# David Ames's posts

#### Posted by David Ames on Apr 6, 2010 06:10 am

#61 -

for the "package" that you listed, it is noteworthy to me that 8a fuses are supplied, being that kaneka modules have a 7a max series fuse size.

also noteworthy is that they list the package deal with the SB3000..according to SMA there is no acceptable configuration to run those modules with that inverter..simply will not work! *see below

i bet tech support will be the deciding factor in the future players in this business.

cheers, dave

EDIT: still trying to figure out why the SMA sizing tools reject that module as an option, could it be the high voltage during the "burn in" period? odd....

*update: pencil and paper show that inverter(sb3000) running fine in series strings of 4 during burn in and after they have stabilized..must just be an issue with the sizing tool.

#### Posted by David Ames on Apr 6, 2010 03:57 am

#62 -

Hi Sorbari Akpea,

i think we see a good book title here!: (hey brother can you spare two hundred grand) subtitled: (how to have fun with fifteen thousand pounds of lead)

"Charge time = 0.4 (1.2 x Amp hours (of the battery being charged) / charge current)

Is this formula correct?"

that equation looks good..that one gives us a very optimistic 80% efficiency for the chemical conversion. seems that is the standard starting point...i find that battery based systems tend to run closer to the 50-60% mark at the end (in a good design!) after all the system losses

everyone comes to find their own methods for working through some of these calculations and perhaps others may have some tips on other methods...but for me i just seem to get into trouble when i attempt to work with units of amp hours (tend to make silly apple/oranges mistakes) i find it much easier to convert all units into watt hours as a first step.

how some of the numbers look from here:

999AH @ 200volts = 199,800 watt hours

40% discharge (60% remaining) = 79,920 watt hours used

79,920 X 1.2 = 95,904 to recharge back to full

95,904 needed/5 hours = 19,181 watt pv array (need to do the 80% thing again with that too!) = 23 kw array

the good news is that if we use some power during the day while charging we get to skip that 80% chemical conversion thing and use it as it's being made..sort of..but those watt hours not going into the battery still need to be made up for with a longer charge time.

i hope this is a "paper" project and not an actual system.

have fun! dave

#### Posted by David Ames on Apr 4, 2010 02:23 pm

#63 -

surprised we have not heard back from george, he may have it sorted out?

not much info on those Condumex controllers around either..saw some talk of one called the CX7 (7amps) if we are using that one then bingo.

"Once those clips that hold a fuse in place get hot they have a tendency to get worse and worse from then on. The metal loses its finish, the metal gets softer, if they are soldered to a pc board, one or both can lose continuity."

yup, seen that problem. seems that once those holders overheat even once, things are never the same again. have even gone as far as soldering the fuses into the holder as a workaround.

curious that george mentions the "spring" output. same thing here..the last two weeks of march and the first two weeks of april is when i record the all time highest outputs on my small pv array. (highest wattage not highest daily production)

cheers, dave

#### Posted by David Ames on Apr 2, 2010 07:13 pm

#64 -
hey tracy and welcome to the group,

sounds like an exciting project! i was exposed to a great quote the other day that popped to mind when i read your posting.

"I have a plan so cunning you could put a tail on it and call it a weasel."

although the phrase conjours up a humorous image, it is not meant to be derogatory in the least. in fact i see your plan as perfect in every way.

1. have to nail down solectria on the low limit specs- there should not be any. i know we can do it (run a small/even tiny array) with the xantrex gt's and the sunnyboys. but the solectria string tool won't let us go to less than 1.1kw- i suspect it is just an issue with the sizing tool? not 100% sure though.

in an effort to find out i requested clarification from the fine folks at the company.

on 3-31 i sent the following to the east coast tech link:

"hi folks,

question. will the pvi3000 run with a very small array?   example, pv array of only 250 watts stc with voc well within the operating window? the string sizing tool only goes down to 1.1kw

thank you, dave"

on 4-1 sent this request to the west coast tech link:

" hi allison,

a quick question if i may?

will the pvi 3000 run with a very small array?

example...a 250 watt stc array with the voc well within our operating window?

great string sizing chart! well done, however we only go down to 1.1kw as the smallest array.

thank you, dave"

no response from the company yet.. we shall see, it may take a few of us to hold them down while you go through their pockets looking for the secret information!

2. your local utility may have a minimun allowable grid tie contract. here we need 2 or 2.5kw (depending on who you ask) for a net metering contract. *see below

3. there will be placard issues..aka signs for your current system parameters.

