David Ames's posts

Posted by David Ames on Mar 29, 2009 10:57 pm

#121 -  Renewable Energy > RE General Discussion > Re: Two panel, one charge controller aboard sailboat..Questions???
 hello stephen.

 ahh, life aboard. can you tell us more about your charge controller model # and the proposed placement of your second module? ie: distance from first module and from your controller? we may indeed want some kind of isolation here.

Posted by David Ames on Mar 27, 2009 04:16 pm

#122 -  Renewable Energy > Technical Discussion: Other > Re: mixing solar panel voltages within a single solar array
 hi john,

 just my opinion here..i really think it would be wise to stick within the pw1000 family of modules, you might get away with the 95w or the 105w to mix with those 100watt modules you have but i would not wander too far away from there. the reason here is that each module has a unique i/v curve that the mppt controller tracks and we can throw the controller a curveball by mixing the array with different modules. be warned that there are non-ul approved pw1000 modules lurking out there and our inspector will be looking for the ul rating with a grid tied system.

"Are strings considered to be in parallel? Could strings be run at different voltages, basic question but I dont know how this inverter is designed."

 yes, with multiple strings the strings are in parallel.
all strings in an array have to be at the same voltage but you can run separate arrays at different voltages on separate inverters.

"Anybody know where I could pick up some PW1000's. I've tried E-bay?

There has to be some distributor out there with a couple laying around:)"

 i agree, you were able to find those four. just a thought here..if you find someone running one you might offer to trade it for a new module of their choice?

 are we having fun yet?

best regards, dave

Posted by David Ames on Mar 27, 2009 03:41 pm

#123 -  Renewable Energy > Technical Discussion: Other > Re: Battery care for summer camp

�  sure, that might be doable to use some of that power while you are away staying warm for the winter. a few low wattage led's setup as dusk to dawn or a few other fun things come to mind.

 how about an automatic game camera to record any visitors you may have while away?


 or a cool data recording weather station?


 your right about leaving a battery on a trickle charger but with a solar float/trickle we give the battery a nice break in between charge cycles. and in effect we are cycling the battery ever so slightly.

 i'm beginning to think i need a cabin in maine!

kind regards, dave

Posted by David Ames on Mar 27, 2009 03:06 am

#124 -  Renewable Energy > Technical Discussion: Other > Re: blade dimensions for a wincharger 1222
hello bert van hoye,

 as a bit of fun i have been looking around for information on that vintage wincharger of yours. it seems that there have been many requests over the years from folks around the world looking for these elusive propeller plans to no avail. the wincharger.com website claims that a dutch gentleman has a dutch language manual with the plans in it? lots of great photos of original condition and restored models around though. i see several variations in the rotor design even in those that claim to be all original an might guess that there were a few different suppliers for the "stock" propeller.

 check out this one listed as "new old stock" it looks exactly like some of the photo images of propellers from the original machines.


 bert, i bet if you set your mind to it you could use parts of that old prop of yours as a guild to knock off a prop as good or better than the stock one. while keeping in the spirit of that original one. do you believe that the prop that broke was actually 70 years old? amazing...

good luck with your project. as you said should be fun!

regards, dave

edit: update! i located the original patents issued to john albers for the prop and assigned to the wincharger corporation. some good info there with blade profile.


Posted by David Ames on Mar 25, 2009 12:21 am

#125 -  Renewable Energy > Technical Discussion: Other > Re: mixing solar panel voltages within a single solar array
�  hi john,

 "Now what if I put 9 panels in a single string. 43V x 9 = 387Vdc. Thats really high but in tolerance. 34.6 x 9 = 315Vdc thats within the Mpp range of 139-400Vdc. I really dont like the 400 volts DC. Seems awfully lethal to me."

