Please @rderr confirm the following according SOL modules:
They don’t have any intelligence.
They are not able to communicate.
The voltage measurements are done by the Sky (same circuit as used for Sky’s batteries compartment) and accordingly show the output of the SOL module not the battery voltage of the SOL included battery directly.
The solar panel charges the SOL’s battery as soon the light is strong enough (do you know how much light is needed?).
Charging the battery is independent from temperature (beside the physical conditions, means no active control).
Pleas tell a little on the battery performance in respect to temperature, especially at low and very low range.
Do you have any details on the physical conditions of the charging process at low temperature ?
history shows that wfstaff has at least some intelligence and communicate a lot. They are perfectly capable of measuring voltage of the batteries, and by using an external charger they can charge the batteries even when the light isn’t strong enough. Being highly active weather man they work under extreme physical conditions.
Sorry about the late reply, I was just notified of this thread.
They don’t have any intelligence.
There is a charge controller in the SPA that is responsible for setting the max charge rate and voltage on the battery in the SPA.
They are not able to communicate.
That’s correct. The sky has no way of communicating with the charge controller.
The voltage measurements are done by the Sky (same circuit as used for Sky’s batteries compartment) and accordingly show the output of the SOL module not the battery voltage of the SOL included battery directly.
The SKY is measuring the battery voltage of the SOL. The SOL module’s battery is connected directly to the SKY.
The solar panel charges the SOL’s battery as soon the light is strong enough (do you know how much light is needed?).
Correct.
I don’t have the numbers for how much light is needed.
Charging the battery is independent from temperature (beside the physical conditions, means no active control).
The charge controller is setup to prevent charging when the temperature drops below 0 °C (-32 °F).
The SPA uses a LiPoFe 4 chemistry which suffers from reduced capacity and higher internal resistance when exposed to low temperatures. The production SPA is struggling to hold a charge in areas with extended periods of very low temperatures. We are testing a solution for this now.
Can you please amplify a little more why the SOL doesn’t deliver energy when the battery is directly connected to the Sky in case of low temperatures.
It looks there must be some regulater logic in between.? What is he logic of this path?
There is no regulator between the battery and the Sky. There is logic between the solar panels and the battery which disables charging when the temperature drops below freezing.
If you mean is there a certain temperature when the battery won’t deliver power, yes but I don’t remember how cold it was. Several years ago Jack Rickard of EVTV.ME did a freeze test of a LiFePO4 cell and at some point it didn’t deliver any appreciable energy. It seems like it was well into the negative temperature range. The SKY has such a small energy demand I would expect that the LiFePO4 cell could supply energy down to at least -40 degrees but I haven’t tested it or seen a test of it. I suppose I could put a unit in my Wife’s freeze dryer and see how low the temperature gets before the SKY stops reporting.
@WFstaff any issues if I were to take a SKY + AIR and freeze them below -40 degrees?