4. should pre-plan for the final system size. at least as far as conduit and "home run" wire size.

a. i would bypass the built in pv combiner (per manufacturers instructions) and do a combiner box(s) at the array. with properly rated (watch the voltage ratings) equipment.

b. "home run" the conductors from pv combiner to the inverter.

5. did you notice that those kaneka GSA-60  modules have a preferred orientation? we want the "laser" lines pointing in the up/down direction with an inclination of at least 10 degrees. (some of the thin film designs have "polarization" issues, resulting in an odd photon cancellation phenomenon?)

6. we want to be sure that module (gsa-60) is going to still be around and available for the future expansion of the system!

not really much help. but wanted to at least give you some kind of feedback and get the ball rolling.

kind regards, dave

edit: added caveat #6 ..bet there are many more as well.

*update 4/11 -seems the rules have changed here in ct and i can net meter with no lower limit. sweet.

#### Posted by David Ames on Mar 19, 2010 04:08 pm

#65 -

good topic and some informative posts here.

as we can see there are soo many variables.. a small load and cutoff points are close to our settings, a large battery bank won't "dip" as much as a smaller one and so on.

a good chance to thank solarjohn for his chart. john, i have been using your SOC chart and have it hanging for easy reference at several systems..each set up is a little different than the others but your chart gives folks a good "feel" for whats happening. thanks john, ..i highly recommend it to others.

cheers, dave

ps.sj, get home soon! it's time for planting...it's strange how a place (the bay) can be soo beautiful and yet ugly at the same time. stay safe!

#### Posted by David Ames on Mar 15, 2010 06:27 pm

#66 -

Ain't that the truth! well said ray. it's still a mystery to me as to why they can't give us a better range of voltage adjustments on these things, especially the high end stuff!

think about the poor newbie who reads that his equipment "protects" him from overdischarging his bank and that confidence in the equipment is the thing ruins him.

if we go in and change things we void the warranty.

manufacturers are you listening?

cheers, dave

#### Posted by David Ames on Mar 13, 2010 03:43 pm

#67 -

Hi Glenndie,

afraid we are still having trouble understanding exactly what you have there for pv modules.

are these a "store bought" name brand solar panel? (if so do we have the name or full data sheet?) these numbers sound odd..could it be these are a "home brew" module? could it be that you made the 100 watters out of 42 cells and are making some more with 30 cells?

i do know that some of the "ebay" type specs for the cells can be very misleading and hand assembled panels are questionable as far as predicting output and lifetime estimates.

oh., and our controller takes care of the function of blocking diodes..no worries there. (however many commercial modules have "bypass diodes" built in for shading concerns)

kind regards, dave

#### Posted by David Ames on Mar 12, 2010 06:08 pm

#68 -
Hello Glenndie Gigante,

more details are always good.

couple of things that may help. that sb50dl will let us feed it up 57voc on the input side of things. being in the philippines it takes away our cold temp correction worries so we should be able to series those pv modules for a better shot at getting the power into the battery bank. (we may be getting excessive voltage drop due to hot modules)

might think about going with a battery bank about three times that size. we have the potential (if all goes well) of harvesting close to 100 amp hours @ 12vdc each day and need a bigger place to store it.

dave

ps, was that 2x100watt pv modules or 100watt total? specs please.

#### Posted by David Ames on Mar 11, 2010 03:05 pm

#69 -
never had the chance to work with a "miller" controller (the fieldlines link) not sure what ever happened with tom- he used to write for a few magazines and be active in the HAM chatter on the net..he may have become overwhelmed with requests for advice on his controller design and gave up?

put together and used several of glen's (Ghurd) controllers with happy results.

glen designed the circuit and pcb and sells the things out of his basement for twelve dollars a pop! with every sale he includes \$1000 worth of free tech support to his customers ..kinda like here at altE.

or

note: all of these controllers will need a "dump" (usually power resistors) for an ametek 60, a resistor bank rated at about 0.7 ohms and 200+ watts would do it. the whole idea with a controller/dump load is to fill the battery up and get rid of any extra that would result in overcharge. kind of like bailing out a boat..all the while keeping our wind turbine loaded and under our control.

best of luck with your project and kindly keep us posted with your progress.

cheers, dave

ps. with a good sized battery bank and a watchfull eye we can run a small wind turbine full time without any controller at all. just the blocking diode.

edit: changed 0.07 ohms to 0.7ohms YIKES big difference.