 we have to back up a bit here. as much as we want to get the most out of the equipment we have in hand, we just can't get away with a string of more than seven of those 100watt pw1000's

 lets go back over to that SMA sizing chart james linked us to.
 when we put your data in (assuming the sb1800u & swr1800u are one and the same)not knowing your exact jersey location i went with atlantic city new jersey. record low is -23*f (1942) and average high is 85*f (july). the closest choices are..�  -22* and 86*f.

 the sizing tool gives us 1 string of 5 in series, one string of 6 in series or 1 string of 7 in series,
or 2 strings of 5, of 6 or of 7 in series.

 mr. cormican has given some valid reasons to avoid the 2 series strings of 5 and i might trust his judgement on that.

 that leaves us with the 6 or 7 string option.

 the reason we can't go with more modules in the series string is just as voltage drops in the higher temps the voltage increases in the lower temps. these higher voltages can (will) be destructive to our inverter, not just stopping production as the high temps will.

 i sure like that idea of picking up a sb700u to make use of those 4 extra modules (6 on the 1800 & 4 on the 700)

 or that other option of 2 more photowatt modules to make up a 2 string array of 6 in series.

 keep at it..good to get everything worked out first.

kind regards, dave

Posted by David Ames on Mar 23, 2009 05:39 pm

#126 -  Renewable Energy > Technical Discussion: Other > Re: mixing solar panel voltages within a single solar array

  thanks for that technical tidbit. good info as usual!


edit: p.s. still curious of there is any difference in the sb1800u and the swr1800u?

Posted by David Ames on Mar 23, 2009 03:15 pm

#127 -  Renewable Energy > Technical Discussion: Other > Re: mixing solar panel voltages within a single solar array
 hi john,

 out of curiosity and in an effort to be of some help i have been looking at some of the product information on your proposed setup. so far it looks like you may indeed be able to run two series strings of five for your array.

 we have to look into it some more. if that option proves wrong looks like you will be limited to an array made up of seven of those pw1000 modules (the 105's?) due to temp correction for the garden state.

 where are you seeing that 192v startup requirement? from some of the info i've gathered we need a minimum vmp of 139v?

here they are calling it MPP Vpv a strange way of writing it?
 it's difficult to find information for this original sb1800u. and it looks like SMA no longer supports it with a sizing calculator.

 in any case we won't be able to run some of the modules at 12v and others at 24v due to the difference in the imp and isc of the paralleled vs series modules. that would be like trying to run completely different panels.

 looks like best case would be to pick up two more modules for two strings of six. and worst case is two strings of five with the possibility of going off line on a record high temp day. or running one string of six/seven modules.

 hopefully a few more folks chime in..

best regards, dave

oops i see james beat me to the punch.

Posted by David Ames on Mar 21, 2009 05:20 pm

#128 -  Renewable Energy > Technical Discussion: Other > Re: Battery care for summer camp
 hi james,

 i can share some thoughts on how i might go about what you are shooting for. i lived for several years when i was a kid at the base of beautiful mount katahdin. can still remember being amazed to look up in july and see all that snow. can also remember making a few bucks in the winter shoveling off the roofs of local mobile homes in a nearby park.

 when choosing the makeup your pv array (assuming we are going to leave it in place)(rooftop?) we might want to consider a nice small framed module in the smaller wattage range over some of the larger 200 watt ones for loading reasons.

 for the winter i would decomission the array and pull ~100 watts of pv out and mount it on a south facing wall making up a small winter array to maintain my bank. not sure what your planning on for a battery bank size. but even the limited output of this small vertical array should keep our battery bank in float for the winter.

 agm's are great if you can swing it. but the workhorse of most stand alones is still the floodies and a quality battery with plenty of water room toped off in the fall should do fine, i should think.

 i would stick with a good quality charge controller with temp correction here and tend to stay away from a shunt type controllers with this application.

 should be able to knock up, scrounge, or buy some kind of battery box. a charged and "tickled" battery will handle the cold fairly well. we just won't have our rated capacity until it warms back up in march.

