Michael B's posts

hey, great idea tom. why did'nt i think of that?

whoa tom, easy tiger! not trying to step on any sensitive toes there. my reference to doing more homework was not directed towards you but James. he is the one who is going to harm his batteries if not doing things correctly. the only reason i suggest more homework be done is because my answers (suggestions) are not complete. my assumption is that it is not a problem with discharging, but charging. i realize that these are jells. his solar and generator are probably both sent through a charge controller that has its setpoints for jel batteries (something like 14v max as opposed to 15v or there abouts for an eqalization charge). this would (could) cause chronic undercharging, or at least not bring all cells up to even (ever). as the cells become unbalanced, the problem will be magnified through repeated charge/discharge cycles, growing a bit more pronounced each time. i dont believe the problem to be power (read as amps) but voltage. best of luck either way. -m

dear tom,
i beg to differ. i think perhaps an occasional (once a year?) deep discharge may not be terribly bad. but to drain them basically all the way down will do much more harm than good. these are lead acid, not nicad/nimh like the batteries on a cordless phone, or lithium as per a cell phone.
my guess is that they are not getting enough charge. this is why we have an equalizing charge, to bring all cells up to a full (over)charge.
on the plus side, sealed batteries (sla) are maintenance free. the down side they are maintenance free (unmaintainable). they also dont take an equalization charge well (irreversible offgassing, explosions, etc.). without looking, i think james said that he has had these for about 3-4 years. while thats not an exceptionally long life span, i would not expect a whole lot longer for sealed batteries under regular, moderately strenuous charge/discharge cycles (daily use, 30-40% dod, occasional undercharging).
you can apply an equalization charge, but it must be very carefully applied, at the absolute minimum voltage that will create an overcharge condition, and not for very long. i would hope that you do a little more homework to figure out for exactly how long and how much voltage to apply before doing so, if you should choose to take any of my advice (god help you!). -m

most everything on a car is 12v. this is why 12v is so much fun!

hey travis. there are essentially two different types of solar systems. one that is nearly 100% efficient, where all that excess is never lost is called grid tied. the other, the kind you have (and the kind i love) is called off grid.
the biggest problem i see with your plan (one of which i have given much thought) is with your lead acid batteries. lead acid, when not receiving a charge or when partially full, begin to corrode (age). so that extra battery sitting partially charged, just waiting for that day when that extra trickle comes its way, will be slowly (quickly?) dying. if you simply took that battery and parrelled it with the other, then you have increased your capacity by what your backup was going to be anyway.
a diversion controller (like a c40 on diversion mode) would be an easy enough solution to a full battery bank situation, but where to sent all that extra power? nicad or metal hydride battery bank (which does not suffer the same "under charge" problems? or perhaps an electric heating element (water tank?)? one of my favorites is a pump that pushes water up into a tank to be used later with a hydro turbine to generate on demand (a cheap solution i am sure!). let me know what you come up with and how it works out, i have been working on the same puzzle myself. -m

Hey wow! this sounds like a great idea. how much does one of these trees cost? What is it made of? plastic?
how about using the money you would have used to make fake trees (plastic?) and put it towards planting real trees.
unless you think i can burn your fake (artificial) trees in my stove to cook my food and keep me warm? would we use a diesel doser to bury your used up filters?
hate to be a kill joy here, just think some (un)common sense is in order.

ok, found a great site. what is being said makes sense as well.  http://www.windsun.com/Batteries/Battery_FAQ.htm#Battery Voltages
they have a nice little lesson on batteries. they say that lead acid is lead acid, sealed, gel, or flooded. full is full.
the only restrictions are as per charging. flooded like a little overcharge now and then (to mix electrolite as well as to bring multipule cells all to the same level of charge) but gel/sealed dont like much overcharge or to be charged to quickly.
happy reading, -m

just found on the trojan website 12.73v is what they consider 100% soc or a specific gravity 1.277. of course, if you are measuring specific gravity, then i guess that you probably measuring flooded batteries right?
oh well, the quest continues.

trent, try battery university (batteryuniversity.com). between them and the trojan website you should be able to figure it out. best as i can figure out you should still be sitting between 12.65 and like 12.8.
do us a favor and post any more specific answers you find. i am curious as well.
best of luck, -m

hi robert, any way to build a garage or covering for your cart? if you had the space, there is potential to build a roof with the optimal angle and exactly south facing. you would then be able to fit any modules (solar panels) you wanted. having the "best" angle can really pull all the value out of those modules. just a thought. best of luck, -m

hey marcin, looks like you have 4, 12v nominal modules (evergreen perhaps?). this makes 12, 24, or 48v system relatively straight forward. 25 batteries is not an even number, so something will have to happen there.
mppt charge controller will be the best charger available to you, but you have many cheaper alternatives. the mppt controller can potentially yield up to 30% more "juice", but if this is only temporary or emerangcy power then a pwm controller is a very viable option. i have a c40 and have had no problems with it. i got the optional display so i can see a little bit of whats going on. morningstar also has a huge selection at a reasonable price. i have never used their products hut have heard good things. i think displays are always good, unless you plan on having some other monitoring device ( like a trimetric battery monitoring). nice to know what is happening (or was happening).
try to pick an inverter or two that you like before you decide on a charge controller. some inverters have charge control features, others will affect your choice of charge controller (24v inverter with a charge controller that does not have a 24v option, etc...).

