this is why
Hi Folks, This is why Li batteries are not a good fit for me. https://weather.gc.ca/city/pages/sk-32_metric_e.html -40 on Wednesday night.
Forum Discussion
It is like a broken record around here.....
Let's do a quick apples to apples comparison between a $500 100Ah SiO2 Battery and a $500 100 Ah LiFePO4 battery..
The LiFePO4 battery is rated for 2500 cycles at 100% depth of discharge at 0.5C charge/discharge. Now go to the SiO2 spec sheet, in order to get 2500 cycle from the SiO2 the maximum depth of discharge is ~50%. So right there you have twice the 'usable capacity' from LiFePO4 relative to SiO2.
If you dig a little deeper (page 2 of the SiO2 spec sheet), the SiO2 only has a run time of ~60 minutes at 0.5C which would yield 50Ah. However, to meet the 2500 cycle lifetime, you don't want to go below 50% SOC, so that limits you to 25Ah from your 100Ah SiO2 battery.
Conclusion: LiFePO4 has 4x the 'usable capacity' SiO2 for the same lifespan for the same price.
The answer is about the same if you treat the SiO2 gently, let's limit the discharge to 0.1C and 50% DOD. In which case the SiO2 gives you ~2500 cycles, but still only yields 240 min run time to 50% DOD = 40Ah. In comparison at 50% DOD the LiFePO4 yields 13000 cycles - so 5x the 'usable lifetime'.
Conclusion: LiFePO4 has 5x the 'usable lifespan' of SiO2 under the same use scenario and price.
The thousands of dollars saved by using LiFePO4 over SiO2 would surely be plenty of money to pay for what ever upgrades are necessary to keep the LiFePO4 batteries warm.
Let's do a quick apples to apples comparison between a $500 100Ah SiO2 Battery and a $500 100 Ah LiFePO4 battery..
The LiFePO4 battery is rated for 2500 cycles at 100% depth of discharge at 0.5C charge/discharge. Now go to the SiO2 spec sheet, in order to get 2500 cycle from the SiO2 the maximum depth of discharge is ~50%. So right there you have twice the 'usable capacity' from LiFePO4 relative to SiO2.
If you dig a little deeper (page 2 of the SiO2 spec sheet), the SiO2 only has a run time of ~60 minutes at 0.5C which would yield 50Ah. However, to meet the 2500 cycle lifetime, you don't want to go below 50% SOC, so that limits you to 25Ah from your 100Ah SiO2 battery.
Conclusion: LiFePO4 has 4x the 'usable capacity' SiO2 for the same lifespan for the same price.
The answer is about the same if you treat the SiO2 gently, let's limit the discharge to 0.1C and 50% DOD. In which case the SiO2 gives you ~2500 cycles, but still only yields 240 min run time to 50% DOD = 40Ah. In comparison at 50% DOD the LiFePO4 yields 13000 cycles - so 5x the 'usable lifetime'.
Conclusion: LiFePO4 has 5x the 'usable lifespan' of SiO2 under the same use scenario and price.
The thousands of dollars saved by using LiFePO4 over SiO2 would surely be plenty of money to pay for what ever upgrades are necessary to keep the LiFePO4 batteries warm.