Split this off from the roof insulation topic to keep from drifting too bad. :) GK
Hey Glenn, how did I miss the fact that you have a Bergey Wind Generator? Tell me all about it. I looked at them awhile back but, got scared off due to a lack of wind where we are.
It must be a great product, it's made in Norman, OKLAHOMA!!!!
Okie Bob
PS: almost forgot, I finally got a Pickett slide rule before I graduated from OU. They are metal and all were a yellow color as far as I know. They were the hottest things going way back then!!!
Norman, Oklahoma. Is that a small province in China, BoB? :-?
The manufacturer is in Oklahoma but I am sure I saw China somewhere on the parts... but non-the-less, it is likely one of the best wind generators on the market. I have heard horror stories about some of the others. A dealer told me he sold 6 of some other brand and had to take them all back due to major problems -- burning up etc. No problems with the Bergey. Just hook it up and go.
It comes with a fairly sophisticated controller that steps up the low voltage (low wind conditions) to usable voltage for charging 24v batteries- a circuit breaker, solar regulator for a hybrid system and a circuit for a dump load regulator to burn off excess power as you should not take a wind generator off line-- they go wild in the wind when unloaded. They fold sideways to control excess wind so they won't fly apart.
I designed and built my own 85 foot tower from things I learned from their instruction manual and I did sneak in a couple questions to the factory rep. I'm a bit of a tightwad and a couple grand is a couple grand. :)
Glenn, I think China is the manufacturing sister country of the new US of A. They know how to make things and we used to but, can't anymore. We have to farm it out to them and lost our ability to do anything except service things they build.
So how long have you had the Bergey? Did I see that it is a 5 kw unit? Can you give me an estimate of the cost of the system and cost of the tower you made and cost to erect it etc? I don't think I could erect an 85' tower by myself and I don't have access to heavy equipment anymore unless I rent it.
Do you have any good buddies at Bergey? I have wanted to stop in and visit with them. Norman was my home for many years and I'd love to live there again. Course it's the home of the University of Oklahoma, my reason for loving it!
Okie Bob
China is the manufacturer because corporate America is selling us out, BoB. Maximize the bottom line -- give the investors a pittance and make the CEOs wealthy. Don't worry about the working class - they don't need jobs. When I was trucking a student from Taiwan broke his car don in New Mexico. He was ripped off by a repair company -- had to leave his car and we gave him a ride. On the way to California he told us that Taiwan is just an assembly plant for American companies. Now it is China.
Of course one of America's finest police felt it was his duty to give me a ticket for hauling an unauthorized rider. That really endeared them to me. >:(
I've had the Bergey running about 4 years now. Roughly around 2 grand for it and 2 grand for a tower. Price is a bit higher on it now. This is a 1 KW unit - their small one - XL1. I didn't look up the pricing but I think it is on their site. Their policy was to let you have a dealership if you bought one and could install and service for others -- and passed their qualifications along with no dealer in your area. I may be able to get you a discount and have it shipped there but not sure as you are not in my area.
I think you could stand your own tower, BoB. I could tell you how to make it and you could put it up with a gin pole Literature may be online for their pipe tower along with instructions for the small one -- bigger may be another story. Several small ones are better than one big one anyway.
http://www.bergey.com/
Bergey Windpower Co., the worlds leading supplier of small wind turbines
Pix BoB
(https://i35.photobucket.com/albums/d184/glennkangiser/WeatherStn12-23-05004.jpg)
(https://i35.photobucket.com/albums/d184/glennkangiser/WeatherStn12-23-05003.jpg)
I put this up by myself, BoB. About 10 hours with no outside help -- chain hoist - tree and a gin pole.
Looks kinda scary. Reckon it will stay up there? ::)
I reckon so, desdawg. Near 5 years now -- maybe I should go tighten the cables now that you mentioned it. Top is 85 feet - 4 20 foot sections and 5 foot top section. It is mounted on a base that is staked into the ground with 3 foot steel stakes.
