Ken Hall's posts

1) The straight math answer is about 30 hours, or 7.5 days.  I would suggest a 20% DOD (depth of discharge). That will only take about 12 hours to replenish. The smaller DOD should double your battery life.
2) Do NOT mix different capacity batteries in the same bank.  You should not even mix new and old batteries of the same type.  It can set up circulating currents.  Like a chain, your battery bank is no stronger than the weakest link. And sometimes it seems weaker than the weakest link.
3) NO, see #2
4) NO to both panels. You don’t want to mix them in the same array. But yes, you could hook up an 80 or 100 watt panel with that controller.
5) Yes, you will need a larger one before you add a second 100 watt panel.
6) Three 100 watt panels wired in series is 100 watts at 36V. Wired in parallel, they are 300 watts at 12V. So, just parallel them.
7) By the time your system is large enough to require 24 or 48 volts, you should have a 115VAC inverter. You shouldn’t have to worry about 12V.
8 ) You can’t get PV charge control and LVD from one C35. You will need it as a PV charge controller. If you want LVD (and reconnect), you wire a second C35 between the battery and the load, as a load controller.

Power from the PV array would be used to charge the batteries (if low) and to supply power to the “backed up” loads. (Loads that have been transferred to a new distribution panel off of the inverter) If your power usage on those circuits is low during peak sun hours, you will end up with very little power production from your PV.

I would suggest you rethink your position and type of inverter. Buying a fully integrated grid tie inverter with battery backup, so that you do NOT sell power to a “Reliable grid”, doesn’t make much sense to me.

You can build a solar system and transfer certain loads to it. Operate it as a stand alone system with grid backup.  That would allow you to use all of the solar that you generate.

At the other end of the spectrum, is a grid inter tie without backup. If you do not buy a large battery bank, you could invest that money into more PV.  With a larger array, you could sell more power and possibly justify the additional meter and the monthly fee.  As long as you are generating the solar and making income from it, does it really matter to you, who is consuming it ?

I looked at 
http://www.solarpowerrocks.com/mississippi/
They indicate that you may have a five cent spread between your purchase price and the solar selling price.

I would suggest that you don't worry about it.  Buy the trailer system now.  Live with it for a while. Then design your house system. It will help you make better decisions about the house system.
When you get the house done, you can sell the "trailer" system to someone. It won't be wasted money.
The only way you can do what you are asking, is to get a lot of professional help to design the house system now. Then purchase selected pieces of it for your trailer system.
Don't even count on reusing batteries. Mixing older batteries with newer ones, is not generally a good idea. They will most likely be different sizes anyway.

Jerry:
I am not the best person to ask about real cold weather for long durations, and batteries (California). Perhaps someone with more cold weather experience will jump in here.

What I can tell you is that I do not like to see a working battery get below about 50 degrees internal temp. The batteries have a large thermal mass, so they do not change temps rapidly. Using an insulated battery box helps keep the ambient temp extremes (hot or cold) from affecting the internal temp too much.
The float charge and the insulated box will help, but I would still expect the battery temp to drop over time. If you do make a snow trip, you would need to treat the battery as cold, even though you may have heated the cabin to warm and toasty.

The other topic that I'll toss at you is the box venting. I would give some thought to venting the box outside the cabin. While that may raise some cold weather issues, I would not want a battery bank venting fumes and H2 into the living space of a small cabin. During warm weather, heavy battery use, equalizing charges, etc, you can get a fair amount. The smaller your cabin is, the larger this issue would become.

Ken

I am not aware of any problems with the marine disconnects, when they are from a good company and sized correctly.  I've used tons of them on DC installations, both in smaller Alt Energy applications and on boats.  Most of the heating of electrical equipment happens when you push it above 90% of its rating. You won't be getting close to that.  I am not pushing the switch over James recommendation, just replying to your question.

I like his recommendation of the igloo cooler. I don't remember where your cabin is, but have the impression that it gets cold there in the winter. I was going to ask where exactly you are going to put the batteries and how cold you would expect that area to get in the winter.

When you say 4 AWT I am assuming you mean 4/0, not 4 AWG.  I’ve seen that terminology from a couple of “inverter stores”. It’s a bit of a sore point with me. 4/0 is “four aught” or sometimes “ought”. It means four zeros.  Call me old fashioned if you wish, but I can’t help but wonder how much they know, if they don’t even get the name right.