 just my opinions here..

good luck, dave

Posted by David Ames on Mar 9, 2009 07:25 am

#129 -  Renewable Energy > RE General Discussion > Re: What is energy?
thanks for the information as well as the entertainment.

 the news broke several years ago that orville wright did not have a valid pilots license that cool december day back in 1903 at kitty hawk. now there are rumors going around that neither of the brothers had aeronautical degrees from an accredited university! oh the nerve, who did they think they were?

in jest, dave

Posted by David Ames on Mar 5, 2009 11:05 pm

#130 -  Renewable Energy > RE General Discussion > Re: How to run a small DC motor??????

 hi guys,

 joe, your thread has provided the impetus for me to have a read into solar powered motors and linear current boosters. interesting subject...looks like you are on the way to a successful project. if i am understanding correctly the LCB allows us to undersize the pv source and not have to worry about any of the too little or too much power issues.

 as usual Mr. Schmidt has provided some very useful and interesting links to help us to understand our subject.

 thomas you are killing me here with all these great links, i can't risk not checking them out-as i may miss something good..i'm off to try that soda can static motor! thanks!

 cheers, dave

Posted by David Ames on Mar 3, 2009 12:05 am

#131 -  Renewable Energy > RE General Discussion > Re: All You Need to Know About Renewable Energy

 hi folks,

  my local sunday paper has a rather challenging crossword puzzle every week that i sometimes can get close to completing. they have started offering a telephone help line that you may call to receive the answers to the puzzle at $1.00/per pop..where is the fun in that?

 why is it that everyone wants to try and cash in on the renewable energy bandwagon? there are big boxes just crammed with "secrets" on every corner, if you would only send in your $49.95 blah, blah...

 all you ever wanted to know about these renewable energy methods is out there for the finding. i urge folks to do their own homework on these subjects and find out for themselves what might work best for their situation. you are sure to find this is a very rewarding approach when you research and come to your own conclusions.

 by the way, i have a bridge for sale, in excellent shape...........

have fun

Posted by David Ames on Mar 1, 2009 12:04 am

#132 -  Renewable Energy > RE General Discussion > Re: I want to run a Servel gas/electric refridgerator off of solor power

 heres a freezer turned into a fridge that uses just 3kwh per month! thats as much as mine would use in only one day.


does this sound believeable? sure looks legit...

happy hunting.

Posted by David Ames on Feb 26, 2009 02:50 pm

#133 -  Renewable Energy > RE General Discussion > Re: Saving Money on Water Heating
hi folks,

 jon, i can back you up on those claims of energy savings on that water heating issue. i have been using a similar technique for the past 18 months and the results have been nothing short of dramatic. in my case though being in a rented flat i have not altered the hot water tank in any way. i simply leave my tank off until ten minutes before showering turning it off just before getting in.

 this tank is a 40 gallon unit with one top and one bottom 4500 watt heating element. the ten minute on time is enough to heat the top 10 or so gallons of water from the standing temp (room temp or slightly above) to a reasonable enough shower temperature. that amounts to just 750wh's per shower. i find the key to this method is not to stir the tank with a huge volume of water draw to keep the tank from mixing. this low flow shower head does the trick nicely.


 we have all seen the warnings about under heated water tanks. namely the threat of legionnaires'


 i have never been concerned about the health risks with this method but is something to be aware of. i occasionally find myself driving around town without my seat belt on and that is a much greater risk in my opinion.

 the one thing that has me worried a bit though is the cycling of the breaker every day. the action of these double breakers is very violent and i wonder just how many on off cycles (not trips) they might endure.

regards, dave

 ben has some interseting topics on the altE blog pages.


