David Ames's posts

Posted by David Ames on Oct 4, 2010 04:07 pm

#31 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: Xantrex MPPT low output problems

 hey matt,

 should be OK to just use one of the outside tabs (half the diode)

how about that metal tab on top? are we touching anything with that? it's the same as the center tab electrically.


ps: good going with the sketch posting! Wink

Posted by David Ames on Oct 2, 2010 03:59 am

#32 -  Renewable Energy > RE General Discussion > Pictures and Sketches
 hey gang,                                           

 often when trying to convey a thought, share a project or describe an issue, words are not up to the task.

 have never found any official policy about posting pictures in the forum and have tried a few without being shot down.

 we found if we open a free account with photobucket

it's easy to share any image or sketch that you have uploaded and include it in with your forum post.

 simply upload to photobucket or a simular service, size to something reasonable then copy the image code and paste it into your comment.

 here is a sketch from this forum copied as a picture to my photobucket album.

here is a screen shot of the image code we want to insert into the forum thread.

should show in the post preview..and good to go.

it's all good fun!
cheers, dave

edit: as a reference, the pic sizes here are 460x345..seems to fit well? much bigger and they seem to run off the screen and mess up the text.

Posted by David Ames on Oct 1, 2010 07:44 am

#33 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: Xantrex MPPT low output problems

 readers at this point may be wondering what mosfets are and why we are talking about them...sorry about that...they are the chips inside the ssr (solid state relay)

Posted by David Ames on Oct 1, 2010 04:43 am

#34 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: Xantrex MPPT low output problems

 have not used those three legged flyback diodes your buddy set you up with..looks fine for this though.

 trying to do a write up on picture posting. we need to host our files somewhere, i use photobucket. best to size them to something reasonable like 500x400 for screen scrolling and folks like me on dialup. just copy the IMG file from photobucket to your post.

 did a quick paste up for the ssr/load/diode..careful with the metal tab it's electrically hot!

 easy to get confused with these..see how the load negative goes to the battery negative and the load positive goes to the ssr negative! and ssr positive goes to battery positive..reminds me of the polarity markings when we plug those teckno wacko mc type pv cables end to end when adding cable..the polarity markings swap with every new plug!

cheers, dave

edited to add: yes on the inductive load question, better safe than sorry..if the diode is not/was not needed it still won't hurt anything to be there.

further edited to add: matt give me a bit to check a cleaner cut sheet on that three legged diode..i may have it orientated a$$ backwards? gotta go find a symbol lookup table..YEP, had it wrong! the metal tab and center leg is the pointy end of the symbol..sketch is now corrected with a cleaner copy.

yet another edit: added "Pictures and Sketches" how to post..http://www.altestore.com/forums/Renewable-Energy/RE-General-Discussion/Pictures-and-Sketches/index.php/topic,2272.0.html

Posted by David Ames on Sep 30, 2010 11:55 pm

#35 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: Mixing battery sizes in one battery bank?
Curious- why do you have 3 red cables coming from your positive bus bar in your battery combiner pic?

cheers matthew,

 the three large red and black cables are separate 4/0 inverter feeds. that system is running two 2.5kw and one 1.5kw @12v inverters.

one 2.5kw MSW to a 1800w pizza oven and other small loads..
a second 2.5kw MSW inverter to a large commercial coffee maker and a bunch of smaller loads and the 1.5kw pure sine wave for the band electronics/amps ect. the system runs a coffee house and we go thru about 5kwhs over a four hour period.

by the way, how do you post pics or diagrams in your response, Dave? I'd like to do the same. -Matt

matt, i'll put up a separate post on that..was never sure if they allow that on this forum but have been sneaking some pics in here and there and the administrator has not said anything or banned me yet so it may be ok? Wink 


edit: added "Pictures and Sketches" post.

