|HOME||D.I.Y. Wind-Solar "Off Grid" ARTICLE||Sidewinder Photo Editor||SUcommanderXer Script Editor|
DANGER: Using a Wet Cell(flooded) direct vented to atmosphere lead-acid Battery Bank "The Rules"This Page: http://www.windsolarhybridaustralia.x10.mx/wetcellaccumulators.html
More than 4 Flooded lead acid vented to atmosphere batteries is no longer an injuring life threatening explosion, IT IS "A BOMB"!
Whether 2v or 12v accumulators, using a wet cell battery (non sealed - vented to atmosphere) is extremely dangerous!
The basic rules - No fires! Garbage Incinerator, indoor wood hearth, wood barbecue, wood fuel range cooker, pot belly stove, leaves e.t.c. EVER!
Always use gas,oil or electric heaters and cookers!
Flooded lead acid vented to atmosphere system is not for fools or lazy!In the past few years in Australia, a quantity of suburban dwellings have been destroyed in explosions by fools thinking they can sensibly house wet cell (flooded) direct vented to atmosphere off grid batteries in things such as garages or as silly, in their house!
Totally sealed batteries such as AGM and GEL-lead crystal or totally sealed wet cell lead acid would be fine, but unfortunately they cost twice as much as "wet cell ventilated to atmosphere batteries that quickly create an explosive poisonous atmosphere during use or charging".
When wet cell batteries discharge or charge they give of an extremely flammable , mildly poisonous explosive gas called "Hydrogen" that is generated by the chemical reaction of oxidizing the lead plate from the acid salts causing water to have its Oxygen atom split from its' hydrogen atoms.
There are rules to using and maintaining a wet cell battery bank system.
Link: 12v 100ah accumulator - dry charged - flooded lead acid [NOTE: Correct use and maintenance of this can give 15 - 20 years life span - (domestic requires 12v 5000ah to 6000ah "B.bank size quantified @12v ampere")]
1. Bank housing is outside of a dwelling and must be(compulsory - mandatory) at least 10 meters from it , (it is not allowed to be within or near any residence or building not specifically designed for "solely housing the wet cell vented to atmosphere battery bank"). The risk of injury, explosion or poisoning is "too real" to allow close proximity to living areas.
2. Because the charge controller(s) must be housed with the battery's there must be separate sealed wall compartment directly backing the battery bank to prevent gasses reaching the controller(s), but allow heat and temperature changes to progress quickly through the wall to the chargers(sealed inner sanctum). The chargers themselves must be kept dry but well ventilated (makes this a bit wobbly as a temperature incubation action for its environment so will only ever be somewhere around the required temperature). The charger must be kept well ventilated to prevent its dump load resistor being too hot(if the dump load resistor is built in with the charger).
3. The Battery Bank housing(inner) is totally sealed with a special 8 meter (minimum) ventilator tower that has an Air-IN(narrower) tube and an Air-OUT(wider) tube from the battery bank atmosphere.
This means that with very little inner housing internal space and very low air speed past the outlet nozzles of the two hoses the hydrogen will be removed AND, if there were to be any ignition of any remaining hydrogen in the confined space(or outside), such an explosion would be unlikely to ever be of any severity! (and ventilating by running long distances of tube with a fan are not required).
One final note, always put a few totally 180o "S"-bend(kinks - do not crush closed) into both hoses up the pole a meter or so before the nozzle(hose end) outlet, and again another before the inner housing connection. This is to stop the force of any direct blast back down the hose.
* Clean hoses of spiders and alike regularly by taking them down and running water through them.
4. Electrolyte levels(sulfuric acid solution) in each battery must be checked at least once per week, there will be a marker on the transparent battery casing showing the upper and lower allowed levels for proper operation.
5. No naked flame or smoking or electrical work to be within 10 meters of the battery bank housing.
6. Before opening the battery bank door "all flammables or possible flammable triggers must been removed from the vicinity"
7. After opening the battery bank door, the housing must be leaved open for 10 minutes prior to commencing any actions within it, near it, or upon it to clear the explosive hydrogen gas build up occurred from its' charging and use.
8. The temperature shielding from sunlight by three non contacting ventilated wall sets (See: "Ensuring battery service life")(lids with the corners slotted - grooved through 1cm to allow air flow) and basic continuous 20o Celsius environment of the batteries is much the same as sealed battery environment control, except the inner most wall set are totally/completely sealed sealed and ventilation is done by the two tubes extended to the top of the ventilation tower (8M high)!
9. The inner door/housing-cover must be fastened tight non moving(no rattle or looseness) and sealed, but one more item - locked! to prevent tamper by children, and the ventilation tower and its' tubes must not be tamper-able or climbable either!
10. Read the manufacturers sulfuric acid solution percentage information for the batteries and use the correct solution percentage.
11. Use only distilled water to top up each battery cell. You can easily make a still using a clean unused 20L plastic drum-canister and around 10 meters of plastic fish-tank-tube sealed into the pouring hole of the 20L drum, by placing the drum full of rain-water in the sun and running the tube up to roof level and dangling the remainder in a coiled ball down around a pole in the shade(do not allow sunlight to get to the collector) into a clean drum never used for anything except distilled water.
12. One final action needs to occur as maintenance on flooded wet cell lead acid batteries. A process called "equalizing" is required to occur around once every three months or as recommended by the manufacturer for the model specification. Equalizing is a process of lifting the battery voltage to heavy state of over-voltage deliberately to excite or re-excite the batteries chemically.
An easy way to make a ventilation system is the same principle of putting your wind turbine higher, the air has tendency to move a little faster higher in altitude.
Seal one end of some hose material into the inner battery bank compartment and take its length to the top at 8M and bend it over in a hook shape with 5 inches to the end pointing down to prevent rain entering it.
The only other method is to run the two tubes(one inlet one outlet - with small continuous blower extractor fan out there 100 meters away also) underground to 100 meters away and up a three/four meter mast.(keep the inlet outlet orifice points apart at least 1 meter)
Some links if you want....