Bigger Battery Booster

Food for thought…
Not sure if the Tempest solar panels are different than the SPA panels, but early on I noticed that the SPA panels charged in a very wide range of conditions. Even to the point that they had a decent output voltage on full moon nights.
I’ll have to do more testing with my ‘dead’ SPA to double check…
–Sam

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when not connected to anything that draws power, it is much easier to get to a decent voltage, though getting a voltage from full moon, almost feels like a miracle device. It might be that the charging of the SPA panels draws less power.

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Decided to put in a pair of Eneloops while I wait for the LTO. I manage to fit them in without cutting plastic on the other side of the battery compartment. The tempest is a preproduction test unit charges at about 2.45v up to 2.58v

The voltage is holding well. Not sure what will happen when the Tempest tries to charge, I think the charge voltage will be too low to get any meaningful capacity? I got 1.3 years out of a set of Eneloops in a Sky, maybe my LTO battery will arrive before it starts charging.

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the charging circuit is build for the LTO battery. It stops charging at 2.8V, so, i don’t think this is a good solution, but it might work for the time being.

I just realized that what one could do is to get an extra of the original sized lto batteries and put it in parallel with the existing one. I didn’t check for space but it might work. Be careful when connecting the batteries in parallel because if there is a voltage difference there might be flowing a big current for a short while. Perhaps first level them out using a resistor to limit that current.

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Hi sunny,

Just saw that your test tempest ( with the bigger battery) went offline today.
amazing it was online for 44 days ( if i calculated correct)
Hope that Weatherflow read this, and adapt the casing for the bigger battery .
This bigger battery should cover all long winters .
Thinking of buying one for me now also
Thanks for testing

You are quicker than me. I was waiting for it to go offline. Amazingly it want all the way down to 2.11V The original tempest stopped at 2.32V. But I have to assume this is due to some firmware upgrade.
I’m going to convert my other tempest as well.

Hi Sunny,

This week i got my batteries for the tempest.

Installed the bigger battery today.

Thanks to your clear instructions in the forum, my tempest is now ready for long dark winters.

Regards

Karel

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@g.k.krijger great. Did you insert some foam to prevent the battery from rattling against the housing?
yes it lasted a whopping 44 days without direct sunlight, but I was hoping that it would have lasted more than 14 days before it hit 2.39 V (when the sampling rate of the wind is reduced).
Could you test yours by first fully charging it and then leave it inside and see how long it takes before it reaches 2.39V?

Hi sunny no i did not insert foam,

I cut away the original holder for the battery, bought a glue stick at the action shop

The bigger battery fits exact in this glue stick.
Removed the glue, clean the tube cut a part from it and with montage kit i glued the tube inside the tempest
drilled a hole at the bottom of this tube (to let moisture out if it ever goes inside)
And then screwed the tempest together again.
The bigger battery fits now tight and can not ratle.

I dont think i will charge it complete take it in and wait for the battery level to drop .
My tempest is connected to my Home Assistant, and i have automations which only work with input from the tempest

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what is you station ID so I can watch it charge/discharge?

Hi sunny,

Sure this is my Tempest

Sad news is that it didn’t charge very well at all. So this isn’t the solution. Could be a bad battery. I don’t know why it wouldn’t charge enough. Does it need slightly bigger solar panels? Someone else made the same change and that one still works perfectly.

How has your upgrade performed to date? I bet it’s working great!!

did you read my post just above yours??

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Hi , don’t know who is asking who ?

I can tell that my tempest is still working great,

Of course with dark times ,the battery level goes down, but mine is still online, and also charges
when there is direct sun ( slowly of course because the sun is not very strong)
Since days are getting longer again , i think my tempest will survive dark dutch winters with its bigger battery :wink:

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Sorry to hear that. Hope it gets resolved

I bought my wx station with indiegogo since the begining , buy i have noticed the wx station has started to go out of battery. I’m leaving in Central America and i have decided to look for answers about station battery endurance . My tempest went out of warranty i guess so I’ve decided to do Sunny procedure moreover I’ve bought exactly what Sunny have mentioned. Baterry from China and I’ve used a dremel to remove the battery bay from inside the station. If you need any info im glad to help.




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Wow!! Great project.

I don’t have the problem myself (live in Florida), but your solution was so cool and WELL documented I appreciate the entire process.

I was very quickly ready to recommend a remote-battery-pack and you squelched that with great reasoning!!

Thank you for the post

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