#### Posted by David Ames on Mar 8, 2010 04:37 pm

#70 -

hi robin,

"I know that I need some sort of chargecontroller, but I wonder if I can connect it without the chargecontroller and charge the battery?"

you can run it without a controller while being supervised but i would NOT run it for very long unattended.

here is a diy controller that rivals or surpasses the high priced wiz-bang commercial units. (IMHO)

http://ghurd.info/

note: in this configuration the battery controls the wind turbine and the controller controls the battery.

i got the crayons out and put together a few scribbles to how we can run things (for demo) before we install a permanent controller.

standard configuration with stud diode. (these can get pricey and be hard to find at times)
http://www.surplussales.com/semiconductors/Diodes-3.html

optional configuration with easy to find bridge. (radio shack part #276-1185)

we included a demo light here (small tail light bulb would work)..we want to NOT stall the machine out here by going too big...

things will get complicated if we try to run a light without the generator being loaded by a battery.

we want to size the blocking diode BIG..something like 20 amps and 50 volts minimum. with a heat sinking mount.

cheers, dave

#### Posted by David Ames on Mar 8, 2010 04:34 am

#71 -
hi john,

sounds like a fun contraption you have worked up there!

"Any thoughts???"

-couple things stand out...

..those lights are killing us.
..that inverter running is robbing us.
..looks like we are in the red before we even sell one stick of firewood.

how it looks from here,
lights- 39 watts for 12 hours = 468 watt hours
idle inverter (however we are not really at idle here)
idle inverter- 0.8 amp draw (per spec sheet) for 24 hours = 230 watt hours. (0.8amps x 12volts x 24hours)

lets stop there for now. and add 468 and 230. so far we need 698 watt hours for a 24 hour cycle.

the perfect output for a kc130 in hartford in march is 4.5 sunhours (per data tables) x 130 watts = 585 watt hours (in reality we won't get even close to that)

the battery side of things sounds kinda ok (the mixing is not so great)..looks like about three days backup. as it is now, with a fully charged battery you might go three days without solar input (no vends)..and with a fully charged battery and perfect solar input (no vends) it might run as long as a week or so. sorry

a few ideas come to mind.

edit: re-thinking this last bit. "it might run as long as a week or so." ..it might actualy chug along for several weeks before it crashes..

#### Posted by David Ames on Feb 25, 2010 12:17 pm

#72 -

thomas,

i don't think we will find anyone who will come out and say it's OK to run equipment outside of it's published ratings. but that is what i would do.

had a brief look at those programable wirsbo thermostats and did not find one that would work..those were all hardwired "voltage stealing" units i saw.

what we need is a battery powered job (stand alone)..lots to choose from..you are correct to question the max current rating and the relay option may be a better bet..(although we will still be running outside the ratings..ie 24vac verses 12vdc)

here is a doodle to show the possible hookups.

cheers, dave

#### Posted by David Ames on Feb 25, 2010 11:56 am

#73 -

cheers to Robert and the altE store!

well done.

#### Posted by David Ames on Feb 23, 2010 02:10 pm

#74 -
hey guys,

yep, bet with such low current the standard thermostat would work a treat.

another option might be one of these no frills universal jobs our hosts have available.

http://www.altestore.com/store/Lighting-Fans/Vent-Fans/AEE-Solar-Fan-HeatCool-Thermostat/p5633/

some nice ratings with that one...wish they gave a link to the full spec sheet?

sounds like you are good to go..those were seperate pumps without any electronic zone valves?..also, we might want to go bigger than the standard telephone/signal wire with the hookups.

cheers, dave

edit: .."one of these no frills.." should read.. "two of these.."

#### Posted by David Ames on Dec 16, 2009 01:50 am

#75 -

lee,

i see a big problem here..with your wife witnessing this problem solving, she will now expect all kinds of miracles from now on around the house!

"600+w  Ye.......hawwww
Silly Me"

sounds like that was worth a few hours on the roof..and confirmed your gut feeling.

"so with my handy multi meter..."

these darn things are pretty useful, every solar installer should think about investing in one.

thanks for the update.
cheers, dave

#### Posted by David Ames on Dec 11, 2009 03:58 pm

#76 -

sounds like the perfect plan lee.
kindly keep us posted.

cheers,dave

#### Posted by David Ames on Dec 6, 2009 11:50 pm

#77 -
sorry to all the great installers out there doing fine work.
but this is disturbing.
My installer just spews out a bunch of algebra to explain that the 340 watt figure is really more like 600 watts.
Actually the panels are all run parallel to one breaker in my flex 500 then to the flex 80 controller.

lee,
you sound like a bright guy/gal. bet in a very short time you could digest enough info to sort this out- if there is in fact a problem. there may not be.

