Looking for a 12 v dc "PowerPack" battery that produces A/C

[W. eWatson]

I have a Xantrex battery like the Subject description. It has a radio,
the A/C receptacles, and a small light. It is rated at 24 AH. I need
something like it for 36 AH. Anyone know where I can get one?

 

[W. eWatson]

Any room in the existing case? If so, put in a bigger battery.

Absolutely no way to do that.

 

[Winston]

Absolutely no way to do that.

Just add radio and light to the power socket
on this 50 AH pack:
http://www.xantrex.com/power-products/backup-power/xpower-powerpack-1500.aspx

--Winston <-- Mr. Helpful

 

[Winston]

On 2/19/2012 1:37 PM, Winston wrote:
(...)

Nice find. Heavy price. I think some years ago, CostCo was selling, maybe, some that might have been in the 30AH+ range
for much fewer $. I have the Xantrex HD 600. $160 or so. The big one might be useful for emergencies, but I only need
36AH for occasional car trips. Smaller size would be better than the 50AH. Health device usage in my case. Car batteries
won't hack it.

You could assemble the ingredients into a hard
shell rolling suitcase...

Perhaps it's time to update the health device instead?

For example, I set up a 100 AH battery for a friend's
12 V CPAP machine. It saved her the cost and hassle
of a hotel room during a recent power outage and will
run for several days between charges if necessary.

--Winston

 

[W. eWatson]

You could assemble the ingredients into a hard
shell rolling suitcase...

Perhaps it's time to update the health device instead?

For example, I set up a 100 AH battery for a friend's
12 V CPAP machine. It saved her the cost and hassle
of a hotel room during a recent power outage and will
run for several days between charges if necessary.

--Winston

The health device is a CPAP unit, and is as modern as is available. It
seems to consume 4 ah per hour. When I'm car camping, it's useful to
have the CPAP unit run longer than 6 hours. Same purpose here as your
friends. I have an inverter that I carry in my car, but I don't think
trying to run it off my car battery would be useful. When I get home
some weeks from now, I think I'll check with APRIA who makes the device
and see if they have some such device.

 

[Winston]

On 2/20/2012 1:23 AM, Winston wrote:
(...)

The health device is a CPAP unit, and is as modern as is available. It seems to consume 4 ah per hour.

Without the humidifier? That's a lot of current.

Her unit measures about 30W (2.25 A D.C.) without humidifier.
Her first unit required 120 VAC and was not nearly as efficient.

It is neat running straight off the battery with this latest unit.
It's a 'Philips System 1'.

When I'm car camping, it's useful to have the CPAP unit run longer
than 6 hours. Same purpose here as your friends. I have an
inverter that I carry in my car, but I don't think trying to run
it off my car battery would be useful.

I concur. An efficient 12 VDC unit and a separate >30 AH
deep cycle battery is what you want.

When I get home some weeks from now, I think I'll check with APRIA
who makes the device and see if they have some such device.

Doubtless they do.
Also suggest check freecycle.org.


--Winston

 

[Tom Biasi]

Nice find. Heavy price. I think some years ago, CostCo was selling,
maybe, some that might have been in the 30AH+ range for much fewer $. I
have the Xantrex HD 600. $160 or so. The big one might be useful for
emergencies, but I only need 36AH for occasional car trips. Smaller size
would be better than the 50AH. Health device usage in my case. Car
batteries won't hack it.

Did you check to see what your health insurance will pay?
Tell them you need more backup time where you are.

Tom

 

[W. eWatson]

....I have no humidifier. I'm largely guessing at the AH. I used the Xantrex
one evening, and woke up after about 5-6 hours and noticed I had 30%
power left. That seemed a little too close for comfort.

Without the humidifier? That's a lot of current.

Her unit measures about 30W (2.25 A D.C.) without humidifier.
Her first unit required 120 VAC and was not nearly as efficient.

It is neat running straight off the battery with this latest unit.
It's a 'Philips System 1'. Mine is a Philips RemStar.


I concur. An efficient 12 VDC unit and a separate >30 AH
deep cycle battery is what you want.

I did buy a big 12v dc battery a few weeks ago at Costco, but for other
purposes. I never got a chance to look at the AH. Slightly less the
$100.00. Pretty heavy. Must have been 40-50 pounds. I'm a long way from
home now.

 

[W. eWatson]

Did you check to see what your health insurance will pay?
Tell them you need more backup time where you are.

Tom

An interesting thought. I'll do that when I get home in a few weeks.

 

[Winston]

...
I have no humidifier. I'm largely guessing at the AH. I used the Xantrex one evening, and woke up after about 5-6 hours
and noticed I had 30% power left. That seemed a little too close for comfort.
Mine is a Philips RemStar.

