Looking to build a LifePo4 battery for an RV and was thinking of using 8-272AH cells for 2-12v 272ah in parallel for 544AH@12V total. I have run across some interesting articles posted on this forum and was wondering if the information below (#1) is still the current and up to date view of LifePo4 battery technology? I have 1120w of solar
1. "The first consequence of installing an oversize battery bank, especially when sustained charging is involved as with solar panels, is that the bank remains at a higher state of charge much longer, if not most of the time. This is very detrimental to its ageing for reasons that were developed earlier. Lithium cells like cycling because it means they don’t spend any amount of time near full; alternatively, they can sit happily
half-discharged, or even lower, for years."
If this is true how do you keep the batteries from the full charge to protect them?? Would you set your float charge to equal 90%SOC??
2. "Single 3.2V prismatic LiFePO4 cells can nowadays be obtained in huge capacity, as high as 10000Ah. Commonly available cells range between 40Ah and maybe 1000Ah. It should be pointed out that the larger sizes are intended for stationary applications where no accelerations, vibrations or shocks are ever experienced.
A sales manager at Sinopoly I was talking to was adamant about using 100Ah or 200Ah cells only for assembling marine battery banks, with 100Ah being preferred and 200Ah acceptable. Large cells simply don’t have the structural strength-to-weight ratio required to be taken to sea on board small crafts and would exhibit shortened life due to internal mechanical damage arising from on-going vessel motion. It is common sense: as a cell becomes larger, its internal weight increases much faster than the rigidity and surface area of the casing and the casing is all what holds the plates together in a prismatic cell.
Failures have been reported on vessels equipped with 700Ah cells following ocean passages: some cells were suddenly found to be losing charge inexplicably, rendering the battery bank completely unmanageable and the matter ended in a complete write-off. All big-brand commercial marine lithium battery packs on the market today are built from cells no larger than 200Ah."
So is it not a good Idea to use 272AH cells in a build for an RV?
1. "The first consequence of installing an oversize battery bank, especially when sustained charging is involved as with solar panels, is that the bank remains at a higher state of charge much longer, if not most of the time. This is very detrimental to its ageing for reasons that were developed earlier. Lithium cells like cycling because it means they don’t spend any amount of time near full; alternatively, they can sit happily
half-discharged, or even lower, for years."
If this is true how do you keep the batteries from the full charge to protect them?? Would you set your float charge to equal 90%SOC??
2. "Single 3.2V prismatic LiFePO4 cells can nowadays be obtained in huge capacity, as high as 10000Ah. Commonly available cells range between 40Ah and maybe 1000Ah. It should be pointed out that the larger sizes are intended for stationary applications where no accelerations, vibrations or shocks are ever experienced.
A sales manager at Sinopoly I was talking to was adamant about using 100Ah or 200Ah cells only for assembling marine battery banks, with 100Ah being preferred and 200Ah acceptable. Large cells simply don’t have the structural strength-to-weight ratio required to be taken to sea on board small crafts and would exhibit shortened life due to internal mechanical damage arising from on-going vessel motion. It is common sense: as a cell becomes larger, its internal weight increases much faster than the rigidity and surface area of the casing and the casing is all what holds the plates together in a prismatic cell.
Failures have been reported on vessels equipped with 700Ah cells following ocean passages: some cells were suddenly found to be losing charge inexplicably, rendering the battery bank completely unmanageable and the matter ended in a complete write-off. All big-brand commercial marine lithium battery packs on the market today are built from cells no larger than 200Ah."
So is it not a good Idea to use 272AH cells in a build for an RV?