Over paneled and charging my Lifepower4’s to much?

[Jack Rabbit Off Grid]

I have 600ah of Lifepower4 batteries 3650w of REC N-peak2 panels 5s2p running though a Victron 250/70 thats set on factory LFP settings 56.6v. I never use anymore the 80ah of my batteries at night. Even on overcast days my panels will recharge the batteries all the way up by noon. The panels are not even mounted yet. They are just laying on the ground facing kinda southeast strait up.

Is this going to hurt the batteries over time? My voltage never drops below 53.6 ish. I’m making this much power and it’s not even summer. I do have a 12k mini split I’m installing before summer but it won’t draw much from what I’ve researched.

Dave

 

[sunshine_eggo]

LFP can typically be charge at 0.5 - 1.0C In your case, that's 300-600A. It depends on your battery's cells and their ratings.

Your MPPT is limited to 70A.

If the MPPT is actually putting out 70A, you could check each of your interconnects to insure the current sharing between the batteries is roughly equal.

 

[MisterSandals]

If the MPPT is actually putting out 70A,

I would consider throttling your MPPT back a bit so that it doesn't run hot at 100% in hopes that it will last longer. If you can get a gentler charge at 50A, it will be much easier on the MPPT and likely better for your batteries too.

 

[SignatureSolarJames]

@Jack Rabbit Off Grid you are good, the cycle life calcs are based on 5 hour rate (120A) Thanks for getting your gear from us

 

[fratermus]

Is this going to hurt the batteries over time?

I am similarly overpaneled (750w:100Ah). In practice I rarely see more than 0.3C charging by solar since I've hit my targets before local solar noon.

If you are worried about overcharging I suppose you could charge to (and "float" at) somewhat lower voltages. AFAIK there are few compelling reasons to run the bank up to 100% SoC every day, or to hold it there.

 

[Jack Rabbit Off Grid]

I just reread my question and don’t think I asked it correctly.

I’m under the impression that LFP batteries like it best between 20 and 80%. My setup is bringing them back to full charge of 56.8v everyday. I think the Victron gets them to 95% and I have my shunt set seeing that as 100%.

If this makes better sense? I’m not good at conveying myself correctly. I’m an old diesel mechanic not a diesel technician.

 

[HRTKD]

The default charge voltage for Victron MPPT is 14.2 volts (56.8 for a 48 volt system). You can adjust this down if you don't want that high of a charge. The batteries will rest to a lower voltage. The float voltage is typically 13.5 volts (54.0 volts for a 48 volt system). Your solar charge controller probably isn't running at 56.8 for that long and likely is at 54.0 most of the time.

 

[MisterSandals]

My setup is bringing them back to full charge of 56.8v everyday. I think the Victron gets them to 95% and I have my shunt set seeing that as 100%.

A lot of us “conservative chargers” charge to 3.45Vpc. I consider this a gentle 100% charge.
Some have said this is the minimum cycling to maintain healthy cells, especially if your BMS only balances at this level.
3.45Vpc x 16 = 55.2V

I recommend trying around this level to see how it goes.
I also like having my float voltage just below where my cells settle after a couple hours. Mine settle to 3.35V so I float at 3.32V If you use this method, see where YOUR CELLS settle, and base your float off of that.

Think of this as a starting point, you can tinker as you see fit.