Jump to content

Kalahari Meerkat

Members
  • Posts

    217
  • Joined

  • Last visited

  • Days Won

    3

Everything posted by Kalahari Meerkat

  1. Don't know the unit, but if its anything like this unit, then the specs on the MPPT end would require rewiring for Voltage, rather than Current, methinks... Max PV Array VOC: 500V DC MPPT Range @ Operating Voltage: 90 ~ 450V DC
  2. I guess that includes me... yes, if Voc is, lets call it 50V/panel and 7 in series, your Voc at around 350V would be well within specs for the MPPT input of your inverter, in fact you could do 9 panels in series, 450V and that should be ok, with a few Volts to spare, maybe go for 8 in series times 2 seperate strings into your inverter, this keeps the current per string lower and thus the cabling sizes a bit more in check. But your setup should also be ok, as for this would be on the battery end and not on the MPPT input side... and as for nope, you'd need to see Vmp in reality, bu that should be close to 3185W/10.92A (assuming that's Imp as in Amps at max power), then the end result should 7 panels worth of Voltage... thus 3185/10.92=291.667V and this divide by the 7 panels is 291.667/7=41.667V app. per panel at maximum power...
  3. Yup, prime example is the Janvanniekerk1 account which upped his postings up to 8, from the 1, in this thread, none of any value or consequence.... re-hashing biodiesel postings from 2016, but nothing of value as far as I can see, other than stating he bought a 6.5kWh battery for 16995 or whatever it was, but 0 information about where the battery came from (maybe from some dude that stole it from a repeater high site?) or what make it is or how long its been in use... So, guilty until proven innocent, Jan, that means make contributions that have value and help others and saying you actually received what you ordered has 0 meaning, what? a roll of toilet paper? was it? by now, I would not believe a thing you post, even if you now posted that you ordered an inverter and batteries from this outfit, even if you provided documentation, based on your postings, I'd be skeptical of anything coming from you. Sorry, normally I don't want to be this negative, but anyone stating solarzone is a good outfit appears to know very little since just browsing a page or two of theirs would show one that they know less than very little, assuming they are legit, which I can't see how they could be.
  4. I was going to comment on that earlier, but then decided to let this topic die, since the solarzonesa.co.za is obviously a scam outfit, and the ones suggesting it isn't may be the ones running the outfit, possibly. Either way, all the supporters of this scam operation have each one posting in total, the one supporting the scam, should pretty much be the convincing point that it is a scam and the 4 supporters of the scam should not be taken at their word... guilty until proven innocent, for now, I'm afraid...
  5. Ok, you are further north than I am, if Centurion is accurate, here we are @95degrees and 50km, from Upington. Are your tubes in shadow for part of the day? This time of year you guys shouldn't have too many clouds and being further north than what I am, I would think you should be able to get a more than comfortable temperature out of the setup, assuming trees don't spoil the suns path to the tubes... mine is actually facing between 15 and 20 degrees real, thus somewhat east of due north. We can not expect to still have warm water on the morning, at 1.2degC this morning, I would have been surprised, but as it is not even ice cubes came out of the pipes this morning here.
  6. What exactly is this? We have a 100 or 150 liter (not 100% sure of the size) cylinder with 12 glass evacuated tubes attached for water heating, at this time of year, I can get a hot shower, at times, even need to add some cold water, in summer, it is way too hot (needs an afdakkie), but, this is off gravity fed, low pressure water system, no municipal water and water is fed from a 1000 liter Jojo tank on a 6 or 7m stand... (water cylinder says Afropulse 483 on the side...)
  7. The Voltage is the relevant one here, as long as the Voltage of the panels stay within the limits of the inverter, all should be fine, since the inverter will limit the current drawn.
  8. RS485 is supposed to be able to run for *LARGE* distances, so I'd suggest, run a single twisted pair of RS485 to the adapter at the computer....
  9. I still reckon you should consider homebrewing, look at this one for inspiration/using that circuit/design to construct your own, it would be a lot less costly than having to purchase one and I'm willing to bet that the one you've linked to contains pretty much Alistairs circuit from 2000.
  10. I'm not aware of anything of value that can be bought, you'd have to homebrew a unit and yes, one would probably keep it connected, if the batteries are in good condition the desulfator would not consume just about any power and do not much, but whilst the batteries need it, it would produce measurable pulses to help the batteries get in better shape again and still not consume much power.
