Thoughts on This Setup

[cohunter14]

Wanted to see what everyone thought about this setup for an off-grid cabin we have:

(8) Costco golf cart batteries
(4) Trina 300 watt Mono 60 Cell Solar Panels, 2 in series, 2 in parallel - specs here: Trina 300 watt
Victron Energy SmartSolar MPPT 100v 50 amp Charge Controller
Giandel 24v Pure Sine Wave 3,000 Watt Inverter

This setup gives 5,376 usable watts of power from the batteries at 50%. The setup will be used to power a 1/2 HP Well Pump (roughly 1,150 watts per day) along with roughly 1,800 watts of power for the rest of the house (high-end estimate). The cabin is in Colorado, where we average over 5.5 sun hours per day.

Would you change anything with this setup or do you see any reason to bump up the inverter to 4,000 watts?

Appreciate any thoughts or opinions!

 

[chrisski]

instead of 5.5 useable hours of solar a day, try using a solar calculator, like in my signature block. That way you can see if your batteries and panels will meet your needs for your area. I would think you’ll find you would produce 5.4 kw per day only in the summer, if even then.

 

[cohunter14]

The calculator is a little confusing, but it shows that I would have full batteries 86% of the time and empty batteries 1% of the time. That should be sufficient for me as we won't be using it much, if at all, in the winter as it's not very accessible due to snow. And even if I do use it in the winter, the well won't be in use as we'll shut it off and drain the plumbing for the winter.

 

[chrisski]

I think your results are reasonable enough to know you may need to turn on the generator occasionally.

For pump to inverter size, I can’t help. There’s other water pump threads where people have given inverter size and type for a 1/2 hp water pump.

For the estimate, I think you’re saying 1800 watt hours + 1150 watt hours = 2950 watt hours per day.

 

[cohunter14]

For the estimate, I think you’re saying 1800 watt hours + 1150 watt hours = 2950 watt hours per day.

Correct.

Regarding the pump, I'm not sure on the starting wattage yet, but I've seen that 1/2 HP pumps can have starting wattages up to around 3,150, which should still easily work with that inverter. I just wasn't sure if there would be any other reason I would want to consider a higher wattage inverter that I wasn't thinking of, which is why I asked.

 

[MichaelK]

Here is a pump chart that another member originally posted. You did not mention whether or not your pump was 120 or 240VAC. Your Giandel is not going to power it at all if it is 240V, but if it is 120V, then the starting surge might be as high as 55A, or 6600W. You should read through the specifications for the that inverter very carefully to determine if it can handle a starting surge that high. I've measured the starting surge of my own pump with an "inrush current" meter, and I found that the numbers in the table closely match my real-world numbers. At first glance, I'd say this system design is a bit too light to power what you want.

 

[cohunter14]

The pump is 120v and starting wattage is 5,200 watts. So with a 3,000 watt inverter that has a 6,000 watt surge rating, I think I should be fine, right?

 

[MichaelK]

The pump is 120v and starting wattage is 5,200 watts. So with a 3,000 watt inverter that has a 6,000 watt surge rating, I think I should be fine, right?

The answer to that question is "yes and no", depending on the kind of inverter you have. Basically, high-frequency transformerless inverters are cheap, light, but only have milliseconds worth of surge capacity. Those are brands like MPP, and some Growatts. Low-frequency transformer based inverters are more expensive, heavier, but have surge rating in the seconds to minutes range. Those brands might be Magnum, Outback, Schneider, and SMA.

So, again, go into the detailed specifications of your potential inverter and determine how long it can surge, not just how much it can surge. Don't just buy something based solely on watts. You may find yourself very dissappointed. I would not buy anything that can't surge 200% for at least 5 seconds. BTW, if a particular inverter brand doesn't specify how long, then avoid it completely. They are likely trying to hide that spec.

 

[12VoltInstalls]

The pump is 120v and starting wattage is 5,200 watts. So with a 3,000 watt inverter that has a 6,000 watt surge rating, I think I should be fine, right?

No, that Giandel is a very good lower priced inverter but forget about surge rating.

The nice thing with Giandel is they do incorporate ’soft start’ into some models but I’d guess you need a 6000W inverter. And that’s a guess.

 

[cohunter14]

Alright, well this obviously throws a wrench in my plans then as I thought I'd be good to go. What would you guys suggest for an inverter that will power things with no problem? Obviously not looking to break the bank here, but it sounds like it's going to cost more than I initially thought.

 

[12VoltInstalls]

Those brands might be Magnum, Outback, Schneider, and SMA.

What would you guys suggest for an inverter that will power things with no problem? Obviously not looking to break the bank here

Look at the michaelk suggestions. Then you’ll know the prices and determine if that breaks the bank. In theory and perhaps likely they’ll last forever.

On the other hand I had ~4 years on a Giandel 1200W with no issues. I only ran the Reliable QZRELB for a month but it was great and very low idle consumption.
Just get pure sine; I knew better- nevertheless, I uncannily confirmed that modified sine inverters kill electronics and fridges.

 

[GLC]

I agree with 12voltinstalls, try the Giendel. I have been running a couple of them for a couple of years. Good pure sine wave inverters, low idle watt usage. My 4000 / 6000 watt consumes about 7 watts at idle with no load. It does not have an exterior stand by switch. Units are beasts. One runs most of my normal ac usage including washer, microwave, tv's and 2 ductless ac units.

 

[cohunter14]

I've been doing some digging on the Magnum, Outback, Schneider, and SMA and obviously there is a big jump in price. Would looking at something like the Growatt 6,000w, the Rich Solar 6,500w, or the Midnite DIY 5048 be a terrible idea just to keep costs down a bit?

