UPS
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For those looking at a backup for pi only, I found this on AliExpress with (claimed) 2500mAh battery so it should get 4-5 hours on a pi 3. I buy one and will give a feedback, I have regular and long power cuts here and this should ensure continuity for at least logging all MySensors events.
If someone knows about a safe DIY circuit for li-ion or even better li-FePO4 (much safer) that I could use for smaller things like a GSM node or wifi gateway, please share !
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There is also this cheap solution https://www.aliexpress.com/item/6W-5V-UPS-mobile-power-Diy-Board-Charger-Step-up-DC-DC-Converter-Module-for-3/32790658678.html
There is also this cheap solution https://www.aliexpress.com/item/6W-5V-UPS-mobile-power-Diy-Board-Charger-Step-up-DC-DC-Converter-Module-for-3/32790658678.html
Thank you that can be useful for small nodes, I will buy one to test.
Not for Pi unfortunately as it's not powerful enough. -
my rpi3 usually uses 0.3A @5v with peaks of 0.6, I think it will be within 6W without problems
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actually it is just sitting there headless with a NRF24 connected to it. I checked consumption with relays and with 5 relays on the consumption goes from 0.3 to 0.6A. I have 8 relays but I guess there will not be many of them on at the same time for a prolonged time.
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Hi guys
I am using MySensors together with OpenHAB to protect my home and also for access control
To make more sense I decided that all security related sensors shall be powered via battery
To make even more sense I run my gateway and the box from an UPS. But...That UPS uses 220V AC to keep its 12V DC battery in shape. That's fine.
But when it goes off the grid it converts 12V DC to 220V AC back to 12V DC for box (which powers Raspberry via USB)Would it make sense to have a pack of LiIon batteries that supply directly the box via some DC-DC regulator? And have the LiIon cells charged/balanced via these boards found on eBay?
I imagine there would be a cut-off voltage unit that would protect the cells.
Your comments on this matter would be welcome.
As i am not able to design any electronics, best would be to use board found on eBay or similar...
Thanks a lot for reading and even more thanks for your input
See ya
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I'm using on of these
http://www.pimodulescart.com/shop/
I have LiFePO4 4000mAh battery pack - this is enough to weather the longest power outage
@alexsh1 thank you for the link.
I'll give a try to the AliExpress version first for financial reasons, but I'll check yours if the cheap one fails. -
@alexsh1 thank you for the link.
I'll give a try to the AliExpress version first for financial reasons, but I'll check yours if the cheap one fails. -
@alexsh1 thank you for the link.
I'll give a try to the AliExpress version first for financial reasons, but I'll check yours if the cheap one fails. -
@Nca78 keep in mind that the one I posted is missing battery protection, so you need to have put one (unless your batteries have internal protection)
@Nca78 keep in mind that the one I posted is missing battery protection, so you need to have put one (unless your batteries have internal protection)
Yes on the circuit you linked I'll put a 18650 with protection, I will test it on a wifi gateway.
For RPI I'll use the "hat" with battery that I linked in message above, only 17€ with battery. -
Guys
I am planning to use a 4S li-ion 18650 battery.
Please have a look at my Fritzing sketch :)
![0_1498133897687_IMG_5714[1].JPG](/assets/uploads/files/1498133920245-img_5714-1-resized.jpeg)
Battery pack will be monitored by this item :
http://www.ebay.com/itm/4S-6A-Li-ion-Lithium-Batterie-3-7v-18650-Charger-Battery-Protection-Board/382109076738?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649When off-grid ISDN box and RPi will be powered with that battery via this board :
http://www.ebay.com/itm/Automatic-Buck-Boost-Step-Up-Down-DC-DC-Power-Supply-Converter-Replace-XL6009/142371180585?ssPageName=STRK%3AMEBIDX%3AIT&var=441392018812&_trksid=p2057872.m2749.l2649When on-grid, this charger will charge the battery pack and power ISDN box/Rpi :
http://www.ebay.com/itm/EU-Plug-4S-16-8V-2A-AC-DC-Charger-Adapter-for-18650-Lithium-Li-ion-Battery-Cell-/262728544983?epid=507598255&hash=item3d2bd772d7:g:m6oAAOSwcLxYJaSFIs this the correct way of building my UPS ?
Can i draw current from the charger to power box and RPi while it is charging ?Thanks again for your input/advice.
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isn't it better to buy ready made solution ? e.g. http://www.powerwalker.com/index.php?page=select&lang=en&cat=dc
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isn't it better to buy ready made solution ? e.g. http://www.powerwalker.com/index.php?page=select&lang=en&cat=dc
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haha :) yeah, totally agree :P
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No DIY, no fun ! :wink:
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I didn't read all the comments, so forgive me if this was mentioned. What if you just used an SLA or AGM battery and connected a battery tender to it. The battery tender should keep the battery topped off without over charging it, and I would think have enough power to power the PI also. Then you are converting 220 down to 12, and if the power goes down, the battery tender will just shut off and the battery would take over. No extra loss in converting 12 to 220 and back to12 again.
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