Can I lower the DC input low restart value (restart issue) ?

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Olivier Wouters asked Nov 24, '23

Can I lower the DC input low restart value (restart issue) ?

Hi, I have an off grid system with a multiplus II 48/3000/35-32, a BSL Batt 100Ah 5.1kw and a MPPT. Not much sun for a week now (Ireland) and I don't have a generator. I'm losing 2% of SOC every day which seems fine to me until my inverter decided not to start because of a low battery alarm. I switch the inverter on and off everyday to save energy, I only produce 120W a day (4 panels and trees around). Indeed I configured the DC low restart to 52V and I'm just under 52V (I briefly went over and the multiplus started so everything works), the battery is at 58% SOC. My question is can I lower the value of DC input low restart to 51V (BSL Batt Victron config manuals are quite confusing, I have the value of 51V and 52.5V but the config is ESS oriented ...) ? Will it damage the battery to stay too long too low (by the way what is too long too low :) ) ?

Have a nice day,

Olivier

Multiplus-II offgrid low battery warning bslbatt

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Answer 1 · 2023-11-24T13:12:15Z

kevgermany answered · Nov 24, 2023 at 01:12 PM

Yes you can lower it.

If they're LiFePO4 batteries, no risk. If AGM, you're going to shorten battery life by leaving them in a low state of charge.

Might help if you turn on AES, even though you are turning the inverter off. Search mode is the most economical.

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Olivier Wouters commented · Nov 25, 2023 at 10:54 AM

Thank you very much Kev. For the AES, all my power draws are very low : LED lights (5W each but connected in pair), the gas water heater (always on, use electricity for control), the spark for the gas burner. Would AES suit this scenario of very low needs ? Maybe if I want electricity I just turn on the lights and the inverter would kick in (which would fit my needs at the moment) :). I could try with a threshold of 8W, something higher than what the gas water heater needs but lower than 2 LED lights.

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kevgermany ♦♦ Olivier Wouters commented · Nov 25, 2023 at 12:49 PM

It needs a draw of about 40W to switch AC on. At least that's what I found a while ago. It was supposed to revert to the original value of about 10W, but not sure if this has happened yet. Can't experiment at the moment.

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