My battery backup setup

[rhodesengr]

Rating whr 468 {CAN SOMEBODY TELL ME WHAT "whr" MEANS?

watt-hours. Watts= amps times voltage. The formula is P=I*V

It is pretty much the same as Ah (ampere hours) times the voltage.
Note that if you take the capacity of 39 Ah and multiply by 12V, you get 12*39 volt-amp-hours= 468 Wh.

It means that in principle you can drive 468 watts for 1 hour or 46.8 watts for 10 hours, etc.

[bartbrn]

watt-hours. Watts= amps times voltage. The formula is P=I*V

It is pretty much the same as Ah (ampere hours) times the voltage.
Note that if you take the capacity of 39 Ah and multiply by 12V, you get 12*39 volt-amp-hours= 468 Wh.

Thanks, rhodesengr!

[bartbrn]

Sorry for the link -- didn't see it.

Bart

[Sleepster]

12V Respironics DC battery adapter cable Respironics (Philips) $39.99

ResMed AirSense 10 DC Converter (This DC Converter connects the AirSense 10 and AirCurve 10 to a 12V or 24V battery power source, including the battery used in a boat, car or recreational vehicle) $135

Maybe apples & oranges -- what do I know? -- but this seems to be the Resmed (and Apria) way of doing business.

I'm not trying to defend ResMed or Apria, but the adapter needed for ResMed is a more complex affair. The native voltage for the ResMed machines is 24 volts, so when using a 12 volt battery a conversion is needed, and that's what the adapter does.

The native voltage for Respironics machines is 12 volts, so when using a 12 volt battery no conversion is needed.

[PoolQ]

+1
As usual what may seem like the "best" deal may not be. "12V Respironics DC battery adapter cable Respironics (Philips) $39.99' this is basically a USB cable with fewer wires and different connectors on the ends. Check the price of a USB cable and then figure the profit for that at $39.99

At least the Resmed cable actually boosts the voltage from 12V to 24V which is a switching regulator with magnetics in a box and not just some wire.

But then CPAP's will never hit consumer product volumes and the battery adapter is way lower volume than the CPAP's. The cost is relative to volume to a large extent, and field trials (CPAP, masks, even the tubing), FDA application and processing, blah, blah, blah. Try and get a supplier to build 500 custom cables a year and see what they charge you. To the moon, Alice, to the moon.

[bartbrn]

Please check my post #37.

I got:

ResMed AirSense 10 DC Converter (This DC Converter connects the AirSense 10 and AirCurve 10 to a 12V or 24V battery power source, including the battery used in a boat, car or recreational vehicle)

for $84, and if you apply the coupon "HOLIDAY" at checkout, you get an additional 15% Off Sitewide (EXPIRES: 04/20/2016), for a final price (no tax and free shipping) of $71.40:

QTY PRODUCT HCPCS PRICE/EA TOTAL

1 AirSense™ 10 & AirCurve™ 10 Machine Series DC Power Converter with Cord $99.00 $99.00
Discount ($15.00) ($15.00)
Package: 37297 - DC Power Converter with Cord

Coupon Code: HOLIDAY: ($12.60)
Shipping: FREE Ground Shipping: $0.00
Sales Tax: $0.00

Total: $71.40

[Sleepster]

"12V Respironics DC battery adapter cable Respironics (Philips) $39.99' this is basically a USB cable with fewer wires and different connectors on the ends.

Not quite. There are surge protectors to help prevent damage to the CPAP machine. And a fuse in the other section that allows you to connect directly to battery terminals.

[stevewerth]

I don't get it...you could simply use an APC Pro 1500, 120 volt (1500VA) backup UPS...cost is about the same and no need to screw around with connectors, adapters etc...and it's all contained in one simple, sealed unit. Plug your units' power adapter into the UPS, which has surge protection built-in, and you're done.

They even have smaller ones for much less that would give you what you need...

Why bother building something which looks like a home-build, when for the same or less, you can buy a pre-fabricated unit with more technology built in?

No offence to those of you who have done it, I'm just sayin'...

I run a few of these to power my server rack and some computers @home, until my generator kicks in...

[Sleepster]

I don't get it...you could simply use an APC Pro 1500, 120 volt (1500VA) backup UPS...

You get a lot less battery life because the UPS inverts to AC and steps up the voltage, only to have the CPAP's power brick step down the voltage and rectify to DC. A lot of energy is wasted.

I use a UPS to get me through short outages, but if the grid ever does go down for an extended period of time I will have to pull the battery out of my car and use the cable to hook up to my spare Respironics machine. So far, in four years, I haven't had to do it yet. but I am prepared. Boy Scout motto, you know!

[rhodesengr]

I don't get it...you could simply use an APC Pro 1500, 120 volt (1500VA) backup UPS...

well its a good point. In fact sitting on my desk right now is a Cyber Power 1500 VA UPS for my PC.

The thing is though that some people want compact, lighter battery power. A 1500VA UPS is not that light or compact. Some folks want to run their CPAP while hiking or camping or similar situations where size and weight are more of an issue.