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JaseZA

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  1. I would hook each 12V battery up seperately to a normal car battery charger (assuming you have access to one) and charge each to max voltage (13.8V?) - just need to watch it doesn't over charge as some cheap batteries chargers are prone to doing! This way you know all of them are close to fully charged before putting them all in series. This is called top balancing. Parallel connecting only works when you are actively charging them. It is an option here as well if you have a big enough car battery charger. Ideally you want to charge at greater than 5% C-rating. So here you have 200Ah batt
  2. I would seriously consider spending more money for a battery with effective comms to the inverter. These Mecer units have no easy way to access the cell voltages etc so you are quite limited in the extra control you can add. Unless you're going full DIY with your own BMS, I think you're getting your money's worth on proper comms. As you hinted at, the "BMS" on the inverter just looks at total voltage of the batteries in series. No individual cells or even individual banks. No way of knowing actual SOC, which is critical for best optimization of battery life/utility. I originally ran my ba
  3. If it's a normal resistive element geyser, then zero power. If it's a heat pump there is probably a small draw when idle.
  4. Doing the maths with info from the spec-sheet: Capacity: 12V x 200Ah = 2400Wh 2400Wh x 80% = 1920Wh 1920Wh x 4 batteries = 7680Wh - or 7.68kw for an hour or 3.84kw for 2 hours Max Power (Continuous Discharge is 100A from Spec-sheet): 12V x 100A x 4 = 4800W I don't think I'd personally want to put my batteries through that regularly though - it would definitely shorten the life and would work the inverter hard as well. Better to try and run the geyser as much as possible on solar.
  5. Probably a combination of low temps and cloud edge effect - but it's always great to see more coming out than you paid for! Although I've still never got a better total for the whole day when it's cloudy/cool vs clear/hot...
  6. Hmmm, I wonder if putting a stove on the 40A is too much... I've seen it pull 6kw from the grid. Currently our stove is the only thing not on the inverter so I have to guess it's consumption by taking (prepaid used) minus (inverter output) minus (inverter standby 50Wx24hrs).
  7. The hardest part here is getting an accurate measurement for power consumption of your PC. While gaming my rig uses between 250-400W. Assuming worst case of 400W x 3 hours = 1200wh of energy. Those Mecer inverters are good bang for buck and my first suggestion to people in your situation. You've then just got to work out if the batteries are enough storage. Being lead-acid batteries, you don't want to discharge more than 50% max in order to get decent life from the batteries. 12V x 100ah x 50% x 2 batteries = 1200wh - exactly your requirement. So you should be fine with this arrangem
  8. I've had great service from solar-shop.co.za - they were also great at replying to emails and pricing was competitive. And all the info is available on their website.
  9. I'm assuming you don't have a monthly value for your usage from a bill or prepaid? A good ballpark would be averaging that per day. Initially when doing my calcs for our system I just took a photo of our prepaid meter every day for a couple of weeks in the morning and evening to get an idea. We're two and average 12-15kwh per day with a lot of AC usage but no pool.
  10. While I'm not sure what he had in mind it's possibly like my system: Separate BMS for monitoring battery cells. RaspberryPi for getting readings from BMS and inverter. Also sends data to Home Assistant. Program (like Node-Red on Home Assistant) for intelligently deciding how the inverter should charge/draw from the batteries. Same RaspberryPi sending instructions from Home Assistant back to inverter. This allows me to stop drawing from batteries when they drop below a certain SOC based on any factors I want. Or to charge from Grid/Solar based on whatever I want - like upcoming l
  11. Here it is from another store even cheaper - https://pclinkshop.co.za/ups-inverters-and-powerbank/inverter-battery/vision-12v-lithium-200ah/ I'm amazed by the price of these - works out even cheaper than buying raw prismatic cells... Would love to see what's inside these newer ones! If it's 4x200ah prismatics I'd buy them, strip out the cells and use my own BMS... 10kwh for R25k!
  12. JaseZA

    Bangood

    Just another confirmation - I've ordered around 10 times since lockdown started and haven't had one bad experience using direct mail (tax free)!
  13. How is the low power measurement accuracy on these? Thinking of building it into a plug but want to measure anything from 20W to 2kw...
  14. Ah yes - there was a small thought in the back of my mind that I had it the wrong way round! Thanks for correcting this Coulomb!
  15. It's very rewarding! This was basically my all consuming hobby at the start of lock-down (I placed orders for everything end Feb 2020 from Solar-shop). DIY is not for the faint of heart - especially when installing 6 panels by yourself on a 2-story duplex with a dodgy ladder! But it is well worth it if you have the skills. I did get an electrician friend to help me with the DB side of things but all of the rest I was able to find the info here. Nearly a year later and I'm still over the moon with how things went.
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