Posted by David Ames on Feb 25, 2009 02:29 pm

#134 -  Renewable Energy > Technical Discussion: Other > Re: MPPT and PWM on same battery bank?
hi rett,

 we are getting into a controversial subject here on this wiring method question.

 i am always willing to reevaluate my thinking on a subject when more information becomes available. and believe there are really no set absolute "facts" just informed opinions that we arrive at when considering a topic.

 have a look at this diagrams:

 see figure 4, 5 and 6.now these are "official" diagrams from the company.

figure 4- is a classic example of a "daisychain" wiring method..i would avoid this one at all cost.

figure 5- is much better but we are still sharing the negative conductor. not too bad.

figure 6- nice dedicated inverter feeds and disconnects. this, in my view is the way to go.

 some good discussion on the topic of inverter stacking on this previous thread.

 oops gotta go for now, we are sure to get more opinions on the subject..and thats a good thing when trying to weigh our options.


 back again. having another glance at those diagrams. number 5 is not that bad after all-and number 6 is a cleaner version of number 5 with a nice enclosure (like yours) with the ground block and grounding conductor shown. also they show the battery bank strings tied together at the bank, not such a bad thing with just two strings. an alternate way, especially when we start getting into many parallel strings, is to run them (all the strings) to a pair of busbars then sink and source from there. otherwise the standard advice of keeping the parallel strings to two or three max is important. anyway that is not an issue here and it looks like we won't have room.

 more opinions..it sure would be nice if there was a product that would tie those breaker inputs together with a good sized block that we could land those big lugs on that are comming up from the bank. effectively creating a positive buss in a small space (like the midnight solar combiner fingers do in their PV combiner box). somewhere along the line we have become used to using our battery interconnects and battery posts as busbars...

 so i cast my vote on the method shown in figure 6 of the xantrex installation manual.

have fun. dave

"what one man can do another can do"
sir hopkins in the edge

Posted by David Ames on Feb 25, 2009 03:00 am

#135 -  Renewable Energy > Technical Discussion: Other > Re: MPPT and PWM on same battery bank?

 gee rhett,

 you have been holding out on us! what other good stuff have you got tucked away over there?

 as you know those Mitsubishi modules are what we are calling an 18 volt nominal panel ( a half step between nominal voltages?). lucky for us that we also have an mppt controller to go with it. now before we get too excited, a word^ about those bz 500's. i use the plural because that same controller came/comes in two different flavours and that may make a difference in our application here. first off these are all around great products for the price and i cut my teeth into mppt with these controllers, however they are not true open format mppt controllers like the mx, fx or apollo products and are "optimized" for their expected use. i have found that the 500 is good across limited ratio of mppt voltage conversion. example: on a 12 volt system we can run a 12 volt nominal module, an 18 volt or a 24 volt nominal array with good results. and any array with a volts open circuit (voc) above 50voc makes the bz 500 unpredictable. now thats the first flavour...the same looking model the bz500hv seems to like a voc between 30 and 80 voc and still has that same voltage conversion ability. ie across one full step in voltage. example: 24 volt system using 24 volt nominal, 36 volt and 48 volt nominal array.

 if you take the four screws off the front cover you will find a paper label giving the firmware version and the 500 or 500hv designation. i could never get a series pair of 18 volt nominal modules (36 volt nominal for the string) to run with the 500. but had no trouble at all running them with the 500hv.

 so i would have a look at the label and see what we have. if it's the 500hv i don't see a problem if it's the bz500 i would still try it and see if it might work. it would do no harm as they are both rated with a 100 voc limit. worse case would be to send it in for the upgrade service they offer. that company is very customer friendly, don't be surprised if you call and get frank himself on the line.

or via email:

Frank Lewon BZ Products  bzp @ bzproducts.net "

 see a full discussion of topic on this thread:

"* Will the 2 different type controllers work with each other?"
 they should play well together, folks do this all the time.

"* If I need to get another controller, should I get the MPPT?"
 these oddball modules are most efficient with mppt but will work with standard pwm with lots of lost potential.

