Battery Boxes...What One Company Designed

Sealed lead acid batteries don't vent hydrogen like a standard wet cell (that only happens if the charger malfunctions). In fact they're designed to "recycle" it within the battery. Here's a link to a fairly well known manufacturer.

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GS Batteries has been around for many years. They're the only batteries Edwards installs in their fire alarm systems (in Canada at least). The Rep for Western Canada used to show a video of the manufacturing plant in Japan. The building was huge (covered many acres), and there were only seven people working there because everything's automated (at least back in 1987). I'm not entirely sure that most of the processes weren't controlled by earlier versions of Elk Magic Modules... :-))

Reply to
Frank Olson
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probably sealed batteries, so no hydrogen to vent.

Reply to
Steve Spence

Depends on which circuit *after* the UL-listed class 2 supply you ask about.

As needed and appropriate, and depending on overcurrent devices and intervening converters, the subsequent wiring complies with:

Article 411 lighting (isolated;

Reply to
Marc F Hult

Cheers? Now you've got me fretting/thinking again ;-) .

Years ago I built a mobile environmental research lab that carried a couple hundred cubic feet of H2. The lab was quite air tight and I'd work and sleep in it during Minnesota winters. The H2 was being continually used for scientific instrumentation to create a flame so it wasn't immediately discernable whether some was escaping into the lab atmosphere. The lower explosive limit of H2 is only about 4% ...

If someone has authoritative information on current best management practices for hydrogen from small battery banks such as we are discussing, I'd appreciate knowing. Also reasonable priced H2 sensors. A quick f/google showed me that they are still an obstacle to progress.

TIA ... Marc Marc_F_Hult

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Reply to
Marc F Hult

| >[big snip] | >| Together they provide nominal 60 amps at 28vdc and 20 amps 14vdc =~2000 | >|watts. | >| | >| A Baldor natural gas 28vdc genset has been purchased (not yet installed) to | >| kick in during power outages that has additional capacity for additional | >|28vdc | >| and 120VAC UPS needs. Controller is a Bouchette A120 | >| | >|

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| >| | >| The choice of 28vdc was driven in large part because this the highest nominal | >| voltage that meets the requirements of the under-30-volt sections of the | >| National Electrical code (NEC). | >

| >What NEC circuit class does your 28V wiring fall under? | | Depends on which circuit *after* the UL-listed class 2 supply you ask about.

What serves as the class 2 supply?

Dan Lanciani ddl@danlan.*com

Reply to
Dan Lanciani

In message , Too_Many_Tools writes

How much hydrogen do you think will be evolved ?

Cheers, J/.

Reply to
John Beardmore

Inteli-Power PD9180 and PD9160 (now Progressive Dynamics) as I wrote in my previous post. See

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I'll try to post some pictures to my web site in the next few days.

Marc_F_Hult

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Reply to
Marc F Hult

| >| >[big snip] | >| >| Together they provide nominal 60 amps at 28vdc and 20 amps 14vdc =~2000 | >| >|watts. | >| >| | >| >| A Baldor natural gas 28vdc genset has been purchased (not yet installed) | to | >| >| kick in during power outages that has additional capacity for additional | >| >|28vdc | >| >| and 120VAC UPS needs. Controller is a Bouchette A120 | >| >| | >| >|

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| >| >| | >| >| The choice of 28vdc was driven in large part because this the highest | nominal | >| >| voltage that meets the requirements of the under-30-volt sections of the | >| >| National Electrical code (NEC). | >| >

| >| >What NEC circuit class does your 28V wiring fall under? | >| | >| Depends on which circuit *after* the UL-listed class 2 supply you ask about. | >

| >What serves as the class 2 supply? | >

| > Dan Lanciani | > ddl@danlan.*com | | | Inteli-Power PD9180 and PD9160 (now Progressive Dynamics) as I wrote in my | previous post. See | |

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Interesting. I had no idea that you could get class 2 supplies with such high power output. Maybe I'll have to reconsider my low-voltage distribution analysis...