The pivot for the gin pole is also on the steel mounting base. The gin pole is removed after the tower is erected.
What was hard was weaving the cables around all the oak trees by myself as it went up. I didn't want to cut them. Needless to say that was not part of the recommended procedure.
I am always amazed at those towers. They look so flimsy at first glance. 85' is pretty tall. Have you had to take it down for maintenance on the generator?
I don't really want to think about taking it down. :-/
There are no moving parts except what you see moving, and I read something about it possibly going 10 years (I hope for more and won't pull it down until a problem develops - the bearings are sealed.). I could get it down though, knowing how I put it up. Guy wires are used every 20 feet and all of them attach to the gin pole and it must be carefully controlled as it is let down. the side wires need to be controlled also and in a even flat plain that would not be a problem. There is nothing even or flat around here. That makes it quite a project.
In reality though - you are only supporting about 100 lbs plus thrust. Only about a 50 lb or so pull on any of the cables at any given time. You just have to get it up and guy it properly in 4 directions at each joint. The tubing can be as thin as 4" exhaust pipe. Wind at 85 to 100 feet is about 3 times that on the ground and as a minimum you must be at least 30 feet or so above the tallest trees to prevent turbulence. My site is not ideal but works well. Occasional turbulence from wind coming up from underneath rather than straight as we have a ridge within 100 feet in either direction (drop from the ridge either way).
Makes good old solar look pretty simple.
It's all pretty simple Des.
To sum it up, figure out how much power you can afford or need (not always the same)
Buy batteries for that amount,
Figure out how to charge the batteries....period!
For most people, a combination of solar, wind and a powered generator is the answer. For people with water, throw in hydro.
I get annoyed wit one of the better off grid boards. One of the most knowledgeable people there always answers a question with a question. He's no help to the new people and scares off more people than he attracts.
I consider wind a semi-reliable bonus. It works nights and cloudy or stormy days also. :) Does about 25% of my power. Many times gives me a boost when I need it.
Glenn - you spent roughly 4k 5 years ago - has it paid for itself yet?
Glenn, I just glanced at the Bergery site and yes, the cost has gone up a bit but, not that bad. About $2.5K now plus tower.
I'm really a novice on wind power but, really interested. I didn't take the time to research it but, looks like you are generating
mainly 24V to use to charge your batteries? 48V seems to be an option on some sytems. Guess that is for the newer batteries?
So all your power is converted from the 24V battery to 230VAC 50Hz? I'm sure there is a good reason for that but, most US appiances don't like 50Hz power. Suspect it is not that difficult to convert to 120VAC but a frequency changer is not cheap so you would have to go with the 50Hz?
Why couldn't you simply convert the 24V out of the wind generator to 120VAC 60Hz and not store it in a battery. Just use what you can when you can as you only have a 1KW generator anyway? Am I missing something here too? I could probably find the answers to these questions but, figure I'd be lazy and let you answer!
And as MelH asked, what has the pay back been to date? Or can you tell? Very curious.
Okie Bob
Bob, I'll let Glenn tell you about the output on his, but to answer your question in part, direct conversion is very difficult. I have a 12 V system because it's easier to produce charging current with the lower voltages. (Homegrown system)
My generator is capable of putting out 120 volts DC. Transmitting AC is more efficient if you need to go any distance but the raw voltage is too erratic to be usable. It can go from 8 volts to 120 in a few seconds.
Anyway...at the battery bank. the AC is rectified and put into the battery. The battery acts as a giant capacitor and maintains the wattage at a constant state, There is a charge controller that reads the battery voltage and dumps the charge to another circuit (In the controller I built, it dumps at 13.8 volts).
The dump circuit can go to anything including ground. Some people send it to a water heater but mine goes to a second controller for a dedicated battery. The primary controller handles both the wind and solar.
