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diy solar

All-in-one drawbacks?

wingedlizard

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Jun 22, 2022
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Raleigh NC
I have built a small solar generator ( 350w, 40a mppt, 1000w inverter, single 12v 100ah lifepo4 battery), and I'm thinking of getting a bigger inverter.

I will need another battery to support a bigger current draw of the inverter, and will probably want to double my panels as well. May go from 12v to 24v too.

The All-in-one seems to make sense financially -- I get a bigger mppt, bigger inverter, a charger and a automatic transfer switch as well as better programmability and monitoring.

I am wondering what the draw backs might be. It seems the bigger inverter would cause less efficiency ( I've heard as much as 80w draw at 'idle').

Is there a minimum pv panel wattage, before going with an all-in-one?

My goal is to run a garage refrigerator ( 1500 wh per day @ 120w) and add my water well pump ( 260 wh per day but peak draw is high at @1400w ).

http://desertprep.info has a spreadsheet, and when I plug in all the data, I get the following ( 1 day 'reserve'):

Design Specifications for Your Generator
Minimum inverter wattage 1,900 W
Minimum battery AH reserve 313 Ah
Minimum solar panel wattage 768 W
System energy throughput 75.0 %
Projected available daily load power 1,418 Wh
Standby generator run hours 2.1 hr
Standby generator fuel (/day) 2.1 gal

The automatic transfer switch could allow me to use a smaller total battery AH, since I could automatically switch to Utility A/C when batteries were low ( or even automatically charge the lifepo4 batteries if they got to low).

Does going with the all-in-one have drawbacks I am not thinking of?
 

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Components are generally cheap and may not be consistent between production runs even for the same model.

IMHO, idle draw is the biggie. Plan for 45W/3000W of inverter power. That's 1.1kWh of juice just to have the inverter turned on. That's 84% of the capacity of your 100Ah battery.
 
I can’t seem to find a single all in one good for off grid made by an established company. (Was hoping something like xantrex , Schneider, solaredge)

Does anything like this exist ? May end up with one from Renogy but they appear to just be rebranded Chinese stuff because the renogy one looks the same as ones sold by eco worthy and powmr.
 
Drawbacks to consider:

If one part fails, the entire unit has to be sent back for repair. For instance, I had my first Growatt have a failure on the PV MPPT portion. Everything else worked fine, but no solar input was a big problem, and I couldn't just have that one part repaired or replaced - I had to send the entire thing back for warranty service. Shipping costs are much higher as a result - you have to send the huge, heavy thing back and forth for service.

Every manufacturer has a different balance for the components. The Growatt SPF 6000T - DVM, for instance, can only handle 3kw of solar input, and it outputs 3kW per 120v leg. Solark usually has a much higher solar input capacity than its inverting capacity. The AC charger has a certain capacity as well, and the transfer switch may also have a limit.

There are a lot of conveniences with an all in one, but there are downsides, and it's much easier to hide limitations when you aren't looking at each part individually.
 
Not sure why the double post. This one can be ignored.
 
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Not sure why the double post. This one can be ignored.
well point us to the 'other link' then.

btw, I've upgraded to two 100ah lifepo4 batteries and four 175w panels. The renogy takes 520watts ( or 1040 @ 24v ).

3x175w is 525w ( 5 over the 520w supported ), but I have never seen more than ~85 percent of rated.

Going with a growatt, I can use all 4 panels in series ( 700w ) and switch to 24v, and later add another string of 4 panels and 200ah more battery.

This is getting addictive ( and co$tly).
 
I am going with Growatt 24v spf 3000. looks like 3kw 24v inverter would cost 2/3rds of the aio.
You should watch this video about the limitations of a AIO when being used in conjunction with a generator. I use an AIO and love it but I had to work around this issue it is a common thing with almost all AIO units. The issue I’m referring to is just I’ve 3 minutes into the video
 
video about the limitations of a AIO when being used in conjunction with a generator
Many units you can program the amp limit of the built in utility charger. Even the little 1012LV-MK I have has that feature - which I used because my wintertime supplemental power was only 12ga at a few hundred feet and I didn’t want to use it harder then necessary.
 
The comments in this video are mostly true for almost all inverter/chargers. Higher grade units are less susceptible to the issues described. Victron wants even more of a safety factor. For a 3000W inverter, they want a 5000W generator.

It has to do with the fact that inverters CAN'T be inverters and chargers at the same time.

The big difference seems to be the typical AiO is very sensitive to generator quality and may reject dirty (or not-so-dirty) input for charging where Tier-1 hardware will accept sloppy input and often have provisions for accepting truly horrific input. My Quattro will accept 90-135VAC by default and can be configured to accept 45-65Hz input as well.

Should those provisions not be adequate, it has a "Weak AC input" function which further increases the tolerance for dirty input power:

"Weak AC Input
Weak AC input should be checked in cases where problems during charge arise. Some generators generate a waveform which makes it difficult to charge with the normal charge mechanism. If this option is checked another mechanism is used which will enable the device to charge under practically all conditions.



Disadvantage of using this option is that the power factor will be less than 1."

This option limits charging to about 80% of the programmed charge current.
 
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I have both Descete components and a AIO running. I tend to prefer the "separate" components. Easier to monitor with shunt meters and customize. However the battery charge and grid assist to load is also nice. So I've got both. If something dies I should be ok
 
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