Posted by David Ames on Sep 30, 2010 11:27 pm

#36 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: Xantrex MPPT low output problems

sounds like you are on to a reasonable theory.

don't have an xw here but have had similar units that act funny under certain scenarios.

some speculation:

a) the prosine may have a decent size capacitor bank onboard to help smooth out any stray interference caused by other equipment and we don't see the problem when left on?

b) the satellite internet system is most likely powered by a switch mode power supply (high frequency PWM) which may cause anomalous behavior (had a battery desulfator cause trouble like this)

3) not sure on your diode setup? should be ACROSS the coil power supply in "flyback mode"

d) some strange grounding/ground loop issues?..the xw does not like the battery grounded anywhere except through the built in GFCI circuit. see tech bulletin.

possible actions:
after checking any grounding issues and flyback orientation could install some ferrite beads/cores on all the wires from the aux trigger and satellite power lines..next step might be a parallel capacitor across the line to smooth things a bit..?

kind regards, dave

edit: matt had a look at the crydom relay..it's an ssr! like Johnny used to say. "that i did not know" so.. cross off that flyback on the coil- no coil to worry about. rather as you pointed out we are protecting the output mosfets with the flyback across the load. we do need to check that the load is on the low side (negative) for those n-channel fets though?

Posted by David Ames on Sep 30, 2010 05:15 am

#37 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: Mixing battery sizes in one battery bank?

hey guys,

agree that it's not the best or a "by the book" situation.

sometimes in the real world we do what we have to with the resources we have at hand.

we can make things less bad and more good by (electrically) moving the battery terminals off the batteries and onto a common busbar.

in a setup like this we want to pick a cable size, length and matching lugs and use the same for all our runs to the buss. (all cables #2awg and five foot each would be reasonable) if we are doing an inverter i would suggest a maximum size of 2.5kw connected with 4/0 cables from the buss.

some scribbles for a visual...

a pic of a battery combiner that supplies 500+ amps on a regular basis...

it's all good fun!
cheers, dave

*just one guys thoughts here and always open for a rethink.

Posted by David Ames on Sep 10, 2010 01:06 am

#38 -  Renewable Energy > Technical Discussion: Other > Re: blade dimensions for a wincharger 1222
 hallo bert,

 i would love to have a look at any info you have uncovered.
in your searches you must have come across alton moore III's work? very handy.

 comparing your numbers that is a very fast blade and power predictions sound about right.

 my email is:

*edited out*

 i hope to stumble across one of these wincharger machines one day..the more people with this blade info the better!

cheers and many greetings, dave. 73de kb1mzf

..email to be edited out after contact..

edit: removed email..VFB.OM.TU.VE.55&73!

Posted by David Ames on Sep 10, 2010 12:46 am

#39 -  Renewable Energy > Technical Discussion: Small Wind Power > Re: Two turbines, one battery bank.

 hi philip,

 congratulations on your wind turbine build! this stuff is tons of fun.

 sounds like your rectified ac mill is working well and this second "dc generator" is a wind turbine also? if so, yes we want to have a blocking gate (diode) on that as well..both feeding right into the battery bank.

 getting close with the c40 loading..will the max combined output be less than ~500 watts?

 it's very important to get yourself set up with a reliable dump load for your battery bank..as overcharging is the second best way to ruin a battery bank, the first best is to undercharge it. i would suggest a resistive load of about 0.4 ohms rated at 500+ watts. we have some wiggle room there +/-.

 a couple of scribbles for a visual-

dc mill with stud diode

dc mill with rectifier as blocking diode.

rough sketch..(fuses and disconnects not shown)

cheers, dave

ps. any pics?

Posted by David Ames on Aug 5, 2010 04:06 am

#40 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: Sunsaver MPPT with RM-1 remote (Morningstar)

 thank you for that update. it looks like the free version 7 software will be the ticket...when you get access to a pc that is.

 also good to know you got a response from morningstar. not sure all the company's realise how important that is.

 cheers, dave

 hope it's ok for a brief hijack of your thread.

 here is an ongoing rant for the google-bots and web crawlers to take home.

 i have attempted to contact other company's without a response of any kind.

EDIT: this post continued on with the name of the company and my personal dissatisfaction with their customer service.

i have edited it out due to possible legal issues...

