04/22/2020 at 13:57 •
I compared AEM10941 to BQ25570 and it shows that AEM10941 is the best for solar.
For thermal I would choose BQ25570
02/10/2019 at 15:28 •
The low leakage AVX 10F 2.7V supercapacitor that I used was specified to have 30uA max leakage current, and that worried me because low power applications can have 20uA average current. Is my supercapacitor really so leaky?
I have tested 3 different supercapacitors. One is from the well known brand AVX and two others are brandless supercapacitors from Aliexpress.
After keeping the capacitors at a charged high voltage for 24 hours I simply measured voltage decay every day with a cheap multimeter and calculated i_leak=c[F]*(u_yesterday[V]-u_today[V])/t[s]
The tested supercapacitors
- AVX SCCT20B106PRB 10F 2.7V, specified to have 30uA at 72hrs
- Pixiuonline J469Y 1F 2.7V from Aliexpress
- ZHIPU CXHP series 1F 2.7V from Aliexpress, specified to have 8uA at 72hrs
And the result is put in this chart
Supercapacitor leakage current over days
- Interestingly the low leakage 10F AVX supercapacitor had a lower leakage than the 1F supercapacitors from aliexpress, while I expected larger leakage for larger supercapacitors. So it seems that the AVX is really low leakage.
- the leakage after 72hrs is below 1uA for all supercapacitors which is much lower than expected (30uA for the AVX and 8uA for one of the others). Apparently the max leakage in the datasheet is much higher than actual leakage. Maybe because it is specified at the full temperature range and I tested at 25 degrees.
- the leakage in the first 24hrs is much higher than after 72hrs but still less than 10uA for all supercapacitors
I conclude that my tested supercapacitors have a leakage current (1uA/72hrs) much lower than many low power applications
10/28/2018 at 14:33 •
10/22/2018 at 20:51 •
The batch of 50 arrived. They were assembled by Elecrow and shipped in Saturday. So it took 3 days for shipping!
10/21/2018 at 12:46 •
I created a test rig for AEMSUCA because this Monday evening I expect to receive the batch of 50 from Elecrow, China.
The way it works. The AEMSUCA is pushed between the diagonal 0.1" header pins to make electrical contact. Then 1.5V from the AA alkaline battery is applied to the solar input pins and the LEDs connected to the 3.3V and 1.8V outputs turn on when the circuit fully works. This tests all functionality of theboard except for the status output.
10/20/2018 at 14:22 •
For the HackadayPrize 2018 I designed a Tiny Solar Energy Module. It is cool because it can harvest enough energy from indoor light to power simple BLE or LoRa applications. I am selling two boards on Tinde for $24.90. One stores it's energy into a Li-ion battery, EAMLION, and the other stores it into a pair of supercapacitors, AEMSUCA. This is really cool because now you can make applications that runs forever from indoor light without a battery!
Tiny Solar Energy Module project on Hackaday.io https://hackaday.io/project/159139-tiny-solar-energy-module-tsem
AEMLION is sold on Tindie for $24.90 https://www.tindie.com/products/jaspersikken/solar-harvesting-into-li-ion-battery/
AEMSUCA is sold on Tndie for $24.90 https://www.tindie.com/products/jaspersikken/solar-harvesting-into-supercapacitors/
10/17/2018 at 19:20 •
I have built an AEMSUCA (solar harvesting into supercapacitors board) and two 2.7V/10F supercapacitors into this $12 BLE temperature humidity sensor and connected a 70x70mm 4V/100mA solar panel. I modified he AAA battery compartment to fit the supercapacitors. I have removed the internal 3.3V boost converter and powered the BLE device with the AEMSUCA 3.3V output directly. Finally I placed it all on a 3D printed wall mounted back plate.
Some time ago I have tested the battery charge current with this 70x70mm solar panel and found 280uA at 500 lux. Since this BLE temperature humidity sensor uses ~50uA on average I believe the application can be powered from indoor light even at 150 lux for 10 hours a day. It runs uninterrupted since Sept 26th 2018.
On my Android phone I have installed the Mijia Temp app to collects BLE advertisement sensor data. I love the app because it works well and it does not require acces to call log contacts, camera, and files on my phone like the official Xiaomi Mijia app.
I am going to sell the AEMSUCA on Tindie in a few weeks. Currently a batch of 50 is being produced at Elecrow in China.
Besides the AEMSUCA I have also created the AEMLION, it's almost the same board but it stores it's energy into a Li-Ion battery. I am selling AEMLION on Tindie.
09/30/2018 at 19:19 •
On Sept 18th I haved ordered 50x PCB assemblies from Elecrow and have shipped AEM01941 ICs using DHL to the assembler Elecrow in China for assembly of 50x AEMSUCA. The parcel is still on it's way to Elecrow. DHL track and trace did not give any update after Sept 19th, so I am a bit worried. I have asked support from DHL.
09/23/2018 at 11:34 •
In May/June I have designed the 1x1 inch Tiny Solar Energy Module to take part in the HackadayPrize2018 Power Harvesting challenge and won! And then I received a lot of interested in selling it. However since most projects have different power demands and people want to choose their own solar panel, I decided to remove the onboard solar cells and make two even tinier designs derived from the TSEM. They are both 0.8x0.6 inch small. The first is the AEMLION which is charging a Li-ion battery and the second is the AEMSUCA which charges a pair of supercapacitors.
09/22/2018 at 18:41 •
Today I have received AEMSUCA R2 PCBs and assembled one. It works as expected, I'm glad because I have already ordered 50 PCB assemblies from ELecrow which are currently in production.
I have connected two (link) 0F 2.7V supercapacitors from AVX. When supercapacitors voltage was high enough the 3.3V and 1.8V regulated outputs were enabled