Charge and discharge simulataneously

[PaulLad]

I just got off the phone with Signature Solar and they're telling me that I can't discharge and charge the EG4 Lifepower battery simultaneously. Please tell me this is a mistake. Now I'm trying to understand what I'm supposed to do for power while the battery is charging? I'm really confused. Doesn't every off grid system have to charge and discharge batteries at the same time? Or do you need to have multiple batteries so you can charge one while the other is running your loads? Any insight is appreciated.

 

[DougfromdaUP]

You can't charge and discharge any battery simultaneously. A battery is either charging, discharging, or has no current flowing.

You can, however, have many things connected to your battery at the same time- some drawing current, and some providing current to the common connection point (commonly called a bus.)

 

[Q-Dog]

Technically correct, power either goes in or goes out of the battery ... can't do both at the same time.

BUT. If your charging system is making more power than you are drawing from the system, the excess will go into the battery. The overall result is you will charge the battery.

 

[DIYrich]

Now I'm trying to understand what I'm supposed to do for power while the battery is charging? Any insight is appreciated.

If PV is producing less than you need, the PV goes to Load, and the rest comes FROM the battery.
If PV is producing more than you need, then PV goes to load, and the rest goes TO the battery.
If PV is producing exactly what you need, then PV goes to load, and nothing goes to/from the battery.

If you need to charge from grid (say at night) then grid supplies both charging and load.

 

[sunsurfer]

Just a case of lost in translation. Another way to think about is the charging current gets diverted away from battery when load is higher then charging rate. The batteries will fill in any power the charger can’t meet

 

[PaulLad]

Let me rephrase this. They told me I can't run loads while charging the battery. Sounds like they're wrong.

 

[DIYrich]

Let me rephrase this. They told me I can't run loads while charging the battery. Sounds like they're wrong.

That's wrong. See my prior post. however, if you have a limited input (say 10kw generator), and you are using 10kw, then there is nothing left to charge with.

 

[timselectric]

Call again.
If you get a different person, you will get a different answer.