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Panel Orientation?

Posts: 600

Location: Michigan

posted 5 years ago

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S Bengi wrote:FRANK:
It seems like he has a hot water tank with a temperature differential from top (70C) vs bottom (40C). That is 'heated' by solar thermal with a 'backup' electric heater element. It's possible it is a 50gallon tank. I do agree that with the manual and some time he will be able to save/record all the current settings, And then play around with stuff (worse case he can revert back to a last know working configuration or reset to factory default or call the company to remotely configure stuff.

GRAHAM:
You said that the rear house will soon be occupied and it will have it's own hot water system. just a FYI, the rear house pulls it's energy supply from the same battery bank. So it will not lessen the draw in fact it will increase it a bit, unless the rear house is fossilfuel/biomass (not electric). The good news is that she can have her tiny hot water tank for the morning and you don't have to try to heatup the entire big tank in the front house for a 6am shower instead you can wait until the sun recharge the front house water tank by the afternoon.

Bengi, if there is already a modulating tankless water heater after the solar storage tank, i would soooooo, be done with any electric heating of water with the confines of that electric system. No way would i pump and dump a lead acid battery 3 times a day to avoid legionella if there is any other way at all.

Now, if the company would have actually done a thorough design workup, assuming the client gave full disclosure of intent ( for some reason they rarely do, but i drag it out of them on a site visit and followup communications) there would be little if any disparity between request and supply.

Graham, I would go over your contract and negotiations. If you let them take care of you and they cant program or size it correctly, id hold them to it. If they sold you on this will do what you want, you will get it even if another company does the work and the original company pays the difference...... no fun, but we are talking piles of time and effort turned into monetary units, hopes and dreams, time and offset, production and capability of what you relied on them to provide and signed on the line for.....

Graham Chiu

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Posts: 637

Location: Wellington, New Zealand

posted 5 years ago

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frank li wrote:

It is common to be locked out of a leased system or one with batteries under warranty by the manufacturer. Id go through the datalogs and make sure the battery has not seen a damaging level of charge or discharge. Lithium has way different parameters, like C/1 charging! Ouch.

I managed to get into the admin side by guessing the password. Unfortunately it is indeed setup for a Lithium battery!

I'm going to ring the vendor asap. Could the batteries have been damaged by these settings?

frank li

Posts: 600

Location: Michigan

posted 5 years ago

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Graham Chiu wrote:

frank li wrote:

It is common to be locked out of a leased system or one with batteries under warranty by the manufacturer. Id go through the datalogs and make sure the battery has not seen a damaging level of charge or discharge. Lithium has way different parameters, like C/1 charging! Ouch.

I managed to get into the admin side by guessing the password. Unfortunately it is indeed setup for a Lithium battery!

I'm going to ring the vendor asap. Could the batteries have been damaged by these settings?

I would not change any settings. There is usually a log of this. If you change settings it may immediately void mfr and installer warranty.

Those settings will never give good capacity and in fact will never charge lead to full under any normal use.

frank li

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Location: Michigan

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frank li wrote:

Graham Chiu wrote:

frank li wrote:

It is common to be locked out of a leased system or one with batteries under warranty by the manufacturer. Id go through the datalogs and make sure the battery has not seen a damaging level of charge or discharge. Lithium has way different parameters, like C/1 charging! Ouch.

I managed to get into the admin side by guessing the password. Unfortunately it is indeed setup for a Lithium battery!

I'm going to ring the vendor asap. Could the batteries have been damaged by these settings?

I would not change any settings. There is usually a log of this. If you change settings it may immediately void mfr and installer warranty.

Those settings will never give good capacity and in fact will never charge lead to full under any normal use.

Additionally, your limited to 2400-2700w charge and discharge???, likely the battery could take 60a just fine. There is some difference between 50a at say 48v and 57v or 59v on the way to a tapering absorbsion charge.

On charging 50a would be good ok for 300ah..... discharge? Only if the conductors cannot take more, which i doubt since it has a real inverter. Which reminds me... people drooling over lithium beware, not all lithium have the heroic charge discharge current profiles one would expect.

Some actually do, but many may have good cycle life, storage capacity etc, but have such a puny, miserable rate and conductor size that they need to be paralleled a half dozen times to ever power a serious load.

