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Author Topic: tesla powerwall. does it actually require a compatible inverter?  (Read 3536 times)
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« Reply #15 on: November 06, 2017, 07:23:05 PM »

Hi RIT, I think we've got to the point of violent agreement here.  Smiley

In terms of the input side of an MPPT inverter, it modifies its input reactance rather than resistance to find the Maximum Power Point, and it's not necessarily the lowest reactance. If you keep dropping the reactance (resistance) the panels actually drop the voltage since they act as a constant current source at a given light level over most of the voltage curve. This leads to lower power transfer (power=volts x amps)

That was something I had to read up on last night as I assumed the same thing, but what I found indicates that the MTTP does the exact opposite. The MTTP is able to make a PV panel operate at all points along its published IV curve, an example diagram of which can be found here

The few comments I was able to find indicate that to control the input power the MTTP changes its characteristics so that the current flow is reduced, which then pushes the voltage up. I guess it is safer/easier to implement a solution that takes the panels to an 'open circuit' configuration, rather than an 'short circuit' configuration.
While I had a look around I could not find a good document covering this process.

2.4kW PV system, output can be seen at  -

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« Reply #16 on: November 06, 2017, 08:34:32 PM »

Thanks gents,

Its a shame the pv and storage stuff wasnt modular. I know they are now becoming so, i suppose its the price early adopters pay for the latest tech. They are getting cheaper to be fair.
One part of my brain tells me to go get one, the other tells me wait a while, which is probably the best thing to do.
Id love to be able to use the leaf battery i already have.


7.5kw solar pv
Prius plug in hybrid conversion by myself (now reverted back to standard prius)
Nissan e-NV200 wheelchair converted vehicle
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