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shumbaman

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Everything posted by shumbaman

  1. Thank you Coulomb. I am making enquires through the channel from which I recently purchased the Syapse to see if it is a clone or genuine Voltronic. My feeling is that it is genuine but I am not confident enough to go ahead and try a Firmware upgrade. Ironically since my initial post I have had no issues with the inverter not charging when grid power is restored.
  2. I have read most if not all of the historical posts on the firmware being used on this inverter and I am looking for clarification. The inverter reports U1 as 69.02 and U2 as 112.14. Solar Assistant on the Raspberry Pi also reports Firmware as 69.02. I am running with SUB as the Output Source Priority and SNU as the Charger Source Priority. I have 4 * 100AH Huawei Lithium batteries with the Absorption and Float Charge both set to 53.5 volts I am noticing that when there is no solar generation and mains power is available the voltage flatlines at 53.5 (which is what I would expect) but when the solar starts to kick in the Battery voltage drops to around 49.5 very quickly and then oscillates up and down for the period that Solar generation is available. During this period the Battery SOC is not affected in any material way and is reported by Solar Assistant as 100%. I am just curious to try and understand if this is normal and why it is happening. The main problem I am having is that sometimes when mains power is restored after a period of load shedding the inverter enters Bypass mode (as it should) but the charger does not start to charge the batteries which have been depleted to around 70% SOC and reporting a voltage of around 49.2. The only way I can get the inverter to start charging is by setting the Output Source Priority to Utility First via Solar Assistant. As soon as I do this the batteries begin to charge and If I reset the Inverter back to SUB the charging continues until the battery voltage reaches the 53.5 preset value. I have seen some other posts reporting similar behaviour and wonder if this is a firmware issue? If so where can I get the latest firmware to address this issue? Any help would be greatfully appreciated
  3. for Axpert type inverters SUB/SBU is a good option to maximise the use of the available solar. However when solar is not available (particularly at night) are you better off switching to grid or to battery? Using batteries will obviously deplete them but if you have enough PV power they should recharge during the following day and if you have enough battery storage you can see out the night and wait for the solar to start the recharging again in the morning. It all boils down to the economics and the savings derived from less grid usage compared to the the fact that by cycling the batteries they will not last as long. Anyone got some experience or ideas on this?
  4. SBU/SBU is a good option to maximise the use of the available solar. However when solar is not available (particularly at night) are you better off switching to grid or to battery? Using batteries will obviously deplete them but if you have enough PV power they should recharge during the day and if you have enough battery storage you can see out the night and wait for the solar to start the recharging again in the morning. It all boils down to the economics and the savings derived from less grid usage compared to the the fact that by cycling the batteries they will not last as long. Anyone got some experience or ideas on this?
  5. Is it necessary to run the BMS on these batteries and does anyone know how to do it?
  6. I recently had some interaction with a local South African supplier who stated the following on their website: "The Pylontech Lithium-Ion battery has a DOD of 80% when used with the Axpert or Infinisolar inverters which compares to 50% for typical lead-acid batteries. In order to provide the same storage capacity the minimum suggested replacement options, whereby Pylontech is used to replace the most commonly used 48V lead acid battery banks. When used with Axpert, a Pylontech US2000 2.4kWH battery will deliver 1.5kWh usable energy when discharged at 1.2kW, and at 600W power draw 1.9kWh usable energy can be utilised..." The Nominal capacity of the US2000 is 2400 W and the Useable capacity is 2200 according to the spec sheet. I queried his figures as follows: "Please could you detail how you come up with the capacities of 1.5 and 1.9 for the discharge rates of 1.2 and 600.As I understand it the 80% DOD useable capacity of the US2000 is 1.920KWh and the Pylontech recommended discharge current is 25 amps or (1.2KW). Why is it that you state that the useable capacity at the recommended discharge rate is only 1.5KWh? " Their response was a follows: "The usable capacity is 2200 for the US2000 so 80% is 1760wh But remember the inverter is around 90% efficient so there is further loss. So that leaves you with 1.5kWH" If this is the case then it is somewhat misleading to promote these products as 2400 watt capacity as it means absolutely nothing in the real world. Am I right?