"* When I combine them,whatever they are, is it OK to let them wire together on the bars inside of the Trace DC 250 Disconnect, or can the two leads not 'touch' each other?  If not, how then?"

 yep, right to the same busbars.

 rhett, about adding onto that bank. for the purposes of this public forum lets assume that the existing battery bank is less than a year old and is in good shape. what i would do is double my bank with the exact same batteries using identical cable, lugs and wire lengths. an exact copy of what you have. then run that second series string up to the dc250 power center and parallel them there at the dc buss.

 best regards, dave

^ comments about the bz controllers are based on my experience only..your mileage may vary.

Posted by David Ames on Feb 22, 2009 10:59 pm

#136 -  Renewable Energy > Technical Discussion: Other > Re: Xantrex C-series charge controllers - CM panel

 thanks for clearing that up."I have determined that all of the information on the CM front panel relates only to what's going on with the diversion load." nothing beats actual testing, and i see now (block diagram pg3 of c40 manual) that this is the only measurement possible with the controller behind and in parallel to the battery bank. so the batteries always hold the rectified turbine output down then the voltage increases to our set point then starts the metered dump through the controller. still leaving us in the dark as to battery inputs..however, in the case of fully charged batteries the metered readings will be our generator output. still somewhat useful.

 i have had good luck with these little meters. note: always keep a load on them.


 this meter will run standalone with a 9v battery for 3 months and continuously using our battery bank. maybe put one between the bridge output and the bank?

 good luck with the testing, good data speaks volumes about a product and the integrity of the folks behind it

best regards, dave

edit: rereading your post, surely you can't mean you are loosing your "total amp hour data" between visits? if so we must be powering down sometime between readings.. curious.

Posted by David Ames on Feb 22, 2009 02:39 pm

#137 -  Renewable Energy > Technical Discussion: Other > Re: Xantrex C-series charge controllers - CM panel

 hi bruce,

 still looking for that info for the c-series cm display, and to keep your thread alive. everything i see so far is saying.. no, it does not add power totals to the running counts. i'm sure a few of the other folks here are having a stab at trying to find a definitive answer for you. we see lots of wording like "depending on application" and the recommendations of dedicated diversion loads like water heater elements which would lead one to believe that the diversion power is unregulated and has not been sent through the controller. generally this "extra" power would not want to be added into the battery charge totals so we know where we are with our battery bank.

 i can see how knowing what that total production is would be of some use, especially during testing and evaluation of a new product. we can always put in some other inline meter to measure that diverted power then add it to the cm reading totals. or meter the input before the c-40 (or 60) and subtract the cm for the diverted totals.

 so it looks like you are in the market for a controller with metering abilities? if someone had a c-series with the display running wind or hydro it would be easy to tell if the cumulative totals are adding up during diversion. anyone?

 perhaps consider the c40/60 without the cm/cmr and go with the pentametric with multiple shunts for the logging.

 have fun,

cheers, dave

Posted by David Ames on Feb 22, 2009 01:10 pm

#138 -  Renewable Energy > Technical Discussion: Other > Re: Do C-40 controllers go bad?

 mr. fouraker,

  thanks for sharing your little adventure with that c- series controller. it's nice to hear of a happy ending to a problem. have to keep that one in mind when working with that controller...you can't be the only one this has happened to. and kudos on that logbook, a year from now you will have a full seasonal cycle for the records. the only trouble i see now is that your wife now has bragging rights to being the house solar system expert!! good luck on that sir!

 best regards, dave

Posted by David Ames on Feb 9, 2009 03:03 am

#139 -  Renewable Energy > RE General Discussion > Re: off to on grid

 hi tony,

now..i mean this in the kindest way. but, it's hard to understand the power units you are trying to use.

 i think using this as a key.
"I spend $315 for 2kw/h per month for a 1000 sq. feet."

 you mean 1440kwh's for the month? an average of 48kwh's a day? or aprox 22 cents per kwh.

interesting product, those enphase inverters. looks like a good solution but is still up and coming. looks like there are some connection issues with certain utility providers requiring separate meters and of course an associated fee to go with it. also not sure if it's possible to opt out of the monitoring service that the company has. i'm gonna keeping watching this one.