Posted by David Ames on Jul 13, 2010 12:40 am

#41 -  Renewable Energy > RE General Discussion > Re: Whisper 200 wind turbine FYI
 holy cats Jon!

you must be living a "clean" life, buying cases of girl scout cookies and helping busloads of grey haired ladies across the street to be treated so kindly by the lightning gods. that could have gotten real messy and expensive!

think there is a chance the machine was engineered to fail in that mode? me neither.

great info for others searching for the same problem.
and an innovative homebrew fix! thanks for that.

cheers, Dave

edit: spelling

Posted by David Ames on Jul 10, 2010 08:09 pm

#42 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: Battery not charging - defective charger or depleted battery?

 hi leo,

 i was re-reading this thread and wondering how you are making out...

 i can't see how i missed the obvious and easiest way to try to get back up and running..that is to put a battery charger on the battery for a while to bring that voltage back up to greater that 6 volts.

 some chargers won't start up with a dead battery either, but some of the older "dumb" chargers will (usually the heavy transformer based chargers will run into a dead battery or most any other load.

cheers, dave

Posted by David Ames on Jul 7, 2010 05:47 pm

#43 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: Alt-E SOLARVOYAGER ™ Gold PV RV KIT

 hey tim,

 the wiring and the 5.5 amps output sounds very good!

 a bit confused on the "25% drop in voltage"? are we talking about going from 14.1v to 10.6v (that would be bad) or are you referring to the 4 stage LED display? from 4 lights to 3 lights (no worries there)..

 we are not sure what you have for batteries or what model xantrex charger/inverter you have. so hard to offer much on that. if we have the flooded lead acid kind with caps that let us add distilled water to them then we can equalize them by raising the charge voltage to about 15.5v for a few hours..(the standard advice to follow manufacturers recommendations apply)..

 i'd let the system run for a week or two and do more fishing if i were you! (as long as we are not talking about the 10.5v scenario from above)

 my money is on things are fine and you may be just worried about that fourth little led..and it may take a little time for those batteries to get used to working..in that regard i'd run things a bit, use some power and see how it does!

 happy to talk more about the batteries and the inverter/charger with more info. can probably crank the M20 up to 15.5 volts for a while if we have to...oh! did that M20 come with a temp sensor? and do you have it installed?

 also depending on your battery(s) we may want the float setting at a different (higher) setting..the M20 comes set at 14.1v, i run mine at a 14.4v setting for a bank of group 27 batteries and higher still for a bank made up of six volt trojan batteries (14.6) and much lower on some sealed valve regulated batteries (13.8 )..

 cheers, dave


Posted by David Ames on Jul 6, 2010 05:05 pm

#44 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: Battery not charging - defective charger or depleted battery?

hi leo,

 a reading of zero volts is never a good thing for a battery (our lead acid type). that said, the battery is probably toast...but, sometimes they surprise us and will come back enough to give limited service.

 could do your own "bootstrap" by connecting the pv module directly to the battery for an hour or two? just be very sure of polarity and keep an eye on things for a while..if we can get the voltage up above the 6 volt start up minimum she may start back up for you?

 that SG controller is a rugged little devil and hopefully it did not fry like some of the others will when connected open circuit, (no battery)

 good luck, dave

ps..if we see the battery voltage climbing up thru ~16 volts or so and still rising (during "bootstrap") that would reason to discontinue the attempt and go shopping for a new battery.

Posted by David Ames on Jun 23, 2010 11:18 pm

#45 -  Renewable Energy > Technical Discussion: Small Wind Power > Re: PMA wild voltage output.
 hi philip,

 what happens here with these alternators and generators when they are connected to a bank of batteries... is that they become "coupled" to the voltage of the battery and don't rise much above that. in a 12 volt system we won't see voltages much above 16vdc or so. the key here is to ALWAYS have the generation source connected to the battery to hold the voltage down to the battery level and keep it (the mill) under our control.

 so the battery keeps our wind turbine under control and a charge controller keeps the battery voltage controlled.

 hope that eases some of the concerns as far as open circuit voltages..i'll try to restrain myself in commenting about windblue pma's and companys that tout open circuit voltages and short circuit amps information as being important in some way.

 welcome to a fun hobby.


edit: oops! we should have mentioned the bridge rectifers as well, it (the rectifer) chops the ac voltage up into plus and minus pluses (a real rough dc) and then it goes to the battery.

