LiFePO4 - maintaining the battery life

[joshje]

I have a LiFePO4 lithium leisure battery, and I understand that it likes to be stored at ~50% charge.

Our camper has solar + Victron MPPT, as well as a Victron DC-DC, and so our leisure battery is always at 100% (at least whenever I check it).

Now that we’re approaching the winter season, and I don’t expect to be using it nearly as often, I’m wondering how other folks store theirs over winter.

I’m imagining turning off the MPPT so that it no longer receives current from the solar panels, and possibly also turning off the DC-DC, in case we turn on the engine. Is that what others do? Or is there a way to “tell” the battery what level to charge to?

In case it’s useful our battery is a Poweroad PRLC-100

 

[Dellmassive]

If the battery is be left for 6mnths or longer....

Draw the battery down to 50%.

Then disconect it.(remove the POS cable)(or shut off the isolation switch)

You should check the battery within 6mnths and add a topup charge if needed.

When your bring the battery back into service,

You need to fully charge it to reset the battery BMS to 100% charged.

 

[joshje]

Thanks @Dellmassive.

I wonder, instead of “fully” disconnecting it, could this power button be used to turn off the battery, or will that still cause some amount of power drain?

 

[joshje]

Oh, actually I see that perhaps this switch serves as an isolator switch (disconnects all appliances from load). We usually leave this in the off position when not in use, so if that’s enough this is a simple solution.

 

[Dellmassive]

Thanks @Dellmassive.

I wonder, instead of “fully” disconnecting it, could this power button be used to turn off the battery, or will that still cause some amount of power drain?

View attachment 172096

That's the sleep button.

And should work as an isolator.

 

[Mick]

I have a LiFePO4 lithium leisure battery, and I understand that it likes to be stored at ~50% charge.

Our camper has solar + Victron MPPT, as well as a Victron DC-DC, and so our leisure battery is always at 100% (at least whenever I check it).

Now that we’re approaching the winter season, and I don’t expect to be using it nearly as often, I’m wondering how other folks store theirs over winter.

I’m imagining turning off the MPPT so that it no longer receives current from the solar panels, and possibly also turning off the DC-DC, in case we turn on the engine. Is that what others do? Or is there a way to “tell” the battery what level to charge to?

In case it’s useful our battery is a Poweroad PRLC-100

I set up my Victron MPPT with a ‘parked’ profile that doesn’t charge from solar if the battery is above 12.5v. Which is always is. If my battery is at 100% and I am not going to use it I leave my Victron inverter 13a socket switched on and it drains at 0.5a. After about 3 days my BMS recognises no power and turns off By then the SOC is at about 80% and stays there.

 

[DXX]

I just checked the manual for my Valence LiFePO4 and it does not mention storing at 50% SOC, however it does say that it can be stored for up to 12 months at full charge without need for a re-charge as it will be in sleep mode.

 

[joshje]

I set up my Victron MPPT with a ‘parked’ profile that doesn’t charge from solar if the battery is above 12.5v. Which is always is. If my battery is at 100% and I am not going to use it I leave my Victron inverter 13a socket switched on and it drains at 0.5a. After about 3 days my BMS recognises no power and turns off By then the SOC is at about 80% and stays there.

Interesting! Mind sharing a screenshot of your settings? I might copy you!

 

[Dellmassive]

I just checked the manual for my Valence LiFePO4 and it does not mention storing at 50% SOC, however it does say that it can be stored for up to 12 months at full charge without need for a re-charge as it will be in sleep mode.

that sleep mode only applies when the battery is part of the OEM master battery pack with the Valance master controller.

so single Valance batterys dont sleep on there own, ( as the internal BMS is shut down unless you have the USB data PC cable to temp wake it up)


........................


the standard advice across nearly all lithium battery manufactures is to long-term store at 50% soc. (as this is the most chemically stable point)

eg:

How to store LIFEPO4 12v batteries

How to store my lithium battery? We receive the most problems, especially in winter. The answer depends on the temperature and time you store the battery.

explorevanx.com

It is strongly recommended to store lithium batteries indoors during the off-season.
It is also recommended to store LiFePO4 batteries at a state of charge (SOC) of approximately 50% or higher.
If the battery is stored for a long time, cycle the battery at least once every 6 months.
Do not store discharged batteries.

 

[Mick]

Interesting! Mind sharing a screenshot of your settings? I might copy you!

Here ya go. I got the voltage wrong in the above post. 13.10v and 13.2v work.

 

[BoroBoy]

Mick, What is the "Expert Mode" selection for?

 

[Mick]

Mick, What is the "Expert Mode" selection for?

Select it and find out It allows you change a number of setting that you really don't want to be messing with. Peukert factors, tail current etc and all sorts of other electrochemist types stuff that may just f*ck up ya day .

 

[BoroBoy]

Thanks. I asked because I couldn't be arsed going out to the van in these Baltic temperatures oop North.

 

[Mick]

Thanks. I asked because I couldn't be arsed going out to the van in these Baltic temperatures oop North.

Cheers mate! I went out in -6c to help you. That’ll be more extra cake from your Mrs then

 

[BoroBoy]

I am sure she will be baking for our next meet.