S Bengi

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FRANK:
I agree if there was a separate tankless water heater after the solar hot water heater that connects to the shower that he uses after getting home from work in the evening. I would not waste any energy heating up the '50 gallon' solar-hot water tank. I might be wrong but I don't think he has such a tankless hot water heater in the front house. There is only one in the daughter/rental unit.

Yes the charge and esp discharge rate for a Li battery is way too high for a lead battery. Do contact the solar company to fix it. Don't let volunteer to them that you logged into the admin area. And don't change anything. Its never a bad idea to take screenshots.

Iterations are fine, we don't have to be perfect
My 2nd Location:Florida HardinessZone:10 AHS:10 GDD:8500 Rainfall:2in/mth winter, 8in/mth summer, Soil:Sand pH8 Flat

frank li

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Location: Michigan

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Graham Chiu wrote:

frank li wrote:. Could the batteries have been damaged by these settings?

I missed this. Absolutely they could. Undercharging AND discharging deeply could have seriously impacted cycles/ service life if they were exposed to the treatment for much longer than a couple weeks, sometimes less depending on number of cycles. There is probably a total amp hours in and out log. Also a time since last "full" which, at those settings has never happened......

You can tell them frank said hi!

Graham Chiu

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Location: Wellington, New Zealand

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So, I've managed to talk to my suppliers, and they'll send the values to set the inverters for Lead Acid. The battery tech confirmed that I'm undercharging the batteries, and when they register as flat, they're probably more likely only 80% discharged.

The supplier wants the installers to come back and separate the panels so none overlap, but wants to keep the 30 deg tilt so I get more power in winter.

Yes, I have a standard solar hot water ready cylinder in the front house, with supplementary electric power to top up. The rear house has an instant gas hot water system which is supplied from my cold water.
Perhaps I should have done this in the front house. Just a dumb solar hot water cylinder, and a top up instant tankless gas hot water. Sounds like a more economical way to heat the water.

Graham Chiu

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Location: Wellington, New Zealand

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So, I've changed the settings as per their instructions. Not sure why they didn't log in remotely to do this.
The Charge Max Current is normally set to 54 amps but since I have two inverters each is set to 27 amps.
Web portal is still talking about Lithium batteries ... maybe I need to close down and restart the inverter?

frank li

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Location: Michigan

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Graham Chiu wrote:So, I've managed to talk to my suppliers, and they'll send the values to set the inverters for Lead Acid. The battery tech confirmed that I'm undercharging the batteries, and when they register as flat, they're probably more likely only 80% discharged.

The supplier wants the installers to come back and separate the panels so none overlap, but wants to keep the 30 deg tilt so I get more power in winter.

Yes, I have a standard solar hot water ready cylinder in the front house, with supplementary electric power to top up. The rear house has an instant gas hot water system which is supplied from my cold water.
Perhaps I should have done this in the front house. Just a dumb solar hot water cylinder, and a top up instant tankless gas hot water. Sounds like a more economical way to heat the water.

Good on you Chiu! 2.5 hours (and increasing with the season) of lost production every day..... for decades is not good, even at 20 percent nameplate for the time of day. That is good full bright sun and 2.5 hours is 2.5 hours.

If there was room, no installer worth their socket wrench would have laid out that roof without shade analysis either in person or represented in a blue print from the designer.

The battery might want load testing and definitely need an appraisal of total ah delivered to and from them along with a deep hard look at what they were subjected to, tempered with the duration it occured. If those batteries have been like that for a month or way worse, a few, id push for replacement simply on incorrect set up. There should be a statement regarding this in the battery and inverter literature. The manufacturer will say its the installers responsibility to have correct settings to avoid equipment damage voiding their warranty and the install company or supplier will say you changed the settings voiding theirs, so all communications should be recorded and preserved.

Thats a bunch of ifs and worries. Its a beautiful place by the looks of it and with renewable equipment flying high and proud! All in all its a nice system and i hope you enjoy owning and using it for many years.

Phil Stevens

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Graham, the 30 degree tilt is only useful if the panel axis is close to due north. Unless I'm reading the maps wrong with respect to the orientation of your house, the panels are aimed ENE and your vendor is wrong about the optimum angle.

