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| Can anything be done about AC load "ripple"? |
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| gf:
--- Quote from: paulca on July 07, 2023, 11:33:05 am ---Top balancing a battery using the inverters build in charger (reversing the inverter). The unit is apparently not able to cope with the battery terminating charge input sudden while it's feeding it with 16 Amps AND running a 350W inverted load. I imagine those 16 amps current in the transformer coil has suddently nowhere to go and instead of letting it spike the ACOut well over voltage it has no choice but to trip out completely. BANG darkness. This one did self recover though, the power came back on 1 minute later automatically. --- End quote --- Strange :-//, because * Battery charging usually does not terminate abruptly, but current decreases gradually when the battery becomes full. At the end of the absobtion stage, the battery current should be already pretty low. [ If the BMS happened to turn off unexpectedly, you should check whether your charger settings possibly violate the battery/BMS specification. ] * While the battery is AC-charged from mains, the transfer switch relay is closed and the load is powered from mains, too. The load cannot be powered from inverted battery power at the same time. The Victron inverter/chargers are not double conversion (AC -> DC -> AC) devices, like many UPS, but the bidirectional inverter either acts as inverter, or as charger, but not both at the same time. |
| paulca:
A single cell reached 3.650V before the pack was at the absorb voltage. The BMS ended charge. You are right, in charger mode the AC is passthrough. It still doesn't help it with the current coming through the transformer. However, it is capable of inverting while running on ACIn. It has a weak AC boost feature. This is used by boats when they come up to very limited shore power, like some might only be 10 Amps. While charging the battery from that and you switch on a 20 Amp stove, the current will switch to coming out of the battery to reinforce the AC. As this involves grid-tie operation, even though it shouldn't export, I have avoided it... I don't need that feature and I haven't put "grid codes" into it, the tick box is there is config even with no grid codes, so maybe it is able to operate in some way that it guarantees no export. |
| gf:
--- Quote from: paulca on July 08, 2023, 09:57:30 am ---However, it is capable of inverting while running on ACIn. It has a weak AC boost feature. --- End quote --- Sure, but then the inverter does not charge, but discharge the battery. [ Only an additional charger (e.g.a solar DC charger) could then charge the battery simultaneously. ] --- Quote ---You are right, in charger mode the AC is passthrough. It still doesn't help it with the current coming through the transformer. --- End quote --- The passthrough current does not flow through the transformer. In bypass mode, AC input and AC output are directly connected via relay. Only the AC current flowing into or out of the bidirectional inverter passes through the transformer. |
| nctnico:
--- Quote from: paulca on July 06, 2023, 10:54:26 am ---Interestingly, if I look at the voltage chart, it does not have that noise. it's 230V, 50Hz stable. it droops and spikes with high load changes, but it doesn't have the noise. This makes sense as it's load driven noise, the power requirements are altering, probably constantly, the graph resolution is only 0.2Hz tops. So if voltage is stable and the VA is bouncing it means the current is bouncing. --- End quote --- Did you ever consider the load isn't constant? Just look at your process monitor on your computer. You'll see it jumping around which translates to more or less power consumption. There is nothing wrong with your setup. The problem is you not really understanding how electricity works :box: |
| jmelson:
--- Quote from: paulca on July 06, 2023, 10:54:26 am ---I need an AC capacitor and I know they don't exist. How do you store alternating current? With an alternator, aka a flywheel. I don't think a ton block axle and some AC induction motors/generators is worth it though LOL --- End quote --- Well, a great big inductor in series with a big capacitor will store energy at its resonant frequency. Jon |
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