Dan Lanciani ddl@danlan.*com

Reply to
Dan Lanciani

They have gotten very much cheaper, smaller, cooler, more robust, more powerful

-- and Ul. and ULc. What is not quite what I'd like is efficiency for this particular family of devices. They are rated at ">80%" at unspecified load. In real world, this might mean 60% under low load. Course they may just be rating conservatively.

The RV market is big enough to the create volume needed to avoid niche-market pricing. This particular design (sold under at least three names) has been around long enough for the engineering to tested and solid. I imagine RV owners as a group are not the most gentle on equipment.

IMO, Key here is UL and internal transformer isolation. But I haven't probed to see whether it is specifically UL for Class 2. I am satisfied that it means engineering needs.

The other important part of a distributed DC system is use of isolating DC-DC converters. There are plenty of NOS devices to be had in a variety of Vin and Vout, nominal telco 48vdc being especially prevalent on the resale market.

I generally assume that all equipment that came with a wall wart and is located more than ~10m from the primary battery bank should be isolated (again) unless known otherwise. DC-DC converters also provide the current limiting to 'convert' the battery into Class 1. The NEC specifically states that a plain old zinc dry cell is Class 2 (not 1) because the potentially high current capabilities. I wonder how many door bells of yesteryear, connected with 20AWG bell wire, were in violation ? ;-)

Marc Marc_F_Hult

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Reply to
Marc F Hult

| >Interesting. I had no idea that you could get class 2 supplies with such | >high power output. Maybe I'll have to reconsider my low-voltage distribution | >analysis... | >

| [...] | IMO, Key here is UL and internal transformer isolation. But I haven't probed to | see whether it is specifically UL for Class 2. I am satisfied that it means | engineering needs.

Hmm. But if it isn't UL listed as a class 2 supply then it can't supply class

2 circuits. Class 2 supplies have some pretty stringent requirements for current limiting (not just over current protection--source impedance is a consideration). Last time I checked the most power allowed for a class 2 supply in the lowest voltage range was 100VA. (At higher voltages the power is reduced disproportionately IIRC.)

Another issue is that even if the supplies are listed as class 2 you can't interconnect them unless they are also listed for _that_. (721-45(b) in the 1999 NEC)

| The other important part of a distributed DC system is use of isolating DC-DC | converters. There are plenty of NOS devices to be had in a variety of Vin and | Vout, nominal telco 48vdc being especially prevalent on the resale market. | | I generally assume that all equipment that came with a wall wart and is located | more than ~10m from the primary battery bank should be isolated (again) unless | known otherwise.

I assume that anything that came with a wall wart needs to be isolated regardless of location unless it has no other external connections. Sometimes the negative power input is not common with the "common" of any other connection. Very annoying...

| DC-DC converters also provide the current limiting to 'convert' | the battery into Class 1.

You probably want to "convert" to class 2, but I don't know if DC-DC converters are generally listed for that. (If you convert to class 1 then you are stuck with class 1 wiring materials and methods on the load side, making the whole thing more trouble than running high voltage to a wall wart. :()

|The NEC specifically states that a plain old zinc dry | cell is Class 2 (not 1) because the potentially high current capabilities.

It's sort of the other way around. A dry cell (provided it is < 30V and has

Reply to
Dan Lanciani

Oh yes...that answers why no active venting...the batteries were indeed sealed.

Thanks for answering that little mystery.

TMT

Reply to
Too_Many_Tools

A question for the group...

This battery box I have has its batteries arranged in two groups of four with one group mounted above the other group.

How have you organized your battery box?

Are they all laid out horizontally, stacked on shelves, mounted in roll out drawers or what? I am looking for ideas for efficient layout of the batteries and this battery box is one approach. It seems to work well except for the fact that the bottom layer of batteries would be difficult to access for maintainence.

TMT

Reply to
Too_Many_Tools

Caught me

Yes, you caught me- 36 works fine

How will you get either 72 or 96 volts with only 8 X 6 volt batteries

- Maximum voltage POSSIBLE with this battery pack is 48.

Reply to
nospam.clare.nce
.

With AGM batteries it more the heat than the hydrogen they are worried about.

Stratification of acid in AGM batteries is, AFAIK, not only not an issue, but not possible.

