Battery connected to MPPT input !?

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Dec 20, 2018
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What would happen if we connect a battery to a MPPT controllers input, sure with the right voltage.Especially on a micro inverter? E.G. a 250W micro inverter conected to the battery bank instead of the solar panel, would that work?
 
Yes it works but it Will pull max from the battery that the device can
 
But it would not harm the device in any way? Do I need to limit current? My plan would be to connect it to the battery bank and always feed 250W for average consumption of the house. In germany it is allowed to use these devices if registered.

I could stop it maybe with batrium and a relay at a defined voltage, would that work. Batrium got lots of things with the expansion board right?
 
That's an expensive BMS for just 250w - obviously if you can current limit the DC input you'll have control over its AC output.

What's the input voltage range of the micro ?
 
Would need the BMS either way that would only be a small extra gadget.

16-60 V and MPPT range is 27-48 V. Not even sure if it would work on 14S sytem.

Yes that would be good to have control over it. But i don't have an idea how to limit current. Especially without lot of loss.
 
If you use one of the many ebay Ali Boost converters which have a current limiting function, then you can easily use them to fake a MPPT behaviour. Thy seem to have a Power limiting function once you are beyond the current limit, and at least my line coverter settles easily on the 80 % level of the max voltage as it is used by MPPT for a panel.
See my first threads here, if you are more interested ill look them up for you.

Nhe Frankfurt here, btw.

What type is your Inverter ?
 
Maniac_Powerwall said:
That's good variable AC power input would be nice. This could help alot. Thanks Cherry
If they are equal, then the variable resistor for the CC funktion is in the back circuit of a Op Amp.
If you want to do this electronically, its a bit difficult.

If you need an old fashioned method then think of foto resistors, or PM me for details.
 
When I tried that on an MPPT gridtie inverter I had to use a current inrush limiter ICL, aka, NTC thermistor, or the inverter detected it as a short and shut down. The MPPT circuitry expected more of a slow ramp up in voltage and current. The solar panel and battery looked more like a dead short to the mppt circuit.

rearden
 
You seem not having done what was recommended here.
 
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