"I think a good goal would be 1.5 kw/h per month for a 1500 square foot home with 50/50 grid and tie in electric."

so if i'm reading right that 1.5kw/h is 36kwh's per day?
using a daily average of 4 hours of full rated sun we need an array of 9kw. conservation can go a long way at reducing that daily demand and when we look at the system cost, it can be a motivaitor as well.

"Maybe the question should be put out to the community is not how many panels or on/off grid system but how many kw is need per square foot of living space."

i think about this one alot. my grandparents lived most of their lives with 0kwh's and right now there are billions of folks living without any power what so ever. so the "kw needed per square foot" would have to be on a case by case basis.

some good info here about power.

best regards. dave

Posted by David Ames on Feb 3, 2009 04:51 pm

#140 -  Renewable Energy > Technical Discussion: Other > Re: solar/wind on Xantrex C35 and no charge from wind at night.

 hi daniel,

  yep, sounds like a good bet to me. i would still go thru the trimetric shunt though. do let us know the results!

cheers, dave

ps: i'm curious..have you found a modification to disable the internal regulation of that bird? or were you talking about the voltage set point adjustment on the body of the turbine?

Posted by David Ames on Jan 31, 2009 02:50 pm

#141 -  Renewable Energy > Technical Discussion: Other > Re: How much do I need?
 lucky for us, if we are on the grid our local utility provider has been keeping very good records of our power use. so a good starting point is our utility bill. if this is a standard residential rate it will be in kwhs used for the billing period and often broken down to average daily use. (some of the commercial rates with demand calculations can be difficult to decipher as to actual usage)

 here in the u.s. the average is somewhere around 900kwh's a month-aprox 30kwh a day.

 our forum host here at altE has some easy to use calculators for helping to get an idea as to sizing for our needs. check it out here:http://store.altenergystore.com/calculators/on_grid_calculator/

 have a look around their learning section for some good info on both solar pv and wind. with wind (more-so than solar) alot will depend on available resources (wind speed).

 if you have your utility bills handy but are unsure of how to work the numbers into the calculations, come back here and you will find plenty of help. the folks here can get real close to real life system expectations given accurate data.

 regards, dave

edit:live link http://store.altenergystore.com/calculators/on_grid_calculator/

Posted by David Ames on Jan 29, 2009 03:29 pm

#142 -  Renewable Energy > Technical Discussion: Other > Re: What is wrong with my system?

 hi gary,

 good advice on beefing up on that wiring and battery bank. me thinks that's gonna help alot.

"simple and cheap as well."

 i agree that this can be "simple" but cheap? i guess that is relative. someone without company connections might expect to pay about five grand for a 1kw array of pv. for me that ain't cheap. i was thinking prices might start to come down a little by now. where are the $1/watt modules we all were promised? maybe next year..

cheers and good luck, dave

Posted by David Ames on Jan 24, 2009 01:38 pm

#143 -  Renewable Energy > Technical Discussion: Other > Re: Specific Gravity - are my batteries charged or not?
 hi folks,

 things are getting curiouser and curiouser, has anyone else had time to read through some of the product documentation for those blue-sky controllers? and this is not to pick on or single out the blue-sky people but some of the "fixes" they have come up with are beyond the average "consumer" to have to deal with.

 on the "fix" for a clicking relay they want you to go in and chop out a diode from the circuit board!

 this ones even better...

 in the above tech update they tell you how you have to build your own voltage offset circuit to trick the controller into an equalization voltage!

 it appears the attitude with manufacturers and/or their engineering departments is. as long as there is an aftermarket fix to the problem they can just hum along business as usual.

we can do better.

edit: note that these examples are "old" fixes from the sb2000 model. but according to the 01 date on the first tech update blue-sky has been aware of the set point issue on the sb2000e since then. and as a favor they will be happy to sell you a tool to make up for their design flaw.