I don't understand why you are considering your PV amperage for the diversion controller.
The PV should be connected through a solar charge controller. The wind through a diversion controller. The two systems should either meet at the batteries, or in a DC source center.

Jerry:

Unless you plan on down sizing the wiring, I do not see any advantage to downsizing the fuse.

You need to use some type of disconnect upstream of the DC fuse.  The disconnect is located as close as reasonable to the positive battery post.  What that disconnect looks like probably depends on who is inspecting your work.  In many cases I’ve used a marine type battery switch.
http://store.altenergystore.com/Enclosures-Electrical-and-Safety/Miscellaneous-Electrical-Parts/Switches/DC-Switches/Blue-Seas-OnOff-Battery-Switch-300-Amp/p250/

I’ve also had  “Nervous Nellie Inspectors” insist on Industrial grade DC load break disconnects.  That gets a bit more expensive.

Ken

The XW6048 is a 48vdc inverter. It will not work on a 24vdc battery bank. You will either have to go with the XW4024, or plan on a 48vdc battery bank.

Jerry:

A single Xantrex C series controller is designed to function as a charge controller with PV Panels.  When you connect it to a wind or hydro generator, you set it to function as a diversion controller.  Attempting to use it as a charge controller from some other power supply usually will result in damaging one or more of the power supply, charge controller, or batteries.

I think you should use the Prosine regardless of the battery size and loads. If there is a difference in efficiency, it is only 1-2 percent while running. Your load estimate will have a larger error than that. They are essentially identical in standby, which is where they will be 90 plus percent of the time. The added features of the Prosine make it worth the small difference, if it exists.

The battery charging efficiency of the Prosine also needs to be considered. It was designed to be as efficient as possible on 15 amps input.  Many of the larger battery chargers out there, are less efficient if limited to a 15 amp input.

My bet would be that your total system efficiency (generator run time, power into batteries, and power out) will be better with the Prosine. For a MorningStar based system to come close, you are probably looking at a $400-$500 battery charger. 

You are right about installing the PV system before fall, if you leave the batteries at the cabin.  As long as you are making regular trips in for construction and fully charging the batteries before you leave, not having the PV should not hurt the batteries.  But if you find your time interval between trips starts stretching out, or you find that time before you leave doesn’t allow the full charge, that would also be signal to start hauling them home, until the PV is installed.

But meanwhile, I think you need to backup and re-think what you are doing here.  You started with the idea of a solar system.  You have the inverter/charger and a generator. You need the charge controller, PV panels, and batteries.

The price of the batteries to support a large microwave/toaster scared you. You are downsizing the solar. Meanwhile, the costs of an ac system that you did not originally mention are growing.

Your 3500 watt generator is going to be good for about 30 amps. Normally, this is phase A and phase B, good for 15 amps each. If one phase goes to charge the batteries, you are still limited to 15 amps for the kitchen. That will not run the microwave and toaster at the same time.  If you take both phases for large load use, you have to perform some type of switching, to bring the battery charger into play.  This will happen whether you build in a cabin wiring system, or if you just use two extension cords.

To support the battery charging, microwave and toaster at the same time, you will be buying a 4500-5000 watt remote start generator (or larger).  What do you think that will cost? What about the duplicate wiring, switch panels, etc., that you will need ?
I don’t think you have been looking at the costs of that.

I would toss the toaster. Use a non-electric stove top toaster. They are still available.  I would really give some thought to the microwave.  Just how much is it worth to you ??  Whether you put it on the solar system or an ac system, it is still costing you money.  The only way you can run it inexpensively is with the generator you have.  If your family really “needs” the microwave, electric toaster, hairdryers, etc, make them run an extension cord in the window, and pull the cord on the generator. They won’t get used nearly as much that way.

The way to get out least expensively is size your battery system for the lights, fan, tv.  Use the inverter that you already have.   Save a lot of dollars by not having two ac systems. Put a few of the dollars that you are saving into your battery bank/PV panels. If you size it at 450AH, it will support additional small loads easily.  Conversely, if your lighting/tv/fan estimate turns out to be on the low side, you may already be in trouble.  You will find it far easier to live within the 450 AH rather than the 225AH.


Ken

Jerry:
What do you mean with “questionable solar exposure” ?? This is the first mention of that.
Also, what is the meaning of “future PV panels” ?  Is it just a general reference that the entire system is in the future, or are you thinking that the PV might be installed later than the batteries ??
Also, what size generator are you thinking about ?

