DIY USB charger ready!

Math?
Because my Tempest is bricked after one winter?
Because i need externally charging to wake it up?
Compare values before and after?
Calculate what capacity would be needed for working here in the Alps?

But that doesn’t explain how you think the power booster won’t help. Furthermore, you take your experience with one device and jump to a conclusion.

i don’t think the your ‘empty’ battery period during winter would or could cause the battery to fail. ‘empty’ is a relative term, the unit might stop reporting, but the battery can hold power well below 2.3V. Perhaps something went wrong during your recharge trials. For sure currently the battery does discharge way too fast.

It was you who revealed the possibility to charge the device exactly in this post. The only difference instead of using an USB-Charger is to use a fully charged LiPo. If this could be the problem then i wait for the first one who connects directly to USB 5V, like you think it should work.

Your source for this information was not revealed i think?
Anyway i revoked my bricked device with this method. Thanks. And i posted this here, because i think that i cannot be the only one having this kind of quality issue…

i don’t know, but something went wrong, and yes it can accept up to 5V, but mine also connects using something like 4V, not 5V. You definitely have a problem, with the battery discharging way too fast.

i don’t know, but something went wrong, and yes it can accept up to 5V, (from weatherflow in personal message: " just supply it with around 3v (3v to 5v is fine)"), but mine also connects using something like 4V, not 5V. You definitely have a problem now, with the battery discharging way too fast.

my Plan B


Maybe there could be an option for 2500mAh depending on space.

that is my plan B. I have them already on order for some time. But currently there isn’t enough space to just swap them out. (but I’ll make some space :wink: )

One of the consequences of using LTO cells with the Tempest is the relatively large amount of capacity unavailable to the Tempest after it can’t function any more. I think this is one of the reasons it can take so long to wake a Tempest back up after it has been off line for a long time.

I’m not sure if it can’t function below 2.39. I think they just decided to stop the sensor and radio below 2.39 to safe power.

Best specs i found for now: LTO lithium titanate battery 18650 2.4V 1300mAh Discharge down to 1.8V. It must be the battery. More and more i think i received an outlier.

it might be the battery, or some other part of the unit is drawing too much power.

It can function down to about 2.32V. At least that is where I remember my first field test unit quitting at and it didn’t have any power saving mode at that stage of testing.

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my mistake, i should have said 2.32V. as I’m not convinced that the unit actually stops working completely below that voltage. It might, but I’m not sure.

Just for reference: I compared the voltage on the pins during perfect sunshine. I assume it is the charging voltage after the regulator, not the effective solar panel voltage. And it is a bit higher than the displayed battery voltage in Tempest portal.