uhi22 wrote: ↑Thu Jan 25, 2024 7:47 pm
"Boosting" is the wrong word. It would mean to create a high output voltage from a lower input voltage, at least this is my understanding. We need the other way around.
Yes, precisely - I believe the sequence needs to be something like:
Battery pack voltage (low side) used to precharge the converter.
Once converter pre-charged, boost it to (say) 400V at high side.
EVSE plugs into car and we request 400V ('high side'). It 'sees' 400V, no massive inrush as voltages equal.
Hence we boost from low voltage to high, rather than buck down from high to low pack voltage.
At least that's what I think, please don't throw stones at me if I am wrong. Or only small ones if you have to.
johu wrote: ↑Thu Jan 25, 2024 7:58 pm
I think I'd let the charger do the hard work (i.e. the current control).
That's my thinking. If Clara can instruct the EVSE to provide a specific voltage and current, then I control the duty cycle to feed my battery pack.
So 3 questions:
1. Can Clara instruct an EVSE to provide a specific voltage and current (within sensible reason)? e.g. 400V, 20A? Does it have a low current limit at 400V (for tapering end of charging)?
2. Does the Gen 3 inverter/converter offer any advantages to the Gen 2 for this use case e.g., higher current limit, more / safer controllability?
3. I am not clear on how to get the low side to 'draw' current from the high, I presume I must reduce the boosting of the low side to a value below 400V to get the current to flow, hopefully subject to the maximum current one has set the EVSE to supply?
9kW is not brilliant. I was hoping for nearer 20. However, any charge is better than no charge!
Thanks both.