LiFePO4 Batteries: Discussion Thread for Those Using Them as House Banks

[CatNewBee]

This are the categories of the app, the windows UI has more detailled functions for the MultiPlus and Quattro..

[noelex 77]

The Victron ip65 chargers have a storage setting for lithium, but this has the same voltage as the float setting (13.5v for 12v batteries).

So the storage setting does not do anything with lithium batteries.

There are three profiles. The voltages for these profiles are fixed and are not user adjustable.

[john61ct]

Originally Posted by newhaul

So I would say no it doesn't but with the low self discharge rate of Lfp you don't need a charger hooked up at all with less than a years layup ( IMO ymmv )

This "storage" feature kicks in after a short time of no loads drawn.

That algorithm does not require this charger, I am not "promoting" that (necessarily, unless I maybe get credible evidence that its profile settings are sufficiently user-customizable.)

But I see I see such an algorithm as potentially **very** useful,

not **only** for actual long-term storage, but anytime energy inputs are constant enough and high enough current to carry loads without drawing on the bank.

Thus avoiding the sitting-at-Full syndrome so harmful to longevity,

without needing to isolate the bank from the charge buss, nor the loads buss.

For example, sitting plugged into the dock.

[john61ct]

Also, that (finally) sensible

14.2V / 3.55Vpc

setpoint reco from Victron is I think a landmark validation of the "avoid the shoulders" outlook.

[CatNewBee]

...

[john61ct]

Originally Posted by CatNewBee

I do not see a reason why the other units, like the MultiPlus or the normal MPPT controllers would have different settings abilities, they use a similir UI and likely the same software.

One would think so, and

that is also my **hope**

but I suspect they were unusually illogical for the Dutch in this case.

Perhaps a desire for simplicity, or higher profit margins, won out in this case.

> Download the Victron Connect app and use the simulator, you can load any Victron Device and tweak the available settings.

Apparently that may not be the case with this specific charger.

________
> For storage I simply change the settings to my needs.

See above why this is not just about long term storage.

> I am not aware of a second pre-set of parameters to switch back and forth between use and storage by a single setting.

That is exactly the feature they've implemented with this charger.

The only question is,

can it be used in conjunction with selecting LFP, or perhaps via a user-custom program?

as we are hoping.

[CatNewBee]

...

[john61ct]

Originally Posted by CatNewBee

... Attachment 199736

Do you have evidence **this specific charger** is compatible with the VE.Bus comms protocol?

[CatNewBee]

You can choose the device desired from the categories.
This are only screenshots from the top of the list, you have to scroll for more...
Just play around with the device desired.

[john61ct]

Originally Posted by noelex 77

the storage setting does not do anything with lithium batteries.

There are three profiles. The voltages for these profiles are fixed and are not user adjustable.

That is as I suspected.

However, that auto-switch into Storage mode algorithm to my mind, holds a lot of promise.

[newhaul]

Originally Posted by john61ct

This "storage" feature kicks in after a short time of no loads drawn.

That algorithm does not require this charger, I am not "promoting" that (necessarily, unless I maybe get credible evidence that its profile settings are sufficiently user-customizable.)

But I see I see such an algorithm as potentially **very** useful,

not **only** for actual long-term storage, but anytime energy inputs are constant enough and high enough current to carry loads without drawing on the bank.

Thus avoiding the sitting-at-Full syndrome so harmful to longevity,

without needing to isolate the bank from the charge buss, nor the loads buss.

For example, sitting plugged into the dock.

actually after 24 hours of no load

[john61ct]

Yes, a very short time, compared to what most people call "storage"

[john61ct]

Originally Posted by CatNewBee

You can choose the device desired from the categories.

That is only relevant for charge sources that are both user-adjustable, and VE.Bus compatible.

Not all such Victron devices are.

Even SPI, I2C or CAN would be fine, but I suspect no adjustment is possible with this particular unit.

I'd be very happy to be proven wrong.

[newhaul]

Upon further reading of the specifications page , I would personally have to recommend that you don't use this with Lfp for long term storage .

Lfp don't like being fully charged.

Storage Mode: Less maintenance and aging when the battery is not in use The storage mode kicks in whenever the battery has not been subjected to discharge during 24 hours. In the storage mode float voltage is reduced to 2,2 V/cell (13,2 V for a 12 V battery) to minimise gassing and corrosion of the positive plates. Once a week the voltage is raised back to the absorption level to ‘equalize’ the battery. This feature prevents stratification of the electrolyte and sulphation, a major cause of early battery failure.

Because of this statement in there
Once a week the voltage is raised back to the absorption level to ‘equalize’ the battery

And then there is this part
Also charges Li-ion (LiFePO₄) batteries LiFePO₄ batteries are charged with a simple bulk – absorption – float algorithm.

And the Lfp float is 13.5v or fairly close to what is normally considered by most of us using Lfp to be considered fully charged .

And we all know Lfp hate being kept fully charged for long periods.

[john61ct]

Yes, the automatic switching into SM is the key bit

as is that precise maintenance voltage.

Going back to some version of Full every once in a while while actually in storage is A Good Thing.

Many LI chargers actually have a precise Discharge function for exactly this purpose.

I agree that anything causing the SoC to sit at Full while real loads are not active is A Bad Thing.

But again, not pugging this model charger, just discussing an ideal version of that algorithm, perhaps to be imolemented via Arduino or PLC.