High DC Ripple after Installing New LiFePo4 battery

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Kobina Obu Beecham asked Apr 28, '24

High DC Ripple after Installing New LiFePo4 battery

LoUpgraded to my 1st LiFePo4 battery after 9 years and 3 sets of Gel batteries.
System works perfectly except that occasionally the system restarts and connected loads lose power.
System is restored usually within a minute.
Manufacturer doesn't specify Absorption Voltage so I dont know where in VE Configure 3 to insert Absorption Voltage.
Manufacturer specified Bulk Voltage but I dont know where in VE Configure 3 to type in Bulk Charging voltage

Done some reading on the High DC ripple and my question is exactly what voltage settings do I need to configure in VE Configure 3 to prevent the batteries BMS from kicking the Inverter off occasionally?Logs from Inverter. Not all were logged but at least this incidence was logged
The new liFePo4 BatteryAlarm message I received from the VRM Portal

Multiplus-II

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klim8skeptic ♦ commented · Apr 28 at 06:44 PM

@Kobina Obu Beecham One thing of note about your battery specs.

The label on the shipping carton list the battery as 5KWH.

The maths does not add up. A 25.6v, 100Ah battery gives a capacity of 2.56 KWH.

Make sure you operate your battery discharge as 2.56 KWH.

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Answer 1 · 2024-04-28T13:42:11Z

JohnC answered · Apr 28 at 01:42 PM

@Kobina Obu Beecham

The battery's Bulk V means the same as Victron's Absorb V. Float same on both. See what happens when you set to recommended values.

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Alexandra ♦ commented · Apr 28 at 05:09 PM

@Kobina Obu Beecham

Bulk/absorption is definitely set a bit high there, the battery is trying to say 'no more, thanks'.

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Answer 2 · 2024-04-29T11:36:09Z

Kobina Obu Beecham answered · Apr 29 at 11:36 AM

Thanks for the suggestions.
I have noticed that when I make the ff changes:
Absorption Voltage = 27.8V
Floating Voltage = 27.5V
VE Configure automatically sets the battery type to "no corresponding default"

When I click on battery type and choose Lithium Iron Phosphate, the software automatically modifies the settings to:
Absorption Voltage = 28.4V
Floating Voltage = 27.0V

I am going to ahead and create a new battery type to upload into the Multiplus. Hopefully this should adapt the Multplus to charge this particular battery accordingly.

Is it safe to upload this configuration into the Multiplus? Should the Charge Curve remain Fixed?

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JohnC ♦ commented · Apr 29 at 11:53 AM

@Kobina Obu Beecham

Yes, that should be ok. A 1hr Fixed Absorb time is fairly typical, but these little details should be checked with the battery supplier when you get a chance. They're the ones holding the warranty..

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Kobina Obu Beecham JohnC ♦ commented · Apr 29 at 08:43 PM

Thanks so much everyone.

Uploaded the configuration, the Multiplus accepted it and the system has not gone off since the change. I think it always happened when the battery charge level crossed the 95% threshold.

Once again thanks everyone.
Victron sure rocks

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