The batteries are what do the work. They have a high enough amperage to accommodate The starting surge on motors as well as provide constant voltage to the inverter. The inverter will give either a pure or modified sine wave. I have a 5K modified sine wave that handles everything but very sensitive computer equipment and believe it or not, some window fans and a 1K pure sine wave inverter.
From there on, it's plug and play :o
I should sit quietly here and let Glenn pipe in, but I can't. I'm bored, home with a terrific sinus infection, and I love to talk alternate power. :)
Glenn is totally off grid. No batteries = no power at night (solar PV) and no power when no wind. Hence the need for batteries. Wind generated power is too variable to be used without a buffer of batteries.
Where'd you get the 50 Hz from? I'm certain he runs 60 Hz with 120 VAC except for the water pump (240VAC) You can piggy back some inverters to get 240 VAC.
I do have a PV array on the suburban home. It's grid tied with a small battery bank for emergency outages. I only do 120 VAC to a few select circuits in the house from the batteries/inverter. There's an automatic changeover switch if when the grid fails. I can count on making about 400 - 500 Kwh in an average month. So most months I also pay the power company. March, April & May we had credits. The rest of the year nights are longer and the furnace runs more and of course in the summer the A/C eats up as much again as we make or more.. I'm not sure I'll ever see full payback, but then again who knows how high the power company prices will go. But knowing that there's power available is quite nice.
My battery bank is 24 VDC (8 - 6 volt AGM 220 Ahr units). You can run 48 VDC if that's your choice. Can save on wire sizes/costs if there's any long runs. 48 VDC battery banks limits your choices of some equipment though.
If you are grid tied as well as generating by solar your system must meet the rather rigid specs the power company sets. I imagine the same rules apply for wind. You can actually see the meter run backwards on a sunny day. :)
My cabin will be too far from the grid tie point to be economically feasible... $55K to connect. It could be shared with my neighbor, but he's already setup with PV panels and batteries. I plan on 48 - 60 VDC from the panels to the charge controller. The charge controller will change that to match the 24 VDC battery pack. There'll be a 120 VAC inverter capable of about 3500 watts or so, My generator will be used for backup and equalizing.
Wow -- I go to work for the day and the forum goes wild. :)
MelH -- depends on how you look at it I guess. For me it paid for itself the day I put it up --- no power company - not under the thumb of the gov. etc. Financially -- I guess I need to put down some numbers an maybe Don can work them out. ;D i don't consider it to be a way to save money. I consider it to be a step toward independence.
Lets say 5 to 10k for Power company hook up -- no need.
We paid $100 to 300 per month at the conventional house for power per month so lets say our conservation value of our power here is $200 per month or $2400 per year (not that we would use that much the way we live now but we would use that much if we had it.)
We still have all necessary conveniences including a 20 cu ft freezer, 8 cu ft freezer, appx 8 cu ft antique electric fridge -very energy efficient, 2 laptops - printer - wireless DSL print server, microwave, coffeemaker, air compressor as req'd, welder sometimes, compact florescents as necessary - trash compactor as necessary, standard washer and standard propane/electric drier, 1.5 HP standard 240v pump -pumping about 600 gallons of water per day. Shop lighting and tools as necessary.
Also a propane RV fridge. Bosch HX 125 Tankless water heater. Convert whatever you can to propane -- no electric heaters.
If I hadn't made mistakes along the way learning off grid on my own - costs could be -
$2500 Wind Gen 1KW - built my own tower -cable and clamps included - scrap pipe and steel not included.
$1800 12 6V batteries @375 ah each.
$3200 2-4kw used trace inverters and cable stacked for 240v
$10000 appx 2000 watts solar panels @$5 per watt. Didn't build frames yet - sitting on roof, but could be built from wood.
We use all standard house wiring and fixtures so cost would be the same as whatever you spend now plus any wiring from the inverter to the panel.
I added an extra controller - say $400 and misc. pump control relays and timers -- used2 - 12v auto relays in series (24v system) to control 240v relay to cycle pump when batteries overcharge.
