Combining multiple power sources to charge LifeP04

[Just-ify]

Hi folks,

Newbie here.

I'm busy planning my purchases for a solar system and have a question regarding charging of a LIFEP04 battery with multiple power sources.

If one has multiple non-grid power inputs (e.g. 3 MPPT controllers, or solar panels and a wind turbine etc.), how would one combine that as a singe input to the hybrid inverter/battery?

Would one use a 'busbar' and wire all the 12v into this central point and then wire that with a positive and negative into the primary charge controller of the inverter (assuming it's in the voltage range of the hybrid's charge controller) - or would you wire it straight to the battery and let the BMS of the battery handle the rest?

Thanks - learning every day

Edited March 7, 2023 by Just-ify

[wolfandy]

12 minutes ago, Just-ify said:

Would one use a 'busbar' and wire all the 12v into this central point and then wire that with a positive and negative into the primary charge controller of the inverter (assuming it's in the voltage range of the hybrid's charge controller) - or would you wire it straight to the battery and let the BMS of the battery handle the rest?

I have previously used an external MPPT to charge the batteries using a busbar. The batteries, the MPPT, and the battery input of the inverter were all connected to it. Worked perfectly.

Biggest challenge is getting the charging settings right across all devices connected - e.g. synchronizing multiple MPPT or between MPPT and grid charging.

Other small downside is that the inverter obviously is always thinking that it was running on batteries while in reality the power feed comes from the MPPT. But that's only a 'display' problem and not a functional one.

[Raj35]

@Just-ify there are some inverters that has an AUX port / Gen port which you can use. 

[Scorp007]

On 2023/03/07 at 12:24 PM, Just-ify said:

Hi folks,

Newbie here.

I'm busy planning my purchases for a solar system and have a question regarding charging of a LIFEP04 battery with multiple power sources.

If one has multiple non-grid power inputs (e.g. 3 MPPT controllers, or solar panels and a wind turbine etc.), how would one combine that as a singe input to the hybrid inverter/battery?

Would one use a 'busbar' and wire all the 12v into this central point and then wire that with a positive and negative into the primary charge controller of the inverter (assuming it's in the voltage range of the hybrid's charge controller) - or would you wire it straight to the battery and let the BMS of the battery handle the rest?

Thanks - learning every day

I would be inclined to say each source is connected to a busbar system as each need to sense the SOC of the battery. I would think to wire all the sources to the inverter controller could be problematic depending on the make. For a Deye/Sunsunk it wont be a problem. You do mention 12V so it seems you have a 12V system in mind?

MPPT/PWM that have auto configure also need to sense the battery voltage in order to adjust itself for correct charging.

[wolfandy]

39 minutes ago, Scorp007 said:

I would be inclined to say each source is connected to a busbar system as each need to sense the SOC of the battery.

Just to be a bit more specific - the common busbar will allow all systems to measure the battery voltage, not SOC

[Scorp007]

27 minutes ago, wolfandy said:

Just to be a bit more specific - the common busbar will allow all systems to measure the battery voltage, not SOC

SOC as we use it was the wrong word. The controllers need to know which of the 3 or 4 stages of charging is required. 

Edited March 25, 2023 by Scorp007