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Everything posted by maxomill

  1. maxomill

    Good Batteries

    have a guy that needs new batteries at present he has 8 100 ah bats 4s 2p being a old 48v system with about 3.4 kw panels and 2 pwm charge controllers I told him to go with 4 series 12v 200 ah bats to simplify things Now the big questions battery recommendations excl lipo I have been impressed with Omni power in the general range of 2500 cycle lives Trojans are good but seem to be in the 1750 cycle life range or maybe I'm looking at it wrong cheers all
  2. maxomill

    Home Use max Current?

    v series inverter running self consumption 20A inverter supply 63A Eskom supply breaker use max 6.5 kw 0 DC battery demand unless eishkom off 10a charge from inverter 35 A PV max current 0A export but can do 1.2 kw cheers
  3. maxomill

    Solar Panel Wattage vs Size?

    just an idea might fit your scenario since you want grid tied high voltage panels like this https://www.sustainable.co.za/renewsys-deserv-260w-high-voltage-solar-panel.html there are others out there as well grid tied likes high voltage check it out cheers
  4. maxomill

    OK to connect parallel PV strings without fuses?

    great reading guys just a quick question there seems to be that 2 fuses are mentioned a lot why the chances of the two fuses blowing at the same time are minimal are there scenarios of sometimes the positive leg fuse verses neg leg fuse ? just curious cheers
  5. maxomill

    Good Batteries

    thanks guys @Jaco de Jongh there wont be any icc but I love the battery monitor idea cheers
  6. maxomill

    Good Batteries

    thanks guys but no lipo no pylons as I believe they need to talk to the inverter remember I have a pwm cc to consider looking at 4 x 200ah in series or something trying to get to the 20 k range for complete set also want a victron battery monitor to switch back to Eskom any ideas on that would be appreciated cheers
  7. hi there always loved this idea but where's the 50 v come from what mods do you do cheers
  8. maxomill

    Losing my mind

    at the point where you show the two meters whats the load on the inverter does it match the output of the out meter
  9. maxomill

    Losing my mind

    HI there what geyser do you have and how many people in the house cheers
  10. maxomill

    Series String Mystery

    sounds like you have a floating earth on your old panels are you sure the old panels are actually earthed and to where did you have shoes on when you got the tingly feeling do you still get shocked if panels are not connected to the inverter is your inverter earthed
  11. maxomill

    6 Parallel vs. 12 Series Solar panels

    I have a v series which I run in self consumption mode does the goodwe not have that or at least a swap back to Eskom maybe as batteries are expensive thanks for the great info interesting reading cheers
  12. maxomill

    6 Parallel vs. 12 Series Solar panels

    hi guys am I reading this right at about 8ish your batteries are at about 25% soc . does that mean 75 % depth of discharge ? what are the cable sizes from the panels . thin bad thick is good just asking cheers
  13. maxomill

    Hare Brained idea

    Bare with me for a moment and you might see something interesting so I have a spare 37 voc 250 w panel and was wondering if I could charge a 12v battery with it but im concerned that the controller could not accept 37 v or at least 31 while starting ( yes it pulls the panel down to 12v while charging but still concerned) so I have a 110v 1500w geyser element lying around which I placed in line with the solar panel this caused a voltdrop over the element of 18v which meant that the controller now also got about 18 v which it should be quite happy with ( 18v x 6 a = 108 w ) ( I also connected the element straight to the panel and heated a cup of water in 20 minutes while playing around ) the controller that I used was a TES on off type not wanting to maybe damage a general type scc when the small battery that I used was fully changed then the contact opens and charging stops also meaning that the power draw by the element stops MY BIG QUESTION Knowing that a pwm controller throttles down the input as the battery charges up could we not have all the solar power going to the element when the battery is fully charged . in this case 37 v x 6a = 222 w what can I do to make this happen idealy I need to connect pos to neg closing the element circuit at the controller allowing all the power to element but that would probably make the controller go boom! Im looking at a bigger picture here solar power from roof in line with element ( axpert scenario 100v ish ) and as batteries get full / load gets less then more power goes to geyser 2 for the price of one so to speak im sure this could be achieved using a wind turbine controller with a dump but that's a slep to get and install Kaak idea or not ? cheers Max
  14. maxomill

