DIY solar configuration for cabin

[SunEagle]

Stuck in a 12v box?
Explain why a pair of 6v batteries is better than one 12v.Reggardless of 24v or 48v system.Explain why a 200Ah 12v battery is any different from a pair of 6v 200Ah batteries.

To answer your questions,

A 12volt battery system limits you on the size of your loads and total panel wattage to about 1000W with the largest MPPT CC at 80amps. If you need to enlarge your system it is better to go with a higher battery voltage at least 24V and up to 48V.

A 200Ah 12v battery is really very heavy and hard to move around if needed. Going with 2 x 6V 200Ah are easy to find and much easier to lift and move. They are probably also least costly then that one big 200Ah battery.

[Sunking]

Explain why a pair of 6v batteries is better than one 12v.Reggardless of 24v or 48v system.Explain why a 200Ah 12v battery is any different from a pair of 6v 200Ah batteries.

Ask your back as it knows the difference between a 65 and 130 pound battery. Point you are missing is if you need 200 AH batteries, buy 200 AH batteries. 12 volt 200 AH are very rare because they are so large and heavy. Example try to find a 12 volt 300 AH battery. Bet you gave up because not many if any exist because they would be way too heavy.

Ever seen a 2-volt 4000 AH battery? I have thousands upon thousands of them. Bought and installed everyone one of them. What you see below is a -48 VDC 16,000 AH battery in Earthquake Resistant Racking with Spill Containment. About a 50,000 pound, $200,000 battery, and a $150,000 buss bar above it. They are in a basement of a high rise building with a Data Center in the basement. One of three -48 VDC plants in the basement. Each battery plant capable of 5,000 amps.

[J.P.M.]

Ask your back as it knows the difference between a 65 and 130 pound battery. Point you are missing is if you need 200 AH batteries, buy 200 AH batteries. 12 volt 200 AH are very rare because they are so large and heavy. Example try to find a 12 volt 300 AH battery. Bet you gave up because not many if any exist because they would be way too heavy.

Ever seen a 2-volt 4000 AH battery? I have thousands upon thousands of them. Bought and installed everyone one of them. What you see below is a -48 VDC 16,000 AH battery in Earthquake Resistant Racking with Spill Containment. About a 50,000 pound, $200,000 battery, and a $150,000 buss bar above it. They are in a basement of a high rise building with a Data Center in the basement. One of three -48 VDC plants in the basement. Each battery plant capable of 5,000 amps.

Off topic and not a knock or an argument starter, but I used to do a fair amount of seismic design for relatively heavy and large tankage containment that was probably less mass/volume than most batteries or what's shown in your attached photo. The foundation and containment look familiar, but where's the structural elements that will contain lateral seismic forces ? Lots of different ways to do it, but I don't see of the ones I'm familiar with. If those horizontal "C" channels are for seismic, I'd suggest that's putting a lot of faith in the welds between the horiz. and vertical members and the baseplates for the vertical members. Doesn't make it wrong. It just looks incomplete without some way to resist lateral accelerations is all. Maybe I'm missing something. Clean design, but I'm not sure I'd stand next to it in an earthquake.

Respectfully,

[Sunking]

NP JPM. In Telecom, Earthquake hardware is divided up into 4 zones of 1, 2, 3, and 4 with 4 being Japan and California as an example. What you see above is Zone 2 Bracing requirements. I will look around in archives and see if I have some Zone 4 stuff I have done in CA or Missouri. Yeah Missouri is Zone 4 believe it or not up around St Louis.

[J.P.M.]

NP JPM. In Telecom, Earthquake hardware is divided up into 4 zones of 1, 2, 3, and 4 with 4 being Japan and California as an example. What you see above is Zone 2 Bracing requirements. I will look around in archives and see if I have some Zone 4 stuff I have done in CA or Missouri. Yeah Missouri is Zone 4 believe it or not up around St Louis.

Thank you. No need for further stuff. Hard to be, and no need to be critical of stuff that's been signed off on and operating, especially from just a photo.

I believe I understand seismic zoning/design/ASCE - 7/etc. well enough, or more correctly, did once upon a time before retirement. The zones are, or were, one of the common denominators for ASCE seismic design, pretty much regardless of industry. The Madrid fault and associated consequences in/around MO were a surprise to me as was the notion that most of San Diego co. & some immediate environs are/were only zone 2 and not 4+ as a lot of the rest of SO. CA.. Being in the NE U.S. at the time of my initial training, I figured everything in CA was shaking like jello on springs most of the time.