  11. The problem is the inverter will also consume, some run at approaching 100Wh, then over 10hours of darkness, that will be an easy 1kWh gone... so, you'd need to see what the inverter draws when no load is on it, from the batteries, to see how much this will drain the batteries...
  12. If its a pressurised system, then you could, I'd imagine mount the tube system elsewhere, even ground mounted, assuming you have space and have a spot, not too far away that gets sun all day... maybe... I have my solar panels ground mounted, roof mounting would have limted the production... my neighbour who put up panels a week or two after me, has been cutting down more and more trees around his house, since his roof mounting move was a stupid move, in my eyes, he has plenty of space (11 Ha in total) and could have put the panels where he could still have the shade from the trees without it impacting his solar panels.... c'est la vie...
  13. Ok, then you are looking at gravity fed from a Jo-jo tank? that would be low pressure, unless you're wasting energy running a pump to pressurised the household water.... so the low pressure evacuated glass tubes setup cost a whole lot less than you seem to indicated and that would be the suggested route with maybe a low-ish (1kW) power electric element in the cylinder as add-on, to help out when the water's a tad on the chilly end... but basically the evacuated tube setup works pretty well and when the sun doesn't shine the solar panels generating electron flow wouldn''t do too much either to help heat up the water... just my thoughts on the matter, the evacuated tube low pressure setup is probably half of what you're stating... looking at this one for R 7k7... so around 1k7R X 2 more than the normal one, you're looking at, that's R 3400.00 more for the two solar HWC vs the convential...
  14. Those are reasonable numbers, I reckon and 70% or around 70Amperes in 3 or so hours, would require less than 30Amperes from the charge end, can your charge controller provide, let's say 30A to charge the battery with? You'd need around 400-odd W on the solar panel end to make this work.
  15. Yes, the panel will feed whatever its Voltage is to the charge controller/inverter/whatever you are using to charge your batteries with and this unit would then, if its an MPPT do a DC to DC conversion from the voltage supplied by the panel to the correct voltage to charge the battery, but this conversion should occur with fairly low losses, give you more current (Amps) on the battery side, than what the solar side is presenting. Having written this, please ensure that the panels are not generating a higher voltage than what the charge controller can manage, basically a lot of folks around here are running their houses off 5kW and larger inverters, which can happily use 200 even 300V or higher at relatively low current, 8 or 9Amperes to charge their 48V battery banks and generate 220V otherwise form the excess power produced by the solar panels, basically you need to know how many Volt the charge controller can utilise on the input side and ensure that you do not exceed this, else the magic smoke may come out
  16. You should not and can not charge the battery at a higher Voltage than specified by the manufacturer, for a 12V replacement, which is what you battery is, most likely, 14.4V should be the maximum Voltage you should ever try to charge at. The time it takes to charge would then be determined by the current (Amperes) that is provided to the battery. If the max charge rate is 0.5C then 50A is it and for longer life expectanct try 0.3C or 30A, which would then be under 4 hours still to recharge from totally flat, which you hopefully won't be doing... how fast do you need to recharge and how deep do you discharge the battery?
  17. NMC, not NMO, sorry, either way, these are the less expensive cells, mostly used by the vehicular industry, but not ideally maximised for long life in stationary setups, like most of us would want energy storage for, for now anyway. I suppose maybe one should wait and see what Aluminium-Ion batteries end up doing life/energy density/cost wise....
  18. I actually was contemplating getting one of the Hubbles to start the battery side off here, but since the cells are NMO, I shall have to re-think what I will be looking at, I really still like the LTO idea, but I need to figure out whether the inverter could manage the voltage range of the LTO's... 20 in series, charge at 2.8V ea, that would be 56V , discharge down to app, 1.9V, that's 38V... not sure the inverter would still be able to function at this low a DC battery voltage... if we make it 22 Cells, that would be 62V app. down to 42V app. time to kick tech support about the range of battery voltages the Sunsynk would be able to live with, I guess, else LiFePO4's would have to do the trick X 16 in series...