Meanwhile, you can toss the idea of feeding a solar charger with a generator based dc source.

Ken

Jerry:
I am glad you took the warnings about battery sizing to heart. But I think you misunderstood the message.  There is nothing wrong with using the large inverter. You just have to be careful not to put too much load on it.

You can install the Prosine off of a breaker in your main electrical panel, using a 15-20 amp breaker. You tell the Prosine what size that breaker is.  You run the inverter output to another distribution panel, usually next to the existing main panel. You then transfer your lights and a couple of outlets to this panel.  This will involve some rewiring. How much, I can’t tell you.  In some cases it is easier to run a new system (wiring, lights, and outlets) off of the new panel, rather than to try to unscramble and reconnect “parts” of the old system.  It might look funny having 2 ceiling lights in the same room, but that would also give you generator driven lights, should the inverter/battery system fail for some reason.
I like to use different color outlets or label them, so that everyone has a visual reminder of which outlets are the inverter outlets.

By limiting the outlets (and lights) that are connected to this inverter distribution panel, you are limiting the load that you are placing on the inverter/batteries.  All other electric, remains in the main panel.  Your generator is connected to feed the main panel.

When you fire the generator to support the larger loads, the Prosine will limit the current that it draws for charging, so that it will not trip the breaker.  Because you tell it what size battery you have, it will limit the charging current to the battery to a safe level.

I would still give some thought to increasing the battery size. 4 T105’s would give you 2 days storage at 20% DOD.  Nice to have on that overcast weekend when the generator fails.  Also gives you better discharge/charge rates.  But whether the benefits of the larger battery, will offset the cost increase, is ultimately your decision to make.

Ken

Walt
The batteries are the heart and sole of any power system. Buying them on a dollar per amp hour basis makes about as much sense as hiring the cheapest computer programmer you can find. You usually get what you have paid for.

The first thing you need to do is, to identify and quantify how much load you want to support for how long.  If you intent is really to run the entire house without cutting back, you can do that. But it will be expensive.

A few years ago, the average house in NY used about 500kWh a month.  How close do you come to that average ?  And how many days (or hours) of power do you want, before you have to run the generator.

The Alt-E library has some good resources and some calculators.
http://howto.altenergystore.com/

I would suggest do a load inventory of the loads that you wish to support during the power outages. Then size the system accordingly. You will save more money by supporting only the “emergency loads”, than you will by skimping on the battery price.
 
Ken

John.
I would connect the load, to the load terminals. It will allow the controller to monitor and control all loads. (Not just when sun is out)
The controller will protect your battery against overcurrent and overtemps caused by load. It also limits battery discharge to 11.4 volts. Preventing discharges below this limit, will prolong battery life.

Ken

John:
The Prostar Manual has easy to follow instructions.  If you don’t have the manual, you can get it here.
http://store.altenergystore.com/mmsolar/others/Morningstar-ProStar-Manual.pdf
If you have questions after reading it, you will be able to ask specific questions.

Also, because there are some “real good deals” out there, please confirm that you do NOT have the PS 30M-PG (positive ground version).
Your statement that “We won't be running any direct loads”  also needs clarification as to what that means, exactly.
Ken

Jerry:
Even though you try to make the wires identical, you have no guarantee that they are, or that they will stay that way.  One or two broken strands will change things. You end up with a strong battery and a weak battery.
The weak battery will draw the strong one down to its level.

Parallel them and use the larger cable/fuse.
You would also be looking at additional cable costs in the future, if you decide to expand. The full size cable now will handle any battery size in the future, up to the limits of your inverter.
Ken

Jerry

Your list is a good one. Following it, will prolong the battery life. In daily use, the batteries would have a 3-5 year life expectancy. You can get 4-8 if they do not get abused. Abuse them on a regular basis, and they will only last a year or two.

You asked again about limiting surge loads.  Surge loads are very short duration, lasting from a few cycles, to several seconds. They are most commonly caused by motor startup. While they may draw large currents, the short duration of them will not normally harm the battery. 

Although the inverter makers call anything above their rating to be surge capability, most of this is really peak loads of limited duration. So, are you asking about surges ?  Or are you asking about peak loads of short duration ?  (eg 1-5 minutes of microwave, 5-10 minutes of blowdryer)  These are the ones that I worry about controlling.

