Bubba on batteries :P

[msx]

just out of curiosity, has anyone tried to run bubba on a battery? For example one of those inside the cars?
i'm sure that would be a very funny way to void the warranty

[John W]

Haha. A was thinking about it too, just a couple of hours ago!

It doesn't draw much power, just about 1A. So you could probably run your Bubba for two days on a 55Ah car-battery.

But you will need to build a circuit that cuts the power if the voltage drops too much. Because i don't think the hardware will work so good if it gets under 12v.

// John W

[johannes]

Interesting ideas!
The specs are 12V +/- 10% (that is 10,9 - 13,2V), since the 12V power goes directly to the disk. Thus, you need to regulate the voltage somehow, since car batteries can have voltages over 14V if I'm correct?

Bubbas electronics will work fine between 8-15V, so the disk is limiting. Maybe there already are UPS:es with 12V output (for emergency lamps and such) that would work? Probably much cheaper and slimmer than regular 110/230V UPS'es. If anyone finds any, please let me know!

[zmannen]

You can go to any ordinary accessory shop for cars and find a suitable regulator. Just checking Clas Ohlsson in Sweden http://www.clasohlson.se/Product/Product.aspx?id=383374 this is one that would do the job for under 10 Euro.
Good luck
janne

[johannes]

Thanks for the tip!

However, make sure to read the regulators spec. before using it in critical applications. It probably doesn't cut power when voltage drops too low, this will most likely crash the disk and may corrupt your file system etc.. My guess is that it only regulates downwards, it looks too cheap to do something else. But I might be wrong.

[zmannen]

One simple way is to use a mechanical relay with a selfholding button, I'm sure you know how to do that, and when the voltage drops the holding current for the relay will become to low and the relay will fall. If you have the power supply for the Bubba via the relay everything will stop until reactivated by the selfholding button.

A more semicoductorlike approach would be to use a Zener diode and a transistor controlling the relay rather than the "inaccurate" holding current I mentioned above.

janne

[Kermit]

Use a DC-DC regulator with a 1A 12V fast fuse on the input.

I can't tell if the clasohlsson one is any good, but if you should do this then you probably already know how to solder on togheter your self. Using only a zener is ok if you know that the source is current limited but it's not the case.

Connecting the bubba directly from the battery is a big no-no. A battery is not currrent limited. A 1A fuse will easy pass through 10A current for some seconds to burn your bubba and will easy make it a nice blue box that smell a bit burnt. In a car you also have big transients from the generator that will most certently mess your bubba up without a DC-DC regulator.

Martin

[johannes]

A 1A Fast fuse won't work either since disks sink around 2.5-3A during spin-up. The bottom line is that you need a 12V +/-10% Voltage, with a transient supply capacity of around 3A and a sustainable capacity of 1A. That's why a think a off-the-shelf 12V UPS would be great, if available. Any tips?

[zmannen]

Well in this case the zenerfunction is only to create a trip point for the relay. It is Not connected to the battery of course!!

janne

[lkbrow1]

I bought a power supply a couple of years ago for a simular purpose.
It is made by LIND Electronics. Inc in Minneapolis MN USA. It puts
out 12 volts at 2.5 amps. One end plugs in a cigarette lighter.

[dacc]

Would something like this work, connected to a battery?

http://www.powerstream.com/12V-backup.htm

I'm trying to create a solar powered Bubba, and have little experience with electronics. I think I need to trickle charge something like a car battery, and then use something like the above to power the Bubba.

Questions:

• Will I be able to bypass the DC -> AC -> DC conversion that would be required for me to use Bubba's provided power supply?
• I'm using an SSD drive, and so I suspect power consumption will be much lower than with a mechanical drive. Does that mean sustained power might be under 1 amp? If something claims that the low end of its range is 3amps, does that mean that 3 amps of current will be "consumed" regardless of the power requirements of the device?

Thanks!

- Daniel in Seattle

[mcg]

dacc, I was looking at this *exact* page. It seems to me that the 3A model should be sufficient. I wanted to connect the Bubba to a UPS, and this seems like the most sensible way to go about it. If anyone else has any thoughts I would definitely like to hear them.

[mcg]

I actually have a 12V UPS in my garage---it is used to power my fiber-to-the-home (FTTH) transceiver. Here's another page that advertises something like that:
http://www.provantage.com/cybersheild-d ... 092274.htm

[mcg]

OK, sorry for three posts in a row, but I really think I'm onto something here.

Here's the manufacturer's web site, with an entire list of "FTTx Telecom" power supplies:
http://www.cyberpowersystems.com/produc ... pment.html
Each has different voltage and power ratings.

The key question is what is the true peak power requirements of the Bubba? Their base unit, the CS24U12V, is rated for 24 Watts, which certainly seems like enough. But the power supply we would be replacing is rated for 3A (if I understand correctly), so by that measurement we'd need something larger.

Also, what if we sought to power both a Bubba Two and a Bubba Storage together: what's the total combined power draw we'd need to support for those?

[mcg]

Another idea: the Belkin Residential Gateway Battery Backup: 12V, 30W
http://www.belkin.com/IWCatProductPage. ... _Id=355124
Seems kind of pricey when new, but I've seen some used ones out there.