Posted by David Ames on Jan 23, 2009 01:56 am

#144 -  Renewable Energy > Technical Discussion: Other > Re: Li-ion for storage

 hi tony,

 the link you provided has the highest capacity li-ion battery packs i've seen. before they will even sell you one you have to fill out a waiver and explain your intended use as well as charge and discharge intentions. looks well made..each module enclosed in an explosion proof box with all electronic controls inside. looks like for about $2,500 someone could put together a true 100ah bank (@11vdc) that might compare to a 500ah bank of lead cycled to  %20.

 are you thinking of taking the plunge?

happy hunting, dave

-don't think much of those flexable pv modules, seems like more of a speciality item, like for backpacking or G.I. use.

edit: looks like that $2,500. 100ah bank was for the 37vdc nominal. the 11vdc bank would be even "less" expensive.

Posted by David Ames on Jan 22, 2009 12:04 am

#145 -  Renewable Energy > Technical Discussion: Other > Re: Specific Gravity - are my batteries charged or not?

 hi folks,

 sally, i agree with the advice to get those batteries back up to full charge and take it from there. i would try to get those set points back to the default settings and watch how things run. did you see the technical bulletin issued for that controller? i believe it deals with the issues you are experiencing. looks like all adjustments should be made with the bank right at the top of its charge for the readings to be accurate.


 this tech update was issued back in 01 and revised in 03,  one would think that the issue has been resolved by now..but who knows?

 hang in there, you will be up and running in no time..you just have look at these things as learning opportunities!

best regards, dave

Posted by David Ames on Jan 21, 2009 01:33 pm

#146 -  Renewable Energy > Technical Discussion: Other > Re: Check My Calculation

 hi max,

 the first thing that came to mind when reading your post was, is there any way to go with a 12vdc bulb in your application? you should be able to find an automotive bulb with the proper ratings.

 if the use of 12vdc bulbs is out of the question then, i would take actual readings with my meter to see what the measured input and output are. i'd especially be concerned with the metered inverter draw from the battery both idle and while powering the bulb.

 we can test these low currents safely with our meter in line from battery output to inverter input. the measured inverter draw is really going to be the make or break on this setup. with your digital multimeter, use the 10amp option. (even the $10 meters are surprisingly accurate) see what the current draw is on that inverter. we know our 5 watt bulb will account for about 420ma and anything over will be inverter losses. we may be disappointed to find that the measured draw on the inverter is much higher.

 i would also check the pv production the same way-when it's nice and sunny can we see production in the approx 1amp or better range?

 these readings (more so the inverter measurements) will give you much better raw data to work with.

 we may be on the big size with that 110ah battery and would think a 25ah might work out better with the limited charging source available. (less self discharge losses and higher input to amphour ratios)

best regards, dave

Posted by David Ames on Jan 20, 2009 01:11 am

#147 -  Renewable Energy > Technical Discussion: Other > Re: kids science project with solar

 hi tom,

  good stuff working with your son on that science project together. not just for the sake of learning but for the life long memories it builds between father and son.

  here are some pre made kits. (some assembly required)


you will see all kinds of others like it searching around.

  this looks like a fun one..gotta get this myself!


 a spinning motor or a jumping grasshopper is a sure way to get the kids attention but once you have them captive the project should hit them hard with the principles behind it. the science behind the "photovoltaic effect" and such.

 perhaps help your son get the actual solar data for your exact location. then make up an array with the proper angle of tilt and power production estimates for the cell used. then figure out how many of these cells it might take to run the school for example.

 you should be able to power a cell indoors with a bright (non florescent) light. i believe the quartz lights work well for this. in fact all photovoltaic modules are tested to standards (stc) indoors with a calibrated flash setup.