The DC fuse is there to protect the inverter. While it would also provide some level of protection for a large battery bank, it doesn’t provide any significant protection for your small bank.  Downsizing the DC fuse to 200amps would not be worthwhile. It would just limit the inverter, without adding significant protection for your battery. A sustained 200 amp load will do almost as much damage to your bank, as a 300 amp load.

IIRC, the Prosine uses a 300 amp class T fuse. It takes about 100 seconds at 600 amps to blow it, or about 1,000 seconds at 450 amps.  That is why you can peak and/or surge the inverter above 3600 watts.  And the inverter is supposed to load limit itself, before blowing the fuse.
A 300 amp breaker is supposed to kick out within a few cycles of exceeding the 300A. It would effectively limit the inverter to 3600 watts of surge/peak.

What is your current wiring situation in the cabin. What is the main breaker ? How many 15 amp circuits do you have/plan ? And how is the generator wired in, if it is ?

ken

I think the 4 GC2’s would be better for your use.  450 amp hours, vs 390 amp hours. Equally important, is at about 62 lbs apiece, they will be easier to lift than the 121 lbs, when you have to change them.  You will probably be changing them often. Until you learn a few “hard to learn” lessons.

An off grid system has to be sized for it’s intended use. It also has to be balanced, batteries, inverter, generation, and USAGE. You are putting a larger inverter on small batteries, with smaller generation, and expecting not to hurt anything when you ask it to do a bigger job than it was sized for.

The fact that you are even considering the possibility of a microwave and a toaster being operated at the same time on this size of battery, suggests that you are in for a “learning experience”.  The best solution would be don’t have either one in the cabin. Second best would be a single outlet, forcing people to switch plugs and preventing simultaneous operation.  Put the refrigerator (assuming its electric) on a switched outlet and turn it off while preparing meals (or other peak periods), to prevent it from kicking on and further peaking the load. Don’t have a convenient plug for that large power tool. Drag out the generator for large loads.

Everyone using the cabin has to be load conscious. Otherwise, they will act like they are at home with an unlimited source.  When you put 2 or 3kWh on a system designed for 1kWh, your batteries will have a short life.

You might want to purchase a Kill-A-Watt meter and put it on some of your appliances and get some hard data as to how much you really use them. Beginners tend to underestimate how much use they actually get. You also learn such things as a 1000W microwave draws close to 1500W. (The 1000W is the output, not the electric draw)

If you size your system for 1kWh, you have to learn to live within that allowance. If living within that allowance is unacceptable, you have to increase the allowance.

If you want more power, do a worse possible estimate. Cabin full of people, extensive microwave, toaster, blow-dryer, and large power tool usage. Then size your system for that.  It will cost more money up front, but changing batteries every 1-2 years is not cheap.

Don’t look at tripping breakers as a nuisance. Tripping breakers in an off grid system is a gentle reminder for everyone, that someone is exceeding your predetermined limits.

Your question is confusing.  You say that your loads are 750 watthours or 882Wh at 85% efficiency. That is 73.5 amp hours.  Then you are talking about peaking at around 200 amps.  It shouldn’t happen.
If we pack most of that into 5 peak hours of usage, that would indicate a typical load of about 15 amps. Your peak loads probably won’t be more than 30-40 amps, unless there is something you haven’t told us about.

Batteries discharge rates (and charge rates) are discussed at C rates. Your 225 amphours is most likely a C20 rate, 20 hours to discharge or about 11.25 amps.  When you discharge it at a higher rate, you will not have the same capacity. You will get about 180-185 amphours out of it at a C5 rate (45 amps) or about 105ah if you use a C1 rate (225amps). A dead battery in less than ½ hour.

Your 73.5 AH gives you a state of charge (SOC) of about 67% on a daily basis. I would give some serious thought to doubling your battery bank. If you make it a 450 AH bank, that would prolong your battery bank life. It will give you about an 83% SOC on a daily basis, and 2 days power before you hit the 67% SOC.  It would also give you a 22.5 amp C20 rate. 

Without hearing about the charging side (panels, generator?) we really can’t talk fusing. But if your peak load or charge will actually be 40 amps or less, I would be tempted to fuse the system at about 50-60 amps and consider anything above that value to be a dead short.

Juan:
AC generation is far superior to DC for your system. You can convert AC to DC with a battery charger if you do go with battery banks.

I don’t think that you want to try to put your entire system through a battery. The cost of batteries, inverters, etc would probably be prohibitive.

