Advice on what installer recommended

reefbum · December 2014

We are building a new home in Florida and wanted to have certain critical loads on dedicated sub-panel with solar/battery/propane generator.
Critical loads panel includes
1 x 240 single phase 1hp well pump
1 x 900w microwave over range
1 x GE Profile 25cf fridge/freezer
2 x wall outlets in kitchen (charge cell phones/ipads/single cup coffee maker)
2 x wall outlets in master br (night stand outlet on each side of bed)
1 x wall outlet in family room (65in led tv)
1 x wall outlet in office (laptop)
4 x Ceiling light fixtures (16 x 7w led bulbs)

What the installer has recommended is
5.4KW solar array (18 x 300w panels Renogy RNG300P)(2 strings ea 9 panels)
1 x Connext XW+ 6848
1 x Connext XW+ PDB (power distribution panel)
1 x Connext 80-600 MPPT Charge Controller
1 x Connext Combox
1 x Connext battery monitor
1 x Connext Auto Gen Start
1 x GB 48volt 1608Ah battery bank (24 x 2v cells)(all 48v cables at 4/0)
1 x Auto battery water system with RODI system feed from our well with 5gal tank
1 x 6KW Propane Generator
Any other needed items and disconnects etc..
Total cost about $30k

Installer states that the critical loads panel should be set up as an off grid panel with solar as the primary charge method and grid power as the secondary charge method. Generator only to be used for charging in the event of grid power outage.

As a first time solar user, does what the installer is recommending sound correct to those of you that have similar setups?

Regards

Cariboocoot · December 2014

Re: Advice on what installer recommended

Welcome to the forum.

A couple of questions:

1). How often and for how long does the power fail?

2). Do you like spending lots of money for stuff that's going to sit there doing nothing when the power isn't out?

I ask that second question because the equipment listed is quite capable of back-feeding the grid while it is up which will make it much more worth the investment. Without enabling the GT capacity it's money wasted.

The truly critical item on the load list is the refrigerator, which must have power available on demand. The well pump and microwave - you could start the generator as-needed; auto gen start isn't really necessary. The 'leftover' power from a refrigerator system could power your other needs.

So it comes down to either going whole-hog with a GT & battery back-up system or do you want a less expensive truly minimal needs system?

Personally I would not select any of the Conext equipment due to its history of being buggy.

reefbum · December 2014

Re: Advice on what installer recommended

1) My wife has talked to a few others in the area and they have told her that the power goes out for 1-3hr quite frequently and that during any major storm the power can be out for 3-10 days.
As our area is a bit rural and the power company takes care of the areas with the most population first, leaving our area mostly last.

2) Sorry I forgot to mention that the installer did tell me that the the system would be setup to GT any excess power back to the grid.

When planning the home build we put a budget of $30k on solar/generator system, so we would like to maximize the use of this budget. As the installers quote came in very near our budget I suspect he has talked to our GC which is the only other person that knew our budget for this. Hence the post here trying to get others perspective on installers proposal.

As for the auto gen start, and auto battery water system. I requested that the system be as automatic as feasible due to the need that I travel for work frequently and the wife is in no way technical and would have no clue how to water batteries, start/stop gen and manually operate transfer switches and such.

What equipment would be better in your opinion?

Regards

westbranch · December 2014

Re: Advice on what installer recommended

I'll add that that is a battery bank that is 4 times what I have under assembly..and more panels ~ 1Kw more, see my sig line below... and I am not in the sunniest place (charging-hours wise).

What is the number of days of autonomy that are planned for? ie days without ANY sun?

Just where in Florida do you and Yoda plan to live?

hth

Cariboocoot · December 2014

Re: Advice on what installer recommended

Okay having the grid-tie makes this much better!

I live pretty far from you so can't speak to the value offered, but we do have some forum members in Florida so perhaps they can give you a better idea there.

As for equipment choices:

If the idea is to keep it as non-tech as possible, I'd suggest skipping the auto-watering and flooded cells and go with AGM's.

The 600 Volt charge controller is just a waste of money. It's twice the cost of standard controller and offers no advantage for most installations. A MidNite Classic would serve you better, with its WhizBang Jr. battery monitor attachment.

And as for the XW6048 ... well that was replaced with a new model because there were so many problems with the old one. I go for an Outback Radian, and possibly the 4kW version rather than the 8kW; it depends on what peak loads are expected during outages. That would also allow a smaller battery bank.

