David Ames's posts

Posted by David Ames on Jul 19, 2008 11:53 pm

#211 -  Renewable Energy > Wanted > Re: 3 years off grid! female designed & constucted homestead seeks 80 watt panel(s)
hi karen,

  good for you. i bet your grandfathers would be proud.
please contact kerry at customer service. she has a pv module with your name on it. supply her with the shipping details and choose between the sharp ne-80eje 80 watt or the kyocera kc85t 85watt or the mitsubishi mf110ec4 110watt module. the account has been taken care of.

hope this helps, dave

karen please consider adding some gallery photos of your homestead.

Posted by David Ames on Jul 17, 2008 06:07 pm

#212 -  Renewable Energy > RE General Discussion > Re: First RE System is Planned

 i was thinking about your system today and i believe i may have muddied the waters with the three phase comment. it should be made clear that a three phase run is in no way immune to ohms law and the closed loop calculations for wire resistance still stands. i have since downloaded the manual and it does indeed say to use an awg#8 wire run for your distance! i think we can all agree that that recommendation is ridiculous. i think they are just covering themselves for safety (amps). i like mikes transformer idea. the new whisper 200hv model is using that method.

 if your unit does not have the whisper controller included consider using the c40. you will have to buy/build a bridge rectifier and a resistance dump load of some kind.

 for that nice 1kw of solar you have planed i would start looking at the apollo or the outback mppt controllers. both of these are true open format controllers and will handle most any array you decide on going with. and yes everything should be fed into the one battery bank.
 sorry for the confusion, all the best, dave

Posted by David Ames on Jul 16, 2008 12:17 am

#213 -  Renewable Energy > RE General Discussion > Re: First RE System is Planned
hi eric f.

 it's great to see that you are trying to nail down these details before just diving in with your wallet. you are sure to find something you missed along the way. but that is the fun of the learning.

 i see the wire run problem as a mixed bowl of fruit. we are attempting to use our dc wire tables for the turbine run. this turbine feed comes all the way to your power room with "three phase wild ac current" and then is sent through a bridge rectifier and changed to ripple dc and then right to the battery bank. we may well see 150vac @ 150hz comming from the turbine...a word of caution here about trying to measure it with a regular multimeter. don't. it took me three meters to learn that one. also you will find that your batteries love that dc ripple charge current until they get to the very top of their charge, then you have to start dumping. the c40 should work out nice for that. and the suggested wire gauge per manual is the way to go.

 for some great wind advice check out paul gipe and the guru of wind hugh piggot.

all the best, dave

also sometimes it's easier to beg for forgivness than to jump through all those permiting hoops. my local inspector was by on another matter and happened to notice my set up. and all he said is that looks nice. your ahj may not feel the same. in any case be sure to follow at least the fall rule. that if it comes down it lands on your property. build strong!

Posted by David Ames on Jul 12, 2008 11:19 pm

#214 -  Renewable Energy > RE General Discussion > Re: Power needed for remote wireless signal repeater

 in the previous post i should have said that the chemistry of the battery all but shuts down in extreme cold conditions. we still may be able to get a fraction of our capicity- say 10 or 20%. but would force an increase of storage capicaty by a factor of ten. ie.. where a 200ah might work we would need something in the order of a 2,000ah bank for extreme cold operations. yikes!

all the best, dave

Posted by David Ames on Jul 12, 2008 04:14 pm

#215 -  Renewable Energy > RE General Discussion > Re: Power needed for remote wireless signal repeater

mr. fletcher,

 at first glance the problem you pose seems very reasonable to accomplish. but upon further study what will be required is right on the cutting edges of available technologies.

 i state the above, not to throw cold water (in this case solid ice) on your project but to made us aware of the limitations of todays systems in extreme cold conditions.

 when we take a look at how the big boys do it. we see that they most always employ a genset along with their pv sites. why is that we ask? with the exception of a few very exotic battery examples-all battery chemistries shut down at very low temperatures. there is however a few pure pv repeater systems that have come on-line right up in your neck of the woods. check out nwtel. this is the interesting part. they are employing the use of something called phase change materials (pcm) to enclose their battery boxes. i have never seen anything like this before. these pcm's store heat as a chemical reaction when they change from frozen to liquid states and release it back when they change back to a solid! interesting to read about.

 back to our problem. we have to find a way to keep the batteries at a reasonable operating temperature (in this case warm enough). i would shoot for a comparatively balmy 0*c. and from what i see. a simple insulated box ain't gonna do it. first- we can look into how many joules of heat we might extract from our equipment. second -we can look at building a thermal mass like a solar slab that gets charged with a trombe wall of some kind. third option might be to heat the batteries with the batteries like they do on some of spacecraft and rovers.