you can find plenty of help here with recommendations/answers to specific questions. ever used any meters at all? that sort of thing?

rattlesnakes don't hide their nature or their appearance they are as they are..we know one when see it. really remarkable creatures.

you may have found a snake of a different kind..or will be able to teach him at bit more of that spewing "algebra" of your own.

he may be the best installer in texas but time should be taken to answer a customers questions in full.

kind regards, dave

#### Posted by David Ames on Dec 4, 2009 02:18 am

#78 -

hi lee,

quite a change for you moving from alaska to texas. your probably still running around barefoot and wearing t-shirts this time of year in texas!

it's hard to try and second guess someone elses install remotely on the internet. i have to assume he went with two strings of two at 48 volts nominal into that fx80 for your 24 volt nominal system?

sounds like a nice mix of equipment there for an off grid system.

the output will be VERY dependent on your site and the orientation of the modules...i would like to have the ability to adjust them for the seasons in a setup like this.

340 watts peak output is not super bad here with a 700 watt peak stc array but we would always like more.

that outback controller has a nice logging function built in to give you a record of your running daily totals and those totals are really more important than any reading we happen to see during the day at any given moment. for your location we might reasonably expect an average daily total of 1.9kwh's or approx 70ah's at 24v nominal. (houston data of 3.5 hours peak sun and 80% efficiency with a good site location and orientation).

so it's not that bad but more would be gooder!

hows that bergey working out for you?

just one guys thoughts here.

kind regards, dave

#### Posted by David Ames on Nov 7, 2009 11:18 am

#79 -
So...after taking millions (~80) in taxpayer grant money, Evergreen solar decides it is all about the money after all and announces it will pull up stakes and move it's operation to China.

The Massachusetts taxpayer takes another one on the chin with broken promoses, while slick ad campaigns tout a green company image of honesty and trust.

Evergreen Solar is now on my list of offshore questionable imports, and we have removed them as a preferred product when working up our systems.

Hard earned taxpayer dollars have invested in string ribbon with apparently no strings attached..shame on Evergreen.

http://www.xconomy.com/boston/2009/11/05/evergreen-solar-to-move-solar-panel-production-from-massachusetts-to-china/

edit: corrected spelling

#### Posted by David Ames on Oct 14, 2009 10:02 pm

#80 -

hi dan,

this previous thread may be of interest (post#11)

http://www.altestore.com/forums/Renewable-Energy/Technical/DR-series-inverter-stacking-problem/index.php/topic,1232.10.html

also, we may be able to get the trace/xantrex tech dept by phone.

good luck, dave

#### Posted by David Ames on Oct 12, 2009 12:25 am

#81 -
hi max,

any chance you disconnected the negative line and saw that reading go to zero? we might expect a few mA back current flow, more likely down into the micro amps. 100 mA will be way over and i would confirm by the above test. i bet you don't have a problem.

i can offer this. for the first year or so of running these RE systems i was forever chasing ground loops and stray voltages and currents around with my DMM and these anomalous readings came and went with the weather/humidity/moon cycles? etc. tell ya, i just gave up worrying about them after a while and after reading about "long wire" induced voltages and measuring different spots on the chain link fence out back i found that these odd readings are not that odd after all.(especially with the cheap testing equipment i use).

not so sure if that helps at all other than in the early days it's hard to know just what your system is up to, whats "normal" and whats not. then after a while... you can just "sense" any trouble at a glance.

regards, dave

edit: max i wanted to add the reason i commented that "i bet you don't have a problem." is these diodes are mostly good or bad and not much room for anything in between. to really test it we should take it out of the circuit.

#### Posted by David Ames on Oct 3, 2009 06:32 pm

#82 -

holy cats! a four letter extra!!!

if the folks here only knew the rigorous testing and body of knowledge required for that fcc ticket.

i think i see the uncertainty you were having after spending so much time in the qrp niche. (tiny ultra low power transceivers). you have been working in the micro world of power compared to this macro power setup here.

so happy to hear you powered up and decided to complete the system. still might be a good idea to have one of the high power HF guys over to have a look as well if you still can't get a "real" expert in.

fun blog you have there "solargoddess"

good luck, YL!

