robwolff3
How do you turn this thing on?
- Joined
- Oct 12, 2021
- Messages
- 42
I have a 280ah 48v LiFePo4 in a backup configuration with my grid-tied MPP LVX6048WP. The battery bank sits at a fullish charge waiting for a grid outage and then backs up my critical loads. Not wanting to over wear my batteries in this application its seems best to keep them at 80% or 90% SOC as opposed to say 100%. The MPP seems to have two options, continuously float the batteries at a particular voltage all of the time or turn off the charger once the desired voltage/SoC is reached. When the charger is turned off the MPP continues operate in bypass mode from the grid and it always draws about 88w from the battery bank. Over the course of about a week this slowly draws down the SoC of the bank 10%. At this point I would have to reengage the charger and top off the bank so it remains ready for a grid outage. A sensible cycling seems like between 80-90% SoC?
I'm just not sure if cycling between 80-90% SoC once a week or just continuously floating the batteries will wear them less.
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On a side note if you want to go further down this analysis with me. I landed on a backup application because my 14 kWh bank barely covers my critical loads for 24 hours in the winter, definitely not all of my house loads so if I discharged my bank during non-solar hours to offset grid usage and hit a non-sunny days streak here in the Midwest, I may end up in a spot with a depleted bank not ready to back up my critical loads and have to run my generator.
My TOU rates are 12c 7pm-11am and 22c 11a-7p, so I could try beating the peak rate but then do I charge the bank with off peak immediately after or wait till solar the next day. What do other people do that are grid tied with a smaller battery bank?
I'm just not sure if cycling between 80-90% SoC once a week or just continuously floating the batteries will wear them less.
---
On a side note if you want to go further down this analysis with me. I landed on a backup application because my 14 kWh bank barely covers my critical loads for 24 hours in the winter, definitely not all of my house loads so if I discharged my bank during non-solar hours to offset grid usage and hit a non-sunny days streak here in the Midwest, I may end up in a spot with a depleted bank not ready to back up my critical loads and have to run my generator.
My TOU rates are 12c 7pm-11am and 22c 11a-7p, so I could try beating the peak rate but then do I charge the bank with off peak immediately after or wait till solar the next day. What do other people do that are grid tied with a smaller battery bank?