Posted by David Ames on Jun 17, 2010 10:30 pm

#46 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: Alt-E SOLARVOYAGER ™ Gold PV RV KIT

 hey tim,

 did you have a look at this line sketch?

 try to keep the wire runs as short as possible. we cut
that long mc connector in half to plug into the pv module and then cut it again when we get to the controller.

 i'd be tempted to go a bit heavier with the wire for the short run from the controller to the battery bank..could do parallel runs of that #10 if it's all thats available. in any case try to get the controller as close to the bank as possible and keep the wire run SHORT.

have fun in the mountains!

cheers, dave

Posted by David Ames on Jun 13, 2010 11:21 pm

#47 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: Need help with RV charging system

 hey guys,

 sounds like both of you are looking at the same type of system.

 could be that the lack of responses is due to the rest of us being jealous over having not having a fun RV of our own!

 tim, had a look at that packaged kit..looks like a good option. at first blush it may sound a bit high but the balance of system (BOS) components really add up..

 william, your up to about the same as tim but looking a bit smaller. definitely doable and 40-80 watts of pv can do some real charging on a bank of batteries while the rv is not in use. if used boondocking (is that the right word) a 60 watt module might get you 2 hours of TV a day or so. (60 watt x 5 peak sun hours = 300 watthours. TV at 150 watts on two hours..just guesses here)..have you looked at any of the components at all. any preferences? are your expectations in line with the above scenario?

 if there is one bit of advice that might be helpful it's try to have a "good" sized battery bank for what your needs are. in this case i believe bigger is better if you have the room.

 also think it's a good idea to work up a "loads" list. really helps to get a perspective on power use.

 also. also we want to keep in mind if we are using dc power or plan to invert (change to ac power) for any or all of our uses.

 could be helpful to have a look at some of the other rv/solar discussions we have had on the board. there is a tiny search box up top on the right (really too small for folks to see) type in "rv solar" or "camper solar" for a look.

 happy to come back with some reccommendations if your still game. perhaps we can get some of the rest of the gang to input their thoughts as well. this time of year lots of folks are busy outside and let the computer have a rest..or it's that jealously thing!!

 hopefully we don't get any "drive bys" LOL

 trying to stay on topic, dave

Posted by David Ames on May 19, 2010 03:42 am

#48 -  Renewable Energy > Wanted > Re: Wanted, used deep cycle batteries in CT

 hey conrad,

 bummer having to replace that battery bank..always a bit hesitant to recommend used batteries to anyone. i've made do with some used stuff that came my way as freebies, and it's always hit and miss with that option.

 if there is a zero budget? might try sweet talking one of the local marinas into letting you check out some of the "cores" scheduled for return to the battery dealer, as some of the boat owners around here seem to shovel the money into their ships with the madness of Ahab. (how some of these guys ever earned any money is a mystery to me)

 if you have some kind of budget to work with..lucky for us we (i'm in hartford county) are in fair shape with battery dealers in CT.

 john mentioned midstate..we also have interstate battery that runs thru the state with on call pickup and delivery (in quantity's).. for a full service battery "builder" we have RAE battery in berlin..if you have a COSCO or SAMS card they have a T105 type battery in stock on a regular basis..wherever you get them, best to try for a set that came from the same lot number/same date.

cheers, dave


Posted by David Ames on May 11, 2010 02:02 am

#49 -  Renewable Energy > Technical Discussion: Other > Re: How to connect a generator with a battery(12v) or with a lamp?

 we gotta' be close to getting an update on the new generator?

 figuring three weeks from the midwest u.s. to clear customs and swedish port authority and a week to change over.