  7. Chris...I have 3 Huawei 100AH 48 V batteries connected to 2 Axpert 4kw/5kva Mecer inverteres. Should I take your figures above for prog 2 and 11 and trebble then (as I have three batteries) and the split those values between the two inverters. That would mean setting both to 30 for each prog. Also I have Program 27 at 51...what are the consequences of that?
  8. A 48 volt Li battery is rated at 6.5 Kwh and can be discharged to 80%DOD. This means that it has an effective maximum capacity of 5.2 Kwh or 108AH. It is also rated for 5000 cycles and costs R50K. 8* 200AH (12volt in a 48volt configuration) Gel batteries at 30%DOD gives an effective capacity of 120AH (equiv 5.76 Kwh). They are rated for 3000 cycles and cost R6k each for a total cost of R48K. The cost and capacity of each of these options is almost the same but the cycles for the Li battery are much much better. Is it a no brainer or have I missed something out?
  9. I actually have a hard copy of that book and did quite a bit of excel work using their data and combining it with other sources in trying to fully appreciate the effect of orientation and tilt on solar yield.
  10. We are getting an increase soon....not sure how much...but I also think that our rate is subsidized to "placate the electorate"
  11. When looking at a tracking system you can consider one based on light sensors feeding into a micro controller or simply hard code the coordinates based on time of day and year.
  12. I was also wondering if you could use these affordable stepper motors used in CNC systems. One thing to also consider though is that the physical size of a 4*3 array swinging more than 30 degrees from the horizontal raises the issue of wind so it would be better to have 4 separate structures of 4 moveable units with each unit having 3 panels. This complicates the design though but not an insurmountable problem. I might look at this a "phase 3" and go ahead with my non ideal solution of static movable frames and see how things work out.
  13. Hi Chris...Yes I have thought of this option and looked up pricing the other day. Based on what I have said earlier I just dont know if the expense is worth it. Glad you have had good times here. We still have good times but the last 15 years have tested us and the current cost of living is frightening.
  14. Thanks for all the feedback. I, like most others on the forum went with Axpert primarily for cost reasons. I firmly believe that Victron offers he best solution but I cannot justify to myself the more than double price.I am in Zim and we pay in US dollars and pay higher prices than you do in SA so being price conscious is essential, especially when you are retired. Many theorists claim that the charging algorithms in the Axperts are not up to scratch and that the transformer-less technology is suspect etc, etc. but after a significant research effort I decided that they offered the most cost effective solution to our problems of 18 hour daily power cuts at the time. Since December though our situation has improved dramatically and like SA we have had little if any load shedding as we are purchasing from Escom at the moment. In fact based on our current regime I dont think that solar (with the exception of water heating) is cost justified as we pay US 10 cents per KWhour. Now I have lived in Africa for over 60 years so I fully understand the concept of what was or what is, is not necessarily the predictor of what will be. In addition as I always remind my SA friends, Africa does not stop at the Limpopo so things could change dramatically in the future so be prepared! I purchased all that I needed to be effectively "off-grid' back in September last year. Initially I installed what was necessary to give me essential backup for the long outages but I am now looking to complete the installation of 2*5KVA Axperts, 3KW of PV (Suntech) and 12*200 AHours of batteries (Narada Acme). The second Axpert will also have 1200 Watts of Suntech Panels attached (these were left over from a previous project). I am also intending to use Jacos software. My Problem at the moment is that the most ideal location for my panels is 50 meters from the most ideal location for the Inverter/Batteries and I have spent weeks, if not months (I am retired so do have the time!) playing with different alternative solutions. I want to have fused circuits for each of the 4 strings and combine them into one line