    Hare Brained idea

    Ok guys the spare panel and test was just my way of explaining how I got the idea sorry I didn't make myself clear, my bad my big picture or question is would it be possible to use this idea on a bigger scale like connecting to a house that has a larger solar set up ? first of all could it work ? and if so, what do we need to do it so on and so forth so my theory is that when the batteries are full or the load is small then all excess energy goes to heating (geyser) and is not being wasted like having an inline dump load my thoughts go along the lines of having a geyser pre feeding your regular geyser which has say a 4 kw element ( 220 v x 18a or 100v x 40 a ) , and gets heated by the pv panels I've seen a couple of posts about heating water with the excess power which is where I'm going but just from a different approach or thinking out of the box im wondering if this way could be easier than monitoring the batteries voltage and special contactors and all those things ps I did like the idea of placing the element in parallel and not series nice pss the hair thing was just a pun as I have very little left , also used it just to emphasize how hare brained the idea actually is , glad to see someone is awake psss what do you call 10 rabbits walking backwards a receding hare line cheers max
  15. maxomill

    New Axpert model from Voltronic?

    I also have the v series and think its the best thing since chappies you can have the grid tie function on or off I run mine in what I believe is called self consumption mode meaning ie it subsidises the solar with Eskom or whatever solar cannot supply it takes Eskom for the rest my main reason for buying this unit was not to cycle the batteries today at 12 I see 10 -40 w at the supply to the inverter, this fluctuates as the load /sun does esp cloudy days im not sure but this could be importing or exporting as the load/sun fluctuates my concern is that my prepaid meter doesn't really care (Hexing type ) but I have heard of others that do and will only accept 40 w before tripping @plonkster wrote this on another thread BEC23 is 40W over a 15 second window. BEC44 is less, though I cannot remember if it's the wattage or the window size. generally the Db is split and my thinking is such that if a small amount is exported from solar side then it will be absorbed by the Eskom side split instead of going to the meter / grid as a buffer so to speak ( usually something is drawing some powersowhere) just a heads up cheers Max
  16. maxomill

    3 x hybrid inverters - Feed to grid ?? Help

    maybe im too simplistic but I think you should install 2 contactors one on each incomer connected to the incomer that opens is the Eskom goes down this means that each inverter will not see each other 3 contactors would be better to isolate 1 and 2 from each other and from 3 cheers
  17. funny you should mention the 650 watt and gap I bought a reconned 150l gap as a pet project last week for R900 (couldn't find a 100l) installed a 650w element and it is pre fed by my waste of money 300l solar flat plate geyser (which got a whole 11 degree raise from 17 to 28 today)( I call it an elect geyser with some solar assistance) I have the gap feeding only my shower and big geyser feeding rest of house it runs off the inverter with no timer and consumes 6 kw daily my electosolar geyser is now set for 1hour in early morning 3kw my usage this week has come down from 15ish to 6+3 so a 40% saving not taking into account that approx. 3 kw comes off solar by putting it on a timer and upping the temp to 65 im sure I could improve on the solar part ( switches off at about 11;30 12 after the morning showers) the other interesting part is that when heating my solar geyser electrically , considering that the element is half way up , I only heat approx. 150 l anyway I guess it takes ages about 8/9 hours to heat up from cold to hot but once it just topping up its not too bad esp since its solar big plus is that we can shower any time of the day ,me and the 2 long haired bipeds are super happy I thought I would mention @Chris Hobson as he has a similar idea cheers
  18. hi @SilverNodashi what kind of element is it screw in or flange type I don't mind cheers max
  19. i see these guys sell a 1000w geyser element cheers
  20. maxomill

