I’m not sure if you quite understand how a PWM inverter works, or how optimisation works, even if you cannot switch it off (which here you can). I did start an explanation, but it became ‘rather long’. I suggest you take a look a PWM inverter youtube design videos. Nobody will start a system with mosfets in fully conducting mode as “DC”. A short pulse via an inductor is how it starts.
At the end of the day we have users here who are using MPPT’s as power DC-DC converters with great success, and that pretty well proves my point that for those prepared to use them (possibly) out of warranty but within spec, this can be a viable option.
We are talking of inverters - and their functioning - or MPPTs?
And I believe you are missing the point… I wasn’t against experimenting, I was trying to say where could be (a possible) weak spot.
Experiment away - which also others said - and, please, report back.
You look pretty convinced and with the opinion formed, so please don’t look for a flame here… Peace man!
LE.
If you really want to do this, instead of using the expensive 450/100, just use a (slightly modified) standard 48V switching mode power supply.
In the end, 265 x sqrt(2) is close to those 400V of the battery, so instead of power it with AC, you directly inject on the input the DC, as long as the AC is anyway rectified.
You just need to choose carefully the power supply to handle the increased voltage - IC, FET and capacitors - but it seems that you know already how to do it. And I’ve said 265, because most of the modern SMPS have a range of 90-265V AC input.
I’ve also used Victron MPPTs as DC-DC converters (i.e. connected a battery to the input) numerous times, never had issues. However, I’ve also asked about this “shorting the input” thing and the official reply on some other thread was that this can happen very rarely under a very specific failure mode of the MPPT and that “shorting the input” has the goal of blowing some fuse that way; no further explanation was given.
So, if you are to do such a setup, make sure you’re using a properly sized fast-blow fuse on the input, since the LEAF battery can definitely push more than 500A through the CHAdeMO port if something fails, before the BMS kicks in. And yes, such a setup is most probably not the MPPT’s “intended use”.
@farmeroz have you managed to activate the CHAdeMO port for discharging?
Shorting the input: ”very rarely under a very specific failure mode of the MPPT”, ie failure of MPPT.
Oooh, its quite a long thread, isn’t it? Anyway waaaay up the thread is the schematic for the plug and associated connections. These look pretty straightforward to me and just require a few optocouplers and appropriate connections. Not sure about the CAN bus that links charger and vehicle but ultimately (voiding more expired warranty) brute force switching the solenoid will work in extremis.