 any news? Smiley

Posted by David Ames on Apr 30, 2010 10:51 pm

#50 -  Renewable Energy > RE General Discussion > Re: Charge Controller for 48v golf cart

 hard to argue with that efficiency, two meanings- as in that's very high and as in most of us would not have the means to be able to measure close enough to argue a case saying it's not that efficient.

 looks like that controller hooks right up to the modules. in this case (steve's) he would have to disconnect his pwm 12v controller and run this one in it's place for 48v charging.

 have not had a chance to use any of these in line series controllers/converters from "solar converters inc" but have some of their other products..no flashy chrome or fancy lights with these! the products i have (a battery desulfator and a voltage converter) work well but are plain in appearance..photocopied label and instructions with no ul sticker in sight.

 these appear to be "voltage only" chargers..ie: no charge stages, just comes up to the set point voltage and stays there- must be a voltage comparator set up.

 no idea at all on the efficiency of a Toyota Prius? but we still have a way to go with battery technology to have a full blown EV as a primary auto..

 all interesting stuff.

cheers, dave

Posted by David Ames on Apr 25, 2010 11:50 pm

#51 -  Renewable Energy > RE General Discussion > Re: Charge Controller for 48v golf cart

hi steve

Any suggestions would be appreciated.

 couple possible solutions..some better than others..some more expensive than others..the most expensive is not necessarily the best.

 solar converters does indeed make a 48 volt model of that controller. model #CV12/48-3PV rated 3amps for 48v banks. this is a constant voltage controller. ie: lets the battery come up to 56 volts (adjustable) and holds it there..it will take quite some time for it to ever get into regulation. <-not really such a bad thing to keep our pv's running while they are able.

 i kind of admire that company (solar converters) they appear to be a small canadian company that finds a need in the market and fills it. have a feeling some of these items are made as one offs as the orders come in..they may need several weeks of lead time to set you up. altE should be able to forward your request.

 or we could do the inverter thing (plenty of losses here). with this option we would have the pv connected to the 12v rv bank (hopefully charged up and in regulation) and run a 12vdc to 120vac inverter from it hooked up to a small 48v charger.

 heres some. the 2.5 or 3.5amp model would be the go.

 consider a timer if you go that route, don't want to forget it's on and invite trouble with the rv bank! (drain it too much)

 or could do with the same 12v controller on your rig and manually configure for charging. sounds complicated but not soo bad if you get yourself set up with a reliable routine and follow it.

heres some scribbles on how it might go.

another option is to double your array and configure that for 48v output..need to invest in a 48v capable cc as well, the ts-45 or c-40 would fit the bill..can you talk yourself into it?

have fun, dave

edit: added link to data sheet..in regards to that 3amp @48vdc rating.


Posted by David Ames on Apr 22, 2010 11:47 pm

#52 -  Renewable Energy > RE General Discussion > Re: What kind of battery we need for 3 panel of 60 watts each one?

 Hello Sebastian Castro,

 welcome to the group and to the fun hobby of solar energy.

 sounds like you have taken the plunge and acquired several pv modules to start off with.

 it may be that folks are hesitant to offer any direction at this point, as we do not have an understanding of what you are wanting to do? lots of different ways of doing things and much will depend on the type of system and it's final purpose.

 is this to be a "fun" system with no real goals..to just kind of to see what all the fuss is about or a "purpose built" system to do an assigned task?

 much of the choices for components will want matching to the rest of what you have and what you want to do.

 so, do tell. what did you pick up for pv modules and what are the general goals of your project?

kind regards. dave

Posted by David Ames on Apr 19, 2010 01:50 pm

#53 -  Renewable Energy > Technical Discussion: Other > Re: Controller fuse burns

 hey George Anna,

 he.he..was just re-reading that babel fish translation and having a chuckle, not quite english no longer spanish..reminds me of that movie "spanglish"

  might even be easier for you in the original format..down the page a bit.


 looks like the amarillo was in reference to the meter colors. that is a snazzy looking meter. bet that is a big selling point. we can add that to our list of "things that are good".

 there can be little doubt that the 17.90 voltage is the open circuit voltage of the module, you confirmed this with the foresite to take two voltage readings at different points in the line..both readings the same means no power going through the wires.