840w of solar sounds like just about enough to charge most any battery bank. the big question is how are you going to wire them all up? or maybe more importantly, what will you be using the power for? just a little power in your shed or maybe a car port for your rv? then you may want to stick with a 12v system. something for the home? then perhaps a 24v or 48v system would be better.
you have a lot of batteries all at the smaller end of amp capacity. you would probably be better running a 48v system to avoid paralleling too many strings (on both the battery end as well as the module end).
you will need to calculate what voltage you will be running at, then what the amperage will be, then what charge controller will be able to handle what you're pushing.
more info would be helpfull in answering more specifically.
what exactly are the modules? vmp? imp? -m

ps tom,
word!
-m

hi gergely and thomas (and everyone else. andy black has done payback calculators and calculations for years, and his computations are probably at least as good as yours (gergely) if not better. no disrespect intended, haven't even looked at your calculator. it's just that mr. black has been doing this professionally for years, giving seminars and working in the re field for a very long time. last heard he was working at ongrid solar. used to be that for "positive cash flow" it took about 10 years, but prices for most components have dropped and longevity, efficiency, and durability have all increased making that $ payback closer to 5-7 years and still shrinking.
but the truth is is that the payback is immediate.
you are no longer getting electricity from coal smoke. or nuclear waste. or a damned river!(spelling correct). or some giant corporation drilling holes into the body of the earth, spilling methane, sulfates, crude oil. or another country (happy places i am sure).
you may have thought that your calculator is not related to any politics, but that is silly. sorry. our every action is a decision and reflects upon the whole of the world (universe).
i still drive a ice. with any luck, soon i will have an electrical vehicle and will have broken yet another link in the dirty chain. hey, wow, just realized that i could charge my new "car" on my home grown electricity. can you calculate my payback for me then?
thanks, -m
ps, everyone check out storyofstuff.com

hey ray, modules are listed at their nominal output, with the potential of (in this case) 15% more than the listed output. in a small battery based system this can be great, but in larger strings can be very problematic. inverters and charge controllers have a maximum (and min.) voltage and current that
they operate within.
so yes, the plus side does add to the power output (on those rare days). -m

hi adrianne. not sure if it will help but i have found lots of sources or links to resources in a few places. alt e is one of my favorites, but you can also try treehugger or homepower. youtube is great if you know exactly what you are looking for. lots of cool methane stuff there. caiso shows current electrical production and usage for California. build it solar is another fantastic site. solar and lots more. nrel.gov is pretty good. the solar living institute has a whole bunch of general info, mostly classes you have to pay for. lots of information on "green" building. battery university is very informative as to battery specifics (maybe too much). and lastly, redrok is nothing more than links to links to links. best of luck and please, keep us all informed as to what you find. -m

hi matthew, yes they should all be the same size. whats more, they really should all be about the same age (or at least the same usage profile). all you will be doing is reducing the capacity of the 200ah batteries, and eventually potentially causing undue wear too to undercharging. two separate battery banks by adding an additional pwm (or other) charge controller? any way, best of luck. -m

Chainsaw!

Sorbari, sounds to me like you are not looking for an inverter at all, but a UPS instead. An Uninterrupted Power Supply will keep a set of batteries charged until power goes out, then whatever is plugged into the ups unit will run on the battery power until utility power is restored or the batteries get too low. These units are commonly sold at computer stores (for computers) and have very little capacity. I am sure someone makes larger units, or you could do like John D says and hook one up yourself with a transfer switch, inverter, battery bank, etc.. best of luck, -m.

Hey Max, this is one of the simplest and versatile charge controllers I know of. Mine is a c40, but the whole series operate the same. You probably don't need a display if you are going to use it solely as a dump controller, but I highly reccomend one if you are going to use it in charge mode.
To change functions all you do is move a little jumper inside the unit. Change your mind? just move it back. Best of luck -m

Mr. bob, i don't know a lot about hydro, but from the looks of it i would say
                       JACKPOT!
your sit looks amazing, not to mention beautiful. my guess is that you will have more electricity than you will know what to do with. this of course depends on exactally what kind of turbine you end up installing.
try some research on homepower (either .com or the paper version). Don Harris is a fellow who lives in the Santa Cruz mountains of California. he is very knowledgable, and the original manufacturer of the Harris hydro turbine (though it is now owned by another company). homepower has several articles on or by this gentleman, as well as many other informative articles on hydro.
you will probably need at least a small battery bank to "condition" or smooth the power, as well as a substantial dump load (large water tank in the paint shop?). whatever you end up doing, please keep us all informed. this is gonna be fun!