 im sorry to have posed all questions and no answers to your problem but there are ways of doing this i'm certain.
just for fun i'll start doing some numbers on the second option (thermal mass) and see what i find and get back to you. perhaps there are other options as well? anyone? perhaps running a 1/4 mile of wire isn't such a bad option?

also i think the motor in an auto acts as a thermal mass of sorts to help you start your car in the morning.

all the best, dave

Posted by David Ames on Jul 6, 2008 12:11 pm

#216 -  Renewable Energy > Technical Discussion: Other > Re: Batteries
yes david, i concurr with thomas that a system monitor may be the best overall investment you could make at this point. real time information will give you an intimate awareness of whats happening with every component of your system. read, research, expierment. knowledge is power. you will become an expert on your system in no time and as a result of your new insight will have a more efficient system with greater capacity simply by default!

all the best, dave

Posted by David Ames on Jul 5, 2008 12:47 pm

#217 -  Renewable Energy > Technical Discussion: Other > Re: Batteries
ok now we are getting a handle on what you have. that vector inverter (using the vec050 as an example)advertises a 90% efficency but that is the power conversion efficency only- there is also a load from the cooling fan "super turbo cooling fan" gotta love those ad men. anyway that load is not counted in the efficency of the unit. its about 40wh. if we run the inverter full time thats about 1kwh a day!
 dave. i do hope you have gone over to solarjohns link and spent a few minutes, hours, days reading. he has a treasure trove of info there. go to his 3/28/07 posting and grab his battery soc chart. i lifted it the day he posted it (thanks john) you do have a multimeter? if not go buy two they are cheap. and with two you can cross reference if you don't believe the first reading. follow johns chart for topping off the banks with the honda. as far as adding any and how many new batteries to the bank goes thats for your pocketbook to decide but at fifty cents per amp hour they are a low cost and effective way to go. now here comes the sticky part of this post. if you have your bank wired like almost all the diagrams you see on the web you have what i call a "self amplified battery bank unbalancer circuit" built into your bank. what i would do is tie these batteries in pairs and pull from the cross corners with all the cable as long as the longest up to a central main busbar. then from the bus to the inverter. you want to sink and source all your power from that bus. you can pick up some real nice 200amp rotor switches for the strings of batteries coming up for less than five bucks a pop. that will end any battery balance issues and give you great control and monitoring abilities. check my gallery photos to get a visual of what i'm saying. also a good starting place for sizing your bus is a minumim one square inch of 1/4 bus plate (cda110) for every 80amps crossing it. fifty bucks will get you a 1/4 x 2 1/2 x 12 inch blank. bigger is better and you will want a good size to land all those big lugs. hope this helps.. please wait for some other comments from more expierenced re folks before ripping your system apart on just my advice. i'm experienced in power systems but still a newcomer to renewable energy.
all the best, dave

Posted by David Ames on Jul 4, 2008 08:41 pm

#218 -  Renewable Energy > Technical Discussion: Other > Re: Batteries
oops. you caught me between posts.

i'm gonna catch hell for this but i would not hesitate a minute in adding more new batteries of the same type to a one year old bank. there i said it.

all the best, dave

Posted by David Ames on Jul 4, 2008 08:31 pm

#219 -  Renewable Energy > Technical Discussion: Other > Re: Batteries
 gee david that sounds like a nice setup you have there. those loads are very reasonable. i figure you are at 3kwh a day tops. those pv modules should be putting away about 1500wh a day. i'm not counting the turbine if its the one i think it is. that leaves another 1500wh a day to be made with a short generator run. i have a feeling you are not topping off the banks at the end of each day? you should be able to make it through the night and then some. did this bank ever last the night? i would not drop a grand for those new t105's until i figure out why this one year old economy bank has let you down. we may be dealing with some less than ideal wiring methods.

info please.
 are these all dc loads? they should be in your case.
 are you inverting?-lots of uncalculated load if so.
 are you topping off at the end of each day with the honda?- you must.

all the best, dave.

Posted by David Ames on Jul 4, 2008 04:02 pm

#220 -  Renewable Energy > Technical Discussion: Other > Re: Batteries
hi david.
 all things being equal and they never are. the T105,s will increase your storage capicaty by 60ha. we would a little more info on what your goals are.
 if your goal is the cycle this size bank on a daily basis we are talking about a 2kw array!

all the best 73 dave

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