The voltage is pretty well controlled by the inverters you decide to use -- I like 24v - more versatile than 12v system - more popular than 48v system -- moderate wire sizes. Some regulators will allow you to series your panels for smaller wire size then they convert down to 24v.
Sorry if I didn't get to everything yet -- I will try to get to more of it tonight.
I'm inverting from 24v DC to 240v AC 60 HZ. I use all normal equipment like a normal house -- even though I'm abnormal. ;D
That was one of my self set requirements. I even leave most of my parasite loads going all the time -- 4 phones on chargers -cell charger - print server is a big one so I unplug it most of the time - it pulls 60 watts.
BoB said
QuoteWhy couldn't you simply convert the 24V out of the wind generator to 120VAC 60Hz and not store it in a battery. Just use what you can when you can as you only have a 1KW generator anyway? Am I missing something here too? I could probably find the answers to these questions but, figure I'd be lazy and let you answer!
You may only have a bit of power when the wind is blowing - not likely enough to power anything often when you need it. Store it in batteries and it is there anytime day or night. You lose a bit in inefficiency that can't be stored but that's the breaks. As a bonus, when it is working well and you are using power, most all of it is used effeciently as it is made with excess being stored in the battery.
I'd hate to have to get up in the middle of the night to microwave the wifes cat because that was the only time I had enough wind power. ::)
The batteries carry you over when there is no sun - such as when it is night or cloudy. :)
I probably do about 450 kwh per month -- never checked the numbers -- just add to it as I need it.
Note that I have a welder as a backup generator also. Fast charge I hook the weld cables direct on CC and throw in about 100 to 120 amps - when the batts are low it brings the voltage up to about 26.5 v and up- about 1/2 hr every so often.. Doing it that way I have to keep an eye on it. This is in parallel with the inverter charger which will taper off as the batts come up.
Welder 10kw generator - Miller is about $3500
That's an impressive setup Glenn. Especially the batteries! I'm using 6V Golf Cart batteries giving approximately 1K storage each.
If I understand you correctly, your using your dump circuit to operate two relays that operate your pump. I assume the pump is on your primary circuit(s) and the dump current just closes the relays.
And you have a storage tank for the water as it's pumped with another pump in the tank for normal use???????????
Pretty neat system! ;)
Even easier, Peter. The Bergey already has a dump circuit built in -- just add a load. Rather than burning it off and wasting it, I connected the control windings of two Ford-etc micro relays - appx 1 cu. in. size in series for 24v so the relays were easy to come by and wouldn't burn out on 24v. The secondaries of them control a 120v power cord that is jumpered into the plug of a $8.50 timer (matched polarity- ) that also controlls the plug -- I set it for 15 minutes every 2 hours during the day -late morning on - pumping about 150 gal water in that time. My well produces 1 gpm so it matches pretty good with this as well as it having extra capacity down the hole. During extra power days as voltage overcharges the batteries the dump load kicks the relays on and burns the excess power off. The dump load is parallel with the timer. Both control the primary 120v coils that kick in the 240 vac that runs the pump
I do not run a control circuit but instead pump to a 2600 gallon tank about 80 feet elevation above the house - water going up and down the same 2 inch line into the bottom of the tank. The 1 inch conduit I was going to run the control wiring in now functions as an overflow from the top of the tank so the water comes back down the hill about 300 feet through the conduit and runs down the driveway prompting me to cut down the pumping time. Actually inflow and outflow match close enought that I rarely have to pump extra water if pressure drops indicating a low water condition.
Note that my pump runs so much more efficiently on pure sine wave inverters that I highly recommend running them rather than modified sine wave. I burned out quite a few tools on modified - mostly variable speed. Note that some variable speed Rotohammers - notably Bosch - will not start even on pure sine wave unless you first start a skillsaw or other motor to smooth the power even more.
Batteries are Siebert (local MFG) L16 - 375 AH -- figure to only draw them down about 1/2 way for best life -- I probably don't watch that close enough -- do as I say - not as I do.