    Ideas - Detect when feeding back to grid

    Hi @plonkster I see your logic Luckily for me my washing machine is on my solar side but having said that I do have a "real power " monitor on the incomer to the inverter and the bastard washing machine does do exactly as you say. I see it jump up and down by about 200w when on/off luckily for me that my prepaid meter "Hexing type" does not trip but does charge I think when exporting . it only shows a diode symbol when exporting I had a kaco gti with a microcare grid tie limiter and it worked but there was a couple of seconds reaction time while things switched on/off I believe that worked by monitoring the phase angle and adjusting the gti output to suit ( it has "one direction" ct s to monitor the coming and goings, anyone know their correct name please tell me ) it also always allowed 100w to be draw from the grid as a buffer I guess I still have the grid tie limiter in my cupboard and not sure what to do with it ( the kaco has been if for repairs forever at a name given to me but someone on this forum, so if you need repairs done please call me and I will tell you where not to go ) I believe the end justifies the means as long as your municipal meter is not too sensitive now back to the LSR,it does have an off delay but I have no cooking clue how fast it will react(sample). I believe it will react quick but how fast is fast I would say that the kettle scenario is okay , washing machine not so much ,again back to the sensitivity of municipal meter I had a quick look and the BEC23/44. seem to have only a 40w export tolerance please check me up having said that, in my case of the Vseries and @KLEVA imeon which are inverters with grid tie functionality it would be wise for us to install the LSR (s) at the incomer to the inverter I think this means the Dump load would be switched on first before the exported power goes back to the house assuming the DB is split into 2 meaning the house( something must be drawing some power) would be a buffer before being exported it goes somewhere along the lines of your point just another point is that the Dump loads must be equal to or greater than the amount you can export I think I will do this at my house as a test . I have a 650w geyser element and about 600 ish w of excess power and let you know how it performs cheers Max ps @KLEVA you could just change the wiring around so that the dump load is an extra load on the inverter if the inverter is powerful enough to handle it ( back to timers ?)
  21. maxomill

    Ideas - Detect when feeding back to grid

    Ok so after a bit of thinking my last post may work but quite high tech , I think I may have a KISS keep it super simple aka Heath Robinson what happens if we monitor the power to the house SCENARIO we are using grid power and as the gti starts feeding power the grid power goes down (gets less) now check this out a LOAD SHED RELAY http://mce.co.za/product/electronic-load-shed-relay/ These guys also do them but min 5a http://www.electrodev.co.za/product/load-shed-relay-dls/ so now we place a load shed relay on the incomer to your house when grid power reaches down to say 1or 2 amp just before we start exporting the load shed relay allows a dump load to be switched Simple ISSUES AND PROBLEMS since the LSR is only capable of taking 32A and the screw connectors will not accept a general 16mm incomer, you will have to split the incomer into say 2 or 3 10mm wires of equal length in parallel which is a slep BUT offers you the opportunity to place a LSR on each wire . what this means is that now you can have a number of Dump loads that switch on proportionally to the amount of power you need to dump and your systems outputs . so for example at 3a dump load 1(small) comes on and at 1 amp dump load 2(big) comes on , the skies the limit. you may also have to install a timer on each dump load so at night when drawing less power nothing comes on (possibly a bypass switch as well for convenience ) The LSR should also be installed after your main switch ( usually stops those ugly sparks , burnt fingers and arc eyes while installing) the thing that does worry me is timing when the dump load come on then all of a sardine the grid power goes up and the dump load may be switched off but the LSR does have 0 to 120 delay setting which should give the gti enough time to catch up or it could just flip flop until the gti has enough sun power to keep the dump load on there are probably other kinks that need to be ironed out so lets chat please shoot me down if and where you can so that we can improve on it and patent this the "Power forum limiter" I used to have one connected in my old system which only allowed the pool pump to be on when the inverter (house)was drawing less than 1400 w so it was impossible to overload the inverter if say the hair drier/dishwasher was on . I believe it was made for low power houses(RDP) and such so that stove got priority over geyser and could never both be on at the same time or if you were running you house off a genie (inverter) I took it out as my new inverter runs in self consumption mode although it can grid tie Yes I know what you are thinking like this guy is so clever that he should have been twins but I do accept credit cards ,blank cheques ,beer and pizza cheers Max
  22. maxomill

