Battery Back up for a CPAP machine

[Jack Crow]

All,.
If anybody is interested I have worked out a good way of doing this.
On the cheap.
I can make a sketch and some photography, then post that to the Flickr service. Might be a way to make a few bucks.

Share a thought.

Jack Crow.

[NxB]

Re: Battery Back up for a CPAP machine

Make a prototype and sell it.

[kc8adu]

Re: Battery Back up for a CPAP machine

many run from 12v already.just substitute battery for the power brick.did that for several neighbors when storms took us out for a week.cut the cord and installed powerpoles.
i have several big batteries to spare here so no problem helping these folks out.one has a ac only model.used a tiny inverter like for a laptop to get that one up and running.

[Jack Crow]

Re: Battery Back up for a CPAP machine

Guys,
SN 1 is on the desk right now.
Will need to document how it was done.
Mostly I used parts that were salvaged from 'dead' PC power sources. In this case the fast recovery rectifiers and their heat sink. The rest of it is not much more than fancy wire work.

Will make up a sketch and share out the particulars.

Be well
Jack Crow in Herndon VA

[Jack Crow]

Re: Battery Back up for a CPAP machine

Guys,
It works.
Got all the connectors on the thing.
Have it jacked into the vehicle battery.
It's working.

Here are some photos.

http://www.flickr.com/photos/9010884...th/6283804937/

Enjoy
Mike

[kc8adu]

Re: Battery Back up for a CPAP machine

crude ups.cool.were you able to adjust the bricks voltage for an ideal float voltage?

[Jack Crow]

Re: Battery Back up for a CPAP machine

KC8ADU
Crude, hell yes.
There is no adjustment for voltage.
Another good reason to use fast recovery rectifiers.
Low voltage drop.
With a car battery plenty of 'over head'.
All it has to do is work for a few years, then something better will come along.

Be well.
Jack Crow

[kc8adu]

Re: Battery Back up for a CPAP machine

i would still mod the psu or substitute one where i can set to around 13.8v.
another option is a cheap maintainer.
otherwise the battery will rot unless you top it off occasionally.
with the maintainer you can dump the resistor.it does nothing unless the voltage is 13.8 or so.

[hardwareguy]

Re: Battery Back up for a CPAP machine

My friend just plugged his into his SmartUPS. He sleeps next to his server rack...I have no clue how, that SOB is LOUD!

[Jack Crow]

Re: Battery Back up for a CPAP machine

H dude,

That is brilliant.

Every UPS I know starts to beep when the utility drops out.
With the blower working, must be hard to sleep through that racket.

Then again computer guys have different 'cues' than the rest of us.
My problem with being an analog geek.

Hope all is well.
Jack Crow

[Jack Crow]

Re: Battery Back up for a CPAP machine

i would still mod the psu or substitute one where i can set to around 13.8v.
another option is a cheap maintainer.
otherwise the battery will rot unless you top it off occasionally.
with the maintainer you can dump the resistor.it does nothing unless the voltage is 13.8 or so.

KD8,
Was thinking of a lamp timer where once a week it cuts off the charger during the daylight hours to give the unit some 'drain' time.

Don't want to use it often on battery because the humidify function won't run.
Found that to be a high speed path to head cold from hell.

Jack Crow