A simple formula for calculating power is liters per second X head in meters X 9.81 X system efficiency.  Using the 750 gpm (47.32 L/sec) and 80 feet of head ( 24.38m) the formula would be 47.32*24.38*9.81*0.54= 6111.407 watts
If you increase the head 10 feet it becomes 47.32*27.43*9.81*0.54= 6875.96 watts
So, you would pick up about 765 watts simply by increasing the head 10 feet.

If you increase the nozzle size to 2.125 inches at the 90 foot level, it will increase your water flow to about 840 gpm (about 90gpm more than you are currently using).  The formula then becomes 53*27.43*9.81*0.54= 7701.307. So you pick up about 825 watts from the increased nozzle size/flow.

By the way, what is the diameter of your wheel ? And what size breakers do you have on the phases ?

Before making any dramatic or costly changes to your system, I would take a look at time shifting some of the loads to time periods where more generation is available. And Energy conservation where possible.  Also, you mentioned some large equipment hammering your system.  Is that equipment automatic, or is someone operating it.  What about your water system, are there any large pumping loads or water heating loads ? If so, are they falling during the overloaded periods ?

Ken
PS The calculated numbers are based on balanced phases. With the imbalance you are experiancing, your net gain could be 1/3 of the numbers shown.

"using a 3 X 24amp old AEG generator hooked up to a water turbine"

What do you mean with 3 X 24 amp Generator ?  Is that a 3 phase generator with 24 amps per phase ? (What is your generation voltage and how many rpm ?)

If so, how are you keeping the phases balanced, load wise?  Part of your problem could be having the majority of the demand on a single phase, at any given time.  The generator probably will not produce 24 amps on one phase with minimum draws on the other two.

Running some rough numbers for 80 feet of head and about 120 feet of 14 inch pipe, I get about 750 gpm with the 2 inch nozzle and about 6100 watts. With the 1.5 nozzle, that drops to about 400gpm and 3200watts.

A new single phase alternator would solve the imbalanced 3-phase problem, but you will still be limited to what you can generate with a 2 inch nozzle, or about 6100 watts.

My guess is that your system was originally designed for a larger use. Something on the order of a 3.4 inch nozzle at about 2000 gpm.
 
Anyway, 3.2kw would give you up to 76.8kWh a day if everything was constant. My guess is that your system runs at a constant water flow, and then the excitation is varied to produce the power required.  If that is the case, you may have a lot of un-used generation during periods of low demand. So adding batteries and an inverter could store this unused power, for periods that it is needed, with or without PV.

As far as measuring your generation, a power monitor would do it.  Or, a watt hour meter like the one on a house. You might need three, if they are single phase and you are generating 3-phase.

"the reason I did not minded about sizing was because I rode that if I am going to be off grid and count with a generator, then the size of the bank does not necessarily need to be precisely calculated."

Jorge:

Getting by with a smaller battery bank because you have a generator, is a false economy in my book.  You can do it, but you are going to pay for it in a shorter battery life.

Battery life is directly related to how deeply you cycle it. As an example, look at
http://store.altenergystore.com/mmsolar/others/USB_AVG_Life_Cycle_Graph.pdf

With a 20% DOD (depth of discharge0, it will survive about 2800 cycles. 30%DOD will drop it to 1800 cycles. At 50% DOD,  1050 cycles. At 80% DOD, you are down to about 550 cycles.
While the total number of cycles may vary between batteries, the percentage drop in the cycles is quite typical for all flooded lead acid batteries.

So, would you want your battery to last 2800 cycles (over 7.5 years) or 550 cycles (about 1.5 years) ?  Personally, I would shoot for a 20% DOD on a daily basis, with no more than a 50% DOD in an emergency basis.  With a generator, you can eliminate the reserve capacity that a stand alone solar system would need for cloudy days.  But in going below that point, the greater your DOD, the shorter your battery life will be.

I would suggest that you attempt to quantify your loads, to properly size your battery bank. There is a load calculator at
http://store.altenergystore.com/calculators/load_calculator/
Or you can make your own spreadsheet.

While a bit time consuming, it will be worth it in the long run.  A side benefit is that it will point out the loads that either need reduction, or would be the easiest to reduce through conservation measures.

I think you should plan on using less expensive batteries such as T105’s (or equivalent) which typically have a 2-6 yr life. Or possibly L-16s, which typically yield a 4-8 yr life,  for your next battery. Either would be less expensive to replace, if you do shorten the life of it.  After you have learned to prolong the battery life, then you can move up to the forklift or other premium batteries.