It'd be interesting to put your ammeter in series
with the power supply and take a current reading.

I did buy a big 12v dc battery a few weeks ago at Costco, but for other purposes. I never got a chance to look at the
AH. Slightly less the $100.00. Pretty heavy. Must have been 40-50 pounds. I'm a long way from home now.

A regular car battery is good and a 'deep cycle' battery is
much better for this low current, long duration load.

I put her battery charger on a timer to prevent it from
boiling the electrolyte out of the battery. This one:
http://www.harborfreight.com/digital-timer-95205.html
It is excellent, if you tape the instruction sheet to
the unit because without it, you'll never figure out
how to program the thing! (Unless you download another
instruction sheet, that is.)
http://manuals.harborfreight.com/manuals/95000-95999/95205.pdf

I set it to charge the battery for a few hours as she
is sleeping and again for two hours after she leaves
for work. This keeps the charge topped up.

I only have to add water to the battery once every
month or so.


--Winston

 

[W. eWatson]

....

It'd be interesting to put your ammeter in series
with the power supply and take a current reading.

My ammeters and other testers are at home. Won't see them for weeks.
....

A regular car battery is good and a 'deep cycle' battery is
much better for this low current, long duration load.

I put her battery charger on a timer to prevent it from
boiling the electrolyte out of the battery. This one:
http://www.harborfreight.com/digital-timer-95205.html

Maybe I can find a store here in Tucson.

It is excellent, if you tape the instruction sheet to
the unit because without it, you'll never figure out
how to program the thing! (Unless you download another
instruction sheet, that is.)
http://manuals.harborfreight.com/manuals/95000-95999/95205.pdf

I set it to charge the battery for a few hours as she
is sleeping and again for two hours after she leaves
for work. This keeps the charge topped up.

I only have to add water to the battery once every
month or so.

For auto use, if there's still enough power in the car battery to start
it, then I would think recharging wouldn't be an issue.

 

[Winston]

W. eWatson wrote:

(...)

Maybe I can find a store here in Tucson. http://www.harborfreight.com/az/tucson.html

(...)

For auto use, if there's still enough power in the car battery to start it, then I would think recharging wouldn't be an
issue.

Sounds like a big 'IF'.

I would consider putting a battery isolator on the cigarette
lighter output, to drive your 24 AH pack.

http://en.wikipedia.org/wiki/Battery_isolator

That way, you are assured the car will start in the morning
and it will automatically recharge your 24 AH pack.

--Winston

 

[W. eWatson]

W. eWatson wrote:

(...)


Sounds like a big 'IF'.

I would consider putting a battery isolator on the cigarette
lighter output, to drive your 24 AH pack.

http://en.wikipedia.org/wiki/Battery_isolator

That way, you are assured the car will start in the morning
and it will automatically recharge your 24 AH pack.

--Winston

I found the device in HF today, but perhaps didn't understand how you
use it. Passed on it for the time being. HF is about 4 miles away. I
see it needs a power source. AC in the picture. How would this work in
an automobile?

Am I supposed to set for some specific time on short of losing all power
from the battery?

Where do I get an isolator? HF?

We are talking about running this off the auto battery and my inverter
aren't we?

 

[Winston]

W. eWatson wrote:

(...)

I found the device in HF today, but perhaps didn't understand how you use it. Passed on it for the time being. HF is
about 4 miles away. I see it needs a power source. AC in the picture. How would this work in an automobile?

Right you are. It would not work in an automotive
application. I don't know of any 'charge timers'
for D.C. use.

Am I supposed to set for some specific time on short of losing all power from the battery?

The proper isolator does that for you. No setting necessary.
There are simple switches called 'isolators'.
Those would not work nearly as well for you.

Where do I get an isolator? HF?

I don't see them for sale at HF but there are auto
accessory suppliers on the net that can sell you one.
I don't know if either of these would be the best possible unit
for your application but I cite them just as examples
of what I was talking about:
http://www.jcwhitney.com/powermaster-universal-battery-isolator/p3066072.jcwx?filterid=c926u0j2
http://www.jcwhitney.com/warn-universal-battery-isolator/p3073642.jcwx?filterid=c926u0j2

We are talking about running this off the auto battery and my inverter aren't we?

Ideally you would eliminate the inverter by connecting a
12 V CPAP to a separate battery, which would charge
from your auto electrical system.


--Winston

 

[W. eWatson]

W. eWatson wrote:

(...)


Right you are. It would not work in an automotive
application. I don't know of any 'charge timers'
for D.C. use.


The proper isolator does that for you. No setting necessary.
There are simple switches called 'isolators'.
Those would not work nearly as well for you.


