Question about some numbers

[jjphat]

Hi folks,
Just trying to get everything to jive right with my solar system. Been reading around online but figured I'd post here to see if anyone had some good solid advice.

I'm wondering how I should set my automatic transfer switch's "Low Voltage Transfer Setpoint" and "Battery Recover Setpoint". I am using the MOES ATS Dual Power Transfer Switch with a 48v 100AH battery which has these numbers:

Battery Max charging voltage 58.4
Minimum Discharge voltage 40

So basically I'm trying to figure out which would be the best numbers to be having the transfer switch go back and forth between the grid power and the battery.

Thanks!
John

 

[DIYrich]

Recommended Charge Profile for DIY LiFePO4 Batteries *Sticky Post*

12V 4S LiFePO4 Battery w/ BMS: Absorption: 14.5V Float: 13.6V Inverter Cut-off: 10.7V-12V (depending on size of load and voltage drop etc) 24V 8S LiFePO4 Battery w/ BMS Absorption: 29V Float: 27.2V Inverter Cut-off: 21.4V-24V 48V 16S LiFePO4 Battery w/ BMS Absorption: 58V Float: 54.4V...

diysolarforum.com

> So basically I'm trying to figure out which would be the best numbers to be having the transfer switch
> go back and forth between the grid power and the battery.

Depends upon if you have net metering and time of use rates.
If net metering and single rate, then never use the battery unless the grid goes down.
If net metering and time of use rates, then you want to use the battery when rates are high.
If you don't have net metering, and single rate then you want to drain the battery before the sun comes up, and use excess PV to charge the battery.
If you don't have net metering and time of use rates, then you want to save the battery for when rates are high. How much you drain before the sun comes up depends upon how much PV will recharge the battery before rates are high (and how much you will use when rates are high).

 

[jjphat]

Thanks! The system is actually not tied into the grid, per se, but the transfer switch is set to flip back over to grid power when the battery gets below a certain level. My question is more concerning the health of the battery. Thanks again...like how far should I let it get down and then when should I set the switch to flip it back over to battery power when it's at a certain charge level

 

[jjphat]

Ah I just noticed the sticky post I'll check that out

 

[jjphat]

It looks like the sweet spots are 56.4 on the high side and 48 on the low side. I had the low set way down at 44 but it didn't seem to like that very much.