small lithium iron phosphate battery

DonF

Renogy is now offering a small 12.8v 300 Ah lithium iron phosphate battery with low temperature protection (https://www.renogy.com/core-mini-12-8v-300ah-lithium-iron-phosphate-battery-w-low-temperature-protection/).  We want to upgrade our 2022 T@B 400 100 Ah AGM batteries and the Renogy will fit in the compartment.  Does the physical size of the battery affect performance and capacity?  Thanks for any thoughts on this.

Horigan

Looks like the footprint is fine, so I would just confirm the height will fit.  The smaller size shouldn't effect performance or capacity.  If installed, you can remove the battery cover and associated vent line plumbing when going to LiFEPO4.

Note that my 2019 400 stock AGM battery was 235Ah.  I doubt the 2022 is only 100Ah.

pthomas745

There are a ton of these 300 ah batteries now.  Many owners have installed the 230 AH LiTime battery in the 400, so compare the measurements of this battery with a 300 ah battery.  Seems the 300 AH batteries are about 1.5 inches longer than this 230 AH LiTime.

https://www.amazon.com/Litime-LiFePO4-Battery-Lithium-Phosphate/dp/B0BYH8J176?crid=HCEDSBW0QQLH&dib=eyJ2IjoiMSJ9.78_Sm3J-8CIrERt40_HYjGJIp2o0RXk4fGd_By3mdcZqkO2kGDXySzgB3PXm_OvveP1z4yshTH2GQOdVThviuglDuzHsNBGOVpx1ns_E-alefuXp1Bo9mfkCFdYj-aEg0hozBWALsaNZWzU4kXtbTaydey5IMuw_lBtinaEVCm7kkwCE_NtLTeb765N80uPfwh5rymK3JHycy2pkkCjxG8sQGESLz8I7ai4FGvO4X6Y.zX4K30Xwxc3PhSgp0AN4BrSkHth_0kYwLCS2_ddOT_0&dib_tag=se&keywords=litime+230+ah+battery&qid=1730654156&sprefix=litime+230+ah,aps,150&sr=8-1&th=1

DonF

Rich - thanks for the clarification.  For some reason I thought the 6v AGMs in our 2022 were only 100 Ah but the Harris web page lists them at 224 Ah.  It seems like if I'm going to replace them I should go for the max Ah capacity that will fit in the compartment without modification.

pthomas745

@DonF your 225 amp hour AGM's are capable of providing "about" 50 percent of those 225 amp hours to get the most "cycles" from them.  That is a nice amount compared to smaller lead acid setups.  The single 200 amp hour lithium would provide "about" 190 amp hours, which is a major boost to your current lead acid capacity.

DonF

@pthomas745 - Thanks for the explanation!  I didn't consider cycles/depth of discharge and that apparently lithium for any given Ah rating can be discharged to a lower level without impacting longevity.

pthomas745

The "50 percent" number for a lead acid is designed to give you the most amp hours for each cycle, but to allow for an "optimum" number of cycles.  Only cycle to 30 percent will give you more cycles over time.  Cycling below 50 percent, or lower, will give you less cycles over time.  The life span of a lead acid battery is directly related to how the battery is cycled.  I managed to get my "first" battery to last for 5 years, but I have a pretty optimum parking spot here at home, and I paid close attention to the status. Keeping a lead acid battery alive for 3 years is...not too bad, especially with having to learn all this sort of thing on the fly. 

Lithium batteries have the same basic lifetime parameters.  But, since we get more amp hours to use for each cycle, in theory we would not be cycling so deeply compared to a lead acid battery.  So, lithium batteries can deliver many more cycles than a lead acid setup might be able to.  Chart below shows the various discharge levels and the "theoretical" number of cycles.  If: your 225 amp hour setup allowed you to use 112 amp hours to reach the 50 percent level, that would optimize the "lifetime" of a battery.  Note how the 40 to 60 "depth of discharge" for a lithium battery (the LIPO4 column) for a 230 amp hour battery.  50 percent of that lithium would allow somewhere between 1500-3000 cycles.  These lithiums will outlast us all!

Depth of Discharge	Discharge cycles
	NMC	LiPO4
100% DoD	~300	~600
80% DoD	~400	~900
60% DoD	~600	~1,500
40% DoD	~1,000	~3,000
20% DoD	~2,000	~9,000
10% DoD	~6,000	~15,000