Aside, I wonder if/how much of the perceived/alleged(?) step up in seismic activity in the Midwest might have fracking as a possible contributing factor.

Short, dumb earthquake story I swear is true: 1st wife followed me to CA by about 6 weeks in the '95 move to San Diego. Turns out there was a mag. 3.5 quake that was quite noticeable but didn't break anything, with an epicenter that was quite close to where I had rented a place. Serendipitously or not, it struck almost simultaneously with a particularly critical time for wifey when we were getting reacquainted immediately after the long absence (with the result of some additional things moving like jello on springs). I got a lot of mileage out of that happenstance for claiming to be able to "make the earth move".

Regards for the professional consideration of the offer for more design info.

[sdold]

I will look around in archives and see if I have some Zone 4 stuff I have done in CA or Missouri.

Like this? This is San Diego, but we do this everywhere in the state:

[J.P.M.]

Like this? This is San Diego, but we do this everywhere in the state:

Same comment as to SK: Seeing only a picture with no design criteria etc., hard to make intelligent comment.

However, assuming zone 4 for a more/less standard design criteria, and what's probably a high importance factor for a human occupancy area/building and other factors, the design seismic adequacy would also depend on expected/design imposed loadings. I expect the design engineer checked the lateral load bearing capabilities of that block wall the alum. channel seems to be attached to, particularly if that empty space between the wall and the vertical channels will contain heavy stuff like batteries, assuming the alum. structure is designed to restrain a seismic induced loading. Sometimes, adding and attachingequipment that's correctly designed for seismic to what are not often the most earthquake resistant structures like block walls can have the unintended consequence of making such a wall, for example, more earthquake resistant than without the added equipment. One bad, no free lunch part of that is that the added structure becomes less robust, often in unknown ways from the perhaps unknown, (or more often) unconsidered wall properties.

Also, and separate from the above, that many holes in the channel flanges won't help the section modulus of the vertical channels. I'm sure the design engineer accounted for that, or, seismic may not be a consideration in the design.

[Sunking]

Like this? This is San Diego, but we do this everywhere in the state:

No Steve that is not quite what I mean. It starts with the equipment racks and C-Channel Standard Aluminum Equipment Racks do not qualify or meet NEBS Seismic Bracing requirements. The equipment racks need no external support like a welded seismic rated Unequal Flange Equipment rack bolted to concrete floor with Hilti 5/8" Earthquake Floor Anchors. RRacks are required to support themselves and cable racking. Either that or manufactures proprietary equipment cabinets that are self supportive.

One thing I see in your pictures troubles me and I will pass along to you for consideration. Hard to tell from the pix but it appears your equipment racks are firmly connected mechanically to the ceiling above via All Thread Rod. I hope I see that wrong and the T-Rod is just supporting cable rack floating above equipment racks. The issue if I am seeing things correctly is you are using the both the floor and ceiling to support floor load. In other words for every inch the floor drops from load, is also transmitted to the ceiling.

Although it is common to brace floor equipment to adjacent walls and ceilings is always done at an angle with hardware that is allowed to move in all planes. Typically cable rack is supported from the ceiling via T-Tods and lateral bracing. Floor equipment is self supportive and not mechanically connected to ceiling system structures like cabling, lighting, and ventilation.

As for cabling breaking off ceiling supported racks to equipment racks employ a Earthquake Waterfall. Look back up at my pix and note cables between battery Term Plates to Over Head Buss. See those big "S" Curves in the cables? It allows for the cables to bend and reach as floor zigs left, right up, or down, while ceiling zags up, down, right, and left.




Here is some old school stuff. Remember Nortel aka Northern Telecom? Here is a DMS 100 switch in Campbell CA part of the Bay area. It contains cable racks behind the light panels. Note equipment line-ups have breaks or missing equipment racks. Done on purpose to allow movement and isolate mechanically. JPM you should like this one.

[sdold]

Like this? Same area. Good point on the all thread, they use that to support the cable tray, then anchor the cable tray with J bolts and U-channel to the top of the rack. I always assumed the top anchors would pull out of the roof joists. I can't remember what's up there, I think maybe steel joists. I need to look at the way other sites are built, maybe it's time to change. Ont thing we do that I'd like to stop doing is anchoring the rack bases to the concrete with no insulation pad.