IF they really are pointed north, that spacing is going to need to be increased a lot to prevent the rear panels from being shaded out from May to August. Otherwise they need to be as close to flat as practical (allowing some tilt for self cleaning).

Graham Chiu

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Location: Wellington, New Zealand

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Frank, the system was only commissioned on the 13th Feb so only 12 days ago. I'm going to talk to the tech for the battery supplier ( who supplied the solar company ) to see what I need to do regarding load testing.

Phil, I just used my compass to check my roof orientation and I'm at 45 deg or NE of magnetic north. They're talking about 1.5 m separation from the top of the panel to the bottom of the next as the remediation. I'll talk to them again. Maybe have the front two rows as flat as practical and leave the last row at 30 deg?

Phil Stevens

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If you leave the last row tilted 30 degrees, it will reach peak output from 10-11 instead of around noon and lose the sun earlier in the afternoon than the flatter orientation. Go up on your roof with your phone and a compass/clinometer app and hold your arm at different angles to approximate where the sun will be at 10, noon and 2 at different times of year. This will give you an idea of what the panels "see."

frank li

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Location: Michigan

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54 56.4

That is an oddball operation manual for the batteries. Language barrier maybe.

Looks like absorb volts 56.4v and float 54v but its murky and hard to establish. Not sure if by "equalize voltage" they mean absorb volts.

I checked outback power nanocarbon battery, a similar if not same type. Its manual was in line with the language translation above.

Looks like return amps would be 5A-5.5A hours in absorb would be about 2.75 hours to start if not using return amps.

And can be charged at 50A. The max is 75A, but in your application i would back down to between 45A and 50A 75A would likely be for industrial use.... shorter life span, more "up time" and quicker back into service.

frank li

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If a single inverter has the amps, you could turn the charger off in one of them. This assumes they are not communicating with each other and that there isnt a portion of the arrays that is connected to the other inverter.

I did not look at your inverter specs and operation manual.

Is the pv ac coupled to the inverter or is it dc to the inverter with an integrated pv charge control, or is there a dedicated pv charge control? I guess also a one line drawing should be in your design package it would be fun to see.

frank li

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Location: Michigan

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And another thing..... the higher tilt is a good thing. Those calculators are for simple grid ties and not always going to fit a self consumption theme too well. If you can dump all excess power into the grid all year for a net zero, thats one thing. The tilt can always be played with based on actual production figures over the year.

A good design would look at where your shortfall would be at if you basically cannot export or have a limit to export. Self consumption or load defection is more off griddy in areas like optimum tilt and even azimuth.... time of use could be a factor also, for some cases or design goals.

Here at 42 deg north and because of seasonal weather patterns, 32 degrees tilt is close to optimum. For a wide swath of the region.

If you are using onsite storage batteries instead of the grid for storage and retrieval, there will be a disparity with a traditional grid tie optimum tilt angles. It still would need to be worked out, im speculating a bit.

Phil Stevens

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Frank - the reason I keep banging on about the tilt is because Graham's panels are not facing north. They're pointed ENE. If they faced north then 30 degrees would be a good all-year choice.

Graham Chiu

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Location: Wellington, New Zealand

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frank li wrote:54 56.4

That is an oddball operation manual for the batteries. Language barrier maybe.

Looks like absorb volts 56.4v and float 54v but its murky and hard to establish. Not sure if by "equalize voltage" they mean absorb volts.

Frank, where do these figures come from? I was told to set absorb to 55.9V, and float to 55.4V.

Panel azimuth is 45 deg based on my compass.

frank li

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Location: Michigan

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Phil, i did not survey or refer to Grahams location and im not contesting anybodys advice. Not what i do.

I was addressing shade on the back rows from arrays in front and that for certain systems a profile more in line with off grid operation.

If you are limited or limiting export to the grid, it needs to balance this and provide more of the homes power over more of the year and not make the most power in a year like a simple grid tie, in effect a shift within site characteristics and system architecture or programming towards a more off grid (like) design goal

All year production figures may not be ideal and iam not sure about the goal of the system, but the way its inverter is marketed and the way it is set up and being operated, it looks to be max self consumption or grid zero or battery assisted net zero with minimal export, if you like.

frank li

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Location: Michigan

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Graham Chiu wrote:

frank li wrote:54 56.4

That is an oddball operation manual for the batteries. Language barrier maybe.