>
Reply to
nospam.clare.nce

Mine are 2 deep, three wide in a single layer.

Reply to
Steve Spence

Interesting.

Thanks for the clarification about Class 2. I musta had at least NEC Class 2 and Class I, Division 2 all jumbled up ;-)

It would appear that the listing for the PD91x0 devices is probably UL 458 (" Chargers or charging functions incorporated into converter or inverters for use in recreational vehicles and boats, as covered by the Standard for Power Converters/Inverters and Power Converter/Inverter Systems for Land Vehicles and Marine Crafts").

For home use, they may need to be listed under UL 1012. " These requirements cover portable, stationary, and fixed power units having an input rating of 600 volts or less, direct- and alternating- current, with at least one output not marked Class 2, and that are intended to be employed in ordinary locations in accordance with the National Electrical Code, ANSI/NFPA 70." ) I dunno.

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Previously I identified four sections of the code that seem to pertain:

Article 411 lighting (isolated;

Reply to
Marc F Hult
28vdc -+->Circuit Breaker--->Dimmer module--->12vdc track UL w/remote xfmr | (Art. 720 + 240) (Art 725.21 Class 1) | +->Circuit Breaker -------------> devices | (Art. 720 + 240) | +----> DC-DC converter ----+---> device (Art.725 Class 2) +---> device ground 14vdc -+----> DC-DC converter ----+---> device | (Art.725 Class 2) +---> device ground | +----------------------------> device(s) (Art 725.21 Class 1)

0 ----------------------------------> ground (Art. 720 and 725 class 1)

Not shown are low-voltage outdoor lighting or telecomm.

Marc Marc_F_Hult

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Reply to
Marc F Hult

Stadium seating is generally a good access for maintenance.

This battery box I have has its batteries arranged in two groups of four with one group mounted above the other group.

How have you organized your battery box?

Are they all laid out horizontally, stacked on shelves, mounted in roll out drawers or what? I am looking for ideas for efficient layout of the batteries and this battery box is one approach. It seems to work well except for the fact that the bottom layer of batteries would be difficult to access for maintainence.

TMT

Reply to
Solar Flare

| >| >Interesting. I had no idea that you could get class 2 supplies with such | >| >high power output. Maybe I'll have to reconsider my low-voltage | distribution | >| >analysis... | >| >

| >| | >[...] | >| IMO, Key here is UL and internal transformer isolation. But I haven't probed | to | >| see whether it is specifically UL for Class 2. I am satisfied that it means | >| engineering needs. | >

| >Hmm. But if it isn't UL listed as a class 2 supply then it can't supply class | >2 circuits. Class 2 supplies have some pretty stringent requirements for | >current limiting (not just over current protection--source impedance is a | >consideration). Last time I checked the most power allowed for a class 2 | >supply in the lowest voltage range was 100VA. (At higher voltages the power | >is reduced disproportionately IIRC.) | | Interesting. | | Thanks for the clarification about Class 2. I musta had at least NEC Class 2 and | Class I, Division 2 all jumbled up ;-)

As in Class I hazardous locations?

| It would appear that the listing for the PD91x0 devices is probably UL 458 (" | Chargers or charging functions incorporated into converter or inverters for use | in recreational vehicles and boats, as covered by the Standard for Power | Converters/Inverters and Power Converter/Inverter Systems for Land Vehicles and | Marine Crafts"). | | For home use, they may need to be listed under UL 1012. " These requirements | cover portable, stationary, and fixed power units having an input rating of 600 | volts or less, direct- and alternating- current, with at least one output not | marked Class 2, and that are intended to be employed in ordinary locations in | accordance with the National Electrical Code, ANSI/NFPA 70." ) I dunno.

Perhaps. However, I just looked at the hookup instructions and it appears that the outputs are directly paralleled with the battery bank, i.e., whatever over-current protection the devices offer does not actually protect the load side. That suggests that no matter the listing the output is going to have to be treated like the output of any other battery bank which can deliver very high current, requiring, e.g., (expensive) class T fuses. And of course, the wiring at that point isn't even class 1. (I used to think that it could be class 1 subpar (b) which goes to 600V with no power limitations, but that's for signaling/control only...)

| Previously I identified four sections of the code that seem to pertain: | | Article 411 lighting (isolated;

Reply to
Dan Lanciani

and even maybe even NCAA Division 1 and 2 ;-)

Yes. See the ASCII circuit diagram in my previous post and at the end of this one. which I think makes this clear. Over-current protection is included.