[J.P.M.]

No Steve that is not quite what I mean. It starts with the equipment racks and C-Channel Standard Aluminum Equipment Racks do not qualify or meet NEBS Seismic Bracing requirements. The equipment racks need no external support like a welded seismic rated Unequal Flange Equipment rack bolted to concrete floor with Hilti 5/8" Earthquake Floor Anchors. RRacks are required to support themselves and cable racking. Either that or manufactures proprietary equipment cabinets that are self supportive.

One thing I see in your pictures troubles me and I will pass along to you for consideration. Hard to tell from the pix but it appears your equipment racks are firmly connected mechanically to the ceiling above via All Thread Rod. I hope I see that wrong and the T-Rod is just supporting cable rack floating above equipment racks. The issue if I am seeing things correctly is you are using the both the floor and ceiling to support floor load. In other words for every inch the floor drops from load, is also transmitted to the ceiling.

Although it is common to brace floor equipment to adjacent walls and ceilings is always done at an angle with hardware that is allowed to move in all planes. Typically cable rack is supported from the ceiling via T-Tods and lateral bracing. Floor equipment is self supportive and not mechanically connected to ceiling system structures like cabling, lighting, and ventilation.

As for cabling breaking off ceiling supported racks to equipment racks employ a Earthquake Waterfall. Look back up at my pix and note cables between battery Term Plates to Over Head Buss. See those big "S" Curves in the cables? It allows for the cables to bend and reach as floor zigs left, right up, or down, while ceiling zags up, down, right, and left.




Here is some old school stuff. Remember Nortel aka Northern Telecom? Here is a DMS 100 switch in Campbell CA part of the Bay area. It contains cable racks behind the light panels. Note equipment line-ups have breaks or missing equipment racks. Done on purpose to allow movement and isolate mechanically. JPM you should like this one.

I like it. I'd also like to get a look at how it's kept cool. How much waste heat got generated ? I did some thermal design work on house size main frame computer systems just about the time PCs were making them dinosaurs.

[Sunking]

I like it. I'd also like to get a look at how it's kept cool. How much waste heat got generated ?

I can give you rough idea at least in terms of watts. What you see is a central office digital switch, the thingy you got dial tone from when you lifted your wire-line phone off-hook. Nortel called this most popular model DMS-100 which means it can support and supply 100,000 phone lines, DMS = Digital Multiplex Switch. Each cabinet has 4 to 5 shelves, and each shelf is supplied with dual redundant -48 VDC 30 to 50 amp circuits. In practice each frame or cabinet would consume from 500 to 2500 watts of heat depending on function. A fully loaded DMS may contain up to 50 frames of 5 line-ups of 10 racks. On say an average sized roughly 40 to 50% capacity as a whole burns 30 to 35 Kw 24 x 7 hours. I will let you convert that to BTU's. Keep in mind that is only for the Switch and not the Transport and Support equipment you cannot see.

This building electrical entrance is sized to 150 w/ft^2 to support everything and today has gone up to 250 w/ft^2 . As for cooling there are two methods used depending on earthquake bracing requirements. If bracing is required means the racks are bolted to the reinforced concrete floor with 4 to 6 Hilti 80mm Earth Quake Floor Anchors. They are set at 80 foot pounds of torque on a 5/8"inch bolt and pinned to the floor. So all HVAC is overhead using Lieberts Wet Chillers. The Returns surround the equipment room along wall perimeter.

The other method if there is no earth quake requirements is used Raised Floor Plenum. The equipment racks are either elevated by T-Rods or frame extensions to elevate equipment frames 12 to 18 inches for the Plenum. Same wet chillers. Now what is interesting in some facilities those huge cooling systems are running on a 1 to 2 MW UPS using 500 volt battery just long enough to get a genny on-line.

Those switches are still in use today for anyone that still uses POTS. That would be your poor telco which is just about out of biz today your Old Ma Bell copper network. Today homeowners and biz do not use much copper Switched Networks anymore. Homeowners today are either wireless with cell phones, and/or VOIP using CATV Internet Service. Both Cell and VOIP DO NOT USE SWITCHED NETWORKS requiring all that hardware. You no longer need a big box with 100,000 pairs of copper wires coming out of it routed all over the city. Just a few fibers and one mother of a Router.