Re-reading your post, Peter, I think you had it about figured out.
Pure sine wave AC output is much kinder to all motors. They run much cooler and also use a lesser amount of power. In the end worth the expense because you no longer have to worry about what AC units might not like the modified (actually square, nothing much modified about it) sine wave. My wifes computerized sewing machine wouldn't run on modified. I also toasted a couple of rechargeable devices on a modified sine inverter.
That is even better! :)
Right now I'm pumping non potable water from a spring to a tank using an Agpump (gas)
In the new place, I'm still going to separate the non potable and the drinking water. The non potable which is spring water and I drink it all the time, is what will run the hydro. I had planned on using pure hydro power to run a pump to a tank at the house.
The well water will run off a 12 volt pump.
I got about half again more water from the same power when I switched to pure sine wave. There are little mickey mouse devices you can add to make the pump a bit better but why bother when the ficx of pure sine is better for everything. I know --- it cost quite a bit more. I did well getting my second one on Ebay.
Grundfos makes a very good pump that runs directly off of the panels. -- No batteries required for a deep well pump.
[highlight]I got about half again more water from the same power when I switched to pure sine wave[/highlight]
It;s in the budget for the new cabin but like you said earlier, the learning curve is expensive. :-[
Do the towers have to be that tall? My desert land is wide open space and the big winds blow constantly, plus I think the association codes limit the heights to 24 ft.
If I had a cat underfoot I would want to be able to nuke it 24/7 so I see where you are coming from. :)
QuoteDo the towers have to be that tall? My desert land is wide open space and the big winds blow constantly, plus I think the association codes limit the heights to 24 ft.
The wind is much better up there. Around 20 mph puts out pretty good power. If you live in an area with an association it is not likely they will want one around. While it is relatively free power, the neighbors will all want their say and at least one won't like it. It does make a reasonably pleasant whirring noise and harmonic noises at times. You also need 30 feet clear above any tree top - roof top or obstacle that will cause turbulence and slow the wind or make it behave erratically.
The cat , desdawg. Not worth much except to look at but she does purr until I go to sleep. I guess that's worth something. Guess I better leave her alone. :)
Glenn, I'm glad you made this a separate topic and maybe you could save it as I believe more people are going to be looking at alternative power pretty soon. I know I am.
Great input for all you guys on this subject. I feel like an idiot not knowing more about it as I do have a degree in EE. Just never really considered wind power as ready for prime time yet. Solar has been so expensive it hasn't been worth a look either. Appears that may have changed.
Tanya, if you go to the Bergery site Glenn gave at the first of this topic there is a whole section on why the towers need to be as tall as possible. So much more to consider than I had expected. But, with POA, it looks like you won't be going with wind power anyway?
I do still have a question about batteries. How long do they last? These are all lead acid, I assume? Seems that would be a rather large recurring cost since so many are used.
I have some knowledge of a solar powered battery charger that uses a pulsed charge that cleans the battery plates as it trickle charges the batteries. They are not too expensive and they claim some remarkable results of extending the life of lead acid batteries. I know an engineer that did some consulting for them and the claim to have gone to the city of Arlington, TX and asked for some batteries they had stacked up as dead, waiting to be picked up for recycle I assume. They put this pulsed charger on them and brought all be three of them back to useful operation again! Understand every Humvee in Iraq now has one on it from the factory. Just have to keep the little solar panel in the sun. I c an get more info if anyone is interested. They do sell them around here at Battery Plus stores.
Okie Bob
Good idea to make this a sticky Bob.
This is a site that sheds a lot of light on solar and is very understandable to people just starting to think about off grid:
http://www.solarexpert.com/Batteries/batchart.html
BTW there are very big things happening with solar technology. One of the most exciting companies coming up is Ascent Solar and their thin film panels. It's one of the few small companies I own stock in. They are boosting the power while lowering the cost. The bad news is that There will be a long wait for delivery after they go into full production this fall.
