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David asked

Frequency shifting problem - with Delta ac coupled

Installer has 4 identical off grid installs: Multi-II 48/5000, ccgx, Delta 5kv AC coupled with ET112 meter, 3 x Lithium PPE batts, no DC charging. (pre-built boards, all cable lengths etc identical) Two sites performing well, but two sites have similar issue around frequency shifting: Charging exceeds Abs v setting by 2v potentially causing damage to batteries, and the Delta ramps off (trips) hard rather than reducing and staying on to feed AC loads. (therefore batts not getting required 4hrs Abs time) (Freq settings in the assistant : 50.2hz, 52.7hz, 53 hz)

All firmwares have been checked and updated with latest, configs checked,

Keen to hear thoughts

AC PV Coupling
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shaneyake avatar image shaneyake commented ·
Can you confirm all the Delta Pv inverters are programmed correctly?
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David answered ·

Addition to above:

1. Frequency ramping starts too late allowing batt voltage to exceed Abs setting.

2. One of the other sites that is now operating well, did have this problem, but was fixed by updating multi firmware and assistant firmware. However that fix is not having same impact at these two problematic sites. Updated firmware V275 today at the problematic site but does not fix issue. This is the same version that is at the site that is working well.

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