Battery Backups - Car Battery Jumpers?

[CollegeGirl]

That's strange - I thought I responded to more of you but those posts aren't showing up. So I'll just sum up - thank you all so much for the wonderful information. I'm making note of all of it in case this doesn't go as I expect. I'll be testing the car battery jumper I purchased with the built-in DC outlets BEFORE the hurricane gets here so I have time to run out and pick up something else (I hope) if it doesn't work. I appreciate all your responses!

[-tim]

Deep cycle batteries are used for solar storage systems and boat trolling motors. I've bought deep cycle batteries at a wal-mart that had a big fishing section.

Many people buy car batteries with a higher "cold cranking amps" of 400, or 900 or 1200. That is useless for cpap or inverter user.

If you are going to get a car battery, get one that fits your car. It could come in handy and you have a charger that can charge it real fast if you need to.

You an also use truck batteries.

The S9 power pack sends a signal to the s9 saying what kind of power it uses. If you just hook up a 24V supply, the humidifier may not work so verify that in other threads before buying stuff.

[sylvie]

That's strange - I thought I responded to more of you but those posts aren't showing up. So I'll just sum up - thank you all so much for the wonderful information. I'm making note of all of it in case this doesn't go as I expect. I'll be testing the car battery jumper I purchased with the built-in DC outlets BEFORE the hurricane gets here so I have time to run out and pick up something else (I hope) if it doesn't work. I appreciate all your responses!

I'm right in the storm's path and I want to go out and get this car battery today. Can you get it at Wal Mart, or where can you get it? I probably should wait until you report back and tell us if it worked?

[archangle]

I called my (awesome!) DME today to talk about finally purchasing a battery pack for my CPAP, and the person I spoke with actually told me that, rather than spend my money on one of those, that I could purchase a car battery jumper pack (If you don't know what I mean, something like this: http://www.sears.com/shc/s/p_10153_12605_SPM5985129508P) instead. I know there have been conversations throughout the years here about various things we could use instead of the cpap battery packs, but I don't remember these being mentioned. The person I spoke with said someone she worked with there had tried it during a storm outage and it worked perfectly, and that it also lasted longer than a cpap battery pack would.

Has anyone tried this? Also, they seem to come at various "amps" - there's 450 amp, 500 amp, and 900 amp versions. Does anyone know which I'd need?

Thanks!

We need to know what CPAP machine you have. Please list it in your profile. There's a link in my signature line.

You need the correct cable for your CPAP to run off of DC.

If it's a ResMed S9 or Philips PRS1, you can run it off of an inverter that makes 120 VAC from 12VDC. Don't use an inverter for an S8 machine unless you remove the humidifier.

"Amps" on a jumper battery doesn't matter for a CPAP machine. More "Amps" doesn't mean it will be better for CPAP. What you need to know is "Amp Hours." Many manufacturers don't list that number or hide it from you.

That Sears battery you have a link for is 14 Amp Hours. The jumper battery might run your CPAP a night or two.

[archangle]

Ugh:
To run an S9 on batteries, you'll need either an inverter, a 24-volt battery, or two 12-volt batteries in series.

There is no reason to use two batteries.

The only way to run an S9 from DC is with the expensive ResMed DC-DC converter. (or with an inverter to make 120VAC). It will run off of 12V or off of 24V.

The S9 power connectors are not available separately. There is a third wired in the connector in addition to the 24V supply connector. No one has figured out what the wire is or hooked up DC without the DC-DC converter. At least, I haven't seen posts from anyone who's successfully done without the ResMed converter.

• ...
• You CAN use a car battery in an emergency, but completely discharging this type of battery will damage it.
• The BEST battery to use is a true Deep Cycle battery for Wind/Solar use. These are extremely expensive, but won't be damaged by being totally discharged.
• The Cheapest compromise battery to use is a Marine Hybrid battery. These are a cross between a car battery and a deep-cycle battery.

A "True" deep cycle battery for wind/solar use is no better than a marine "Deep Cycle" battery other than not being spillable.

"True" deep cycle batteries for wind/solar use WILL be damaged by full discharge. Solar/wind battery systems use "charge controllers" that shut down the system before the battery is discharged too deeply.

Car batteries and marine "starting" batteries are damaged if the battery is discharged deeply. Each cycle does a little harm.