They already have government contracts to fill.
I think the Trace regulators use Pulse Width Modulation which is what keeps the sulfate crystals broken down.
Poor Mans Guides has a good wind power and battery rejuvenation in one e-book- tells you how to build both. Good study for an electrical engineer---- :) or the poor man --- or anybody interested. http://poormansguides.com/
They say 5 years on the L16's but PWM could increase that. Also MPPT - maximum power point tracking on the regulater gives more power for the same amount of panels.
Poor Mans Guide tells how to build the rejuvenator that will rejuvenate forklift batteries which can have a 20 year life - usually lead with antimony added for durability. A bit faster self discharge rate but not usually an issue in daily cycled batteries.
Ive been looking into alt. power for a bit now, and intend to use it on my home when i manage to build one (assuming i can overcome the technical hurdles set in front of me) and i second the poormansguide and also add www.otherpower.com they have some intresting stuff also :)
Otherpower is good however, they are bad about answering a question with many snooty questions. When the answer is given, it's often in a form that newcomers can't understand.
BATTERIES: The longevity of batteries in a alternate energy system depends first and foremost on the care and use or abuse they receive. They are generally flooded lead-acid batteries of varying degrees of quality. Some are lead-acid in a sealed AGM type. They have some advantages, but cost more per Amp-hour of capacity. AGM take more abuse in general. Gelled batteries are the least tolerant of deep discharges and overcharge rates. I would avoid them altogether.
The most common abuse is over discharging the batteries. Longest life starts with restricting the depth of discharge. Yes, they are called deep cycle, but the deeper the discharges, the fewer the number of charge/discharge cycles. Ideally you would only use 25% of the capacity before recharging. Most folks probably run them down to 50%. So sizing the battery bank correctly is the first step in achieving longer life spans..
Other forms of abuse include leaving in a discharged state and allowing the acid level to fall below the top of the plates. Battery life is also extended by performing an equalization charge once a month.
Here's a list or likely life spans beginning with a standard automotive cranking battery.
Starting: 3-12 months
Marine/RV deep cycle: 1-6 years
Golf cart: 2-6 years
AGM deep cycle: 4-7 years (this can vary considerably - the large 2 volt cells can last for 20+)
Gelled deep cycle: 2-5 years
Deep cycle (L-16 type etc): 4-8 years
Rolls-Surrette premium deep cycle: 7-15 years
Industrial deep cycle (Crown and Rolls 4KS series): 10-20+ years
The significant differences listed for Marine/RV deep cycle and golf cart batteries reflects poor care versus pampering.
The most significant difference as one goes down that list is the amount of lead, the thickness of the plates. This is a case where bigger is definitely bigger.
IF golf cart batteries can meet your power storage requirements they can be very good value.
In an ideal or near ideal battery system the number of parallel loops should be held to a minimum. No more than three batteries or series connected cells/batteries should be connected in parallel for minimum maintenance and longest life.
When deciding upon the battery type and configuration you would ideally choose the battery that will supply the power needed with the least number of cells or batteries. Some of the better (higher priced) batteries are available in single 2 VDC cells.
Battery weight must be taken into account for transporting and handling issues.
There's lots of battery information available on the 'net as well as a lot of sources to buy from, but because of the weight freight costs are usually quite high. Best to decide what you want/need and try to find locally, IMO.
I have had personal dealings with http://www.affordable-solar.com/ and http://thesolar.biz/Our%20Complete%20Product%20Inventory.htm I recommend both.
Good information at http://store.solar-electric.com/ but I've never bought from them. http://backwoodssolar.com/ also has good info and a paper catalog full of info for free, but I the prices can be higher.
A couple more wind DIY links
http://www.scoraigwind.com/
Hugh Piggott - Scoraig Wind Electric
http://windstuffnow.com/main/
Mountain Don, great workup on batteries, thanks a bunch.