 with just the few measurements you made at 1pm, if someone were the curious type they could extract the module operating temperature and apply the corrections to all of the performance data provided at standards to plot a new real time performance chart for the module.. with your readings of the "running" module one might extract the line resistance (for that run), make a guess at the wire/distance used, and get an idea of the battery state/rate of charge. (current readings are nice too but a bit more complicated and dangerous so we can guess at those for now)

 the data chart for the ec-102-g


 just for amusement, exchange where 16.7 is on the lower line of the i/v chart for 13.2 then move from the 13.2 (the point that was 16.7) to where 13.8 is to get an idea of where we are running. our main goal here is to stay away from the big dropoff on the right of the chart. looks ok so far (but well on our way down), still have room for about 20*f more on the temp as well (before we fall like a six flags rollercoaster)... (but it would still be nice to reclaim most of that 1/2 volt line drop)

 i always get a kick out of comparing the real running measurements against the "paper" calculations after a system is up..sometimes we can pick up on a bad connection or problem that we can't see by just looking.

 if you take any more voltage readings while running- a set of readings taken about the same time at the pv back, the controller pv input, the controller battery output and right at the battery terminals will give us a better overall view of the system. battery voltage readings are always good to have throughout the day. two that would be good to know is the voltage at the bank terminals right before sunup and right after sundown.

 still should address that faulty fuseholder.

 this next bit of advice would most always be considered bad...but, it may be worth while to bring those other two batteries back online and move that second controller (the cool one) over to that one to see if it will start up and run without interference from the other (hot one). in effect two mini systems?

 question: have you ever seen the voltage on "the one that was high" aka "the cool one" down into the operating range? 13-15 volts?

are we having fun yet?

kind regards, dave

Posted by David Ames on Apr 16, 2010 12:25 am

#54 -  Renewable Energy > Technical Discussion: Other > Re: Controller fuse burns

  some random thoughts,

 a few times today the specs of this controller came to mind and i tried to think of anything good about it.

 then it occurred to me that a controller such as this would be very useful in a "closed" system where we have our modules and loads matched for some kind of daily cyclic function such as walkway lighting or water pumping applications. (made to charge up then run back down each day)

 in systems like ours we are missing alot of charging opportunities with these (even if they run as they should). and it would seem likely that they would "mess" with each other when we try to run them in parallel to the same bank.

 "mess" <- one may come on a hair before the other has a chance to trip on and the first one on might/will keep the other from even starting up at all that day. yikes!

 we did find something good to say though.

cheers, dave

Posted by David Ames on Apr 14, 2010 04:32 am

#55 -  Renewable Energy > Technical Discussion: Other > Re: Minimum string size for Solectria 3000w grid-tie inverter?

 update: six emails and two voice mails.

for those reading and wondering, this is the sort of information we are looking for on the pvi 3000

these are the low limit performance charts for the pvi 1800 and pvi 2500.


 we see the 1800 does well down to 300 watts and drops off the chart at ~100 watts. the pvi 2500 does well down to 500 watts and drops out at about 150 watts. if we use the trend of those charts we should still be on line with the  pvi 3000 down to about 200 watts or so.

 i don't see any way of damaging the unit with low input as that would be a normal occurrence with snow/weather/low light conditions. i understand your concerns in regards to the warranty and excuses for voiding it. could be a chance that alte may have your back covered with post #4? i would like to see that company return some answers to repeated query's none the less!

kind regards, dave

Posted by David Ames on Apr 14, 2010 03:24 am

#56 -  Renewable Energy > Technical Discussion: Other > Re: Controller fuse burns
 some good info there George Anna,

 for others looking on, some more tiny pieces of information on what that controller may be.



some translation: (thanks bable fish)

