Customizing UPSs

[Oren Beck]

Jonathan Hutchins wrote:
> On Thursday 30 December 2004 02:07 pm, Leo Mauler wrote:
> 
> 
>>Keep a small solar array to produce the hydrogen for
>>the fuel cells, and you've got your own electricity
>>generator which is essentially powered off the sun and
>>water, without having to worry too much about long
>>cloudy periods, especially in the winter months.  
> 
> 
> The only application where I've seen fuel cells used for solar electric 
> storage is in space, where I presume the weight penalty of conventional 
> batteries makes the difference.
> 
> In any case, adequate, even practical systems already exist using conventional 
> batteries instead of fuel cells, so if you're interested in this there's no 
> reason not to go ahead and do it.

RE: weight penalty .  IF weight is not a factor look to scrapyards !
Lift truck batteries of obsolete casing styles still possessing years of 
life
often go for the scrap lead price - you haul at your own risks and as is-
  no warranty of course. Now if you have a good working relationship with a
yard they can be bribed into letting you charge a battery over a sat 
nite thru
  mon morning to see if it takes a charge- Bring your own charger. Though
at times a scrapped lifty may have an onboard charger mated to that pack !
Then by restrapping cells and the routinely  overlooked concept of simply
disconnecting some dead cells you can make a pack voltage to your needs.
DO be painfully aware of the quite potentially lethal nature of screwups .
Though lead-acid is humorously most dangerous from it's HYDROGEN 
outgassing .
Google Usenet groups for " battery box " and safety - sadly a large 
flamewar .

Also the large gage wires needed for serious home power projects can be
scrapyarded for the copper market price - usually 15-30 cents on the 
dollar of
  virgin wire at WORST .

Due to the dotcom bust truly cringemaking quantities of GOOD inline 
inverters -
100% duty cycle @ full rated load were literally sold for scrap. In 1000 Lb.
average weight - cabinets and often intended to fit thru a 36 inch doorway .
Shostak metals in KcKs and several of the smaller scrapyards along the 
rust belt
in this area still get these in at times. Often you can get a 200 amp 
PER LEG
@ 240/120  inline inverter for a few hundred bucks -scrap metal prices .
DO be careful to inspect carefully as some have been deliberately 
"decommissioned"
  by removal of a brain board or  other overt sabotage . And also cruel 
destructive
  torch cut up removal renders it mere scrap- or perhaps roll your own 
parts ?
   Then again often they were scrapped when a company outsourced their 
server
farm and a 2 year old Libert or APC power and cooling system got 
curbsided as
  obsolete to the company . Truly a sin !

Where these big iron cored transformer behemoths shine is in near full 
load operation .
Tutorial on SMPS on request but the efficiency of inverts is greatest at 
a certain %
of design load -almost a 60% variance from min safe load to max safe 
load in some
situations . SO running  your whole house on a surplus APC rack is not 
insane  .
The bonus comes because some units in this class were designed to 
interface with
external gensets and handshake with the genset in closed loop . A little 
interface
hacking- possibly using a Linux app ?  and your battery bank reloading 
source can
  be synced to interact peaceably. No breaker trips or  regulator wars .
Note well that the over/undervoltage sensing on big units is often by 
remote shunts .