Volta Power Systems
The available information out there means that temperature plays the largest function in negatively impacting capability followed by a high storage SoC. For optimum cycle life these cells are greatest used at temps where you, as a human, are snug. GEL batteries are still the longest enduring of lead acid batteries however they SHOT THEMSELVES IN THE FOOT making an attempt to promote into a market that did not require a “remainder of the system” strategy.
If we begin with a goal voltage of 14.0V, and drop or lose .42V, this implies simply 13.58V at the battery terminals. Even an LFP bank, which normally operates around thirteen.2V, can come up to 13.6V nicely before it ought to have its present restricted by the cost supply. This is from Balmar, the worlds largest specialty marine performance alternator and regulator manufacturer. If you cycle the LFP bank to eighty% DOD this implies you're in BULK cost mode for approx seventy five% or more of the capacity of the complete bank bank before any kind of voltage limiting even begins. More importantly, this manufacturer is now recommending a max charge voltage, for a 12V bank, of 14.0V for batteries charged in collection or parallel until each battery has it’s own cost supply.
This is good information and it appears some LFP makers are certainly starting to get it. This sort of consequence can completely occur in a lab but it could’t be well translated to a ship using a number of cost sources, all at various cost rates a lot of them using “absorption timers“. As I have talked about before the height protected voltages are just that “peaks”. As can be seen below the cells charged to only a hair over 3.8V then have been instantly discharged.
While these batteries don't have much capacity loss between excessive discharge, corresponding to a 1C load, and mid discharge at a 0.5C load, there are small differences. LFP batteries are not rated at at 20 hour fee like a lead acid battery is. How they're rated for Ah capability could cause lots of headaches making an attempt to truly determine it out. There is plenty of proof out there that implies these cells can easily cycle to 2000 or extra cycles, underneath lab situations, yet there's little details about prismatic cell shelf life and storage.
I favor to think about a BMS as a BIP, or battery insurance policy. It is there solely to make sure your cells can not be over charged, over discharged or pushed too far into temp limits. Not all DIY or manufacturing facility made BMS merchandise characteristic temp monitoring or temp safety. Lack of temp monitoring or low temp reduce-offs can have damaging outcomes. Some prismatic cells are rated at a .5C load or 50% of the Ah rating at 25 Celsius / 77F but others are rated at 100% of capability or a 1C Load at 77F.
A “peak” very quick time period length at this voltage before a turnaround right into a excessive rate discharge is how this lab test was carried out. Over charging forces lithium oxide to form on the cathode. By causing an over charge you've now converted a number of the lithium iron phosphate to Lithium oxide and this isn't good. There is no reconversion or fixing this example and the cell is now irreversibly damaged and capacity has been diminished. Even slight over charging episodes can cause increases in inner resistance and trigger a lack of capability.