I'm trying to use Multiplus as a UPS but have a problem with the transfer time. I have read documentation and forums and all state that Multiplus can do a transfer in 20ms when the GRID drops out. However, I am experiencing a transfer time of 10 seconds instead of the expected 20ms. I cannot understand why there is a pause when the transfer occurs from the Grid to the battery, causing a delay before the inverter is activated.
Tighten the lower voltage tolerance if possible take it up to 200v.
Slower transfer can be solved by a battery that is more capable and larger DC cabling. (What is in the manual is the minimum so you can go higher). If the resistance that side is high (switches etc) I have found this affects the switch to inverting. Check torque on your terminals.
If the power is dropping out it is because the battery side is not taking over the load fast enough.
The battery bank is new and we are using the maximum area on cables 10mm2. the batteries are brand new 4 x Marathon Exide AGM M12V125FT. I tried to crank up the tolerance to 220V, tried 200V , tried 180V. I shall check all this. Do you think that there any special configuration that needs to be done, UPS setting is checked, I have not set any grid code on the grid side.
If it is taking that long to cutover your battery is most likely the cause.
Higher/lower cutoff voltages can sometimes help if there is a brief dip in power but most of the time this is due to the battery not coping with the cutover so AC thresholds will make no difference.
What inverter do you have? What are the loads? What are the battery voltages?
How is the bank wired?
How long are the cables to the battery?
Have the batteries been charged up fully?
@soren_dynamicmill , Do you have a bms between the batteries and the Multiplus?
If so, what are the settings.
Also, the Multiplus is rated at 1000W continues if at 25°C (higher temp will reduce output).
No BMS, it's hooked up directly with the batteries. I guess you don't need a BMS with an AGM battery in this setup.
It was about 20 degrees when we did a test run
Here is the setup
Settings seems ok (but I am no expert)
From my experience, the inverter is extremely reliable so if I have to guess, I would say the same as the other two people, i.e. check your connections, batteries are fully charged, check you cables (length/resistance), etc.
If the above check is good, then you need to eliminate pieces i.e. borrow a different battery or take the inverter to someone that has a 48v pack.
Ps, I assume you uploaded the Settings to you inverter each time you change the configuration.
Yes, we did that and it could be that we have a faulty inverter from the beginning. I have a spare one, I will try that one and see if it behaves the same way. Thanks
This is solved it was no big problem, I was using the Filax 2 switch the wrong way. It was a delay that i didnt know about. The Filax 2 is waiting for stable input and if its stable it will switch after sertained time.
