Discharge capacity of LIFEPO4 batteries.

[pokemasterdanny]

So I was wondering how low I should be able to discharge the batteries recommended on the actual website in order to make sure they last as long as possible. I am referring to the Fortune 100Ah Lithium Battery LiFePO4 3.2V 6C Aluminum Encased batteries, the 24/48V 3kWh LiFePO4 Rebuilt Battery, and the CALB cells? Also, I was wondering how long each type should last me if I take care of them correctly?

 

[gnubie]

If you want to go to extremes charge to 80%, discharge to 20% and, IMO, expect 8000+ cycles. That sort of regime may well see a lifepo4 out last you.

If you cycle them 100% to 20%, typical lifepo4 cells can expect 'over 2000 cycles', to 0% is typically around 2000 cycles. 5-10 years ago this was more like 1000 cycles but things have moved on quite a bit since then, but you'll still find older articles stating that 1000 cycles and several rusted on old lithium-disbelievers-lead-acid-is-king types continue to state it in social media.

 

[pokemasterdanny]

Ok so now lets say I charge and use a battery at the same time, how does that affect the cycles and discharge rate?

 

[gnubie]

You can't charge and use it simulaneously. Current either flows in or it flows out, it can not do both. What you would be describing is having a DC system where battery, charger and load are all connected at the same time. If you momentarily draw more current than the charger can supply, the difference will come from the battery. When conditions change the battery will draw current to recharge.

If you want to dive into the idiot pool, Google search microcycling. Once that crowd has driven you insane, come back here and we'll book you into your local looney-bin

 

[pokemasterdanny]

Oh so if I charge my battery with a solar panel though a charge controller, I can't be using it to power something?

 

[JoeHam]

Oh so if I charge my battery with a solar panel though a charge controller, I can't be using it to power something?

You can, it’s a little bit of semantics.

Let’s say your panel/SCC is putting 10 amps into your battery for this example.

If your load is only 5 amps you are really running the load off the panel and charging the battery with 5 amps.

If your load is 15 amps then you are discharging the battery 5 amps and offsetting the load with the panel.

I am ignoring the fact that the charge voltage will be higher than the battery for this simplistic example.