Looks like absorb volts 56.4v and float 54v but its murky and hard to establish. Not sure if by "equalize voltage" they mean absorb volts.

Frank, where do these figures come from? I was told to set absorb to 55.9V, and float to 55.4V.

Panel azimuth is 45 deg based on my compass.

Graham. I got that right from the side of the battery in your photo, from the narada specsheet you posted and from the narada operation manual for your battery and compared it to outback (Alpha) nano carbon battery charging instructions!

frank li

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Location: Michigan

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frank li wrote:

Graham Chiu wrote:

frank li wrote:54 56.4

That is an oddball operation manual for the batteries. Language barrier maybe.

Looks like absorb volts 56.4v and float 54v but its murky and hard to establish. Not sure if by "equalize voltage" they mean absorb volts.

Frank, where do these figures come from? I was told to set absorb to 55.9V, and float to 55.4V.

Panel azimuth is 45 deg based on my compass.

Graham. I got that right from the side of the battery in your photo, from the narada specsheet you posted and from the narada operation manual for your battery and compared it to outback (Alpha) nano carbon battery charging instructions!

For everybody else, there is no magic, that is how its done. Read and understand all manuals for equipment you are responsible for installing or operating.

Edit) or shopping for!
Frank.

Phil Stevens

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Frank, I get the optimisation tradeoffs. If I was asked to spec a grid tied, low export system for a property like this and could not achieve a northward orientation, I would lean toward NW over NE. Why? Because domestic consumption tends to have a small peak in the morning (before there's any significant power from the sun), and a greater one late in the day. If you want to use what you're generating on site and aren't doing demand shifting like washing clothes and cooking meals in the middle of the day, then maximising your generating potential in the aftenoon makes more sense.

The other reason I would go for NW over NE is consideration of local climate. Places near the coast are more likely to have cloud cover in the morning than aftenoon. It's pretty typical across a lot of the lower North Island in summer to have a marine layer cloud deck persisting until midday.

frank li

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Location: Michigan

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But, i looks soo pretty being set square with the house! I do it all the time.

Sometimes we put east west facing arrays when it totally drops production vs nameplate possibilities, but...... they need or want it on the roof and do not have a roof plane that faces true south, or do not have enough room on the roof planes that do, so you throw 20 percent (arbitrary) more pv watts on the non ideal planes to make it do the trick.

Modules are not $16US/Watt like they were in the early to mid eighties, the are 65 cents a watt, top of the line......
This matters when looking at design to kick the blunders you are hoping to expose, when the design has so many variables.....

Its why its so hard to not eat crow or beat around a bush or while helping with these. We never know the totallity of decisions and or why they were made or what was asked for or promised or even intended unless we were there, almost. It takes days of pouring over the details above when you have all the inputs in order to order and install unless it is cookie cutter for established general sizing configurations and tempered with what is required to integrate.

" Yeah, Bob they are getting a 6kw half on this roof and half on that one, keep it to the west, thay may add panels later, and a oh yeah they need a line side intertie because they do not want a service panel upsized"

Nuff said "Bob" knows they use enphase microinverters and 300w modules so that is all the direction needed.

You have optimum and you have practical or owner preference. Many owners would not tolerate that tilt angle at all, some want it but cant have it because of ordinances or structural or budget limitations.

frank li

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Location: Michigan

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Absolute, Phil. Its why i only yanked on the battery settings, they are absolutely incorrect. Other than that, we have no way of knowing what the confines or agreements were..... in the face of optimum.

You have knolwdge of the insolation characteristics ot the area and that matters. I know exactly where to start thinking about tilt angle depending on system type here in most of the state. Now i need some integration and design goal data and then you get optimum within your budget and other confines. Which is not always optimum.

Again, i do not doubt your advice, just that i have no idea what to do with it im not designing Grams system nor am i being paid to inspect it for design or installatiin errors, so i pick the at a glance foul ball to bang on instead.

I would have to dig deep to find out what is optimum at that particular home and owner.