I would recommend that you use a battery temperature sensor in conjunction with your charge controller and with your generator driven battery charger.  I would also give some consideration to jumping your battery bank to 24V at this time. It would help with your wire sizing and reduce the number of charge controllers that you will need.

I would also recommend that you start with all brand new batteries. Depending on how far you have discharged them, you may have already used 25% (or more) of their cycle life. Putting them into a battery bank with new batteries, they will shorten the life of the new batteries to about the same level.  Best to sell them to someone looking for a bargain, and get a fresh start.

You didn’t say what your inverter is.  If it doesn’t have good load control features, I would consider installing a load controller between the inverter and the batteries.

Ken

Jorge:

Battery banks are sized based upon loads, not generation.  Since you provided no load data, I can understand people being reluctant to comment.

We are also forced to assume other things such as is this a 24vdc system ? The more information you can provide, the better the comments that can be returned.

Assuming that your loads match the generation fairly closely, you would be pulling the 16 battery bank down to about 63 percent state of charge on a daily basis. That is a little undersized.

When you expand to 16 or more batteries, you need to purchase all new batteries. The older batteries will not mix well with the new. 

If you operated the four 8D batteries in parallel with eight golf cart batteries, you have an example of what can happen on mixing different size/age/types batteries.

Ken

You are correct in saying that you used 57.5AH.

If your battery is drained at the end of the 150 minutes, you would have a battery capable of 57.5 AH at a C2.5 rate. It's capacity at a C20 rate would be much higher. (The published AH rating for most batteries are at a C20 rate, although some MFG use the C100 rate so that they claim a higher rating.)

My guess is that your battery has a much higher AH rating. Cycling a battery at a C2.5 rate would result in a very short life of the battery. If you know the make and model of your battery, the specs are easily found. Dimensions can often be used when a model is not known.

There are a number of solar industry associations. They do lobby for producers, when the two interests align. I am not aware of a solar homeowners association. Here are 2 of the industry associations.
California Solar Energy Industries Association
http://www.calseia.org/
Northern California Solar Energy Association
http://www.norcalsolar.org/

You should probably contact PG&E, SCE, and SDG&E directly to inquire about what meters they approve, and what their meter charges are. The big 3 do not always agree on things. Muni’s can also go their own way, but they will usually be in line with one of the big 3.

I think that the “bi-direction meter charge” you are referring to, may actually be a TOU meter charge.   In the PG&E service area, the standard non-TOU meter has been a bi-directional meter for many years.  Many solar systems have been installed on those meters with no additional charges.

Meter charges have been associated with TOU rates (no solar)since the beginning of TOU rates about 15 years ago, or so. (Despite the availability of TOU rates, only a very small percentage of residential customers have switched over to them.) There is a one time upfront charge for the meter (Less than $300, the last I knew).
 
In addition, there are DAILY meter charge rates. I assume that they are for the data handling costs and data links.  (Hundreds of meter readings to be stored and calc’ed each  month vs one). The actual charge varies with the particular rate schedule you are on, ranging from about 5-40 cents a day.  Supplying your own meter would not avoid these charges.

I am not sure if a residential customer can supply their own meter.  The customer furnished meter situations I was involved with, were on an industrial scale, not residential.  In those cases the customer was buying the meter and associated equipment and supplying it to the utility, to avoid the utility overhead costs.  (The utility became the owner of the metering equipment, even though it was customer supplied.)
 
After SB1, the customers (with solar) would have to switch their standard bi-directional meters for a bi-directional TOU meter, incurring both the one time charge for the meter and the daily meter charges.

My understanding of the current situation (post June 7), is that it is customer optional as to whether they go net metering with their standard meter, or go TOU per SB1 and incur the meter charges.  My hope is that it stays that way in the future.

Sounds like you have been getting bits and pieces.

The CEC Rebates are now for newly constructed homes, only. Rebates for the existing homes are now the Public Utility Commission (CPUC) responsibility.

