So Dave, would the SOK Battery 206Ah 12v LiFePO4 Battery Solar Battery be an equivalent swap-out for a Lifeline GPL-8DA 12 V 255 AH Battery?
This is a little confusing (and intimidating) for the non-initiated . . Bill Coleman Entrada, Erie, PA From: Dreuge via CnC-List [mailto:cnc-list@cnc-list.com] Sent: Thursday, May 26, 2022 3:24 PM To: cnc-list@cnc-list.com Cc: Dreuge Subject: Stus-List Re: Batteries again Dave, As I mentioned in previously replies to the list, it no longer makes any sense to buy lead acid batteries(i.e. flooded, gel, or AGM) for a house bank. For lead acid, the AH capacity is highly dependent on the current load due to the Peukert Effect. Deep cycle lead acid batteries are rated at C/20. For a 100AH rated battery, this is 100AH/20H = 5A. This is often called the 20H rate, i.e. 5A * 20H = 100AH. If the actual load is 20A, then the same 100AH rated lead acid battery would only provide 60AH (or 10AH at 100A). And worse, one should only use 50% of a lead acid battery’s capacity as going below 50% substantially degrades the battery lifetime. This means that a 100AH lead acid battery has an effective 50AH @ 5A (or 30AH @ 20A). Let’s assume a 100AH lead acid battery price of $264 (the average of the Amazon prices), then 2 batteries would cost one $528 and one would get an effective 100AH (50%*200AH) at 5A loads. Now, the price of LiFePO4 batteries have come way down in the last few years and their performance and lifetimes are a magnitude better. A 100AH LiFePO4 battery is typically rated at 1C. That is they can deliver 100AH at 100A for 1H(or 5A at 20H or 20A at 5H). They can also charge at amps up to 100A which is impossible for a lead acid battery. And LiFePO4 batteries live 5 times longer. That is, one would expect to replace 5 sets of lead acid batteries before replacing a LiFePO4 battery. Yes, LiFePO4 batteries are more complex as they require a battery management system (i.e. BMS), but there are companies which provide 12V drop in replacements with the BMS built internal to the battery. Top companies like Battle Born sell a 100AH LiFePO4 for $874 and provide a 10yr warranty. Renogy sells a 100AH LiFePO4 for $765. A company, CurrentConnected.com, sells a SOK 100AH LiFePO4 battery for $569 and it has a 10 yr warranty! YouTuber Will Prowse rates the SOK as the best value LiFePO4 12V drop in replacement (see https://www.mobile-solarpower.com/lithium-batteries.html). There are a plethora of cheaper 100AH LiFePO4 batteries that can be found on Amazon, Ebay, AliExpres, …, but one gets little service and limited warrantees, so I would recommend avoiding these. Rather than buying 2 100AH lead acid batteries for $528 at a total weight of 140lbs(70lbs each) , one could just buy 1 100AH LiFePO4 for $569 weighing only 28lbs and get a better performing battery. That is basically the same price. If one takes into account the increased lifetime, the saving is HUGE! If one builds their own DIY LiFePO4 battery, the savings is much much greater. Last year I replaced 2 100AH lead acid batteries with one DIY 560AH LiFePO4 battery for a little over $900 (see my blog link below). The DIY LiFePO4 battery occupies the same location and physical space as the previous 2 lead acid batteries, it weighs much less (95 lbs vs 125 lbs), but has 5 TIMES the capacity. I recently gave a talk on off-grid solar systems a local amateur radio society meeting. The discuss the battery as the heart of the system and make the case for LiFePO4 batteries. My slides from the talk are available on my blog: https://svjohannarose.blogspot.com/2021/10/solar-off-grid-system.html Also, the details of my DIY 560AH LiFePO4 are posted at the link below which includes details about alternator charging. https://svjohannarose.blogspot.com/2021/06/adding-new-lifepo4-to-house-battery.html