  19. Ok, the charge controller should take the voltage and current, in other words, the power, produced by your solar panel and transform/convert it to the right voltage and with low loss, to the maximum amperes it can still extract... you say 18V X 5A that would be 90W produced, but you should not charge your 12V LPO battery with 18V, probably more like 14V would be ok (possibly 14.4V), either way, the 90W/14V would then be nearest to 6.4A into the battery, which if the battery is sitting at nearly 0% capacity remaining (flat battery), then you'd would require 100(Ah)/6.4A=around 16 hours to recharge the battery to full... The 100Ah 12V battery could possibly be recharged from empty to full in 1 hour, by providing it 100A for an hour at 14V or so, but check the specs of the battery, either way, I would not suggest this high a charge/discharge rate for such a long period of time, better for the battery's life would be to say, charge it back to full over 2 or 3 hours by letting the charge current sit at 50A or 34A instead, also realise the cable diameters you'd need to run at the higher current. Either way, I hope you are not connecting the battery straight to the solar panel(s) but are using a suitably specced charge controller between the panel(s) and battery. As for the 400W panels with 45V and 10A, that would be a 460W or larger panel, since 45V X 10A = 450W and you'd be unlikely to get the panel to produce more than its rated for or even close to what its rated for... but if your panels produced 45V and 10A and your charge controller could manage this, then it should provide 32A or so at 14V to charge the battery and this would put you in the 3 to 4 hour range, assuming the battery is totally discharged, which again, you would be wise to avoid, down to 20% of charge remaining is probably ok, but totally flat is going to impact the battery's life negatively.
  20. from https://batteryuniversity.com/ Lithium Nickel Manganese Cobalt (LiNiMnCoO2) — NMC 3.60V, 3.70V nominal; typical operating range 3.0–4.2V/cell, or higher Specific energy (capacity) 150–220Wh/kg Charge (C-rate) 0.7–1C, charges to 4.20V, some go to 4.30V; 3h charge typical. Charge current above 1C shortens battery life. Discharge (C-rate) 1C; 2C possible on some cells; 2.50V cut-off Cycle life 1000–2000 (related to depth of discharge, temperature) Lithium Iron Phosphate (LiFePO4) — LFP 3.20, 3.30V nominal; typical operating range 2.5–3.65V/cell Specific energy (capacity) 90–120Wh/kg Charge (C-rate) 1C typical, charges to 3.65V; 3h charge time typical Discharge (C-rate) 1C, 25C on some cells; 40A pulse (2s); 2.50V cut-off (lower that 2V causes damage) Cycle life 2000 and higher (related to depth of discharge, temperature) So, NMC not *much* higher if at all, than LFP, but lower life, which would be something I'd be somewhat worried about... not sure what the suggested lifespan is from Hubble or the guarantee, but 10 year plus life may be not so likely based on the chemistry that appears to be used...
  21. Again you are not really providing enough information for me to figure out what you are asking, I assume you want to mix 2 panels, again Voltage is the most likely limitation... but just for interests sake, let's say you have a 120W panel that can produce 10A at 12V for its MP values and you have a 280W panels than can strangely also do 10A, but now at 28V for its MP value... if the MPPT connecting these can handle 40V or more at 10A, then putting the two panels in series, would/should give you 40V at 10A going into the MPPT and thus both your panels should produce as much as they are rated at, but I'd imagine that the 120W panels would probably be more like 18V and thus 6-odd amps and the again if the amps at MP (Max Power in case its not clear) are the same for the 280W panel and the total MP voltage for both in series is in line with what the MPPT can manage, then puttng them in series would be best option, I'd say... if the panel Voltages match in terms of MP and the voltage is enough for the MPPT and it can consume/use all the amps provided by the two parallel panels, then all is fine in this scenario as well. I guess one can put down the following as the thumbsuck rule for mixing panels... panels in series will add up the Voltage at MP for their respective MP Voltage and the current limit will be the panel with the lowest IMP value, thus the panel providing the lowest A at MP will be the limiting factor* panels in parallel will add up the current at their respective MP Current and I suspect then, that the Voltage will be limited to the Voltage for the lowest VMP panel Voltage and this will be the power limiting factor* * NOTE I am theorising here, I have not tested this in real life, but these would make most sense to me...