 have fun, dave

Posted by David Ames on Jan 16, 2009 05:28 am

#148 -  Renewable Energy > Technical Discussion: Other > Re: Should I use Trojan or Interstate batteries?

 in the last post you touched on a topic that has been bugging me for a while now. that is..does taking power off the bank as we are generating it actually count in the dod calculations or count as cycling at all? there has to be some losses but when used as made it never really goes into the battery for chemical conversion. when used like this it seems the bank should act more like a buffer than a storage battery? even more, if it were possible to have real tight control over loads it seems that very high efficiencies might even be possible.

 then again thats what the grid tie systems do without the need for the super tight load control requirements.

 i agree on the possibility of those interstate/us battery specs not being directly cross referenceable (is that a word) it's good to know where they came from thou. what is really needed is a "national clearing house" of all battery information in one place laid out on the same grid style chart for reference. now that would be a project!

 best regards, dave

 edit: gordon, we found the real interstate chart

Posted by David Ames on Jan 15, 2009 12:52 pm

#149 -  Renewable Energy > Technical Discussion: Other > Re: Should I use Trojan or Interstate batteries?
 hi gordon,

 sometimes finding battery data for different brand names can be a daunting task. it could carry a name like "interstate" or "big bobs battery" or whatever name. one of the ways to find the actual manufacturer of the battery is to have a look at the MSDS (material safety data sheet) that is required to be available for all batteries sold in the us. when we pull the interstate sheet we find it's made by the u.s. battery corporation.

 here is a homepower battery chart of the big players in the battery business. i uploaded this info off site using member privileges* from homepower magazine.

�  http://www.sendspace.com/file/74cdjv

 here is some cross reference info about who makes what under what name.

�  � http://www.jgdarden.com/batteryfaq/batbrand.htm

�  i have heard some interesting stories from workers in the battery trade that many times the same "core" is labeled with different specs based only on the warranty provided with the purchase.

�  it's your hard earned cash and wanting the best bang for your buck is worth the extra reading time.

 some more good info here.

�  � http://marine-electronics.net/techarticle/battery_faq/b_faq.htm#4

 and here. with more links for drilling.

�  � http://www.vonwentzel.net/Battery/index.html

 *finally a plug for homepower magazine http://www.homepower.com/�  week after week and month after month the folks on this forum have repeated the advice about getting a homepower subscription and i finally caved when the price dropped to it's current price ($65) for the whole shebang. thats all web based services as well as the full publication database on cd from it's conception, over twenty years worth!

 hope this helps, dave

Posted by David Ames on Jan 15, 2009 01:17 am

#150 -  Renewable Energy > RE General Discussion > Re: Solar vs. Wind

 hi guys,

 not sure on that box chock-full-o-secrets. but here is something i don't want to be kept secret. i took a look at that site back on the 12th and have been bombarded with email solicitations since! i used a key in my name so i know the info came from that site. on that front page they "promise" not to sell of share your email address.

nuf said.


Disclaimer and Disclosure

The Alternative Energy Store, Inc reserves the right, within its sole discretion, to refuse or delete any posting or portion thereof, or terminate or block the access to this forum.

The opinions and statements posted on this forum are the opinions and statements of the person posting same, and do not constitute the opinion or act of the Alternative Energy Store, Inc (AltE). The Alternative Energy Store, Inc does not endorse or subscribe to any particular posting. No posting shall be construed as the act or opinion of the Alternative Energy Store, Inc.

Click here for BBB Business Review

McAfee SECURE sites help keep you safe from identity theft, credit card fraud, spyware, spam, viruses and online scams
Desktop Website | Mobile Website


Click on an icon to share! If you don't see the method you want, hover over the orange "+".


What can we do to help you?

Please enter a summary
Sorry, the copyright must be in the template.
Please notify this forum's administrator that this site is using an ILLEGAL copy of SMF!
Copyright removed!!