with that long term...
I'm quickly understanding you get what you pay has great merit in the solar / off grid world... Look up the specs /efficiencies for schneider, samlex, magnum; if only magnums were in stock.
Now I'm looking at importing a Deye... Knowing you "can't anymore" makes me want one that much more.
 

740GLE

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I was leaning towards sungold initially... The more technical questions I ask, the less I am interested...
TP6048 - 135 watts idle consumption (was my first choice) didn't ask about THD
8Kw UL certified - 88 watts idle consumption 10% +/-5% THD 😔 I wouldn't want to feed my well pump with that long term...
I'm quickly understanding you get what you pay has great merit in the solar / off grid world... Look up the specs /efficiencies for schneider, samlex, magnum; if only magnums were in stock.
Now I'm looking at importing a Deye... Knowing you "can't anymore" makes me want one that much more.

What’s your THD of you generator under load?
 

42OhmsPA

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What’s your THD of you generator under load?
I don't know, I never thought about it until joining the forum... Plethora of information here 👍🏻. Next time the power goes out I'll check the frequency with my new meter.
I can't imagine it's great, older 5500w generac. I'd bet the WEN inverter Gen I picked up a while back is much cleaner.
 

SparkyJJO

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Unless It is an inverter generator, it is likely in to 20% range, or higher. Generators are noisy beasts, and not just in the exhaust note.
 

740GLE

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All inverter generators aren’t the best for THD, especially economy ones such as WEN.

I have the small 3500w WEN open frame and I believe it’s modified sine wave inverter, not pure sine wave. Good enough for my needs.
 

Browse

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Can you all take a look at these two products and let me know if they will work as a backup to my generator?

One of these inverters:
https://watts247.com/product/spf-6000t-mpv-dvm/

Two of these rack mount batteries:
https://watts247.com/product/powerup-lifepo4-5-1kwh/

Same basic equipment available from Signature Solar but different rack mount batteries:

https://signaturesolar.com/growatt-48v-6kw-250vdc-split-phase-off-grid-inverter/
https://signaturesolar.com/eg4-lifepower4-lithium-battery-48v-100ah/

Other than cables and some wire, is there anything else I would need assuming I will skip the solar panels for now and just recharge with my generator? Will the inverter and batteries play nice together, BMS, etc?

This would be a cheap "starter" battery backup system for under $5k.
 
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