Marine "hybrid," "charging/starting," "Charging/trolling," or "dual purpose," batteries are less susceptible to damage from deep discharge, but will still be damaged.

Marine "Deep cycle" or "trolling" batteries are even less susceptible to damage from deep discharge, but still are damaged to some degree. This is true for "True" deep cycle wind/solar batteries.

If you're buying a marine battery for CPAP use, a "Deep Cycle" or "Trolling" battery is better than a "hybrid" marine battery. It's probably not any more expensive.

There's no black and white difference between a deep cycle and starting battery. It's a difference of degree in terms of the "sponginess" of the lead plates.

The more expensive sealed deep cycle batteries are usually high quality, and can't be spilled.

[archangle]

Thanks Sloop! So glad to know someone else has already done this! I think with the built-in DC outlets on this thing I don't need a VDC cord... one less thing to worry about. I'll be sure to post here if it works. Hope it will!

???? How do you plan to hook your CPAP to the battery? The cord he's talking about is what goes between the battery pack and your CPAP. Do you already have a DC power cord for your CPAP?

Or do you mean you have a jumper battery with AC outlets? Got a model number or picture? The coupon code would be nice, too.

[CollegeGirl]

Ack, you're right! I do mean AC outlet! This is the one I bought: http://www.sears.com/diehard-platinum-p ... ockType=G1

The charger was already on sale (only a few bucks off, but hey), and the coupon code I used was OCTSAVE. It saved me an additional $15. Even at a little over $100, it's still much cheaper than an official cpap battery pack and will last longer, I think. I can't imagine it won't work with the AC outlets right on it.

[123.Shawn T.W.]

By using the AC outlets built into the jump pack you are using an invertor to change the dc power stored in the battery to AC, then your power brick is changing it back to dc power ... It will consume power to make these changes ... So if you can avoid all the changing/converting your battery pack will last longer, as invertors are not efficient.

If I were you ... I'd take your cpap and jump pack to Radio Shack and buy the cord and little adapter to make them fit ... Try it out at the store, as in turn on cpap. If you have a dc outlet on the jump pack (cig ligher) the cord should cost you less than $20. I just bought one for use in my semi truck ...

[Vince Waldon]

2X... you're losing at least 25% of your power in both directions... so getting something in the neighbourhood of half the battery's energy at the end of the day. If it's a short power outage no problem.. if it's a longer one you may want some of that power back.

[archangle]

Ack, you're right! I do mean AC outlet! This is the one I bought: http://www.sears.com/diehard-platinum-p ... ockType=G1

The charger was already on sale (only a few bucks off, but hey), and the coupon code I used was OCTSAVE. It saved me an additional $15. Even at a little over $100, it's still much cheaper than an official cpap battery pack and will last longer, I think. I can't imagine it won't work with the AC outlets right on it.

That looks like a pretty good unit. I think that's the one Gumby uses all the time, but he hooks up via DC. If so, he has used it a while and has had no problems.

You should get at least a night or two of CPAP, especially with no humidifier.

Its AC output might damage the humidifier on an S8 or M series CPAP. (I see you don't have a humidifier yourself, but I'm warning others.) It might damage older Respironics humidifiers as well. S9 or PRS1 machines and humidifiers are probably OK on the AC output.

I might have to look into getting one of those jumper things myself.

[archangle]

2X... you're losing at least 25% of your power in both directions... so getting something in the neighbourhood of half the battery's energy at the end of the day. If it's a short power outage no problem.. if it's a longer one you may want some of that power back.

You may be a little overly pessimistic on the losses, but there will be some losses.

If I were you ... I'd take your cpap and jump pack to Radio Shack and buy the cord and little adapter to make them fit ... Try it out at the store, as in turn on cpap. If you have a dc outlet on the jump pack (cig ligher) the cord should cost you less than $20. I just bought one for use in my semi truck ...

The Radio Shack adapters have a little plug adapter that allows you to switch the plus and minus leads. If you get it backwards, you will probably damage the CPAP.

It's an excellent idea as long as you don't get the voltage reversed.

