Have you used LiFeP04 open loop with an SMA Sunny Island inverter?
- Thread starter Fingers
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ncsolarelectric
Engineering Support CEO
You can charge LiFePo4 batteries using a float charger for a lead acid battery. You just can't do things like balance them, and never try to "equalize" them with a lead acid charger. However, just float charging them works if they are good cells and the float voltage is not too high.
Thank you for your help.
Are you talking in general, or you know for sure the sunny island is cool with this?
Sorry I have no idea what DC or AC coupled is. Charging from solar, or charging from mains?
Thank you for your help.
AC coupled is when you use a grid tie inverter (usually a SunnyBoy) as the charger for your batteries. If your BMS doesn’t have the ability to disconnect the grid tie inverter, the Sunny Island may not meet the requirements of your BMS.
It’s generally easier to get your BMS to disconnect a DC coupled charger as required.
It’s generally easier to get your BMS to disconnect a DC coupled charger as required.
Agh!
Hence the need for special very expensive bms's with Sunny island. Rec, Batrium or Seplos.
But hang on, if the bms is not connected to the sunny island (open loop / lead acid setting) would this still be the case?
Thank you for another big piece of the puzzle.
I think this is the reason that I origionaly gave up on SMA.
Hence the need for special very expensive bms's with Sunny island. Rec, Batrium or Seplos.
But hang on, if the bms is not connected to the sunny island (open loop / lead acid setting) would this still be the case?
Thank you for another big piece of the puzzle.
I think this is the reason that I origionaly gave up on SMA.
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The problem with “open loop” operation, is that although the Sunny Island can be configured to closely match the battery voltage requirements, you won’t have the ability to taper current according to SOC / temperature, and in the event of a “runner” cell.
This means that you may get nuisance BMS disconnects if the only way you have to protect the cells is for the BMS to disconnect from the Sunny Island.
You can get the BMS to disconnect the PV from the charger, and there are various ways to do this.
I have set up a few SMA systems without comms, it can work but isn’t something i would do with my own system. I don’t consider the REC-BMS to be expensive for what it offers when combined with the SMA architecture.
Thank you that answers quite a bit.
So if I had Rec bms in my batteries, do I use communications cable to the sunny island? I take it that the sunny island comms work in a lead acid setting, and the Rec bms would turn off the grid tie (SB360TL-21)?
So if I had Rec bms in my batteries, do I use communications cable to the sunny island? I take it that the sunny island comms work in a lead acid setting, and the Rec bms would turn off the grid tie (SB360TL-21)?
just a stupid question maybe i have a growatt ark battery + bms connected to a growatt SPH4~10k TL3 BH, now the tempature went down in my garage to around freezing point after some disconnects in the log ( message was 1:Check battery voltage 2:If error message still exists,contact manufacturer. ) I decided to restart my ARK but now it wont come back on line just throws in an error " battery open ". Any idea or experinces with tempuature and this message or sympton? not even sure what " battery open " means.
I have a battery chain saw with a li-ion battery, I have kept it in the boot of my car, anyhow the temperature went below zero C and it will not work until it reaches a higher temp.
I think the answer is keep lithium batteries above zero c, but if it gets to zero disconnect them, don't use or charge them.
My new non sma system, when it arrives, will go in to a shed part of my garage, (small room off the garage), two double glazed doors (one to garage the other out doors) and the ceiling insulated to the max (metal box section roof). I have a portable gas heater to make sure the batteries keep above zero.
Let your batteries warm up, fingers crossed all will be well.
I think the answer is keep lithium batteries above zero c, but if it gets to zero disconnect them, don't use or charge them.
My new non sma system, when it arrives, will go in to a shed part of my garage, (small room off the garage), two double glazed doors (one to garage the other out doors) and the ceiling insulated to the max (metal box section roof). I have a portable gas heater to make sure the batteries keep above zero.
Let your batteries warm up, fingers crossed all will be well.
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thank you very much - cross my fingers for warmer weather
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