    Ideas - Detect when feeding back to grid

    Bear with me for a moment , so while surfing I came across this Optical Utility Meter LED Pulse Sensor Loading zoom See 8 more pictures RRP: Price: £18.97 (inc VAT) £15.81 (exc VAT) SKU: OPS Brand: Condition: Weight: 50.00 Grams Rating: ( ) Availability: Shipping: Calculated at checkout Minimum Purchase: unit(s) Maximum Purchase: unit(s) : Gift Wrapping: Quantity: Buy in bulk and save Optical pulse sensor for detecting LCD pulses from Utility Meters. The sensor can be easily stuck on to the front surface of any utility meter with an LED pulse output. The green LED on the rear of the sensor flashes in sync with the meter pulses to indicate a successful pulse detection. The Optical Pulse Sensor works by sensing a utility meter's pulsed LED output. Each pulse corresponds to a certain amount of energy passing through the meter. The amount of energy each pulse corresponds to depends on the meter. By counting these pulses the meters KWh value can be calculated. Unlike clip-on CT based monitoring, pulse counting is measuring exactly what the utility meter is measuring i.e. what you get billed for. The pulse counting cannot provide an instantaneous power reading like CT based monitoring can. Where possible, we recommend using pulse counting in conjunction with CT monitoring. The emonPi and emonTx can simultaneously perform pulse counting and CT based monitoring. In the case of an electricity meter, a pulse output corresponds to a certain amount of energy passing through the meter (kWh/Wh). For single-phase domestic electricity meters (eg. Elster A100c) each pulse usually corresponds to 1 Wh (1000 pulses per kWh). For water and gas meters they will usually be marked to show the quantity of water (litres/gallons) or of gas (cubic meters/cubic feet) that each pulse represents. Compatible with emonPi (all versions) and emonTx V3.4 (firmware V1.8 and above, July 2015 onward) With the removal of the RJ45 connector or use of RJ45 breakout and manual terminal block wiring the sensor will also work with the emonTH (firmware V1.6 and above) see emonTH wiki and emonTx V3.2 (firmware V2.0 or above) see emonTx V3.2 Wiki. Specifications: Pulse Output: TTL synchronised with the LED light pulses of energy meter. Sensing Spectrum: IR to Light Indicator: LED light at the top which synchronises with the pulses Suitable for: all types of utility meters with pulse output: single-phase, multi-phase meters, water gas and electricity Sticky attachment IP56 Waterproof (sensor unit, not connector) Power supply: 3.3V - 5V Diameter: 22mm RJ45 Connector 1m Cable Technical: Current Consumption - no Pulse (sensor in darkness): 0mA Current Consumption - Pulse: 5.3mA for duration of pulse (standard meter 100ms) Output: Positive pulses output in TTL, is synchronized with the LED light pulses. RJ45 Connector Pin-out: RJ45 Pin 2 - VCC RJ45 Pin 5 - GND RJ45 Pin 6 - TTL Data Spare velcro sticky pads are available (sold separately) The cable can be extended using RJ45 Extender and standard RJ45 cable (not cross-over). idea for GTI export limiting So now that that has sank in the bottom line is that the more power a house uses the faster that the led blinks so what if we place a counter to count the pulses ( the greater the power from gti the less power drawn from grid ) and at a set count then a contactor is somehow switched to switch on a lets call it a dump load this could probably be done using a arduino thingy or now the rhomburg could be triggered here is the full site https://shop.openenergymonitor.com/optical-utility-meter-led-pulse-sensor/ thanks @Chris Hobson for the interesting site
  23. maxomill

