Posted by Marc F Hult on September 16, 2005, 4:00 pm
>Since I am starting the homepower/automated house journey, I have been
>collecting surplus commercial equipment that might prove useful. One of
>those items was a surplus Best battery box for a large UPS. Some
>comments on the construction and design follows.
>The box is designed for sealed 6v batteries (two banks or four) with
>the second bank located above the first. The cabinet is metal with
>galvenized trays for the batteries to sit in. The box was wired for 12v
>at 200 amp with commercial welding cable. There are two in line fuses,
>one per bank. The cabinet is on wheels. The cabinet has two vents
>located on the back of the cabinet, one lower and one higher. The
>cabinet is NOT actively ventilated but relies on natural convection. On
>the front it has a single heavy duty switch to switch the direct
>current. The switch has a ceramic resistor on it (to quench arcs when
>switching?).
>Several things caught my attention. The use of metal throughout the
>box...I would have expected fiberglass or plastic for corrosion
>resistance. Next was the absense of an active ventilation system.
>Third, the lack of an integrated charger for the battery box. I assume
>the batteries are charged through the UPS.
>I plan on making some mods to this box for my home system.
>One is to make plastic tray inserts to keep acid at bay.
>Next is an active ventilation system.
>Third is to consider doing some type of a sliding tray on the bottom
>level to allow one to access the batteries easier during maintainance.
>Fourth is to incorporate a charging system.
>Fifth is to place meters on the front to monitor voltage and amperage
>and add the option for remote sensing.
>Sixth rewire it for a different voltage (it was 12v at 200a)...any
>suggestions?
>I would be interested in any suggestions or comments as to what you
>have added to or wish you had designed into your system.
>Thanks for any and all suggestions.
>TMT
Assuming that you are in US:
Check the National Electrical Code (NEC) which addresses both batteries and
low voltage.
Make sure that the DC/charging system is isolated from the AC, draws not more
than 20 (IIRC) amps source AC, is UL-listed and is not connected to earth
ground.
Above 30 volts, or if the system is not isolated, the NEC is more restrictive.
(FWIW, I have some of your questions. I have a growing 28vdc system.
A natural gas-powered 28VDC generator awaits installation. )
Marc
Marc_F_Hult
www.ECOntrol.org
Posted by John Beardmore on September 16, 2005, 4:22 pm
>Sixth rewire it for a different voltage (it was 12v at 200a)...any
>suggestions?
How should we know ? Did you have any particular load in mind ?
>I would be interested in any suggestions or comments as to what you
>have added to or wish you had designed into your system.
I suspect most of us select components and design systems in response to
some particular need or requirement.
>Thanks for any and all suggestions.
You seem to be coming at this the way a sculptor approaches a block of
marble.
You sound like you've found an interesting item, that requires a total
overhaul to be made stunningly excellent, to greatly exceed the spec
required to meet some undefined purpose.
What are you actually wanting to achieve ?
Cheers, J/.
--
John Beardmore
Posted by MFHult on September 16, 2005, 5:13 pm
>You seem to be coming at this the way a sculptor approaches a block of
>marble.
>You sound like you've found an interesting item, that requires a total
>overhaul to be made stunningly excellent, to greatly exceed the spec
>required to meet some undefined purpose.
>What are you actually wanting to achieve ?
>Cheers, J/.
My sons call this a " hood ornament project" Finding a neat hood ornament,
they say, I would be inclined to build a car under it...
I can't answer for the original poster, but some projects, especially DIY home
automation projects, can be driven by what one can do rather than what needs to
be achieved. That's often OK.
(Ooops... I jist realized how cross-posted this thread is . Oh well)
A common constellation of reasons that do have specific, useful and attainable
objectives (which also happen to be mine) is to provide a power system that
provide:
1) protection of devices in the home/office/farm/cabin that contain
semiconductors and so may be damaged by lightning and possibly other power-line
disturbances
2) a useful amount of back-up power for lighting, electronic, and other
electrical equipment devices that are needed in emergencies
3) some personal outlet for frustration over 'energy dependence' in all its
contexts.
