Continuously charging lithium

[Woodierichard7]

Is keeping my 100ah li battery on charge defeating the purpose?

 

[Woodierichard7]

W battery charger plugged to wall.

 

[Woodierichard7]

I have 225w panels connected. I get maybe 15 to 20 ah solar. But I still drain battery occasionally so I wondered as easy n fast as the charger is, does keeping battery charger connected defeating the good.

 

[John Frum]

Keeping your lithium battery on the charger all the time will decrease the capacity of the battery over time.

Charge termination logic is what separates chargers from constant current constant voltage power supplies.

The means a proper charger should either disconnect when the battery is full or drop the voltage to a safe level.

Which flavor of lithium are we talking about?

 

[wholybee]

It depends on the charger and what the settings are. If "keeping charger connected" means that the charger is constantly charging in "float" then that will damage the battery. Once fully charged, the charger must stop all charging. Smart Lithium chargers will do this, then turn back on once the Lithium has discharged a bit. Cheap chargers meant for Lead batteries will not, and will float and hold the voltage at a high voltage.

 

[Woodierichard7]

Keeping your lithium battery on the charger all the time will decrease the capacity of the battery over time.

Charge termination logic is what separates chargers from constant current constant voltage power supplies.

The means a proper charger should either disconnect when the battery is full or drop the voltage to a safe level.

Which flavor of lithium are we talking about?

LiFePO4

 

[Woodierichard7]

LiFePO4

So I could plug into wall at midnight to hold it til solar kicks n will b good sense.

 

[Woodierichard7]

So I could plug into wall at midnight to hold it til solar kicks n will b good sense.

I even have a GEL system I could plug to.

 

[John Frum]

So I could plug into wall at midnight to hold it til solar kicks n will b good sense.

The optimal solution is for the charger to automatically terminate the charge when the battery is full.
Does your charger have that capability?

 

[Woodierichard7]

Dont know. I do know the charger light turns green n cools down at full.

 

[John Frum]

Dont know. I do know the charger light turns green n cools down at full.

If the lifepo4 battery voltage drops to ~3.4 volts per cell over the course of ~12 hours while its connected to the charger it should be ok.

 

[Boondock Saint]

Depends. All of the above answers are correct, but if you are continuously USING the battery to power something, full-time, daily, then it continuously depletes therefore it continuously recharges in a manner prescribed above. If you run it down in the daytime, (more use than available charge) and there's no solar to recharge at night, and esp if you USE juice at night, then you might probably need to leave it on "shore power" with that wall charger to play catch up. Are there some variables not posted? Or is that battery just sitting there dying of old age? like me.


.

 

[wholybee]

So I could plug into wall at midnight to hold it til solar kicks n will b good sense.

What do you mean by "hold" If you mean hold it at full charge, then no, that isn't what you want to do. Ideally, the battery would discharge somewhat at night. Not totally depleted, but you don't want it to be held at full charge. You want it to discharge. Then, solar charges it up during the day. When solar gets the battery to 100% again, the solar charger turns off, and it starts discharging again, to be recharged the next day. Holding the LifePO4 battery at full charge, or very close to it, will shorten its life.

That said, if your battery is too small, and what you mean is to charge it at night because if you don't the battery will be completely discharged and you lose power, then yes, you can run the charger at night to keep that from happening. But better would be a bigger battery.

 

[wholybee]

Dont know. I do know the charger light turns green n cools down at full.

What charger do you have? If it is the Renogy 20A charger with no markings except an LED the turns from Red to Green, I would recommend unplugging the charger when it turns green. It turns green when the current drops below 2A, but doesn't stop charging.

 

[Woodierichard7]

If the lifepo4 battery voltage drops to ~3.4 volts per cell over the course of ~12 hours while its connected to the charger it should be ok.

I dont know how to check cells. 100ah battery n sealed n battery box.it fully charged n charger went to green light from red n was not warm/running.

 

[Woodierichard7]

What do you mean by "hold" If you mean hold it at full charge, then no, that isn't what you want to do. Ideally, the battery would discharge somewhat at night. Not totally depleted, but you don't want it to be held at full charge. You want it to discharge. Then, solar charges it up during the day. When solar gets the battery to 100% again, the solar charger turns off, and it starts discharging again, to be recharged the next day. Holding the LifePO4 battery at full charge, or very close to it, will shorten its life.

That said, if your battery is too small, and what you mean is to charge it at night because if you don't the battery will be completely discharged and you lose power, then yes, you can run the charger at night to keep that from happening. But better would be a bigger battery.

Hold, last til morning when sun starts charging again. It generally depletes at night. But occasionally I have to put a charge on it to avoid over discharge. But my question was answered. Dont keep fully charged. Let drain at night n what I thought. No charger on it all the time for battery maintenance.

 

[Woodierichard7]

What charger do you have? If it is the Renogy 20A charger with no markings except an LED the turns from Red to Green, I would recommend unplugging the charger when it turns green. It turns green when the current drops below 2A, but doesn't stop charging.

Thanx. That was my answer I was searching for.