Powering mote 24/7 using only a supercap and solar

[NeverDie]

I should point out that even without a boost converter, I'm getting good charging indoors in most locations. I've been investigating boost converters just in case I want a node that's virtually bulletproof with respect to charging from low light conditions, or which needs to power 3.3v or 5v sensors. For instance, the banggood PIR sensor on the other thread requires between 2.7v and 3.3v to power it. It uses so little current though that it should be possible to power it continuously from even a solar node, so I'll be attempting that fairly soon. Obviously, doing it outdoors is nothing new and would be a piece of cake by comparison.

[NeverDie]

@Nca78

Isn't there some place in Vietnam that stocks parts for re-sale so you don't have to order internationally and pay usurious shipping rates? Or is there just not enough demand to support that? Surely, China must have good options for you beyond just Aliexpress.

[Ed1500]

@Nca78 Wow. I guess you are a loyal Aliexpress customer :-)

[Ed1500]

@NeverDie Actually I had expected that for DigiKey Europe as well... but it says 'all shipping from USA'
Well, China also has Banggood ;-)

[gohan]

I ordered the 5.5v 4F ones, I hope they arrive sooner or later

[NeverDie]

@gohan said in Powering mote 24/7 using only a supercap and solar:

I ordered the 5.5v 4F ones, I hope they arrive sooner or later

That could be interesting. Do you have a link?

[NeverDie]

@Ed1500 said in Powering mote 24/7 using only a supercap and solar:

@NeverDie Actually I had expected that for DigiKey Europe as well... but it says 'all shipping from USA'

Well, Europe has a Mouser.com presence, I think. Plus, surely there's other stuff there, like in Germany or the UK or something.

[Ed1500]

@gohan seen those for 15 USD/10 and for 6USD/5

[gohan]

https://www.aliexpress.com/item/2Pcs-Ultra-Capacitor-5-5v4f-Super-Capacitor-H-Style-for-Promotion-Now-Lowest-Price/32772347560.html

[Nca78]

You are right @Ed1500, I receive so many shipments from AliExpress that now the postman is fed up with puting non-delivery notices in my mailbox, now he leaves the packages at the management office of my building, where they advance the tax for me when needed :)

@NeverDie yes I have some local shops, with very cheap delivery options, less than 1$ a;nd delivered the next day when they have stock. But unfortunately the inventory is pretty limited, I use them when the price difference is not worth the wait from AliExpress.

[Ed1500]

@gohan yes, saw those. please keep us informed abt yr experience with those

[Ed1500]

@NeverDie Oh dont worry, plenty of local online shops here for electronic components plus distributors for adafruit and similar.
However, I can order in china and have it delivered to my door often for less money than just the gas would cost me to drive to a local store, or to have it delivered from a local webstore.
The only thing is that sometimes I have to wait 2-3-4 weeks

[NeverDie]

These look quite inexpensive:
https://www.aliexpress.com/item/30-x-ultra-capacitor-2-7v3f/32570929215.html?spm=2114.10010108.1000023.15.qq5cZ7

[Ed1500]

@NeverDie indeed. but 2.7 Volt is a just a bit of a difficult value to work with and putting them in series makes the capacity drop, but I think one could run the attiny 13-25-45-85 from 1.8V so that might be a good combo

[NeverDie]

@Ed1500

Or, maybe this then:
https://www.aliexpress.com/item/Universal-Capacitors-Ultracapacitors-2-7V10F-super-capacitor-10F-2-7V-low-ESR-fast-charging-small-power/32688216790.html?spm=2114.10010108.1000013.4.G3WV1v&traffic_analysisId=recommend_2088_2_81019_new2&scm=1007.13339.81019.0&pvid=1ecf1af6-9158-4f9f-99ff-acaa16690ce2&tpp=1
It's just a wild card as to whether they actually perform according to the advertised specs, though. That's why I think it's helpful if we all share what we're actually using, and whether it meets expectations or not.

[NeverDie]

@Ed1500 said in Powering mote 24/7 using only a supercap and solar:

@NeverDie indeed. but 2.7 Volt is a just a bit of a difficult value to work with and putting them in series makes the capacity drop, but I think one could run the attiny 13-25-45-85 from 1.8V so that might be a good combo

Yeah, and the RFM69--which is what I use--runs as low as 1.8v as well, so it's possibly a good match.

[Ed1500]

@NeverDie 10F now we are talking. But yes I very well understood yr request to share experience. I acn only say thet the 1.5 F's i had performed well and with an RC network thrown together, they seemed in the right ballparc... but apparently seller now sells 1F and I cant vouch for those

The supercap is still a very viable alternative for smaller devices, so I will probably buy more in future and thus interested in which ones are good or not

[Ed1500]

@NeverDie ah yes it does, but the RFM is usually connected to a microcontroller :-) So that is limited choice
i wonder if 1.8 Volt would seriously affect the range of the RFM69 (running mine from 3.3)

[gohan]

Maybe a small booster to 3.3v could be used, since power efficiency shouldn't be a huge deal since the you will have the panel charging most of the time

[NeverDie]

@Ed1500 said in Powering mote 24/7 using only a supercap and solar:

@NeverDie ah yes it does, but the RFM is usually connected to a microcontroller :-) So that is limited choice
i wonder if 1.8 Volt would seriously affect the range of the RFM69 (running mine from 3.3)

Interestingly enough, the lower voltage doesn't seem to affect the range.

ATmega328p's can run at 1.8v also. In theory it should be set to run at 4mhz, but neither I nor anyone I know of has had problems running at 8Mhz down to 1.8v. If you run with BOD off and internal 8Mhz resonator, it only consumes about 150na while sleeping. That's why I haven't bothered going to ATtiny's. Maybe there are other reasons to do so though?