I’m looking for advice from Victron installers and electricians regarding upgrading the AC supply protection to allow higher battery-charging power during my 3-hour low-rate window.
System overview
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Inverter: Victron MultiPlus-II 15 kVA (48 V)
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Batteries: 3 × 15 kWh Fogstar (total 45 kWh)
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PV:
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South: 10 × 470 W (4.7 kW)
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North: 11 × 470 W (5.17 kW)
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West: 9 × 470 W (4.23 kW)
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DNO export limit: 12 kW
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Home annual usage: ~4100 kWh
Current charging performance
During my 3-hour off-peak period, the inverter charges the battery at around 10–11 kW, shown as approx 180–200 A DC on the Victron graph.
This matches the breaker installed in my Solar DB:
- Proteus XL50BRK B50 (50A)
So the 50A MCB appears to be the bottleneck, limiting AC input to around 11.5 kW.
What I want to achieve
I’d like to increase charging power into the batteries so they reach a higher SOC within the 3-hour cheap tariff.
Upgrading the breaker from B50 → B63 (or possibly C63, depending on cable spec) should enable about 14–14.5 kW AC input, giving ~13–14 kW DC charging.
My question
Is it acceptable and safe to request that my electrician upgrade the breaker to a B63, given that the DNO export limit is already set to 12 kW and the breaker only affects AC-in charging (not export)?
I want to confirm:
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Do you agree with upgrading the Fues to increase the AC charging?
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Whether upgrading the MCB conflicts in any way with the DNO export limit
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Whether the MultiPlus-II can safely use 63A AC-in on a single phase
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Can this be done by any installer or does it have to be the original installer. In case the original installer is not available.
