Apologies - went off thread (with my quattro II - (dual AC input)) but anyone could use some of these newly released: Victron Orion -Tr 12/48V-8A (380W) Isolated DC-DC Converter(s) to trickle charge their 48v system via V2L in winter?
Well no, unfortunately you cannot use DC-DC as V2L outputs AC....
. You can of course use a 48V charger from Victron which also has CAN connectivity so it's absolutely possible to link it to a multiplus II via CERBO.
I used to believe that too. But now I'm not so sure.
diysolarforum.com
Nice write up, good explanation. Once we have several devices in parallel the current ratings of the system go up dramatically and power dissipation goes down.I used to believe that too. But now I'm not so sure.
I came across this post explaining how the pair of MOSFET banks works:
BMS MOSFETs Explained
I'm writing this post since it seems there is a lot of confusion (especially in the comment section of a certain youtuber in Australia) on why both MOSFETs in a typical single port BMS are controlled individually and why/how this works when they're in the same series circuit. It will hopefully...
The battery load / supply is relatively benign, no nasty inductive kicks etc. The inverters tend to use SWMPSU controller chips controlling charging current and these switch at a relatively high frequency. Due to the frequency they can respond rapidly to changing load, I doubt there will be any nasty spikes on the DC bus at either side of the switching device.
It will be milliseconds as opposed to seconds.
I drive system into the limits once per week to cause BMS calibration routine to run. Normal operation the batteries run 10 - 90% so the BMS doesn't always cause the processes to stop. When operating from the independent battery charger I aim for a terminal voltage circa 80% so again the BMS doesn't stop the process. I have run it to the extremes at the very start of my system for several days whilst getting the systems to run properly and not once did it give any cause for concern in temperature / voltage spikes etc.
They certainly can respond quickly, if the firmware is properly written. Alas, at the bottom end of the market, which is all that was affordable when I bought mine (late 2016), the PI (Proportional Integral) control loops don't account for integral wind-up, so the overshoots sometimes are in the order of 20 seconds. It's really frustrating to watch.
I was thinking more in terms of the MOSFETS, no nastys would come back to damage them.
What processor? I spent a good few years writing z80 based real time machine control programs and I'm sure somewhere I have a REVAS for z80 if it would help.
It's an NXP MC9S08AC48, apparently part of the HCS08 family. Not one of the 30 or so assembly languages that I've used before, so I had to learn it from scratch. It had irritating features, like the TSX (Transfer Stack to indeX register) instruction would take one off the value, so what was at say offset 6 from the stack (referenced as 6,sp), is now at 7,x! Also, x sometimes represents a 16 bit register (really h concatenated with x) and sometimes an 8 bit register (the low half of hx).
There are some weird instruction sets in different devices, I found it difficult to change between hardware. I did quite a bit with PIC chips the speed absolutely threw me, I struggled at the start.
I used the hitachi 64180 Z80 based processer but with built in i/o, serial, CTC etc.
Aye, Nostalgia is not what it used to be
I do have a Solax X1-Hyb-6.0-LV-EU inverter with a GEN AC input port and a 2x 5.3kWh Solax T-BAT-SYS-LV-D53 battterypack. I was under the assumption that it would work out of the box (save some configuration) for my MG4. But unfortunately it does not work and Solax UK has confirmed that V2L is a completely different concept than a diesel generator and it is never going to work. They have something called 'SolaX PV-Genset solution' but it seems to work for diesel generators only (with ATS or Dry contact communication). Anyone any ideas or got it working ?That is what I intend to do too. Inspired by others on here that have done the same (@Bricktop X PWR and @wattmatters, IIRC).
Something like a Chargeverter or similar would work well, though probably an overkill with the MG4's limited V2L output of 2.2kW. There are some DIY options too.
Edited to add.... unless your inverter has an additional 'generator' input, in which case you can connect directly to the inverter from the V2L output and avoid the cost/complexity of an additional battery charger.
Most UK systems are combined with the neutral, nevertheless its a good point.
Maybe so ... but the "earth" on the MG4 is floating and so is likely to trip out - either by the MG4 itself or via the generator unit.
In general (but noting every individual case is specific), the MG4 is not suitable for direct connection to a home's wiring system with a standard earth-neutral link.
My thought indeed, why wouldn't it work. In my manual Solax defines a Smart Load concept for the GEN port:
Not sure. tested both situations. In on-grid mode nothing to be seen on the inverter and the MG4 keeps discharging. In off-grid mode the inverter detects something but switches off the EPS (essential power supply) to the house and gets stuck in a checking status. Also in this case I see no values from the V2L in the inverter display. We ran a cable from the gen port to an outside box and fitted a plug on that end. That's plugged in to the V2L socket.
