I have a 8800W (7300W LPG) generator connected to my Multiplus II. I can remotely 2 wire start/stop the generator and it quite happily charges the 4 Pytes batteries through the Multiplus. The problem is though, that no matter what I do, I cannot get the Invertor to receive any more that circa 1500W (6.5A @ 230V) where given all the settings I can find in the invertor it should be handling at least the 30A 230V the generator can output.
I should also add, I have 8kW of solar panels which on current good days are pushing 3.7kWh @ 65A to the batteries. Doubt they are the limiting factor.
Multiplus II 48/5000 has 70A maximum charging current to battery, which is about 3.85kW at 55V Vbatt. So no matter how big an AC generator you connect to the MP II input, you’ll never get more charging current than this. In addition, in my experience the current drops below the maximum as the charger heats up. Also don’t forget to allow for losses, typically around 10%, so you need 4.3kW from the generator to get 70A into the batteries.
To use all the power from a generator that big for battery charging, you need at least an MP II 48/10000 – or a second 48/5000 connected in parallel.
Still doesn’t explain why you’re only drawing 1500W from the generator though, should be a lot more than this…
The AC input seems to be enabled. These are screen grabs from when the genny is running. The odd thing is the input power from the genny has never registered corrrectly in the MPII. Clearly its receiving power but does not display the values correctly. -2W when there is very defvinitely 1500+ going to the batteries.
Understood and agree with your figures. There was always an intention longer term to get a 2nd MPII but for now, as you point out I should be getting at least double if not triple the current supply.
A similar problem has been reported before (MP II failing to show AC input current), the cause was the the internal current transformer which measures this was disconnected. There’s a 3.5mm jack socket on the board for plugging in an external CT and this can have a bad contact, plugging a 3.5mm plug in and out a few times fixed this.
Hi Ian, fair suggestion. Forgive me, I’m not on site so cannot check. This seems to be suggestion that I need an external current sensor around one of the live cables and thats connected into this input. I am pretty certain there is nothing connected to that input. Maybe I have misunderstood the configuration here? Why would an internal current sensor be connected to an external input?
You don’t need an external current sensor in most cases, there’s already one inside the MP II. The connector allows you to plug in an external one instead which disconnects the internal one when you put a plug into the socket. If there’s a poor contact on this socket (e.g. dirt on contacts) the internal one can be disconnected even without a plug inserted – pushing a plug in and out usually cleans the contacts and the internal one starts working again.
Those 3.5mm jack sockets are prone to this, that’s why on newer models they were replaced with a removable link.
Ok, that makes sense now. I assumed it was the 3.5mm plug that was already in place in this socket that had a poor connection. What you are suggesting is that this unused plug may be in a state where the internal sensor thinks it is being used but in fact isnt. I assume mine has this “audio jack” type plug where all the current manuals and Victron download images suggest a 3 pole cable insert connector which could not exhbit this type of fault.
Sure, I will have to check what I’ve got when I am next on site unless theres a way of getting that information out of Victron through the serial number. I’ll check.