  22. Any competent electrician should be able to have you powering essential loads fairly quickly, no more than hour outage I'd say, but one would have to look at all you need doing, but you should not need battery power for a whole day... if all you want/need are batteries otherwise, that allow the inverter to provide power whilst the commercial power is down and the sun is shining, you can probably get away with something fairly small, 1 or 2kW/h, but ideally it needs to be able to deliver current, basically if your load varies wildly, dishwasher turning on heater element, you turning on the kettle... the MPPT is not able to respond quick enough to cover this with the solar panels, that's where a battery needs to be able to deliver some current for a few seconds, to make up the shortfall, until the MPPT/solar side is up to speed and generating the power needed... (Worse loads are big mototrs starting, think big-ish compressor, for 1 or 2 seconds this can draw 2 or 3 kW or even more easily, even though the motor may only be rated at 1kW, electric lawnmower hitting a denser patch... 4kW or more short term peak...) For this kind of scenario a 1kW LTO cell based battery would be perfect, the 1kW LTO's should be capable to 5kW sustained power and peak even more, but since you only need this very short term, this is the kind of solution LTO's are ideal for, but I have yet to see any complete products, other than individual cells for sale for home brewing your own battery...
  23. Nope, I am not, so can't really comment, it is part of the OpenEnergyMonitor project, which again, I don't make use of, but you should probably do a bit more research and reading about here as linked to by their their main github page.
  24. As snippeted from here... Lithium Cobalt (LiCoO2) — LCO 3.60V nominal; typical operating range 3.0–4.2V/cell Specific energy (capacity) 150–200Wh/kg. Specialty cells provide up to 240Wh/kg. Charge (C-rate) 0.7–1C, charges to 4.20V (most cells); 3h charge typical. Charge current above 1C shortens battery life. Discharge (C-rate) 1C; 2.50V cut off. Discharge current above 1C shortens battery life. Cycle life 500–1000, related to depth of discharge, load, temperature Comments Very high specific energy, limited specific power. Cobalt is expensive. Serves as Energy Cell. Market share has stabilized. 2019 update: Early version; no longer relevant. Lithium Manganese (LiMn2O4) — LMO 3.70V (3.80V) nominal; typical operating range 3.0–4.2V/cell Specific energy (capacity) 100–150Wh/kg Charge (C-rate) 0.7–1C typical, 3C maximum Discharge (C-rate) 1C; 10C possible with some cells, 30C pulse (5s) Cycle life 300–700 (related to depth of discharge, temperature) Comments High power but less capacity; safer than Li-cobalt; commonly mixed with NMC to improve performance. 2019 update: Less relevant now; limited growth potential. Lithium Nickel Manganese Cobalt (LiNiMnCoO2) — NMC 3.60V, 3.70V nominal; typical operating range 3.0–4.2V/cell, or higher Specific energy (capacity) 150–220Wh/kg Charge (C-rate) 0.7–1C, charges to 4.20V, some go to 4.30V; 3h charge typical. Charge current above 1C shortens battery life. Discharge (C-rate) 1C; 2C possible on some cells; 2.50V cut-off Cycle life 1000–2000 (related to depth of discharge, temperature) Comments Provides high capacity and high power. Serves as Hybrid Cell. Favorite chemistry for many uses; market share is increasing. 2019 update: Leading system; dominant cathode chemistry. Lithium Iron Phosphate (LiFePO4) — LFP 3.20, 3.30V nominal; typical operating range 2.5–3.65V/cell Specific energy (capacity) 90–120Wh/kg Charge (C-rate) 1C typical, charges to 3.65V; 3h charge time typical Discharge (C-rate) 1C, 25C on some cells; 40A pulse (2s); 2.50V cut-off (lower that 2V causes damage) Cycle life 2000 and higher (related to depth of discharge, temperature) Comments Very flat voltage discharge curve but low capacity. One of safest Li-ions. Used for special markets. Elevated self-discharge. 2019 update: Used primarily for energy storage, moderate growth. Lithium Nickel Cobalt Aluminum (LiNiCoAlO2) — NCA 3.60V nominal; typical operating range 3.0–4.2V/cell Specific energy (capacity) 200-260Wh/kg; 300Wh/kg predictable Charge (C-rate) 0.7C, charges to 4.20V (most cells), 3h charge typical, fast charge possible with some cells Discharge (C-rate) 1C typical; 3.00V cut-off; high discharge rate shortens battery life Cycle life 500 (related to depth of discharge, temperature) Comments Shares similarities with Li-cobalt. Serves as Energy Cell. 2019 update: Mainly used by Panasonic and Tesla; growth potential. Lithium Titanate (Li2TiO3) — LTO 2.40V nominal; typical operating range 1.8–2.85V/cell Specific energy (capacity) 50–80Wh/kg Charge (C-rate) 1C typical; 5C maximum, charges to 2.85V Discharge (C-rate) 10C possible, 30C 5s pulse; 1.80V cut-off on LCO/LTO Cycle life 3,000–7,000 Comments Long life, fast charge, wide temperature range but low specific energy and expensive. Among safest Li-ion batteries. 2019 update: Ability to ultra-fast charge; high cost limits to special application. Cycle life seems quite poor one some, like NCA, lets hope they can tweak the chemistry to up those numbers some...
×
×
  • Create New...