Do you know the design goal, and Grahams houshold energy use patterns aside from a snapshot from the last 12 days, because i dont. I dont know what season it is there nothing. So as a general at latitude, as an adjustment seasonal shortfall and another time of use.

So i have to say, it is quite likely i am wrong to even suggest a tilt angle. But something in the posts was telling me otherwise. Ill look back at what exactly i did to you and see. Ill repost it in a quote and wear it like a man if there was a foul. Everytime.

Graham Chiu

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Location: Wellington, New Zealand

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Phil, my wife was asking me the same thing! How come the panels are pointed NE instead of NW which is how my solar hot water is aligned. And you're right about morning cloud which clears later on

I assumed it was because they didn't want to attach the rails to a single sheet of iron which runs front to back of the house. The house was re-roofed just for this install with multiple sheets laid side by side. Instead they've run the rails across multiple sheets, ie. at 90 deg to the vertical seam of the roofing iron. I think I need to ask them since they're going to move the panels, why not realign them to the NW instead. They could use the existing rails that run 90 deg to the vertical seams and then put another rail at 90 deg to the first rail to get the NW orientation??

Frank, my manual reading hasn't quite got that far yet! The float charge on the battery says 2.25Vpc at 25C. I presume pc means per cell. Does this mean that there's 3 cells per battery? If so, does this stack up?

2.25V * 3 * 8 = 54.0V

So, I should be using a float voltage of 54V.

The equalization voltage is 2.30V as per battery specs.

2.3V * 3 * 8 = 55.2V

but they want me to set the absorb voltage to 55.9V.

So, shouldn't the absorb voltage be less than the equalization voltage?

I need to get myself educated on this!

Frank, it's the last month of summer here. I'm trying to maximize the savings on electricity costs. Not to go off grid as it were unless I'm forced to by a power outage

frank li

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Location: Michigan

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Graham said "The supplier wants the installers to come back and separate the panels so none overlap, but wants to keep the 30 deg tilt so I get more power in winter."

I get that.... based on latitude and a battery based system, yes.

Now what has been said is, he is facing away from the setting sun and you think thats possibly where the use is at for graham.

What is the incidence during those hours? It crazy wild. Again i didnt run calculators, or get on his roof with a shade analysis optic (pathfinder) to determine anything. He could have shade over there end of day making it moot, dont know.

Laying down might avoid shade and might pick up some watt hours. When? Graham may have a 4kWh problem in winter for a 400whr problem any other season, dont know.

The effect of what i said is ' if your installer says you will have a detriment in the winter if you lay it down to avoid shade, then id keep the high tilt'........ because i have no reason to believe he is wrong and i only jumped in to comment really on the battery and shade and warranty issues, and your issues.

You are welcome to show me im wrong and im not fighting to be correct here. Absolutely not. But curious
, yes.

Graham Chiu

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Frank, if anything I'll be shaded in the morning by neighbours' trees across the road.
There's no possibility of any shading if I point the cells towards NW.

frank li

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Location: Michigan

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Someone tell me if im wrong, it looks like the system is riding usage. Why else would your battery ever be low unless there is a grid out. By exported energy do they mean exported to the battery?

In order to conduct self consumption your system will have to operate much like an off grid with grid as backup.

Do you only have a billing month to zero out, a year, or are you actually exporting. i am soo getting odd and conflicting signals here!

Its why i say i have no idea what is intended its all odd ducky, maybe because the water spins the other way there dont know.

What i do know is your battery manual.

And here it is.

https://www.google.com/url?sa=t&source=web&rct=j&url=http://en.naradapower.com/upload/at/file/20160616/146604250752765537A1.pdf&ved=2ahUKEwi2q5q6hNjgAhUK_IMKHc6UBC8QFjAAegQIAhAB&usg=AOvVaw0jMtnlWUAxnGIGnsFvMNSy

Graham Chiu

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I just spoke with the distributor's tech and he says it's a two stage charger so that equalization and absorb voltages are the same.
And they recommend slightly higher voltages since my batteries won't be at 25 deg C, but always lower than that (they're in the basement).

frank li

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Location: Michigan

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The very best thing you can do is either conduct shade analysis yourself or watch and get images of it being done. If, digital optics great, if not snap a photo. 165 dollars to be the surveyor. Solar pathfinder.