Now the question becomes, 'where do you put all these batteries'? How do you actually go about maintaining them? I would think you would want a constant trickle charge going to maintain them in as highly charged state as possible. No? I say this because as you point out, at least in marine batteries, the biggest problem is leaving them in a discharged state for long periods of time. Most fishermen used to take their boat out of the water, trailer it home and forget about hooking up a charger until just before they are going fishing again. If a good battery lasts one year, they are lucky. Now a lot of fishermen have built in, on board multistage chargers. First thing I go when I pull into my boathouse is reach up for the extension cord and plug in my boat. Starts charging immediately and I'm ready to go anytime I want. Has allowed me to use the same batteries for over 4 years and counting now.
Okie Bob
Almost forgot, thanks to all for the great sites links. At least now I'll know enough to be dangerous!
Okie Bob
Bob, you want to keep them in a vented box, outside if possible. If and when they start gassing, it's explosive so venting is a must.
I keep mine in a PVC box buried with a vent in the top. This keeps them at a constant temperture. You may not have problems with the cold though.
Keep the batteries topped off by a trickle charge. If it's just for standby, discharge them 10% a couple of times a year.
Check often with a hygrometer and keep the water topped off.
If you go with a 12 volt system remember to use heavy enough wire. I use battery cable. It draws a lot of current. If you have a 1 amp load at 120v, the inverter will draw 10 times the current from the battery or 10 amps.
You won't have any problems, this isn't rocket science.
Hey Okie Bob, you've already figured out how to extend battery life!! Keep them full!
Where to locate the batteries? First some more info. Batteries work and last best at about the same temperatures people like best. Batteries are rated at 25 C (77 F). As temperature increases battery life decreases while capacity increases. Conversely as temp drops battery life increases and capacity is reduced.
At freezing temp the capacity is reduced by 20%. At -22 F capacity is reduced by 50%. At 122 F battery capacity is increased by about 12%. At -22 F battery life is increased by 60%. For every 15 degrees F over 77 F life is decreased by 50%. However, if your batteries are in a variable temperature life will sort of average out.
If the battery bank is large and in an insulated box/container the thermal mass of the batteries will slow down the rise and fall of the battery temperature.
In any event your batteries should be located where they can not be accidentally shorted out. As mentioned batteries out gas hydrogen and oxygen under charge conditions. The higher the charge rate, the more gases. A spark can cause an explosion. Therefore the container must be ventilated to the outside in such a manner to be explosion safe. Hydrogen rises so a sloped lidded box with the ven at the high point will self vent with no need for fans. A low point air inlet will aid the venting process.
Batteries all self discharge when at rest. Self discharge is greater at higher temperatures.
So I guess I didn't really answer exactly where to put the batteries, but you can make a wiser choice now.
Hydrometers measure specific gravity of the electrolyte which indicates the state of charge. Make sure you leave enough room above the batteries to make hydrometer use easy. Also for adding water. Only add water to fully charged batteries as the electrolyte volume is greatest at full charge. The exception to this would be if the top of the plates are exposed. If so, add just enough water to cover the plates. Top up as necessary when fully charged.
The best hydrometers are those with the graduated float cylinder, not the ones with the floating balls. AGM batteries can not be measured with a hydrometer;they're sealed. One must make do with voltage readings. Voltage readings should be taken after a period of inactivity; no charging, no discharging. Six hours without use is usually enough for the voltage reading to become more correct. Under load the voltage decreases and then rises when the load is disconnected.