 

[12VoltInstalls]

terrible idea just to keep costs down a bit

I don’t think that’s a terrible idea. Growatt lacks a bit in support. Although they’re probably mechanically cloned in other brands. I like the US distribution of MPP. You don’t see the volume of complaints against Rich.

I’d probably look at MPPSolar first. Ymmv

 

[MichaelK]

I've been doing some digging on the Magnum, Outback, Schneider, and SMA and obviously there is a big jump in price. Would looking at something like the Growatt 6,000w, the Rich Solar 6,500w, or the Midnite DIY 5048 be a terrible idea just to keep costs down a bit?

This is all about careful study of the specifications. The problem here is that 95% of the solar enthusiasts purchasing these products only look at two values, W and $. That seems to be the standard strategy of what I call "pen and paper" designers that have little or no real-world experience with what they are working with. They see the watts and and see the price, and they say "OK, that will work".

That is of course until they actually assemble the parts together, plug it in, and discover, no, it doesn't work. After experiences with trying to power different loads with different inverters, I've gotten a sense as to what works, and to what is just BS. Yes, I've plugged in small appliances and pressed on and see nothing more than a little red LED come on.

I cringe a bit when I see posts like "well, I don't see why it wouldn't work", or "yes, I think this should work". I base my recommendations on what I've seen working. Or, what other have said they saw working. You may want to balk at the recommendation of the higher priced inverters, but base your decisions on "yes, I have the WigiMax3000" and it starts my 1hp wellpump", instead of "I don't see why it wouldn't work".

 

[Planecrazy]

I think buying a huge inverter in this case is the wrong way to go, I have a Giandel 2000w inverter and its been very reliable in daily use for the last year.

I would try your design and if it doesn't work for you, spend some of that big inverter money on a new DC well pump.

This has been my experience that all the appliances I went cheap on initially are just not efficient as I try to run more and more off solar, so I've had to bite the bullet, and much as I hate it, replace working appliances, although you can always sell the old ones.

 

[12VoltInstalls]

be a terrible idea just to keep costs down a bit

You may want to balk at the recommendation of the higher priced inverters, but base your decisions on "yes, I have the WigiMax3000" and it starts my 1hp wellpump"

This is all about careful study of the specifications

The MichaelK post is the takeaway
I don’t think it’s “a terrible idea” to look at growatt or MPPSolar but these are out there in such a volume that finding posts from users trying to do what you are going to need to do shouldn’t be hard to do.
MichaelK makes a good point.

think buying a huge inverter in this case is the wrong way to go, I have a Giandel 2000w inverter and its been very reliable in daily use for the last year.

The thing is OP isn’t needing a huge inverter or a somewhat casual load inverter. What he needs is one that will run his well pump. Reliably. Your 2000W experience is typical in the Giandel product line, but in that type of inverter 6000W is the opening…guess in his case.

What would you guys suggest for an inverter that will power things with no problem? Obviously not looking to break the bank here, but it sounds like it's going to cost more than I initially thought.

The higher end products should do it considering all the user experience.
I might consider trying a Giandel 6000W pure sine inverter purchased from one of the two or three outlets known for their liberal return policy.

One of these- while it is not inrush capable- does have good use in evaluating and maintaining your solar power system. If you want true inrush the $130 one does that. I have the $60 model; it ranges so fast on startup current you can’t get a ‘reading’ but my 5CF fridge startup on the inverter readout is typically ~800W+ and this Klein does soar to a 6- or 7xxW ish so it shows something. ​

One of the MPPSolar units recently had some well pump activity mentioned in a thread; I’d dig that up. A Giandel 6000W stand-alone might be the lowest upfront cost of things I personally would consider but if you try it whether successful or not please post what you find out so others can know.
FWIW - not apples/apples- my Giandel 1200W has a soft start feature and runs my ~850W shopvac. When I tried hard to shutdown a 2000W QZRELB it appeared to have that feature but it was hard to tell because I didn’t have a way to incrementally add loads. The 1012LV-MK doesn’t appreciate the shopvac startup and I have to rapidly turn on-off-on-off-on to keep the inverter from protecting itself.

The point is try the well pump with some things and see. If a given product doesn’t perform to advertised specifications returning it shouldn’t be a problem.

 

[cohunter14]

I appreciate all of the input. I've spoken with each of those companies I listed about what I'm trying to do, and they insisted it would work. The initial Giandel I listed will not work.

I'll be honest, the reason I'm shying away from the higher priced inverters, outside of the price, is I am not sure what the big advantage is. I've been told it's warranty, but if a Midnite has a 1 year warranty and is 4x cheaper than one with a 5 year warranty, I'm probably willing to take my chances. I should have also mentioned this is for a remote cabin that is going to get minimal use, maybe 5-7 weeks a year max. So, trying to justify buying an inverter that's top of the line, when it won't get used much, is difficult. Not to mention the excess wattage of the inverter is really only going to be used for the well pump. Outside of that, we'll be using simple things like the occasional microwave, vacuum, and coffee maker in addition to lighting.

I am all for recommendations though! I'll be sure to check out the MPPSolar stuff. If there are specific inverters that you guys would recommend, please let me know. Appreciate the help!

 

[12VoltInstalls]

there are specific inverters that you guys would recommend,

I can’t speak for the bigger ones but the QZRELB 2000W I have was like 11W idle consumption. The Giandel 1200W is like 26W. So the bigger ones may also be comfortable to run for standby consumption.
Spending cheap ain’t necessarily wise, but spending wisely on lower-priced components is possible.
In your case components may be the best ‘outcome.’

 

[12VoltInstalls]

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