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Chris Hobson

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Everything posted by Chris Hobson

  1. Ok that sounds good is that PV Voc Max at 25°C. What is your minimum winter temperature?
  2. Grid tie without battery backup question

    Even though I have seen a Goodwe do just this I think it is anomalous and the power was coming from a internal capacitor. Remember here in the Karoo we can go the whole day without one cloud interrupting production. Essentially a inverter needs either be a GTI or have battery backup. Very small loads can either be powered by design or be a unintentional/undocumented serendipitous result of the inverter's architecture.
  3. New Infini Super

    So Voltronic reads and values opinions expressed on this forum. (No not really but one cannot resist the idea that they are eaves dropping). I am a happy Axpert user but am all to familiar with its short comings. My opinion is well documented. http://powerforum.co.za/topic/607-a-new-installation/?do=findComment&comment=8414 http://powerforum.co.za/topic/1323-axpert-voltage-overshoots/ Well the Infinisolar 4kW Super has hit our shores, maybe this happened a while back but I only noticed now. What do I like about its specs? Infinisolar 4kW Super Product Spec Sheet.pdf A 4kW inverter - for my off-grid install the 3kW Infinisolar was too small and the 5kW Plus was too expensive. This is a ½way house in terms of capability and price. It can be paralleled if needed. High voltage MPPT (500V DC). Single string array with no need for combiner box and much thinner home run cabling and fewer losses. BATTERY CHARGING - and TTT is going to like this max is 66V. You can charge Trojan's with this one. It is a true hybrid. Control of inverter uses the same commands as the other Infinisolar and not the same as the V series where control is rather crude. The topology is the same as the 3 kW and the 5kW and so can be installed without batteries. I am not sure of pricing but probably at the R25k mark.
  4. My battery bank is failing and I am contemplating what sort of batteries I should buy as replacements. We are limping along and the batteries last a couple of hours until we go to bed but do not last through the night. I am going to discuss batteries in general and try and avoid specifics so that folk considering battery purchases are aided in their own decision. I think the first decision is deciding whether you want to go vented or not. In our case the "power room" is a corner in our TV/study/workroom so unless I end up with an innovative battery box that vents outside I would not want vented batteries inside our home. Battery boxes are common in the US which is considerably colder than SA and batteries are kept indoors to prevent them freezing. There are lots of designs on the net and I thought I would put a piece of 32mm conduit through just below the window sill. This would not be easy as the walls are over just over 450mm thick. This would enable me to have Trojans the only vented batteries I would consider. If I were to go with sealed batteries one could add Lithium batteries to the smorgasbord of options available to you. The second but probably deciding factor is cost. Lithium and 2V cells (both VRLA and vented) cost a whole whack but should outlast the other options available. I would have to be sure that the Lithium batteries I looked at were compatible with my inverter. I don't think my funding would stretch to a Lithium bank but if I have to replace my inverter too it would make it an exercise in futility. The third deciding factor (for me) would to have batteries with sufficient Ah rating so that I could have a single string of batteries. This would exclude doubling up on the current brand of batteries I already have along with the bulk of the VRLA batteries on the market. So what are my options if money is no object: Lithium that is compatible with my inverter VRLA "sealed" 2V cells Trojan batteries in a vented battery box. My budget is probably going to reverse that order .
  5. Mecer 5kVa settings and monitoring

    I have changed from Lead Acid batteries to Lithium batteries. Pylontech has 48V modules that one connects in series so there no way of attaching a HA02 and secondly the Pylontech has its own Battery Management System (BMS) and so a HA02 is superfluous. Heat is a battery's nemesis. Batteries age twice as fast at 30°C compared to 25°C. So you can be very conservative and have shallow discharges and still your batteries are not going to last long. It was one of the motivating factors for going over to Lithium Ferrous Phosphate as temperature only has a marked effect on the batteries above 50°C
  6. Mecer 5kVa settings and monitoring

    HA01 only balances two 12V batteries HA02 balances 4 batteries connected in series. Voltage for batteries between 2.4V and 12V. HA02 cheaper and more versatile. Therefore I would recommend HA02. email your details, phone number and , address to reception@unipos.co.za. Say you got the details here at powerforum and you will be sent a proforma invoice for the HA02
  7. Axpert 5 kVA patched firmware 72.70c

    There are two version's of Coulomb's firmware. One for LiFePO4 and one for other chemistries (Lead Acid, Lead Crystal etc.) That is unusual. I have seen the MPPT reset but this only that a couple of seconds
  8. Sabre prepaid meters

    I am going to phone you
  9. Sabre prepaid meters

    HI we are about to start a project in a municipality that owes Eskom a LOT of money. It would appear the town will be without electricity twice a day for 3 hours at a stretch. This scenario is likely to continue for several years. Most of our potential clients have Sabre E-SA 015 prepaid meters. Does anyone have experience with this meter?
  10. Axpert 5 kVA patched firmware 72.70c

    Hi Shiggi Welcome to the forum. It does have Lithium Iron support and has a dynamic charging algorithm that is dependent on communication between your BMS and the Axpert. One does not equalise Lithium cells but rather rely on the BMS to either top or bottom balance.
  11. Questions before buying