When charging batteries with a stand alone charger the preferred charger would be one that has built in multi stage charging. Bulk, the highest charge rate, Absorption, an intermediate range that tapers down, and Float, to maintain the charge. I have chargers that go thru the range depending on battery state of charge. When the battery is full there's next to no charge to the battery. If the state of charge drops the charger boosts up. Mine are made by Iota in Arizona, USA! They have several models with varying capacity. I swear they are the best stand alone chargers out there. Variable speed fan cooled as necessary. Get the IQ option for auto charge regulation. They make 12 and 24 VDC models.
http://www.iotaengineering.com/
Most DC to AC inverters that are designed for alternate power situations (not the cheap types found nearly everywhere) have a charger built in. If/when connected to a source of 120 VAC power they will maintain the battery state of charge. In most alternate energy systems there is no permanent 120 VAC connection. The wind, water or solar source is what maintains the charge. In those situations the batteries should be run through an equalization charge (higher voltage charge, about 10% higher than the usual highest rate) once a month for best battery life.
That brings us to the point that when you are totally off grid there is no place to plug in a trickle charger.
Batteries that are allowed to sit and discharge then not used for six months or more may be sulfated so badly they will not come back. Some of the new PWM chargers may bring them back but don't count on it. The Poor Man Guide recommends that even if you get an old forklift battery to rejuvenate, it should have some charge in it and even then you may be talking a month or two with the pulser charger on it to bring it back.
In general batteries that are cycled daily will not get sulfated so badly.
One solar professional I talked to recommended equalizing clear up to about 30 volts for several hours on a 24 volt system to desulfate and bring the capacity of older batteries up. This may cause you to need to temporarily remove the batteries from your system as the inverters may cut off at that point. I tried it once and it did work -- I am a bit of a battery abuser and don't get up to equalize voltage very often.
When off grid you will likely have to kick a generator on once in a while to get up to equalize voltage unless you have a great quantity more panels than you need - which most likely wont often happen --- but it should. Regulators will prevent over charging when not equalizing.
Glenn, there is a solar powered pulse charger available. Mainly used for boat batteries can be used anywhere you have sunlight.
The solar panel is a flexible piece of material about one sq ft in size or maybe a little smaller. Obvioulsy, it is only a trickle charger but for applications where you are off grid seems like to me it would be worth trying? There is a chain called 'Battery Plus' around here and they have them in stock and I believe the retail price is around $60 but could be way off base with that.
Okie Bob
If I am not mistaken, the Xantrex C40 I have is a pulse charger. PWM - pulse width modulation -- I don't know much about it though. The small chargers are great for equipment etc that is not used but expensive per watt for other uses. Things should typically be under $5 per watt.
A small charger would not keep up with my parasite drains -- phone chargers - light on microwave-coffee pot clock - etc. :)
IMO, an alternate energy system that is being used doesn't have any need for a small "trickle" charger of any sort. The system batteries usually need to be charged at higher rates because of supplying power for the electrical loads it was designed to power.
Small low rate chargers (being run off a 120 VAC circuit or small special purpose solar PV panel) are mainly useful for maintaining a state of full charge in a battery that is waiting to be used for something. One thing to watch for is having a charge rate that exceeds the rate of self discharge by too great a factor and cooking the battery... resulting in low fluid levels and plate damage. That's almost as bad a letting the battery sit there at a low state of charge for extended periods. If you're like me you may try to keep an eye on fluids, etc, but sooner or later time manages to slip by and when you look the fluid is lower than you expected.
This is a wind generator thread and I don't know a lot about them other than I know they require a diversion type of controller as they cannot be switched off like a solar PV panel can. The information below on PWM and MPPT chargers comes from my solar power research & experience.
There's absolutely no doubt that PWM controllers are vastly better than the older relay or transistor controllers, still found in some cheap units. The newer MPPT controllers are even better, really coming into their own providing the most available power under cloudy skies. They're also better in winter when you are using more power and not making as much due to shorter days.
Quote...PWM - pulse width modulation -- I don't know much about it though...
PWM info here... from Mornigstar, producer of PWM units
http://www.morningstarcorp.com/support/Why-PWM/why-pwm-1.shtml
Be sure to click on "Next" at the lower right to read the subsequent pages
controller info here...
http://www.solar-electric.com/charge_controls/solar_charge_controllers.htm
MPPT info here...
http://www.solar-electric.com/charge_controls/mppt.htm