    Ideas - Detect when feeding back to grid

    This is @plonkster theory from my old post I've thought of this before. The context was a little different, it was specifically for people like @Wetkit with the tripping prepaid meter, the idea being that you turn on an array of loads (a bunch of 100W incandescent lamps seems like a good idea) to cancel out backfed power. In this application it has to be extremely fast. The effect, when used with a slowly adjusting inverter, is that occasionally some lights go on for a few seconds to absorb the energy. First though, have to ask this one question. Can your V-series avoid feedback (even if by a slowly adjusting feedback loop), and if it can, will your prepaid meter tolerate it even if it does charge you a small amount for it? If the meter will tolerate it, the simply truth is that whatever you pay for those few seconds in the day when it feeds back a little will cost way less than anything you can buy or build to try and avoid it. Just live with it... or add a time switch to turn on some loads. With that said, the idea I had in the back of my mind is this, to adapt the Open Energy Monitor project for this. What that project does is literally sample the voltage and current waveforms several hundred times per second, and then calculate the power and the power factor. Now my thinking is that if it samples fast enough, it should be able to detect whether the current is in phase (mostly) or out of phase (mostly) with each other, and summing the vector product of these readings will tell you which way the power is flowing. The default setup of the arduino sets the ADC clock to 125khz, which allows it to read around 9000 samples per second. You can also mess with the prescaling registers and things yourself and increase this to significantly more. The example code in that project takes about 2000 samples, or 10 full AC cycles, taking into account zero-crossings, before it starts calculating. So in theory you can have a reading every 0.2 seconds... though I suspect in practice it is going to take a bit longer. I had another idea, which is more analog. With this idea, you use a transformer to derive an AC voltage that is within some range that you can measure. Then connect a current transformer (that's placed around the conductor you want to sense) in "series" with this AC voltage source, together with a burden resistor change current into a voltage. The idea is that when your current is in phase with the voltage, the CT adds to the voltage, and if it is out of phase, it subtracts from that voltage. Now, you simply need to measure the difference between these points, average it over a few cycles, and that will give you an idea. If power is flowing in one direction, the CT will add to the voltage and you'll get more positive readings than negative ones, if the power goes the other way the CT will subtract from the voltage and you'll get a more negative values. You have to sum this over a number of cycles because an inductive load factor (for example) will always push back a little on each cycle, but you're interested in the overall value for the whole cycle. The prepaid meter (by the way) does exactly the same thing. You could also just get one of those Rhomberg reverse detection relays from ACDC, though I'm told they aren't very sensitive. cheers
  24. maxomill

    Little Help Required

    I love the idea of placing a cheap digital volt meter on each battery permanently I call it a early warning system you can soon see a problem battery quick question does your positive to the inverter come from the top string and your negative from the bottom string cheers
  25. maxomill

    Ideas - Detect when feeding back to grid

    I don't know the imeon and how clever it is I asked almost the same question a while back as I have the axpert /infini v series which can also grid tie . but I run my set up in self consumption mode to keep things simple, this way means my bats are not used or cycled a cheap idea is to place the item on a timer and when you know that there is excess then set the timer to switch (self consumption or normal solar ) not fool proof though another Heath Robinson is to keep the grid tie on , but switch the inverter off with a timer and run the system off batteries during the day and get the timer to switch back on at a preset time knowing you now have enough excess someone mentioned maybe trying a single phase reverse power monitor http://www.rhomberg.com.au/downloads/SP510.PDF relay which I liked the idea the second part of the problem is that you may need to place some sort of timer in the system to stop it reacting too quick ie the relay has to be on for say 30 seconds before it will switch the dump load on third part of problem is how much are you exporting . pointless to switch a 1000w dump load if you only exporting 100w can you not look at watchpower or similar program and use that can do what you need . I wish I could also look at my posts and read the one about bi directional current sensing, there were some other ideas there that you might like please keep me updated cheers


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