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 .