Time for a new Warpinverter build

Author	Message
rogerdw Guru Joined: 22/10/2019 Location: Australia Posts: 955	Posted: 11:06pm 15 Feb 2021         Clockmanfr said   Here are 2 PDF docs for SMA model SB's,  but in general for a toroid when you pick it up it should be heavy, normally around 25kg to 35kg.  A normal toroid type SMA SB's will normally push out up to 254 to 256vac.  And Yes those SB's were nice made and worked well, but they are old tech so easy cheap to get hold of. Thanks for all the extra detail Clockman. Until recently I didn't realise that SMA had made inverters with toroidal transformers  ...  and now that I do, I am wondering why they are never mentioned as possible donors to be rewound for Ozinverters or Warpinverters. The SMA inverter that I picked up recently was of the later HF transformerless type. I really only bought it coz it was $25 and I figured I'd get my money's worth just pulling it apart and seeing how it ticked  ...  and maybe some bits I could use.     Quote   I only have 5kW of PV going through a MIDNITE 200, and a MPPT TRISTAR DC charge controllers, but they are very expensive controllers but good for finish charging. Most of the battery charging is with the AC coupling 14kW of PV feeding back from those GTI's running the 240vac circuits and back feeding through the 'OzInverter' to the batteries. Hence i reset the SMA SB's internal settings to just a few seconds on and off, and sequential GTI shut down voltages from 242vac 243, 244, 245, 246 and 247vac. I'm not even certain I will really need additional inverters to my Warpinverter system  ...  I think my main reason for asking the questions is because I know I will need battery charging  ...  and wondered if that can be done with an additional inverter alone  ... ...  or whether I will still need a conventional MPPT charge controller to look after the batteries. If that is the case, there have been a number of designs here on the back shed in recent times. I hadn't made plans too far ahead  ...  still have to wind my transformers and work out the drive side.   Quote   PLEASE NOTE, GTI's are best when they are smaller units, i no longer recommend anything over 2.5kW, why?, because when they are big they constantly cycle on off as they overfeed and push the AC voltage high. Thanks, I had picked that up and it does make sense  ...  though I was surprised when I read your pdf's, that SMA recommend that additional inverters (to the Sunny Island) should not be bigger than twice the size of the Island's power. In fact that was all new to me  ...  while I had heard the name Sunny Island, I didn't realise they could be used as a 'mini-grid' with additional inverters  ...  I thought they were (just another) pv inverter! Thanks again for all these details, I'm slowly getting more of the bigger picture.