I have seen way too many issues with online shade tools to ever not use the 96 million mile long straight edge beaming from the sun as the arbiter shining onto my hand held optic.

Graham see what comes out of these? Who could have possibly known that but you and someone who presumably did a shade analysis?

It reminds me to stay out of these except for "will this work" and "what do in need to do this"!

Graham Chiu

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frank li wrote:Someone tell me if im wrong, it looks like the system is riding usage. Why else would your battery ever be low unless there is a grid out. By exported energy do they mean exported to the battery?

Export means sell back to the grid.

frank li wrote:
In order to conduct self consumption your system will have to operate much like an off grid with grid as backup.

Do you only have a billing month to zero out, a year, or are you actually exporting. i am soo getting odd and conflicting signals here!

Its why i say i have no idea what is intended its all odd ducky, maybe because the water spins the other way there dont know.

What i do know is your battery manual.

And here it is.

https://www.google.com/url?sa=t&source=web&rct=j&url=http://en.naradapower.com/upload/at/file/20160616/146604250752765537A1.pdf&ved=2ahUKEwi2q5q6hNjgAhUK_IMKHc6UBC8QFjAAegQIAhAB&usg=AOvVaw0jMtnlWUAxnGIGnsFvMNSy

Thanks for the link. I don't think I can run as off grid because I use too much power. The year before I consumed 17,500 kWh which is apparently more than twice the national average

So, I'm trying to both reduce consumption and reduce the power bills.

Graham Chiu

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Location: Wellington, New Zealand

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frank li wrote:The very best thing you can do is either conduct shade analysis yourself or watch and get images of it being done. If, digital optics great, if not snap a photo. 165 dollars to be the surveyor. Solar pathfinder.

I have seen way too many issues with online shade tools to ever not use the 96 million mile long straight edge beaming from the sun as the arbiter shining onto my hand held optic.

Graham see what comes out of these? Who could have possibly known that but you and someone who presumably did a shade analysis?

It reminds me to stay out of these except for "will this work" and "what do in need to do this"!

Time to fire up the drone to snap pictures of the panels during the day.
I don't think anyone did a shade analysis per se.

frank li

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Location: Michigan

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Graham Chiu wrote:I just spoke with the distributor's tech and he says it's a two stage charger so that equalization and absorb voltages are the same.
And they recommend slightly higher voltages since my batteries won't be at 25 deg C, but always lower than that (they're in the basement).

Well thats the oddest thing i have seen in a while. 3 stage charging is standard. Your battery is the spec to set charge profile from, the charger shouldnt be establishing the profile, it should follow it.

I have never seen a battery or inverter manual that said other than follow battery manufacturer specs on charging, maybe a battery manufacturer compensating for your charger? And again im missing something.

frank li

Posts: 600

Location: Michigan

posted 5 years ago

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Graham Chiu wrote:I just spoke with the distributor's tech and he says it's a two stage charger so that equalization and absorb voltages are the same.
And they recommend slightly higher voltages since my batteries won't be at 25 deg C, but always lower than that (they're in the basement).

But your inverter manual told me it has remote temp sensing.

frank li

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Location: Michigan

posted 5 years ago

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Unless you were talking to the battery tech and he said the number represents the same thing as "absorbtion charge". Again thats why i said its a funky manual, the entire rest of the battery industry is on the same page with absorb and float settings. Most any charger will use bulk to get there.

When i have time ill look at the inverter manual deeper. Because i like the little knob in the website allowing you to turn self consumption up and down, which if you are dumping into the grid to save money, should be all the way down to like, off and batteries on standby float until grid out. Otherwise its going to be a very expensive exercise!

frank li

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Location: Michigan

posted 5 years ago

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frank li wrote:Unless you were talking to the battery tech and he said the number represents the same thing as "absorbtion charge". Again thats why i said its a funky manual, the entire rest of the battery industry is on the same page with absorb and float settings. Most any charger will use bulk to get there.

When i have time ill look at the inverter manual deeper. Because i like the little knob in the website allowing you to turn self consumption up and down, which if you are dumping into the grid to save money, should be all the way down to like, off and batteries on standby float until grid out. Otherwise its going to be a very expensive exercise!