something in the 5 watt range.
let me explain. i started my system with a single 5w module, a 7ah sla battery, and a 150w inverter. then i found that my system was out of balance. after a bit, i ended up adding 2 more batteries, a charge controller, another module. wired things wrong, but nothing blew up and i learned quite a bit. now i am working on fusing, proper wire sizes, grounding.
this little system is now used just for little things, like charging the cell phone or my rechargeable batteries. running the stereo constantly through the summer (really non stop!). it has given me an idea of what i can expect. summer i can run the batteries constantly and they just suck up sunshine the next day. winter they must be babied, production drops to nearly zero. shading, proper angle and orenation , voltage drop, mid summer cleaning, etc. so much easier to fry a $20 charge controller and $60 or 70 in batteries than to add a zero or two to those numbers.
evergreen makes nice modules for offgrid stuff. i think that they make nice modules period. i also like kyocera. not to partial towards bp. not because of quality, more that they are a giant oil co. just my two cents. -m

Alan, I think we are close. LiFePo4 (lfp) are great, but they do have their shortfalls as well. They work great hot, but not as well as lead acid in cold temperatures. A lead acid cell, kept properly charged will live for years and years. Lithium batteries of any type begin to degrade the moment they are manufactured. LFP also have some of the worst c/rate of the lithiums. c rate is more of a determing factor for longevity on lfp than DoD. Their c rate may be equal to or worse than that of lead acid.
If your packs were big enough this may be acceptable for a solar system. For a scooter, just the reduction in weight would surly be worth it. I have a 36v, 12ah battery bank on my ride, and it weighs around 65lbs. Sucks.
Just like solar, the problem with lithium isn't it's particular ups or down, it's the up front cost.
A company by the name of Axion Power is supposedly developing a "light" lead acid. It will be interesting to see if it happens, but i'm not holding my breath... -m

Be very careful. Sizing a gen for off grid can be tricky (at least from my experince).
1 kw gen? Maybe running at max. More like six or seven hundred watt running at best fuel effency (not to mention longevity. Try running your car motor in the red for a while).
Rick and James are right. You'll need enough to run everything, plus have enough left over to charge with. Knowing  how much that is is important.
Need auto start? Very tricky indeed...

Ok John, heres another one for you, but you cant have much of a fear of death. An electric skateboard. I got mine from http://www.exkate.com/ . They aren't terribly cheap, but mine works great. Their charge controllers are not very reliable. Not a very home grown response, and may not be real great on steep hills (especially if you weigh more than 180 lbs. or so), but I enjoy mine. Good luck with your search, -m

Sounds like a pretty good setup. I also have an air x, but haven't really gotten it set up and going. Does it run well in conjunction with the modules? Any problems? I know that the manual says wiring with solar modules may "confuse" the air x's controller.

Wow, nice mix. Solar salad of sorts. By adding different batteries together you have basically put them all at the same capaticy as the weakest one(s). They are all very similar, so it should'nt be of much concern (although it would probably drive me crazy). That they all seem to need the same amount of water is a good sign.
I am interested to know how you have all your modules configered. Seperate charge controllers? -m

Charge your 12v batteries quickly and at a high voltage and they may read as high as 14 or 15v. Doing a proper charge, removing the charging source and then letting the batteries rest before taking a measurement will result in an accurate voltage reading. 12v batteries fully charged should read 12.7v. Fully discharged at 11.7.
Your turbine has a voltage adjustment screw. It may be set too low, but I would highly reccomend that you go back through that that instruction manual. Check out page 22, section 4.1.2 for that blinking light issue. Or even pg. 24. Probably the whole thing though. Lots of important info in there. Best of luck, -m

Tempered glass.
Cleaning agents are getting worse, not better. Try a garden hose. Unless they are totally caked with thick dirt, the derate factor will be less than your wire losses.

Hey Roy, don't let your head explode! Be excited because you are entering an amazing world. Much of this stuff is relatively new, and almost all of it changing fast.
Have you checked out Homepower Magazine? They also have a decent website. They are probably a great place to start. This website here is also a great spot, as well as the staff. Every employee I have spoken to seems to be very knowlegable. I bet the janitor knows more than I do.
Most of what I have read\heard is that solar hot water has the fastest payback. Does that mean it is the best for you? Hard to say seeing that It sounds like you are electricity dominate.
I am a big fan of radiant heating.
All in all, I feel the best "first place" to start is conservation. Not very sexy, but it is the real foundation of renewable energy of any type. A load analysis will help you see what you are using and in which areas you can start  making  reductions.
Electric base board heater - 1500 watts
5 100 watt bulbs           - 500 watts
1973 green fridge          - 8 billion watts
all equals about 4 kw of photovoltaics ($50K ?)

Radiant floor heating      - 5-10 watts
5 cfl bulbs                - 60 watts
high efficiency fridge        - 175 watts
this equates to like .8 kw pv.
Happy studies and hope to hear about your progress. -m