Smart Solar settings for lifepo battery

[Photobug]

I have finally wired up my battery power box. I have a Bioenno 60 ah battery and a Victron Smart Solar in the box.

I do not have a battery monitor. I fully charged the battery using my NOCO Genius charger in Lithium mode when I first got the battery. The battery has sat idle for at least a month.

When I hooked up the completed box to the solar panel it was showing a float charge. What settings should I use in the Victron app to get the best charge into my battery?

 

[dreadlocks]

I used the Lithium setting as a base, set fixed absorb voltage til 2A (0.02C, 1.2A for you), and knocked the float down to 13.4v.. for my 100AH BattleBorn.

 

[luthj]

The instructions for charging the battery (user manual) are not ideal for longevity. 14.6V is the absolute maximum you should see. I suggest the following.

dreadlocks suggestion is good. I would go with 14.4V (max), personally I would go with 14.2V. Assuming no other loads, I would use current for termination. If you anticipate having other loads runnign while charging, I would also add an absorb timer (whichever is reached first, current or time). You can do some testing, but 20 minutes at 14.4V, maybe a bit longer at 14.2V. Note that you will need to test this yourself, as voltage drops in the system will have an impact.

 

[dreadlocks]

yeah Victrons LFP setting is 14.2v, 2h fixed absorb, float of 13.6v.. I just tweaked the absorb and float to be a bit more conservative and not hold the battery so high for so long.. 13.4v float is less of a float charge and more of a storage charge, its ~90% SOC before it'll start taking load back off the battery.

 

[Photobug]

I used the Lithium setting as a base, set fixed absorb voltage til 2A (0.02C, 1.2A for you), and knocked the float down to 13.4v.. for my 100AH BattleBorn.

Where is this lithium setting?

I have not used the smart solar for over a month and have forgotten the settings. I went into settings and found some presets but only see a deep cycle agm for factory settings, no lithium option comes up.

I was forced to update firmware when I turned the charger on this morning.

 

[Photobug]

Found it in user defined presets.

 

[dreadlocks]

I have a lithium preset

 

[Swiftone]

Maybe I need more education on LiFeP04 batteries...this is from the Bioenno power webpage:

We guarantee our entire battery range comes with built-in protection-circuit-modules (PCM) micro-computers that internally balanced cells and confer protection including from overcharge, over discharge and short circuiting.

With this protection do the absorption and float levels matter? At least for Bioenno batteries? I checked with the guys there when I got my smart solar and was told factory LiFeP04 settings were good and the internal protection will shut down charging when charged.

Or are these settings for batteries that have a draw on them? One of mine does (6 to 9 AH a day on a 20 AH battery) and one does not on a daily basis. Both sit on smart chargers 24/7

 

[luthj]

That is just marketing BS. It will prevent the cells from overvolting and failing if you charge them to 14.6V+. It will not prevent the fairly rapid capacity loss from letting the cells sit 100% full, or floating at higher voltages. If you only care about getting 500-1000 cycles from the pack, it may not matter. Though if you were to float the batteries at 14.4V 24/7 you could see over 15% capacity loss per year, even without any cycling.

The internal BMS is like an emergency brake. It is not a substitute for properly configured charge sources.

 

[Swiftone]

Ok. I believe you. What should I set my smart solar charge/absorption/float levels? What dreadlocks has posted above? Right now they are at Absorption - 14.20/float - 13.50

That is just marketing BS. It will prevent the cells from overvolting and failing if you charge them to 14.6V+. It will not prevent the fairly rapid capacity loss from letting the cells sit 100% full, or floating at higher voltages. If you only care about getting 500-1000 cycles from the pack, it may not matter. Though if you were to float the batteries at 14.4V 24/7 you could see over 15% capacity loss per year, even without any cycling.

The internal BMS is like an emergency brake. It is not a substitute for properly configured charge sources.

 

[dreadlocks]

Half an amp tail current for that little LFP.. lowering the float voltage lets battery discharge a bit before it holds voltage w/solar, but you need a load on the battery to pull it back down after.. otherwise it'll just sit at 100%.

If you are storing it w/out loads, discharge it to ~50% SOC and disconnect it.. then when you go to use it again, charge it back up, unlike lead batteries LFP's should not sit at 100% for long periods of time.. the'd perfer it if you kept it between 20% and 90% SOC most of the time, going up to 100% SOC on occasion to balance cells and calibrate any SOC monitors.. going up to 100% daily is fine if your charger stops fairly quickly and you are running loads on it so it dont stay there.

 

[Swiftone]

Cool - thanks. Will do tomorrow rain permitting (yea - we get rain in So Cal...)

Half an amp tail current for that little LFP.. lowering the float voltage lets battery discharge a bit before it holds voltage w/solar, but you need a load on the battery to pull it back down after.. otherwise it'll just sit at 100%.

If you are storing it w/out loads, discharge it to ~50% SOC and disconnect it.. then when you go to use it again, charge it back up, unlike lead batteries LFP's should not sit at 100% for long periods of time.. the'd perfer it if you kept it between 20% and 90% SOC most of the time, going up to 100% SOC on occasion to balance cells and calibrate any SOC monitors.. going up to 100% daily is fine if your charger stops fairly quickly and you are running loads on it so it dont stay there.

 

[luthj]

Dreadlocks suggestions are good. Follow them and enjoy a very long service life.

 

[shade]

The internal BMS is like an emergency brake. It is not a substitute for properly configured charge sources.

It's the difference between control and protection, and like you said, many manufacturers aren't interested in the distinction.

 

[luthj]

Personally I would stick with 13.2-13.3V for system's with full time solar. But 13.6V is the max float I would go.