I’m thinking on a way to put Vera on a backup battery - not UPS - but a battery that would plug into Vera instead of its own power supply. Any idea if there’s any suitable battery with right voltage and capacity on the market? Or some off the shelf or DIY solutions?
What’s wrong with a UPS. That sure is the easy way to go. You could build one but it wouldn’t look as nice. Being that Vera is 5 volt there’s no easy solution. If it were 12 volt you could hook it up to a motorcycle/car battery or rechargable lawn mower battery and have a small charger on it. I’m not sure you could find a 5 volt battery of a large enough size for an extended outage.
You could use a 12V battery with a voltage regulator to drop the voltage to 5V. Like reiserx i’d suggest a regular $50 UPS. It’ll run vera for a long time.
My purpose is to make Vera run 24-72 hours on battery, just like security panel and cable modem do. Both latter have a little battery, much smaller then the one in UPS.
There are few problems with UPS
- it doesn’t hold that long, even on my 1200W UPS. In contrast, a little battery in my cable modem holds 24h and more, UPS does barely few hours - it might to do something with the load - switching power supply
- they designed to handle an average PC load. My APC UPS often doesn’t notice something (Vera) is still connected to it and disconnects once PC hibernates
- it depends on Vera’s switching power supply. In this kind of hardware the least reliable link in the chain is these cheap power supplies
My 1200VA unit runs my cable modem, firewall and switch for more than 8 hours.
Did you try yours with only Vera to see how long it lasts?
Otherwise, get a spare car battery and a cheap 12V switchable output auto adaptor (walmart for about $5). Hard wire it to the battery and see how long it lasts.
Not sure if keeping car battery in the office is good for health
I’m thinking more towards the laptop batteries, or backup batteries used in residential security systems.
You can use any battery you want. But you have to solve two problems
a) get a regulator, so find out the voltage of the battery and get a regulator to convert that voltage to 5V DC
b) find a way to reliably charge the battery. Using a 12V car, marine or even lawn mower battery is easy as you can buy a cheap trickle charger to keep it charged 24/7. Finding a charger to charge a laptop battery might be tricky.
A sealed 12V battery won’t cause any problems being near people. I use one in my basement to power my sump during power failures.
My alarm system backup is 3x rechargeable NiCad AA batteries, I doubt this would last long on Vera.
If i recall NiMH batteries (AA, AAA, C, and D) are really 1.2v and not 1.5 like alkalines. So if you stick 4 of them in series you get 5v. Want more capacitay then stick groups of the 4 in series to gether in parellel.
If you poke around the internet you can find little 4 nimh holders with a USB port out- so it’s already prepackaged for you. i.Trek PDA Battery Extender (Pocket PC PDAs) - Power Solution
But you still have to figure out charging.
(here’s a battery pack with the 5v output that actually has the charger built in: i.Trek Pocket Power Bank (2-in-1 Battery Charger/Extender) - Power Solution)
I’d vote the ups route myself. But if you want to go all battery all the time then you could cobble together something like that.
I think the specs for Vera say it draws 6 watts of power. At 5V that’s 1.2amps
You will need a large battery to deliver 24 hours at 1.2 amps (approx 30 A/hr)
Elk sells a power supply/charger for alarm system http://www.elkproducts.com/products/elk-p624.htm it delivers 6V at 1.2 A (I believe there is a voltage “fine tuning” pot on the board - if not 2 diodes in series with the positive output will drop the voltage from 6V to 5V). I would measure the actual output of the vera supply - often they are higher than stated and use an internal regulator. This board is under $25. Altronix make a similar board AL624 but I don’t think it is adjustable - cost ~$15
The largest 6V battery Elk sells is 12A/hr which would provide 10 hours of backup. http://www.elkproducts.com/products/elk-06120.htm Battery is under $30. Other companies make similar batteries for a little less.
You would also need a transformer and some form of housing. Altronix TP1220 ~ $10
I use an APC HS500 (~$100) to backup my internet connection (for my alarm system - I have a standby generator so only need a minute or two of back-up). For Vera it would only provide you about 1 hour or so of backup but it has the added benefit of an ethernet connection and web interface and allows you to turn on or off any of the 3 outlets as well as see power draw - including a reboot option (power off then back on) for any outlet - COOL!
You are correct, you can read this post for some more details (there are also 1.6v batteries):
This is what I use with my Windows Home Server:
It might be overkill for a Vera, but it will definitely do the job. You can use it with sealed batteries, but I use a deep cycle battery that can be discharged and recharged a lot. I would not recommend a regular car battery since they are not meant to for this kind of use. Good Luck!