Largest load I can vouch for was one of the last data centers I built MCIWorldCom covered 110,000 ft^2 facility. For Battery Plant and Cooling was broken into 6 zones of roughly 20Kft^2. Each DC plant was equipped with -48 VDC 20,000 AH batteries and 6KA rectifiers and those ran at roughly 3000 to 4000 amps at 48 volts or 168 Kw round the clock x 6 zones on the outside perimeter rooms, with 2 Mw UPS to run cooling and data rack 208/120 loads. That is when you get 4160 volt utility lines.

Takes a lot of ice to cool that cookie off. Loose cooling and office shuts down in minutes from over heating.People get a little bent out of shape when phones, internet, TV, banking, and god forbid text quit working.

[J.P.M.]

I can give you rough idea at least in terms of watts. What you see is a central office digital switch, the thingy you got dial tone from when you lifted your wire-line phone off-hook. Nortel called thi smost popular model DMS-100 which means it can support and supply 100,000 phone lines, DMS = Digital Multiplex Switch. Each cabinet has 4 to 5 shelves, and each shelf is supplied with dual redundant -48 VDC 30 to 50 amp circuits. In practice each frame or cabinet would consume and 500 to 2500 watts of heat depending on function. A fully loaded DMS may contain up to 50 frames of 5 line-ups of 10 racks. On say an average sized roughly 40 to 50% capacity as a whole burns 30 to 35 Kw 24 x 7 hours. I will let you convert that to BTU's. Keep in mind that is only for the Switch and not the Transport and Support equipment you cannot see.

This building electrical entrance is sized to 150 w/ft^2. As for cooling there are two methods used depending on Earthquake bracing requirements. If bracing is required means the racks are bolted to the reinforced concrete floor with 4 to 6 Hilti 80mm Earth Quake Floor Anchors. They are set at 80 foot pounds of torque on a 5/8"inch bolt and pinned to the floor. So all HVAC is overhead using Lieberts Wet Chillers. The Returns surround the equipment along wall perimeter.

The other method if there is no Earth Quake requirements is used Raised Floor Plenum. The equipment racks are either elevated by T-Rods or frame extensions to elevate equipment frames 12 to 18 inches for the Plenum. Same wet chillers. Now what is interesting in some facilities those huge cooling systems are running on a 1 to 2 MW UPS using 500 volt battery just long enough to get a genny on-line.

Those switches are still in use today for anyone that still uses POTS. That would be your poor telco which is just about out of biz today your Old Ma Bell copper network. Today homeowners and biz do not use much copper Switched Networks anymore. Homeowners today are either wireless with cell phones, and/or VOIP using CATV Internet Service. Both Cell and VOIP DO NOT USE SWITCHED NETWORKS requiring all that hardware. You no longer need a big box with 100,000 pairs of copper wires coming out of it routed all over the city. Just a few fibers and one mother of a Router.

Thank you.

The systems I had responsible charge for the thermal portion of the design were for Digital Systems Inc. , 1 off systems and were floor plemum type using Trane chillers of both large and smaller sizes - the smaller units being 5K to ~ 20 K BTU/hr. sort of like what today would be called mini split systems for tight temp. control, along with pretty robust filtration systems to try to keep things as clean/dust reduced as possible. The best/most challenging design parameters for me were tight temp. reg. of <= 1-2 F. with little temp. hysteresis of < 2 min. or so, making for high air flow rates which made for noisy operation, borderline (but not quite) needing silencers. As you might guess, I had some real fun with the control systems for the air handlers. This was somewhat early in my E.I.T. career before licensure. The senior P.E. I worked under managed the projects and had ~4 - 5 engineers of various disciplines under him. One of my first serious design efforts, but I had no serious involvement with seismic design at that point in my career. .

I learned a lot, particularly about HVAC controls (from some charitable folks at Johnson Controls) but gravitated over to power boiler, condenser, distillation and pressure vessel thermal and mechanical design with a little bit of cooling tower design thrown in. Most of that work was for power plants, refineries and chemical plants. That's when I got involved in external loadings like seismic and wind.

[Sunking]

gravitated over to power boiler, condenser, distillation and pressure vessel thermal and mechanical design.

What makes me think you liked playing with gun powder and fire when you were a kid? For me it was fertilizer, diesel, potassium perchlorate, and powdered aluminum.