[CollegeGirl]

Okay, so what I'm looking for from Radio Shack is a converter to give my CPAP the ability to plug into the DC outlet (the one that's like the cigarette lighter outlets in the car.) Is that right? Then once I've got that, how do I make sure I don't get it reversed and damage the cpap? Sorry you guys... I'm dumb about this stuff. :p

[archangle]

Okay, so what I'm looking for from Radio Shack is a converter to give my CPAP the ability to plug into the DC outlet (the one that's like the cigarette lighter outlets in the car.) Is that right? Then once I've got that, how do I make sure I don't get it reversed and damage the cpap? Sorry you guys... I'm dumb about this stuff. :p

I wouldn't call it a "converter." That word sort of implies some sort of electronics.

It's just some connectors, a cable and a fuse. I'd call it an "adapter."

I'm a little reluctant to recommend it to you in particular, given your "dumb about this stuff" comment.

However, the info is here: viewtopic.php?f=1&t=83346&p=756194#p756194 It's not really that hard, but don't plug it in unless you're sure you've got it right.

You might want to go ahead and buy the official Respironics cable from our host here: https://www.cpap.com/productpage/respir ... -cord.html Just use the AC outlets this time, because you probably won't the the Respironics adapter in time.

[CollegeGirl]

Okay, I'll just use the AC outlet and see what happens. Hopefully I can find somewhere to charge it during the day if I need to.

[DiverCTHunter]

First off, let me just warn that I'm not an Electronics Engineer, nor do I play one on the Internet. This is from the research I did while trying to design my own UPS-zilla. A lot of this comes from various HAM and Solar / Wind forums.

There is no reason to use two batteries.

The only way to run an S9 from DC is with the expensive ResMed DC-DC converter. (or with an inverter to make 120VAC). It will run off of 12V or off of 24V.

The S9 power connectors are not available separately. There is a third wired in the connector in addition to the 24V supply connector. No one has figured out what the wire is or hooked up DC without the DC-DC converter. At least, I haven't seen posts from anyone who's successfully done without the ResMed converter.

From our host's page on the S9 DC-DC converter: "This converter also allows for use of the H5i humidifier and ClimateLine heated tubing with the S9 CPAP machines while on 12V or 24V DC power." [emphasis added]

Looking at the size of the DC-DC brick, I suspect it contains both a step-up transformer and a decoupling transformer / voltage limiter circuit. It does have the warning about connecting while the engine, so they may only be compensating for the fact that a fully charged lead-acid battery is 1.5 - 2.2 volts over it's operating voltage.

If you use 12VDC input instead of 24VDC input, the converter will have to run a step-up transformer in front of the voltage limiter circuit, which will drop the converter efficiency by anything from 12% to 25% depending on the design and components. Total runtime will reduce by a similar amount. By using 24VDC at the input, you SHOULD get virtually the entire runtime of the battery bank.

A "True" deep cycle battery for wind/solar use is no better than a marine "Deep Cycle" battery other than not being spillable.

"True" deep cycle batteries for wind/solar use WILL be damaged by full discharge. Solar/wind battery systems use "charge controllers" that shut down the system before the battery is discharged too deeply.

Car batteries and marine "starting" batteries are damaged if the battery is discharged deeply. Each cycle does a little harm.

Marine "hybrid," "charging/starting," "Charging/trolling," or "dual purpose," batteries are less susceptible to damage from deep discharge, but will still be damaged.

Marine "Deep cycle" or "trolling" batteries are even less susceptible to damage from deep discharge, but still are damaged to some degree. This is true for "True" deep cycle wind/solar batteries.

If you're buying a marine battery for CPAP use, a "Deep Cycle" or "Trolling" battery is better than a "hybrid" marine battery. It's probably not any more expensive.

There's no black and white difference between a deep cycle and starting battery. It's a difference of degree in terms of the "sponginess" of the lead plates.

The more expensive sealed deep cycle batteries are usually high quality, and can't be spilled.

This is where the marketing twits at the battery companies make things overly complicated. There are various ways of manufacturing the lead and lead oxide plates depending on the expected peak and average amp draw. On top of that, the style of electrolyte also contributes to battery longevity.

I was defining a "true" deep cycle battery as a solid-plate, flooded lead-acid battery with some type of separator membrane to prevent the lead sulfate crystals that form during discharge from creating shorts between plates. These are the $300+ whoppers that can handle the uneven charge/discharge cycles that a renewable energy system produces. All of the marine deep cycle batteries I found were the thicker lead "sponge" style.