Gotta go! -- Lightning and thunder as I type this ;-)
... Marc
Marc_F_Hult
www.ECOntrol.org
Posted by John Beardmore on September 16, 2005, 6:29 pm
MFHult@nothydrologistnot.com writes
>My sons call this a " hood ornament project" Finding a neat hood ornament,
>they say, I would be inclined to build a car under it...
>I can't answer for the original poster, but some projects, especially DIY home
>automation projects, can be driven by what one can do rather than what needs to
>be achieved. That's often OK.
Yes - I've got no problem with that, but asking us what voltage to wire
the bank to seems silly. Likely to be determined by available cable
lengths and thicknesses, surplus or cheap inverters etc...
Cheers, J/.
--
John Beardmore
Posted by John Beardmore on September 17, 2005, 6:45 am
>I ask what voltage because I can wire it in different arrangments...it
>was wired for 12v.
>I am asking because as you point out there are different inverters out
>there.
But only you know what they cost YOU.
Personally I have done a lot of mobile stuff on 24 volts because that's
what trucks use. I don't like 12 because the current requires huge
wires, though I've done a bit of that. If it was for home / stationary
use I'd expect to see some efficiency advantages by going to higher
voltages, but if you charge from PV for example, will you be able to get
say a 96V OPT regulator off the shelf ? And what if one battery or PV
in a string fails ? Probability goes up as strings get longer. Lots to
consider.
>I have a number of surplus UPS inverters that I may use...I am still in
>the design stage on this subject.
Good...
>The APC Smart/Matrix UPSes are sine wave, are CHEAP and large enough to
>be worth using. The downside is that UPS inverters usually have higher
>idle current requirements that dedicated inverters available on the
>market now. I have yet to do the tradeoffs with a market survey. Any
>suggestions you can offer will be appreciated.
None really. The inverters we have used have been cheap, modern, fairly
efficient, fragile, small, switching technology, square wave out and
nasty, or have been hugely heavy, inefficient thyristor fired 50Hz 1960s
technology with massive transformers and sin wave output. All down to
what has come out way.
We also have a huge, and I suspect fairly inefficient 7kW UPS inverter
lurking around but there isn't much point in telling you about that.
One day it will come in handy though.
But given the price of modern inverters, is it worth your just going out
and buying what you need when you know what you need ?
Cheers, J/.
--
John Beardmore
XML site map
>collecting surplus commercial equipment that might prove useful. One of
>those items was a surplus Best battery box for a large UPS. Some
>comments on the construction and design follows.
>The box is designed for sealed 6v batteries (two banks or four) with
>the second bank located above the first. The cabinet is metal with
>galvenized trays for the batteries to sit in. The box was wired for 12v
>at 200 amp with commercial welding cable. There are two in line fuses,
>one per bank. The cabinet is on wheels. The cabinet has two vents
>located on the back of the cabinet, one lower and one higher. The
>cabinet is NOT actively ventilated but relies on natural convection. On
>the front it has a single heavy duty switch to switch the direct
>current. The switch has a ceramic resistor on it (to quench arcs when
>switching?).
>Several things caught my attention. The use of metal throughout the
>box...I would have expected fiberglass or plastic for corrosion
>resistance. Next was the absense of an active ventilation system.
>Third, the lack of an integrated charger for the battery box. I assume
>the batteries are charged through the UPS.
>I plan on making some mods to this box for my home system.
>One is to make plastic tray inserts to keep acid at bay.
>Next is an active ventilation system.
>Third is to consider doing some type of a sliding tray on the bottom
>level to allow one to access the batteries easier during maintainance.
>Fourth is to incorporate a charging system.
>Fifth is to place meters on the front to monitor voltage and amperage
>and add the option for remote sensing.
>Sixth rewire it for a different voltage (it was 12v at 200a)...any
>suggestions?
>I would be interested in any suggestions or comments as to what you
>have added to or wish you had designed into your system.
>Thanks for any and all suggestions.
>TMT