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Limiter inverter with RS485 load setting
#27
(04-03-2020, 08:32 AM)CarlosGS Wrote: I'm wondering if with the constant voltage mode it would be possible to feed the grid stand-alone. What were your findings?

Not quite sure what you mean specifically so I will list a number of different scenario's which I have actually tried out...

Single unit + grid tied : Controls, works fine.

Multiple units + grid tied : Work in parallel without any issues. I'm now controlling 1 on it's own and 2 together (2 RS485 adapters, 1 into 1, 1 into 2). This allows me to effectively switch one off or two off and then switch them off around 70W level.

Single unit + Off grid inverter : This is with the battery feeding a stand alone inverter and then plugging the single unit into the inverter. If the single unit is pushig out too much then the power flows back through the off-grid inverter into the battery (circular loop effectively). I tried this out as a way of increasing off-grid inverter capacity (off-grid inverter 5000W + 3 x 800W) while retaining a high start surge capability. i.e. they can be used off-grid as long as your inverter is designed/capable of reverse power flow (i.e. not a high frequency inverter !!!)

If the supply voltage is constant it would be like the ideal battery and work forever.


This is my control setup now (the max inverter watts does not get used and is instead limited by the other values entered). The 1600W is actually the aggregate of 2 units so in this case I'm limiting the 900W units to 800W and the 800W unit to 700W.  This is to keep them cooler to prolong the working life and keep them in a better efficiency zone.



The issues I was having with the units apparently locking up turned out to be the RS485 adapters I'm using and still figuring out the exact electrical reasoning.

Just noticed the 4th unit watts is showing 0 - actually the code does not update that value on screen as it's just the offset watts I enter...

Also noticed the max watts in the table is not updated.... lol. the min watts in the table is divide by 2. Reason for the random 2x values is I wrote the code on the basis I'm going to add another RS485 adapter to the control each of the 3 units separately.

The reason is that every (random number of seconds) the unit will return a stuatus update of the supply volts and amps, which is used to update the Wh remaining.... BUT each unit has a slightly different calibration and so consistent readings are lacking AND when 2 units send at the same time you get nothing..
If you can't quantify how much they cost, it's a deal, I'll buy 5 of them for 3 lumps of rocking horse ......
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RE: Limiter inverter with RS485 load setting - by completelycharged - 04-03-2020, 08:03 PM

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