question

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ikeakayke asked

VE BatteryLife Bug report: MPPT excess power not available

Brand new setup, DVCC on (off/on makes no difference), MPPTs set to 100A, lynx shunt to monitor battery, all worked fine for a few days, MPPT excess was used to power AC loads even while charging batteries (Victron Gel).

Suddenly Optimized (with or without) BatteryLife is unstable: after discharge to set SOC, no matter if 70%,80% 95%, mppt's are throttled down to the power drawn by battery and no excess PV is ever used while charging. This makes using Optimized useless for night time.

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I uploaded a video with realtime throttleing of mppt's here: https://www.youtube.com/watch?v=pyGGOPrcSDI

Things to look at:

- while charging setting SOC to 100% powers down mppt

- messing with the soc to a lower value sometimes ramps up mppt

- discharging to 95% causes power limit with immediate charging

- setting "keep batteries charged" ramps up mppts while also charging (as it should)

I have another post from before I had installed MPPTs reporting sudden discharge spikes while "keep batteries charged" without any grid loss on AC, it just randomly discharged 2000w, then charge back and so on. I mention this because I noticed the same pattern of "instability" developing after around 2 days of working fine after a clean install.

bug report
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1 Answer
ikeakayke avatar image
ikeakayke answered ·

It seems that after hitting minSOC it does this (limiting pv output to match battery charge) until SOC rises between 3-5% above minSOC (and/or if the new minSOC is too far away up from the actual SOC) at which point it will again start ramping up MPPT to full power (although I can't confirm it always does it yet, but seems like it).

Anyway I found a solution to this issue: never use batterylife, just optimized w/o it, set the SOC much lower so to never reach it, in my case I set it to 50%, then scripted a service in cerbogx that does this: in the morning it keeps increasing minsoc to current soc +2% so to not use grid charger, just pv to charge the battery to 100% once/day, when at 100% changes to keep batteries charged. If it's a nice day, then I will move back to 50% to properly handle loads during day, if not then I prefer keeping them charge until evening when the controlled limited discharge occurs.

So far so good.

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