question

wedgehog avatar image
wedgehog asked

Can I feed a Multiplus-II with another inverter

Hi, May sound a bit silly, but I am trying to just use the internal charger of the Multiplus to charge some Lipo's. I don't want to pay for the electricity so I have some charged batteries of a different type and another, different make of Inverter, so I connected the AC input of the multi to this inverter, but the Multi just will not accept the 230v ac input and keeps going into overload, well there is nothing on the multiplus outputs yet.
I have tried selecting weak Ac, I tried limiting shore current to as low as 10 amps, Also limited the internal charger to 10 amps, makes not difference. I checked the box for accepting a widw frequency range and checked the low and high cut off voltages. I can't find a reason.
Any ideas anyone

cascading inverters
3 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

gabius avatar image gabius commented ·

You can check the YouTube channel « offgridgarage » he did this but with two Victron product, maybe it will help you.

https://youtu.be/SsTkgoN6ENM?si=C5v23dTJXbF7o4jl

1 Like 1 ·
wedgehog avatar image wedgehog gabius commented ·
I don't think you understood the problem! Andy can do it because he is using two victron devices, I am using a cheap Chinese inverter with a Victron and it won't accept it's output
0 Likes 0 ·
vicens avatar image vicens commented ·

quita la funcion SAI

0 Likes 0 ·
2 Answers
derrick thomas avatar image
derrick thomas answered ·

This is not a victron approved or recommended installation method, but it has been done successfully by many. If you are using a cheap Chinese inverter or a modified sine inverter the multi may not like the dirty power. If you can connect to a PC through an MK3 with ve.configure it might give an indication of what's going on.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

wedgehog avatar image
wedgehog answered ·
Hi Derrick, It's definitely a cheap Chinese Inverter, and I have to say I also wondered that, Yes there is a Cerbo GX in the system and I have been monitoring everything, but it doesn't give much of a clue as as soon as I select charger only, it's almost instant that it goes into overload, if you leave it until it recovers it just goes into overload again

Bob


6 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

derrick thomas avatar image derrick thomas commented ·

Cerbo is not going to show you what's going on. If you connect with a MK3 to a PC using ve.config it might give you the reason for the ac input rejection.

1 Like 1 ·
Show more comments
wedgehog avatar image wedgehog commented ·
Hi Derrick, Well I got the MK3 today, connected it all up and had a look, I could see it was loading the Chinese inverter when it started so I did a few tests, the following results have me at a loss.


First I tried limiting the charging current to 5 amps. no change
then I limited the line current to 5 Amps still loaded it.
I unticked the charger box in the Multiplus-II so the charger was off, also the mains output of the Multiplus-II is not connected to anything at the moment. Same result.

How can the Multiplus-II be loading the Chinese Inverter to the point it won't connect when it's internal charger is disconnected and the Multiplus-II inverter is not connected to anything? Yes I know there will be internal capacitors to charge up, but the amount of times now I have allowed it to re cycle those must be charged.

I loaded the Chinese inverter with a heat gun to stabalise it, no change.
I connected a 3KW fan heater to the Chinese Inverter and it ran it no problem
It is a 15KW Inverter, well! they claim it is. Added an electric drill still no problem.

So the Multiplus will not connect to it with no load and no charger, I can see on the computer display the incoming ac drops from 230 to around 170 when the muti comes on and I don't see why it should be loading that much with the above conditions.

Just for tests sake I connected the Multiplus to a generator and it connects fine and when I turn on the charger I was able to increase the charge up to 70 amps no problem and it was all very stable, but again, Initially when I connected to the Generator, which is a 10KW machine, with the Multi connected to nothing and the charger off, I heard a large load go on the Generator?.

Confused now. Bob


0 Likes 0 ·
Show more comments

Related Resources

Additional resources still need to be added for this topic