    A reputable inverter from a reputable company no problems that I can see. So long as the various bits of extra kit SPDs disconnects change over switch etc are installed the extras are not excessive. Kudos to your mate on checking on pricing. The rest of us ploughed ahead and then toted up the final figure.
  12. Newbie mistakes on first solar install

    Yes the HA02 can pass up to 10A. One needs to remember that often the voltage imbalance between batteries is in tens of millivolts so really not a lot of power is being transferred. A 40W fan may make the HA02 work quiet hard
  13. Pairing AGM and Gel batteries

    The recommendation is that you use batteries that are of the same size, manufacture, age and chemistry. Due to practical considerations sometimes one ends up mixing batteries of different ages (replacing a dud battery for instance) or mixing batteries of different capacity 232Ah and 236Ah from the same manufacturer (the difference is essentially minimal). I would however never mix batteries from different manufacturers or different chemistries.
  14. Which batteries should I buy (rhetorical question)

    Hi Tersius Once you have ironed out your install perhaps we could ask you to give us your opinion on the FreedomWon modules. There are lots of folk who are looking to make the change and the lithium market is nearly as diverse as the lead acid market.
  15. DIY Powerwall with 18650 batteries

    This is not quite true. Each chemistry has its own thermal runaway The earliest Lithium chemistry was Lithium cobalt and has a thermal runaway temp of 150°C . This low thermal runaway temperature, poor cycle life and the high cost of cobalt has resulted in this chemistry being replace by blending manganese with other active materials for the cathode Lithium manganese oxide was one of the first replacements of lithium cobalt with a thermal runaway of 250°C. Like lithium cobalt rapid charging can lower this figure. It also suffers from a shorter cycle life. Lithium Ferrous Phosphate with a thermal runaway of 270°C can safely be stored fully charged. It has excellent cycle life and is one of the safest chemistries. With a max charging voltage of 3.65V it does not have the same energy density of other lithium chemistries but that is not a major factor in the solar industry. Lithium Nickel cobalt aluminium oxide shares many characteristics of lithium cobalt but is cheaper and has a longer cycle life Thermal runaway is also about 150°C Lithium nickel manganese cobalt oxide (NMC) is one of the newer cobalt blends results in lowering of costs and better safety (thermal runaway of 210°C ) making it a favoured chemistry of the electric car industry. Lithium Titanate no thermal runaway problems and has a high cycle life but cost are high and is largely limited to the electric car industry.
  16. DC Circuit Breakers

    My partner in crime (Chris-R) is about to import good quality solar accessories (SPDs, DC disconnects, DC (and AC) breakers, fuses, MC4 connectors cabling etc). Watch this space .
  17. need help finding Full schematics for pip 4048

    Hi Kiore PM your e-mail address and I will send you what I have. Have a look at the Aussie AEVA site (go to the lounge) there is an incredibly long PIP 4048 thread where Coulomb and Weber often post portion of the schematics.
  18. Water harvesting and use, same logic as solar systems.

    I like your Dad's thinking Just an observation. We have about 150 000l storage of rainwater on the farm and in my father's time was used for washing clothes, hot water, and drinking. It is the Karoo and we don't get a lot of rain so if you have enough storage you can go a long way. We have scaled back as one of the subterranean tanks has a crack in it. I am too big to fit through the manhole and my staff are too scared to climb down and see. Maybe I should hire one of the Sibanye miners to help. After being trapped for 24 hours my little predicament would be child's play. In a more modern setup in Graaff-Reinet the owner put in several large underground tanks under the lawn in the garden and he and collects rainwater. He is virtually self sufficient and solar too so he really was planning ahead.
  19. Axpert / Mecer 5KVA model

    You can go ahead. That way you can charge your batteries so long.
  20. One year's off grid solar production

    Jip they had Plett time where you go off into the forest partake in recreational pharmaceuticals and then it can be whatever time you want it to be. On a more serious note I think Plett time was an hour behind SAST but it never caught on. Interestingly China which is a huge country only has one time zone.
  21. Panel (Array) ventilation

    If I remember correctly you have 2 Axperts therefore 2 MPPTs and should have panels facing in 2 directions rather than 3. All the panels on one MPPT should face the same direction and have the same tilt. I do know some of the solar pump installers face panels in two different directions on a single MPPT. Pump MPPTs are much more forgiving.
  22. One year's off grid solar production

    Couple of others have a ±60W PV feed through the night
  23. ICC updates

    Manie has been busy. ICC now posting to local and Emoncms.org. With my sometimes unstable internet the ability to do both is great. I see on the update list that a Pi version 2 is available. That must be a major revision. Come Pi ICC users what does version 2 do?
  24. Mecer 3kva Plus

    HI Giles Welcome to the forum. I am guessing but I think the alarm and fence energizer could be drawing more than you anticipate. Looking at the budget for overnight use. 5 hours of LED lights = 270Wh 12 hours of fridge = 702Wh Alarm (guessing 40W) = 480Wh Energiser (again guessing) 25W = 300Wh Total = ± 1800Wh 50% of a 24V 260Ah battery bank = 3120Wh so you are not exceeding 50% capacity. Are you batteries still 260Ah? After 2 years you may have more reduced capacity than you think.
  25. New to solar need a LOT of advice...

    That's the problem. You can import N48 neodymium magnets for under R2k and the rest is fibreglass and enameled wire and bearings etc. I think one could build something decent in the R7-10k range.