OM, dave

#### Posted by David Ames on Oct 2, 2009 08:37 pm

#83 -

hi ann,

i'm with robbie on this one...you can't put those wrenches down yet! sounds like you're all set to go and just need a once over to be sure.

i would recommend that you stop back at the radio club. these guys & gals from the league work with some good size power supplies and switch gear every day. many of the folks involved in amateur radio may have limited formal schooling but can hold their own on the levels of EE's & PE's

we get folks stopping by all the time and there is always someone eager to help. they may come off as somewhat of "odd ducks" at times but are some of the brightest too.

any folks out there looking for sound electrical advice might consider stopping by the local "ham" radio club. they are located across the world. your town hall or the ARRL in newington ct. would know the contacts as they are a big part of the civil defense system.

kind regards, dave
73 de kb1mzf

#### Posted by David Ames on Sep 28, 2009 02:55 pm

#84 -

Hi Tomb,

yep, those batteries sure sound healthy to me. did we ever figure out how/why they got down to that 9.6v level?

don't be alarmed with that overnight voltage drop from 13.31 to 12.66 that would have been just a surface charge and not counted as our voltage.

"Should I disconnect my truck batteries when I get to camp and run on the Trojans alone? "
we did not see this issue addressed. i would recommend that you have your RE system totally separate from your truck batteries. always.

"Lemon Pledge" just the rain works for my area. otherwise just mild soap and water.

good luck, dave

*Tomb..The other Michael B  .sorry couldn't help it, all in good fun:)

#### Posted by David Ames on Sep 25, 2009 01:09 am

#85 -

looks like the fate of perhaps a very important piece of americana is in your hands denis..no pressure here but agree with ken that it may belong in a museum collection some day. that day could even be 20 years from now after your done with it. the very best of luck there with whatever you decide.

also-ken, thanks for helping us to keep the facts straight on the first to generate power issue (we looked some more and now it's starting to lead to the uk as the location of first wind made electricity?) seems like a very foggy issue with claims from all over?

we will never know when/if this page might pop up in someone elses searches on the subject. in that respect each post is writing a bit of history in itself..and if something wrong is repeated enough times it blurs the real history and distorts the facts..in some cases it can even be dangerous!

cheers, dave

#### Posted by David Ames on Sep 23, 2009 03:00 am

#86 -

hi denis,

sounds like you have a page right out of history there with that hebco machine. bucklen (founder of hebco) has the credit of being the (disputed) first to generate electricity with the wind.

hebco started production in 1921 and won a government contract to supply air mail runways (usually just a cleared grass field leased from a local farmer) with providing power for running the locating beacons where no power grid was available..it's interesting to note that these early wind/battery powered beacons were not to guide the pilot to a landing at the airfield at night but used as a navaid/waypoint to confirm the plotted way to the intended night operations airport.

some time back, while looking at wincharger turbines i found some interesting pages about these early machines but darned if we can find them again.

from what i can find-this would be a brushed dc generator and would have sat atop a four legged tower about 35' high and have had a two bladed wooden propeller about 15' diameter. i think these were 32 volt machines and would bet it could see a good kw or two!

when you say 200 plus pounds it sounds like you have the blade hub and tail as well? also "turns easily by hand" makes me think of powered field coils? (unlikely) or maybe we have lost the magnetic field. or depends on what easy means. we need more investigation there..how many wires is a start.

denis you have a super cool find there..any plans?

how it may have looked.

kind regards, dave

#### Posted by David Ames on Sep 13, 2009 10:22 pm

#87 -

hey keith,

i bet those controllers will play together just fine.

your gonna like that bogart 2020 when you bring it on line, i see you enjoy knowing what your system is up to and this little toy speaks volumes.

cheers, dave

#### Posted by David Ames on Sep 12, 2009 06:56 pm

#88 -

thanks for that press release james,

good to see some of the manufactures going back to j boxes and conduit. we all know the systems going in today with the mc cables will never make it to the 20-30-even 50 years! expected life of the module. don't we?

sad to see them being made in china. but why make a million dollars when you can make two. could it be they can't find a willing workforce? lots of folks looking for work here at "home"!

my 2 cents.

#### Posted by David Ames on Aug 20, 2009 11:34 am

#89 -

hi paul,

my apologies for jumping off the inverter topic.

in your OP you mentioned "adapter gets very hot very quickly on a MSW inverter"..it is likely that this adapter is powering an internal battery pack to run the alarm system. we may be able to run that system directly from your battery bank?

these "adapters" usually have the input/output voltages printed on them somewhere. there may even be some info about dc only operations in the manual/website somewhere.

just a few thoughts.
kind regards, dave

#### Posted by David Ames on Aug 18, 2009 08:08 pm

#90 -

ron,

these solid state PWM controllers may be of some help here.

http://www.bakatronics.com/shop/item.aspx?itemid=444

shutting down at night and running at a %50 duty cycle may just get you by.

good luck, dave

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