What’s the typical max voltage? My Tempest in central NJ charges up to 2.77V and stops there. Do others see 2.80V, 2.85V?
Really impressed at how quickly the unit picks up voltage after a few gloomy days.300W/m2 and wham, you see 0.20V added inside an hour.
The LTO cells shouldn’t really be changed over 2.8V. In fact, there is very little energy between 2.7V and 2.8V or even 2.6V and 2.8V. Just see how quickly the voltage drops from 2.8V and how slowly it drops after 2.6V by comparison. If your Tempest is charging to at least 2.6V, it is just fine.
Sure, to be clear, I am seeing no issues at all. I was just curious if 2.77V is the design target, as it seems to charge efficiently to exactly that level for mine. I also agree that the discharge from 2.77V to say 2.62V is 9 hours, and then it can run for 5+ days before going below 2.50V, so there’s an interesting discharge curve too.
Yes, 2.77V is normal. The discharge curve is similar to LiFePO4 cells, though LiFePO4 is at a higher voltage. The relatively flat middle portion of the discharge curve is a nice feature.
Nice! I looked that up, and it’s exactly what I am seeing in the field.
Im from the Delmarva Peninsula so not far from NJ. Like you, my voltage max is 2.77. I can go up to 3 days with complete overcast/mist before my voltage drops below 2.45. On a clear morning, it charges itself in just a couple hours before 10am. I have had my tempest station since September 2021 and though i have had a couple issues resolved since having the unit, i have yet had no issues with the battery voltage.