Let's talk about that battery bank, in fact. Proposed 1608 Amp hour 48 Volts. There is no way an 80 Amp charge controller and 5.4kW of PV is going to charge that, starting with the fact the controller will not even be able to pass the full current available from the array (5400 Watts * 0.77 / 48 = 86 Amps). So there is a design fail there. 80 Amps on that size bank is less than 5% maximum rate which is the minimum battery makers recommend. That size battery wants 10% at least.

reefbum · December 2014

Re: Advice on what installer recommended

Area is Brooksville FL 34614
I believe the proposal gives 2-3days autonomy without sun depending on length of usage of lights and outlets.

We did talk about other battery types but each of the other options was a significant increase in battery price. (current proposal battery price is $8k)

I did ask about the the size of the XW+ 6848 as it seemed a bit excessive to me. I was told that they don't like to install inverters that will operate at more than 60% load and if at any time the microwave should be in use and the well pump and fridge come on that I would need the 6848 for its extra "start up power" capabilities.

I will call on Monday and ask about the charge calculation (5400 Watts * 0.77 / 48 = 86 Amps) and 5% vs 10% recommended rate.
I have asked already about the single charge controller and the answer given was that it allowed to run the array with more panels in series for a higher voltage minimizing the cost of wiring size and combiner boxes.

The solar installer did supply us with 4-5 customer names/phone number that they installed the same equipment. I only called and talked to 2 of these and both seemed very happy with their systems, however I will also ask about the Midnite and Radian systems. I think they are a Schneider dealer, thus their push towards that equipment.

Regards

Cariboocoot · December 2014

Re: Advice on what installer recommended

Quick look at some numbers and I don't see how that equipment list is possible for $30k.
From what I see those 2V cells will run about $26,000 all on their own. Another $6k for the PV, $3k for the inverter ... looks more like $40,000 in equipment never mind any installation thereof.

I'd be suspicious.

Cariboocoot · December 2014

Re: Advice on what installer recommended

reefbum wrote: »

Area is Brooksville FL 34614
I believe the proposal gives 2-3days autonomy without sun depending on length of usage of lights and outlets.

We did talk about other battery types but each of the other options was a significant increase in battery price. (current proposal battery price is $8k)

Can't imagine how that's possible since a quality 2V 1600 Amp hour battery is $1,100.

I did ask about the the size of the XW+ 6848 as it seemed a bit excessive to me. I was told that they don't like to install inverters that will operate at more than 60% load and if at any time the microwave should be in use and the well pump and fridge come on that I would need the 6848 for its extra "start up power" capabilities.

The start surge capacity of an XW6048 is 12kW. No way will all that stuff coming on at once demand that. Nor is it necessary to limit an inverter meant to back-feed the grid to 60% of capacity; they are designed for full output for 4+ hours per day. I think he's just trying to sell you what he knows/has got/can make money on.

I will call on Monday and ask about the charge calculation (5400 Watts * 0.77 / 48 = 86 Amps) and 5% vs 10% recommended rate.

Don't expect to get a sensible answer.

I have asked already about the single charge controller and the answer given was that it allowed to run the array with more panels in series for a higher voltage minimizing the cost of wiring size and combiner boxes.

Only if it is necessary. An array for a 48 Volt system is usually run around 90 Vmp (more efficient down-conversion) and one that size would be 60 Amps maximum at that Voltage and would require 6 AWG minimum (4 AWG better) and that would be good up to 100 feet (150 feet for 4 AWG). What's he trying to run? Lamp cord?

The solar installer did supply us with 4-5 customer names/phone number that they installed the same equipment. I only called and talked to 2 of these and both seemed very happy with their systems, however I will also ask about the Midnite and Radian systems. I think they are a Schneider dealer, thus their push towards that equipment.

Regards

No doubt the customers are happy any time the system works. Beyond that they really don't know if it could be done better or cheaper. If the installer sells Conext stuff, that's what he sells. He will probably not want to talk about any other brand and will tell you the importance of the system integration in buying all the same company's stuff. It isn't true, but he probably believes it.

And just so you know I do not sell or install any company's equipment. I do not work for our host NAWS either. I have fixed a lot of systems that were done wrong. Boy oh boy have I!

reefbum · December 2014

Re: Advice on what installer recommended

I actually called GB Industrial Battery company last week and they confirmed the battery price

GB Industrial email to me
Quantity (4)
New 12v GB Solar Battery, model 6SBY85-25 / 1608AH capacity: $ 2115.50 each x4. *
Dimensions: 41L X 11 1/2W X 25H each x4.
Weight: 996 pounds each x 4.
> Modules are delivered fully assembled with intercell connections.
> (4) modules in series = 24 cells, 48 volts DC.
> Bulk Charge 55.20volt
> Absorption Charge same as Bulk charge for 2hr
> Float Charge 53.04volt
> Equalize 61.92volt for 1hr
Warranty: 7 years
Total cost for (4) units: $8462.00
Free shipping to lower 48 with pickup at terminal, $275 residential lift gate delivery.

