I installed two Quattro 10kva (USA models) in split-phase with Lynx, Cerbo Gx & RS450/200.
Id like to use my older inverter as the back-up source into the Victron gear for a while.
I have two older Magnum MS4448pae inverters with a genset auto-start with old FLA batteries. Been using them for years. Never liked the generator swap over, but the FLA batteries are still good enough to act as a back-up for the new inverters and batteries… “just in case”
Which path should i take to use the old gear hanging on the wall?
Attach the Magnums into the Victrons as the “grid” or as the “generator” ? I have all of it wired (6awg 240vac split-phase) into disconnect boxes to attach it either way
Didn’t work on grid and had to go to work (travel); so, any ideas would be nice.
Trying to swap over the power tripped the gfci 60amp breaker. I reduced input amps to 5a to reduce inrush I swapped L1 & L2 to compensate for phase.
So….
Also, i removed the broken-up, disjointed & unreadable table it tried to paste below (noted).
Cheers,
Original reply post:
Didn’t get any responses; so, i tried ai ( oh boy, that can be finicky)…. I just copied and pasted “as-is”
Cheers
You have a very clean setup and a smart question.
The short answer is: Connect the two Magnum MS4448PAE inverters to the AC Input 1 (“Grid” input) of the two Quattro 10kVA units, not to the AC Generator input.
Here’s why “Grid” input is almost always the better choice in your specific case, and why “Generator” input would create more problems than it solves:
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again… Removed broken-up, disjointed & unreadable table it tried to paste…. that was HERE
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Recommended wiring path (what 95% of people in your exact situation do)
Magnum ME-ARC → tells both MS4448PAE to invert and stay ON all the time (or use the AGS module if you still want auto-start on the old bank when its SOC drops).
Magnum AC output (L1 + L2 + N + G) → your existing 6 AWG → disconnect box → into AC Input 1 of each Quattro (exactly the way real grid would be wired).
In VE.Config (or VictronConnect with MK3-USB):
AC Input 1 = “Grid”
Enable “Accept AC” even if frequency is slightly off (Magnums run 60.0 Hz rock-solid anyway)
Enable PowerAssist
Set input current limit to whatever you feel comfortable pulling from the old FLA bank (e.g. 30–50 A per Quattro so ~7–12 kW total)
Enable “Dynamic current limiter” if you want
In the Cerbo GX → Settings → System setup:
AC input 1 = Grid
You can even give it a funny name like “Magnum Backup” so you see it in VRM.
What actually happens in the different scenarios
New lithium bank is full and loads are low → Quattro passes through Magnum power and charges the lithium bank a little if you want (or set charger to “Off” in the Quattro if you never want that).
New lithium bank gets low → Quattro seamlessly PowerAssists or even takes 100% of the load from the old FLA bank without any blip.
Old FLA bank gets too low → Magnum AGS can still start a generator if you have one, or you just manually shut the Magnums off from the ME-ARC.
You never want the backup → just turn the Magnums off or open the disconnect. Quattro instantly falls back to the new batteries with zero transfer time.
If you wired the Magnums to the AC Input 2 (Generator) terminals instead, you lose PowerAssist, you get a 10–20 ms transfer every time the “generator” (Magnum) shuts down or starts, and frequency-shift curtailment is flaky with Magnum inverters. Most people who tried it end up moving the wires to AC Input 1 after a few weeks of annoyance.
So: Use AC Input 1 (“Grid” side).
You already have the wiring in place for exactly that, and it gives you the most seamless, robust backup possible.
If you ever get real grid later, you literally just swap the Magnum feed for the utility feed in the same disconnect box and you’re done.
oh boy, that can be finicky)…. I just copied and pasted “as-is”