somewhere before reaching the MPPT controller. I have major issues with the routing of the cables as I have a flat roofed house and lots of paved areas between the two ideal locations. This all adds up to a cable bill of a minimum of US700 so I have been spending a lot of time investigating ways of reducing this additional cost. I am now considering a non ideal location for the panels that will reduce the efficiency because of shading. This location will be ideal between the hours of sunrise and 15:00 whilst the sun is northerly but the 15:00 will probably become 14:00 when the sun is further south. Based on this shading regime I am also considering orientating the panels eastward so as to maximize the use of the morning sun and factoring in that that after 14:00/15:00 I wont get much power generation anyway. Having a flat roof house gives me flexibility in the PV installation in that I can make movable frames in terms of the orientation and tilt. I am considering a 30 degree tilt when the sun is in the north and 0 degree tilt when it moves south (our latitude is 18 degrees). Initially I thought of an automatic tracking system as I am into electronics and Arduino as a retirement hobby but all the advice that I get is that its not worth the effort and most of the problems are mechanical. I would be interested in feedback from those interested in my solar life story" above. Regards to all
  15. Thanks plonkster ...I was hoping that the over voltage would simply be ignored and that the unit would simply function as if it were at max voltage. I am not prepared to test it though!
  16. The Axpert 5KVA model has a stated Maximum Open Circuit Voltage value of 145 Vdc. What would happen if the PV array supplied 150 Volts? The reason I ask the question is I would like to arrange my panels in 3 parallel sets of 4 panels arranged in series thereby delivering a higher voltage with lower current than 4 parallel sets of 3 in series. This would allow me to used lighter gauge cabling. Also please confirm that in working out the voltage drops on PV system you use the MP as opposed to the OC spec values.
  17. Hi Chris...thanks for the reference...confirms that thicker cable is necessary. Wher do you get the 75 volt figure from? My Vmp is 92.1 volts
  18. I did consider this option but there are all sorts of other issues that render it a no go. I can live with the loss of 100 watts and just need to know that the cable will be safeand stable. The inverter is a 5KVA Axpert with inbuilt MPPT controller.
  19. The strings will be combined close to the panels so I am looking at what cable to use from the combiner to the controller.
  20. I am planning an installation with 12 panels (3KWatt) in a 4*3 arrangement with a Vmp of 92.1 volts and an Imp of 32.6 amps. Using 16mm2 cable I determine that on a 50M length my voltage drop will be 3.3429 OR 3.6297% and the power dissipation will be 108.9 Watts. Based on my research I feel confident that the voltage drop to the MPPT controller is acceptable but I have no idea on whether the 108 watts is OK or not. Can anyone give me some feedback on how serious or not 108 watts of dissipated power is.
  21. I am planning an installation with 12 panels (3KWatt) in a 4*3 arrangement with a Vmp of 92.1 volts and an Imp of 32.6 amps. Using 16mm2 cable I determine that on a 50M length my voltage drop will be 3.3429 OR 3.6297% and the power dissipation will be 108.9 Watts. Based on my research I feel confident that the voltage drop to the MPPT controller is acceptable but I have no idea on whether the 108 watts is OK or not. Can anyone give me some feedback on how serious or not 108 watts of dissipated power is.
  22. Thanks we agree on the calculations. The inverter specifies a PV Array MPPT Voltage range of 60-115 Vdc so I am assuming that the voltage drop of 6% resulting in an output of 87vdc will be fine. Do you agree?
  23. If I try to position the PV Array closer I run into all sorts of problems with shading. I am aware of the cost but just have to accept it if I want full benefit from the PV Array. If I position the batteries and inverter closer to the PV I then have to run an AC armoured cable to the DB box and that is also expensive. I already have 30 mts of 16 mm so all I need to get is another 30 mts. I just need to know that it will work ok. I think it will but just looking for confirmation.
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