In English

Controller. Measurer for systems Photovoltaic Model CMCX.12-15-20 Description: The controller of load with voltameter, model CMCX-12/15/20F provides in efficient form the protection and signaling adapted for photovoltaic systems that operate with batteries, as much for the apparatuses connected as to the batteries and the same users. In load control he in series consists of a limitor by relay towards the solar modules and another one for disconnection of the loads fed by low voltage of battery. He includes luminous indicators of normal battery, battery low and module in load, fuse, of protection when coming out and selector to inhibit the disconnection by low voltage. The expanded scale, voltameter (10 to 15 volts) this divided in colors to facilitate the user to determine the state of load of its battery (ROJO= low battery, AMARILLO= load A battery average. VERDE= battery with acceptable load). The controller - measuring it is lodged in an attractive aluminum cabinet enameled in black, in whose in front the functions above described are indicated with clarity, besides being the fuseholders, selector of disconnection for cables until caliber 10 with or without connectors. Characteristics: - Nominal Voltage 12 volts. - Current principle of solar modules: 15 amp. - Current principle to the fed loads: 20 amp. - Permissible maximum Voltage: 22 volts. - Levels of operation voltage (batteries seal with lead-acid). - Disconnection of modules (loaded battery): 14.8 + 0,2 volts. - Reconexión of modules 12,9 + -0.2volts. - Disconnection of loads by low voltage of battery: 11.8-0.2 volts. - Reconexión of loads (automatic): 13.2 + -0,2 volts. - Interrupting to select to the automatic disconnection by low voltage (normal) use of emergencia. - Fusible type 3-Ag to the loads in bayonet fuseholders. - Protection against transitory of voltage by Varistor (MOV). - Voltameter with expanded scale of 10 to 15 volts. - Precision -5% of the scale.
 this controller looks to me like.. (others, please jump in if you see different)..a shunt type controller. sometimes called a "bang bang" controller. it goes on if the voltage of our battery drops below ~12.7 to 13.1 volts and have pv power available. and turns off at ~14.6 to 15 volts...no wonder they don't like to provide the specs!

 your test measurements show that the controller that gets hot was running as it should..a bit high with the voltage drop (still gonna loose a tad more before we get to the bank) the voltage output and bank readings would be good to have as well. the one we thought was running right (the cool one) was off both times you checked it. can't be sure on that one until the battery drops below ~12.7 volts. we really would have liked to see both of them running both times you checked. that is a hysterical amount of hysterics (voltage spread) built into those controllers!

also, please confirm both controllers are going to the same battery bank.

 your measurements at night show us that we are NOT shorted back to the modules while off. thats GOOD!

 was thinking you might get your "talkative" friend to bring out some leads off that defective fuseholder for a nice blade fuse holder external to the controller. could probably get any audio/tv shop to do that. i would stay with the 20 amp fuse. it would not hurt to put another inline fuse for each module as well rated at 12-15 amps.

 i'm not here to sell you anything but you can do a LOT better than those controllers..a nice temp corrected pwm multi stage controller (just one) would put you way ahead of what you are running now, your batteries will thank you for it and there is even a chance of reclaiming those that are scheduled for retirement.

 pretty good "bang for the buck" or "pop for the peso" with this one.


kind regards, dave

edit: "..it would not hurt to put another inline fuse for each.." should read ..it would not hurt to put another inline blade style fuseholder for each...those spring loaded type inline holders are trouble!

further edit: i see a terminology mistake here calling that a "shunt" type controller..more like an on/off series controller that leaves our pv circuit open when off.

Posted by David Ames on Apr 12, 2010 02:26 pm

#57 -  Renewable Energy > Technical Discussion: Other > Re: How to connect a generator with a battery(12v) or with a lamp?

 ah yes, never occurred to me that the darn thing could actually be trying to run into a waayy flat battery, (assumed voc) and also that wire size thing...gonna have to up the size either way so now is as good a time as any.

 hope to hear about those voltage questions ken brought up.

always good to have extra eyes on these posts.

cheers, dave

Posted by David Ames on Apr 11, 2010 03:19 pm

#58 -  Renewable Energy > Technical Discussion: Other > Re: How to connect a generator with a battery(12v) or with a lamp?