I don't see them for sale at HF but there are auto
accessory suppliers on the net that can sell you one.
I don't know if either of these would be the best possible unit
for your application but I cite them just as examples
of what I was talking about:
http://www.jcwhitney.com/powermaster-universal-battery-isolator/p3066072.jcwx?filterid=c926u0j2

http://www.jcwhitney.com/warn-universal-battery-isolator/p3073642.jcwx?filterid=c926u0j2



Ideally you would eliminate the inverter by connecting a
12 V CPAP to a separate battery, which would charge
from your auto electrical system.


--Winston

I looked at the specs on the cpap. 5 amps! Found isolator at a local
automotive store, 70A. $42.00. How does this device stop short of
leaving enough power to start a car?

Batteries Plus,a chain, has some batteries I think will help. The have a
store about 40 miles from me. I think I'll finsh on this topic when I
get back home in about 3 weeks.

 

[Winston]

W. eWatson wrote:

(...)

I looked at the specs on the cpap. 5 amps!

That may include the humidifier.
When you get home, you can measure with an ammeter and be sure.

Found isolator at a local automotive store, 70A. $42.00. How does this device
stop short of leaving enough power to start a car?

IMHO, it doesn't. From the little I've read, the 'isolators' are
just two heavy duty diodes mounted on a heat sink. Current from
your alternator connects to the anodes and the cathodes connect
to each of your batteries respectively, preventing one battery
from discharging the other. It's simple and clever:

Diode 1
.---->|------------.
.--o |
| | Diode 2 o
| ---->|-----. ( Auto
.---|--. | ) Fuse
| o | | o
| | | |
| | | |
| | Car | | CPAP
'------' Batt--- --- Batt
Alternator - -
| | |
=== | |
GND === ===
GND GND

(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de

Batteries Plus,a chain, has some batteries I think will help. The have a store about 40 miles from me. I think I'll
finsh on this topic when I get back home in about 3 weeks.

Cool!

We pay more for ampere hours when they
are packaged in small (SLA) quantities as compared
to large (deep cycle battery) quantities....

Best of luck.


--Winston

 

[W. eWatson]

It allows you to charge a second battery, separate from the normal
car battery. They are usually just a pair of Schottky diodes. They
have to be able to handle more the the current rating of your
alternator.

I had a suspicion that a second battery might be used. Probably I would
want the smallest battery I can find that would provide several good kicks.

 

[W. eWatson]

W. eWatson wrote:

(...)


That may include the humidifier.
When you get home, you can measure with an ammeter and be sure.


IMHO, it doesn't. From the little I've read, the 'isolators' are
just two heavy duty diodes mounted on a heat sink. Current from
your alternator connects to the anodes and the cathodes connect
to each of your batteries respectively, preventing one battery
from discharging the other. It's simple and clever:

Diode 1
.---->|------------.
.--o |
| | Diode 2 o
| ---->|-----. ( Auto
.---|--. | ) Fuse
| o | | o
| | | |
| | | |
| | Car | | CPAP
'------' Batt--- --- Batt
Alternator - -
| | |
=== | |
GND === ===
GND GND

(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de



Cool!

We pay more for ampere hours when they
are packaged in small (SLA) quantities as compared
to large (deep cycle battery) quantities....

Best of luck.


--Winston

I think my Fluke meter measures amps. I don't have a humidifier. My one
at home experience with the Xantrex and the cpap suggested pretty
convicingly that 5 hours was about the limit.

 

[Winston]

W. eWatson wrote:

(...)

I had a suspicion that a second battery might be used. Probably I would want the smallest battery I can find that would
provide several good kicks.

That is a good - sized battery.
Your standard 100 AH trolling battery would be good for only
about two day's sleep at 5 A drain.

'Course, if you can manage to recharge it daily, Bob's your uncle.

I think you require a less-hungry CPAP, practically no matter
what you do next.

--Winston

 

[Winston]

W. eWatson wrote:

(...)

I think my Fluke meter measures amps. I don't have a humidifier. My one at home experience with the Xantrex and the cpap
suggested pretty convicingly that 5 hours was about the limit.

Practically speaking, that is probably close enough,
considering the negative effects of complete discharge.

As you mentioned, discharging the battery 70% in 5 hours
leads one to believe that we are looking at 14% discharge
per hour, or a total run time of about 7.1 hours before
the battery is totally flat.

(70% discharge / 5 hours = 14% hourly discharge rate)
and 1 / 14% = 7.14 hours total run time)

Your CPAP unit appears to be drawing about 3.36 A because:
24 AH / 7.14 hours = 3.36 A or about 41 W

Looked at another way, 3.36 A * 7.14 H = 24 AH

That is not *quite* as high as 5 A.

--Winston