DIYbanter - View Single Post - Feeding solar power back into municipal grid: Issues andfinger-pointing

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On 15/04/2011 10:46, wrote:
On Apr 15, 1:03 pm, wrote:
On 15/04/2011 07:41, wrote:

So, do you agree that under the condition of two identical
fully charged batteries at exactly 12V, connected in
parallel to a load, the current will flow from both
batteries through the load? I hope you do.

Your example, while it is correct, have little bearing on real life
problems. The grid can in no circumstances be looked at as identical to
a PV array voltage converted to AC voltage.

Two identical batteries have identical inner resistance, that is why
your example works.

Wrong.

I am not sure what you think I am wrong about here. Could you please
indicate which of my above statements are wrong?

The topic is " Feeding solar power back into municipal grid". How are
the voltage levels when there is a flow into the grid from the PV array?

Maybe I missed a topic change somewhere in the previous posts, which is
easy to do since a few posters here does not bother to trim posts.

Go back to the example in the link, as I suggested to
Homeguy. You have two ideal voltage sources with different voltages
connected through two resistors of different values, one 20 ohms,
the other 10 ohms. That is a basic model of a battery, where the
10 and 20 ohm resistors represent the different internal resistances
of the batteries. So they are batteries with identica voltage, but
different internal resistances.

I did read the example, and yes, I understand Kirchoff's Law.

But you seem to be contradicting yourself, you state above the batteries
have different voltages, then you state they are batteries with
identical voltages. Maybe I am not understanding what you mean.

Solve the equations for the case where the voltage sources
are at identical voltages and you will find that current flows from
BOTH sources. One is NOT at a higher potential than the
other, which is what Homeguy claims must exist for both
to provide current to the load.

I have read all of Homeguy's messages, and I may have missed it, but
does he not claim the need to have a higher voltage to push current into
the GRID, not the LOAD.

I never said current flows from one battery to the other. It's
apparently
Homeguy and now you who are hung up on that for reasons unknown.

The reason of my "hangup" is the topic: Feeding solar power back into
municipal grid.

Your example of batteries with equal voltage might be interesting, but
irrelevant to the topic.