Regards

westbranch · December 2014

Re: Advice on what installer recommended

As for the 600Volt or whatever it will end up being that is primarily to send either AC or DC power over hundreds of feet in order to minimize line losses. How far away will the Array be form the Charge controller and battery bank and inverter?.

Usually the CC and bank will be quite close as will the inverter be to the banks (close ) again to minimize line loss...

reefbum · December 2014

Re: Advice on what installer recommended

Array is about 100ft from CC/Inverter. Battery bank less than 10ft from CC/Inverter.
Looking at proposal it says 10awg from array to CC

Cariboocoot · December 2014

Re: Advice on what installer recommended

reefbum wrote: »

I actually called GB Industrial Battery company last week and they confirmed the battery price

GB Industrial email to me
Quantity (4)
New 12v GB Solar Battery, model 6SBY85-25 / 1608AH capacity: $ 2115.50 each x4. *
Dimensions: 41L X 11 1/2W X 25H each x4.
Weight: 996 pounds each x 4.
> Modules are delivered fully assembled with intercell connections.
> (4) modules in series = 24 cells, 48 volts DC.
> Bulk Charge 55.20volt
> Absorption Charge same as Bulk charge for 2hr
> Float Charge 53.04volt
> Equalize 61.92volt for 1hr
Warranty: 7 years
Total cost for (4) units: $8462.00
Free shipping to lower 48 with pickup at terminal, $275 residential lift gate delivery.

Regards

Okay that's different from individual 2V cells; those are 12 Volt units. Probably forklift type, which have their own problems with charging/maintaining. Makes recharging from that array even worse.

That bank represents about 38kW hours of stored power, btw. You don't really want that "3 days of autonomy" stuff (especially not against an estimated load). Normally you want 25% DOD on the first day, 25% available for the second day (if not recharged) and start the gen on day 3 if the sun still isn't co-operating.

Cariboocoot · December 2014

Re: Advice on what installer recommended

reefbum wrote: »

Array is about 100ft from CC/Inverter. Battery bank less than 10ft from CC/Inverter.
Looking at proposal it says 10awg from array to CC

Why is the array so far away?

reefbum · December 2014

Re: Advice on what installer recommended

I think your correct on the forklift type battery, this is not written in the proposal but if my memory hasn't failed I do believe he mentioned this about a month ago when he was first putting the quote together. I do know when talking about other battery options the price went up dramatically. I thought it was 2v cells because of their email to me
> (4) modules in series = 24 cells, 48 volts DC

Would you then suggest a smaller Ah rating but with individual 2v cells, or some other configuration?

reefbum · December 2014

Re: Advice on what installer recommended

Cariboocoot wrote: »

Why is the array so far away?

Size of house.
Array on south facing roof, 9 panels in series = 30ft + distance from back (south) side of house to the front of home to the far side garage wall 62ft.

Cariboocoot · December 2014

Re: Advice on what installer recommended

I would suggest AGM's; eliminate the battery watering system, reduce the Amp hour capacity, lower price. Watch what happens:

SunXtender PVX-4050HT http://www.solar-electric.com/concorde-sunxtender-pvx-4050ht.html/
6 Volts 405 Amp hour at the 24 hour rate $606 each * 8 = $4848
Stored capacity @ 50% DOD: 9600 Watt hours DC (more than three times what my whole cabin uses in a day).

Changes to charging:
40 Amps peak current @ 48 Volts = 2494 Watt array (less than half what was proposed so less cost). Easily handled by MidNite Classic which is about $600 instead of the XW 600-80 which is about $800. Use 8 AWG to handle current of about 28 Amps @ 90 Volts across 100 feet with

% V-drop.

The array and battery bank can be adjusted upwards if desired but really that would work well especially with a Radian 4kW. Looks like about $7,000 less than proposed system and it will actually work whereas that 1600 Amp hour battery bank is not going to charge from a 5.4kW array so the generator would be running more.

If nothing else you must adjust the size of that battery bank downwards. Otherwise you will be dependent on the gen for charging when the grid is down and that's something you want to avoid. The XW 6048 only needs 600 Amp hours @ 48 Volts to work properly for GT connection, and that would be 14kW hours stored power.

The days of large battery bank & small PV array are gone because PV is very inexpensive now and batteries are not. So the idea is to try and recharge daily if possible, rather than toss the batteries in the scrap heap every two years. In your case you will not be dependent on solar, but why run the gen if you don't have to?