I mean darnit Graham just tell us what is going on. Do you have a grid tie or not? If so, is there some limit to export or a cap on kw nameplate pv are you not allowed to export? Some piece is missing and i dont care about the tilt. Never said anything suggesting an azimuth, never suggested a specific tilt, Phil.

Simply it is generally operated more like an offgrid system, byd type and features and the way its being operated.

frank li

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Location: Michigan

posted 5 years ago

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And that will affect orientation and tilt.

Graham Chiu

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Posts: 637

Location: Wellington, New Zealand

posted 5 years ago

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frank li wrote:

Graham Chiu wrote:I just spoke with the distributor's tech and he says it's a two stage charger so that equalization and absorb voltages are the same.
And they recommend slightly higher voltages since my batteries won't be at 25 deg C, but always lower than that (they're in the basement).

But your inverter manual told me it has remote temp sensing.

Ah, yes, that's another installation issue I discovered. If you look at http://www.solax-portal.com/dz/home/battery_overview/255502 you can see it says for "Inner T" 5 deg C which it clearly isn't in summer. The techs neglected to install the temperature data cable from the inverters to the battery bank. That is also being fixed.

Graham Chiu

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Posts: 637

Location: Wellington, New Zealand

posted 5 years ago

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frank li wrote:

I mean darnit Graham just tell us what is going on. Do you have a grid tie or not? If so, is there some limit to export or a cap on kw nameplate pv are you not allowed to export?

Yes, I'm grid tied. I presume that the system only exports to the grid above that required to keep the batteries at float, and for whatever house load is in use.

Graham Chiu

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Location: Wellington, New Zealand

posted 5 years ago

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frank li wrote:Unless you were talking to the battery tech and he said the number represents the same thing as "absorbtion charge". Again thats why i said its a funky manual, the entire rest of the battery industry is on the same page with absorb and float settings. Most any charger will use bulk to get there.

When i have time ill look at the inverter manual deeper. Because i like the little knob in the website allowing you to turn self consumption up and down, which if you are dumping into the grid to save money, should be all the way down to like, off and batteries on standby float until grid out. Otherwise its going to be a very expensive exercise!

Ok, not understanding here. Does the solax website have a knob on page to show the effect of self consumption vs export?

Usually here we are charged 29c/kWh, and receive 8c/kWh for that we export. So, to save money we are told to self consume as much of the generated power as we can and any generation saved to the batteries we need to self consume when the PV generation is nil

frank li

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Location: Michigan

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Graham Chiu wrote:

frank li wrote:Someone tell me if im wrong, it looks like the system is riding usage. Why else would your battery ever be low unless there is a grid out. By exported energy do they mean exported to the battery?

Export means sell back to the grid.

frank li wrote:
In order to conduct self consumption your system will have to operate much like an off grid with grid as backup.

Do you only have a billing month to zero out, a year, or are you actually exporting. i am soo getting odd and conflicting signals here!

Its why i say i have no idea what is intended its all odd ducky, maybe because the water spins the other way there dont know.

What i do know is your battery manual.

And here it is.

https://www.google.com/url?sa=t&source=web&rct=j&url=http://en.naradapower.com/upload/at/file/20160616/146604250752765537A1.pdf&ved=2ahUKEwi2q5q6hNjgAhUK_IMKHc6UBC8QFjAAegQIAhAB&usg=AOvVaw0jMtnlWUAxnGIGnsFvMNSy

Thanks for the link. I don't think I can run as off grid because I use too much power. The year before I consumed 17,500 kWh which is apparently more than twice the national average So, I'm trying to both reduce consumption and reduce the power bills.

Yeah, that we agree on. In the industry, export means out of the building electric system and usually onto the utility grid, as opposed to say a microgrid with your neighbors in an ac coupled co-op of sorts when metering for that.

If you can simply export your production, id not use the battery at all, outside of backup power during an outage period. Excepting testing, of course.

I know the term off grid is strong and mesmerizing, but i totally get that you are not trying to be or operate off grid.

That is very similar to what your system was doing though. I mean, why are we even talking about batteries being flat after the electric water heater runs if it is not in fact operating with grid assist like a generator in an off grid?

So i am still missing something.

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