This thread was some much needed info! The bulk sucks. I thought of it as bulk charge to 57.6/ 3.6 per cell full. I think it just bulk charges to the float number you set and then float charges up to 100% soc or whatever you set.
I say that because after half a day of stand still I changed float to 57.6 and within a minute or two it jumped my voltage up to the float voltage and the cell voltages went up. Before that it was just staying the same for half the day and my shunt saw very little power if any coming in.
I still have not been able to also get 11 of my 32 cells to charge above 3.4v even with active balancing taking place. 10 or so cells just jumped up to 3.6 right away so I took the float back down after a minute or two. Even when balancing the 3.4 cells are not rising, just going down to 3.3 as the battery is used for heat sink fans and my fridge, etc and the 3.6 cells are lowering at a faster rate.
I'm thinking I just have some weak cells bc they are all basically uniform at 3.4 max and usually at 3.3v everyday while other cells fluctuate higher depending on settings.
I think I will just have "top" balance all the cells to 3.3 which is 70% soc. Just set 3.3x16= 52.8 as my max not 56.1 = 90% soc (battle borns' long life suggested bulk setting).
I loose about 10% soc a night (running 450w AC until about 10pm when the temps are lower in our high desert, and misc stuff like Batrium running on my laptop, etc. That still leaves me with 60% soc the next day. That seems safe than a bunch of cells getting to high.
I had similar issues.
Changed the logic on Program 32 : Bulk Charge Time (C.V Stage)
from AUTO to 480 (8 hours)
I think its more getting it off Auto mode as that appears to make a bad choice and start Floating immediately.
Another thing, bank needs to be below Float for BULK charing to kick in, or so it seems to me....
Spoke with MPP Engineer, they suggested setting Bulk and Float to the same, as (we all know) this systems were not designed for LifePo4...
Not sure i want to do that, as common advice around here to still to use Bulk and Float for LifePo4. But in the interim i have set:
Bulk 56.8v (3.55v per cell
Float 54.5v (3.4v per cell)
Low Voltage 48v (3v per cell)
I set the bulk a little higher than i ideally wanted (3.5 per cell) as it does seem to stop Bulk charge a little prematurely.
Will keep an eye on it at things settle in. May go back to 3.5v per cell again if its behaves itself longer term
Hope some of that was useful !
From another thread, not sure if accurate, but another theory on the AUTO setting... :
I know that when program 32 is set to "Auto", the bulk charge voltage setting is ignored.
When set to manual it does not drop to float until the timer runs out. The timer starts when the float voltage is achieved.
This came up in
another topic awhile back which you might remember.
I need know the settings for my MPP LV5048 for 48v LifePo4 batteries. So far it looks like Boost charge is 57.6, Float charge 55.2, back to grid (unknown), back to discharge voltage (unknown), battery cut of voltage (unknown). Thanks for any help
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