If possible you need to get a fairly accurate Watt hour estimate for your down-time loads. Any 240 Volt loads will be estimated, but you can run a Kill-A-Watt on anything that plugs in to 120 VAC and get some idea how much power you will use there.

reefbum · December 2014

Re: Advice on what installer recommended

Thanks for your help.
I sent a few emails last night to installer and GB Battery Co.

I received a response from GB

> The model 6SBY85-25 GB Solar Battery is in fact a 12volt module comprised of 6 individual 2volt batteries housed in a steel case with removable lid.
> Each 2volt battery can be individually removed/replaced if needed without the need to replace or remove the entire module.
> The module is configured this way to allow us to offer the module in 12,24,36 and 48volt configurations based on customer needs.
> The other reason for this type of module configuration for our RE batteries is the weight of the module.
> Many customers of the RE batteries require residential delivery or pick up the batteries at the terminal with a standard pickup truck.
> To build a 48volt battery in a single module would be about 4000lbs and could not be delivered via "lift gate" residential delivery.
> Most lift gates are limited to about 2000lbs, and standard 1/2ton pickup trucks also could not handle this amount of weight.
> We also offer ($55) an individual battery removal/carrying tool that allows for the customer to "break down" the module for easier moving/handling such as down a flight of stairs into a basement.

> As to your questions about forklift vs solar RE batteries.
> GB Industrial Battery Companies primary source of business is the forklift and industrial battery industry, however we do offer and supply RE (Renewable Energy) batteries.
> They are different from our standard "fork lift" industrial type batteries and are designed for RE use, please see the attached PDF in this email for technical specifications.

> As to the charge rate, your information is correct that we recommend a minimum of 5% and a 10% rate is ideal.
> Your system at 5.4KW is very close to the 5% recommended minimum rate.
> From the information provided to us, we recommended the 1608Ah because the inverter information supplied to us is capable of supplementing
> the charge primarily from "grid" power and generator power as a second source in the event of grid power failure.
> If your installer does not intend to activate the inverters charging capabilities to supplement the charging from grid/generator power
> AND your DOD (Depth of Discharge) is greater than 20% daily then you have 2 options.
> 1. Decrease the Ah of the battery bank which we can also provide.
> 2. Increase the wattage of your PV array and install a second charge controller to handle the additional PV array size.
> If you will be using the generator as your "primary" means to supplement the charging through the inverter, this is going to become cost prohibitive very quickly because of fuel cost
> and I would recommend having your installer take another look at his design and definitely decrease the Ah of the battery bank downward to 600~800Ah. ($3k~$4k)
> I understand that this is a new construction home and all loads are only estimates but you should try to get any and all information you can on your appliances
> and expected loads to try and nail down what your anticipated needs will be. This would greatly enhance our ability to properly size the battery bank for your needs.
> Our current recommendation of 1608Ah is based solely on the information provided to us by your installer on your anticipated needs with a 3-4 day reserve without sun.
> If in fact you do not require/want this amount of reserve then of course your solution is a simple one by reducing the battery size.

> I did take a look at your link of the post in the forum you provided. "cariboocoot" is correct in that many installers have not changed their mind set of "big batteries and small array"
> Many still take this approach because "this is how we have always done it" and it will take time to overcome that mindset as the PV market evolves and systems become more affordable.
> I can say that the install company you have chosen to work with has a good reputation from working with them.
> The customers I have talked to that they have installed and used our batteries have been pleased with the results, as you said they do tend to push the Schneider brand and this could be from
> a verity of reasons from their training and knowledge of the products all the way to profit margins. From my experience all the manufactures out there have good and bad reviews.
> If the money you are spending were mine, I would place more value on the company you choose to do your install than I would name brands. Installation companies
> come and go and finding one that is reliable and will be around for any questions or warranty issues would be high on my priority list.

Regards

Alaska Man · December 2014

Re: Advice on what installer recommended

I'd buy a $3,000 inverter/generator and a propane tank.......... Have the contractor wire in a E-Panel with grid disconnect and an auto start.

When the power goes out, the genny goes on, and Bob's Your Uncle.

Not to mention you just saved about $40,000.00

Vic · December 2014

Re: Advice on what installer recommended

Hi reefbum,

WOW, that e-mail from GB Battery is very, very impressive.

Appears that they are honest, well-informed about RE systems, and actually quite articulate! Impressive, and these Forklift/Industrial batteries are very inexpensive, compared to competing approaches.

Looks like you are being careful in your planning. All opinion, FWIW. Good Luck, Vic

Advice on what installer recommended

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