Sky Solar charger failed - again

Owners
,
#1

Am I the only person in England or elsewhere that doesn’t have sun most of the day?
Twice now the Solar charger on the Sky module has failed, the first time it was replace because of a bad design, water got in
This time who knows what’s going to happen, I’m waiting for support to get back to me

The solar panel is really small, it might be fine in places like California, Nevada etc that gets the sun most of the day but here in the UK from September/October onwards it’s mostly cloudy

It would seem logical that the solar panel is too small, while it might look aesthetically pleasing, it’s not much use if it only works in some locations

Why wasn’t there an option to have a larger solar charger?

Does anyone know the voltage of the solar panel, and / or the maximum input voltage to the charging circuitry?
If I get no help with this as it’s over a year old now I’ll either have to bin it and buy a reputable one from another manufacturer which would be a shame as I like this one
or I’ll have to add a larger solar panel myself

#2

or switch back to batteries, which lasts over 2 years when sampling wind only once every 15 seconds. (you need to remove the solar panels if you do so)

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#3

Yes that might have been ok
but
it never came with a battery holder only the tiny solar panel
also why should I when I specifically bought it to leave up unattended because it “never needed batteries changing”

#4

we are talking about the sky unit, right?, if you remove the solar unit by twisting it, isn’t there a battery door?

#5

The newer tempest has bigger solar panels, but also consumes a bit more energy, because all the sensors are inside one unit. It struggles to keep enough power in many places. Unfortunately, the tempest doesn’t have to possibility for adding batteries at all.

#6

As Sunny said, you have a sky uit and it can be fully battery powered without the solar panel attached (don’t insert batteries and add the solar panel, that will cause problems though)

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#7

Not that I’ve seen
And it’s on a pole at the bottom of the garden unreachable at the moment

#8

Why sell or even manufacturer something when it’s obvious that the solar panel needs to be bigger and it also needs a second battery inside in parallel with the first to eliminate all these issues

#9

What is the voltage range of the charging circuitry?
I’m going to have to pay someone to come and take this down and when it goes back up I don’t want to have to do this again.
I’ll add a larger solar panel myself

#10

just to be clear, you should NOT use the batteries inside in parallel. you have to choose between solar panel or batteries, not both. If you go for batteries, use the recommended ones. (see the picture in my last post in another thread Photos of Tempest and Installation

Why they sell it? I don’t know I guess because people in sunny areas are really happy with it.

#11

I can’t help you with that, but what I do know is that the 8 batteries inside are used as two sets of four batteries in parallel. Those sets are in series. So, if you remove the solar panel AND the batteries, and instead connect an external power source that delivers around 3V, it would be fine.
(it doesn’t have to be exactly 3V, with my fresh batteries I currently have 3.4V, but it probably works even fine at 2.7V)
If you make that external power source something with its own rechargeable batteries and solar panel, it should just work. (as long as the rechargeables work… many types stop working at low temperatures)

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#12

I do know that
I was an electronic engineer before I became disabled.
I’m quite capable of attaching a decent solar panel once I know the maximum voltage of the charger circuitry

#13

That I don’t know, but my suggestion was just to bypass it completely and add your own.

#14

It has been my personal experience that the seals fail on the device then water enters and shorts out the BMS mounted on the side of the battery. The solar panels have been fine.

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#15

One thing I have considered is attaching a larger external LiFePO4 cell in place of the one(s) in the SPA. I have had one of my SPAs die this winter due to not having a full view of the sky like the ones mounted on my roof. If the LiFePO4 cell had enough energy to power the SKY for 3-4 months then it should make it through the winter and recharge fine in the summer. The original SPA had a 1Ah cell and the newer ones have two cells in parallel but only 800mAh.

Due to the nature of most Li-ion type cells and LiFePO4 in particular, you can parallel them, regardless of relative capacity, and they play nice. I tested two 40Ah LiFePO4 cells, with one at about 30%SOC and the other at nearly 100%SOC, by connecting them in parallel and measured a momentary current spike of about 100A diminishing to the single digits within a few seconds. As long as the cell and wire can take it, you don’t have to worry about the SOC being identical when you parallel them. A single charge or discharge will bring them all in line.

If you don’t want to parallel cells you could just go with a single larger cell. I’m sure this one would power the SKY for quite some time: https://www.batteryspace.com/lifemnpo4-prismatic-module-3-2v-20ah-64wh-3c-rate---un38-3-passed.aspx though maybe you would only need a 5-6Ah cell.

EDIT: Here is a LiFePO4 cell which is supposed to handle extreme temperatures and is 2.5Ah cell. Get it with tabs and solder your wires to it and run them to the SPA in place of the existing cells or even in parallel with them.

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#16

That should be easy and take care of the issue. You could pot the entire thing and not worry about water damage.

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#17

I completely agree with you, this product is not for our region. I live in Luxembourg and there is not enough sun to make it work. I jave since years a Netatmo weather station. If you change twice a year the batteries you will never have an interruption in service.

#18

Note that this thread is about the first generation SKY and not the Tempest. The device discussed here is an optional power source for the SKY so it didn’t require batteries being installed.

The Tempest has a completely sealed battery compartment so the water ingress issue is no longer a factor. This is something learned from the SKY and the SPA being discussed here.

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#19

Hi @lewtesco,
As Sunny suggested. If you provide a 3V supply to the Sky it will work. My sky worked down to 1.8V and last voltage report was 1.78V when it failed. That was using Alkaline Energiser AA cells in the battery compartment. When I inserted new cells the voltage was 3.26V.
If you use the solar power accessory as your connection to the spring loaded gold terminals it is wise to include contact grease.
If I was providing a power circuit to the Sky I would solder to the terminals or wires.
I really like the Sky for several reasons and being able to choose the power supply to the Sky is a bonus compared to the Tempest.
And as Skys are no longer available there are people who would like to buy them second hand. Another advantage is their range is much further than a Tempest.
So dont be in a hurry to replace or to bin your Sky :slight_smile:
To help you plan your approach here are where you can see pictures of the Sky internals, and there are also pictures of the solar power Accessory in the forums:

cheers Ian :slight_smile:

#20

Thanks for the info and help everyone
Solar got removed over the weekend and batteries installed instead
I’ll work on a larger battery/solar cell over the next few months to install sometime next year when we have sun again
I do like the suggestions of larger battery capacities though, I was really shocked to discover the one installed is only 1000mAh