Where do I find out about class T fuses ? Searching the 2005 draft NEC came up blank. Why do I need them? Plain old Square D QO circuit breakers are UL'd to

60vdc.

grounded )

Right. ABIK, it has changed and become more restrictive/ less useful. That was my point.

Outdoor wiring low-voltage wiring was separated in the 2002(?). I haven't pursued what the draft 2005 has to say. but I didn't stumble across anything that clarified how to get from one t'other or made life easier.

Yes and maybe not :-)

Yes, from the perspective that you are analyzing the benefits as if the installation is something to be commercialized -- which it is not. There is no reason why a personal endeavor ("hobby") has to be practical, or cost effective. Most of what I see folks doing in comp.home.automation (and perhaps the cross-posted NGs too) would not meet those criteria. Perhaps we need to start a rec.home.automation ;-)

Yes, from social reality that in a system with multiple, distributed components that require electrical power, the conventional approach of providing that energy with Class 2 wallwarts quickly becomes untenable. Spousal factor -- the answer to "Can I put three _more_ wall warts over here so that the open-close and tilt drapery motors and the controller can be powered?" is "No". So what to do ? One part of the answer is distributed DC power in my case.

Yes, examining the assertion that 120VAC is always standard and low-voltage is non-standard. To the extent that many of my objectives stem from, and are ultimately directed at environmental monitoring, 120 AC is very much the non-standard, not low-voltage. When was the last time you saw a AC-powered pH or conductance meter? Or weather station? Or sampling pump, or ... My backyard is

750 feet of river front that we own and I monitor.

Yes, from the standpoint that you see "keeping lines separate" as a negative. We separate AC lines one from another too. Why is this a problem? Why is it not a design advantage to have independent systems? I can rip everything I've installed out and the house and household would go on jist fine, albeit with diminution of smart/automation functionality and emergency and aesthetic aspects of lighting.

Yes, from the difference that you see having to use Chapter 3 materials as a problem, whereas I see it as the cheapest way to get materials in many cases anyway. The power of Home Depotizing as it were ..

Yes, recognizing that I already have a large supply of components for DIY. Sometimes I build things just to convert "parts" into "devices" (in the spirit of rec.home.automation ;-)

Yes, from the fact that the "inherent loss disadvantages of low voltage" is eliminated completely by proportional increase in the cross-sectional areas of conductors. There are, of course, advantages to higher voltages. We converted our house in Spain from 110 to 220 3-phase which made conductors embedded in solid masonry walls much more useful. But that is not the situation in my US home. I am installing new conductors, and don't have to retrofit. The house is

184 years old and this is at least the fifth energy/lighting infrastructure (Candle/lamp; coal gas lighting; knob and tube electrical; 1983 Romex remodeling; 21st century HA )

And maybe *not* ;-) because you have excellent analytical abilities and apply them diligently to a confusing set of facts, boundary conditions, circumstances and regulations in a way that is very helpful to others (too).

I _greatly_ appreciate you helpful comments. You've helped to clarify, organize and correct much.

Regards ... Marc Marc_F_Hult

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+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 28vdc -+->Circuit Breaker--->Dimmer module--->12vdc track UL w/remote xfmr | (Art. 720 + 240) (Art 725.21 Class 1) | +->Circuit Breaker -------------> devices | (Art. 720 + 240) | +----> DC-DC converter ----+---> device (Art.725 Class 2) +---> device ground 14vdc -+----> DC-DC converter ----+---> device | (Art.725 Class 2) +---> device ground | +----------------------------> device(s) (Art 725.21 Class 1) 0 ----------------------------------> ground (Art. 720 and 725 class 1)

Not shown are low-voltage outdoor lighting or telecomm.

Reply to
Marc F Hult

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