The CPUC rebates will be declining in future years.  We are currently at step 2 which pays $2.50 per watt installed for residental applications. This can be "up to half" of the cost (assuming you build a $5 per watt system), but it is definately not as generous as the previous 50% of installed cost. (Step 2 covers 70MW of installations, Step 3 will be 100Mw at $2.20 per watt)

California was a net metering state.  CA Senate Bill 1 mandated that solar go to time of use (TOU) rates. It was a well intentioned law intending to pay more for the solar energy generated during the day, than the cost of power at night. That is, to increase the profit margin of the solar homeowner. However, it had the unintended consequence of driving up the bills for people that did not generate 100 percent of their daytime usage. It was especially noticable in the warmer areas of CA, where air conditioning loads drive daytime usage.

Assembly Bill 1714 gave the CPUC the authority to delay the TOU requirement of SB1. They suspended it effective June 7, 2007 and will delay further implementation of it until after the new TOU rates are developed for 2009.

My guess is that most of the unhappiness was associated with the TOU rates and that has been changed.

James,

I have been thinking about your statement  “The lesson here is to use chargers designed for sealed batteries. “

I agree that the charger type (and/or it’s settings) needs to match the battery type.  But is that really the lesson here ?

Perhaps the real lesson is to select the battery type that is best suited for the application.  For most alt-e systems, I believe that the flooded lead acid is the best choice.  AGM, gel cells, or other sealed batteries should only be used in limited applications where there is an extremely powerful justification for them. The extra money spent on them can usually be saved, or it is better spent on a higher quality flooded cell, a battery monitor, or other betterment of the system.
 
“Maintenance free” is a powerful selling point. However it generally means that the manufacturer did not provide access to the cells, so maintenance within the cells is impossible. It does not mean that the battery could not use the maintenance, just that you cannot do it.

Nor does it eliminate the need to inspect your batteries, clean connections, etc.  I have yet to see a “maintenance free” battery bank out live a well maintained flooded cell bank.

“Maintenance free” batteries also preclude the use of one of the most useful battery diagnostic tools, the hygrometer.

I took another look at your “How-to” section, which I think is a great resource. Battery sizing is covered, but I did not see anything on battery type selection, maintenance, or FAQ’s. Did I miss them, or are they yet to be added ?

Ken

PS For a battery bank that is not going to be maintained, perhaps the extra money for maintenance free batteries, is well spent.

Your posting lacks the details needed to help you.

The term "state inspectors" doesn't help. Most places I've worked, you are dealing either with a city or a county building inspector and/or a utility employee. And, yes, some of them apply their own interpretations of the rules, particularly when they have not worked with the systems very much.
So what is the official name of the office/department demanding the certification ?

Giving us more specifics on the UL certification "desired" and the model wind turbine you have, would help. The statement that Southwest is not UL certified does not help.  Companies are not certified, small wind turbines are. If I recall correctly, the Southwest Air 403 was the first small turbine to be UL certified. So what model do you have?

Also, what make and model is your diversion load ?

Sounds like you experianced thermal runaway or "boiling" of the batteries.

This could have been caused by the batteries not being that low on charge. Or, the warmer summer time temperatures as opposed to colder temps on your previous charges earlier (winter/spring).   

Many of the cheap automotive chargers simply claim their low setting as a float charging cycle, while in reality they simply provide a continous charge. For real float charging, you need a temperature sensor on the battery. A real float charger with temp sensor will shut the charger off when the battery temp gets too high.

When you boil the batteries, vapor pressure builds inside and the vapor escapes. When it hits the cooler ambient air, it condenses.

This one time occurrance is probably not a problem. However repeated occurances will cause the electrolyte levels to drop to a point where you will loose performance. 

One of the great advantages with flooded batteries is that you can add water or electrolyte to make up for the periodic loss of electrolyte.

You are not going to have 14 hours of heavy sun a day.

You need to use "hours of full sun" for calcing your PV panels. The highest rating in the US is just over 7 hours in the southwest or southern Florida. It is only about 4.5 in the northern areas of the lower 48. These are the best figures for summertime. If you do winter camping, different figures must be used.

So, to provide 3600 watt hours a day, you would need 600-800 watts of PV panels.
You will also need a minimum of 600 Ah of batteries.
In addition to the inverter, you will also need a charge controller.

If you provide some more details, (what your 300W load for 12 hours is, what general area your camping is in, what months you camp, and what is the make and model of your innverter) more specific comments would be possible.

Wessel:

Why you would drag up a message that is about 2 years old and reply to it ?? (other than to get a little free advertising)

Also, have you asked permission from the Alt-e store to promote your business on the forum they sponsor ?? I am sure there are different opinions out there, but I feel it is unethical to do it without their express permission.