 SWEET!!! Smiley Smiley Smiley

 super duper job all around..love the tiered approach to keeping our dump load wiring safe (i'm gonna steal that idea for the next build) i see glen has you set up with three banks of four 10 ohm 25 watt power resistors in parallel each bank running off it's own n-channel mosfet. (you did remember the flyback diodes?) you will be good with almost any small wind turbine with that. (total dump rating at 14 volts of 235 watts).

 as you have found out the ametek 60 is not one of the better choices as far as the ametek line goes.


 sounds like we are real close, only need about 30% more rpm to reach "cut in" the wire size is not a factor (yet)..we won't start to drop voltage in the line until we are "loaded" (producing power).

 couple things to try...seeing that these ametek motors all have the same shaft size might consider trading that one in for a better performer? if we stay with that one we have to make it spin faster..

 from your photos it appears you have made your prop about four foot diameter? we can get the blade speed (tsr) up quite a bit with a few mods. hard to describe but here is a sketch.(click to enlarge)

 i would take that blade diameter down to 42" try it and if needed take it down some more to 36"

 again, excellent job there!

kind regards, dave

Posted by David Ames on Apr 9, 2010 05:50 pm

#59 -  Renewable Energy > Technical Discussion: Other > Re: Controller fuse burns

 Hi George Anna,

 please accept my apologies for the gender confusion on my part,<-insert hat tip and southern bow..

 consider the following as opinion/speculation on my part.

 we have problems here..i would advise taking that controller off line, as there may be some risk of things going real bad real fast.

 if you can work on that controller or have someone else work on it (back to the factory would be best) besides checking/refitting that fuseholder. i have a VERY strong suspicion* that we are backfeeding into the pv module from the battery bank. (caused by a failure of the blocking diode(or equivalent)in the shorted mode..this is very rare)

 looking at the link you provided and reading some more leads me to believe you have 15amp controllers protected by 20amp fuses...i hate that style of fuseholder. (those are a poor choice for anything that carries even a modest current) still can't get into the spec sheet without the secret password. @!*.*.RHUBARB!

 what i might do is see if there is voltage on the pv INPUT side when it's dark. do you have a meter?

 while waiting to get that controller fixed i would be tempted (not suggesting you do this) to run both modules on one controller..this will put it over it's rating! (assuming it's the 15amp model)

wish i could be of more help.

kindly keep us posted.


* lots of clues pointing to backfeeding here.

Posted by David Ames on Apr 8, 2010 05:40 pm

#60 -  Renewable Energy > Technical Discussion: Other > Re: Time it takes to fully charge a battery from 40% discharge state

 Sorbari Akpea,

looks like you may be understanding this better than you think you are.

you will enjoy these links on the workings of battery chemistries and their charge/discharge characteristics.



that multiplication factor of 1.2 is an effort to recoup the 20% losses..example: if we take away 100 units, we need to replace it with 120 units to get back to where we started.

you will notice in those links (and explained A LOT better than i ever could) how our battery stores it's energy as a chemical reaction.

afraid we have to get back into the subject of amp hours here as well. drill into that smartgage site where they talk about ah ratings and how the charge/discharge rates effect it's efficiency...many of the batteries used in RE setups carry a rating of C20 (5% of it's capacity) example: a 100ah battery discharged at 5% (or 5 amps) will last 20 hours.(those are full cycle ratings to 100% dod) we stay well above that.. ie: your example of 40%, some folks only go to 20%.

in your above 1400ah example we see that our charge rate is up around the C10 rate (~10% of capacity) and may effect the charge efficiency..some batteries (ie:gell) have problems with higher charge rates and others (ie:agm's) seem to be able to take all you can give them.

to complicate matters more, there are charge acceptance ratios to consider..again explained better in the links. but in a nutshell. we can put the "bulk" of the charge back into the battery with speed and ease but the last 10% or so will only go back in so fast..<- this last bit is a pita in these RE systems and seems to force us (me at least) to run our systems with the battery running in 70-90% state of charge range and only charging up to 100% during our maintenance schedule.

YIKES! looks like i'm rambling on here.

one more link, the AltE store has an interactive calculator for battery/grid systems that gives a good feel for sizing a battery bank and pv array.


cheers, dave

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