Help!!! I need for my CPap

[Jacksonricher]

Help
I am not an electrician, far from it and don't understand it at all. 

My CPap: I have been trying to use my CPap with a inverter plugged into the PowerPoint of my Ford e250. It goes fine for about four hours then shuts down the port because my starter battery is low (at least that's what I have been reading)

I need to run my CPap much longer to get good sleep and not worry about it.

I know, just get x amount of solar setup and I will be fine. Well I don't have the funds to do that, not for a month or two.


The transformer draws/pulls 12v ==5A. I am assuming it will pull 5 Amps from a battery per hour??? Am I correct?

The CPap machine it self says 12v =  6.75 A. 

I have to use the transformer the machine is labeled.

How do I make this work as temporary cheap as possible fix. Plus being able to add to it when I can go full setup.


Thank you
Jackson

 

[Jacksonricher]

The transformer:

 

[Jacksonricher]

A better pic of the transformer:

 

[Trebor English]

Does your CPAP do humidification with heat?  Turning that off will make it use less power and last longer.

 

[Jacksonricher]

I disconnected the humidifier.

 

[Trebor English]

You have an inverter that takes 12 volts and makes 120.  The power supply takes 120 volts and makes 12 volts.  At each step there are losses in the conversion, often 20%.  

It would be nice if you could just connect the CPAP to the battery avoiding the losses.  The problem is that the battery voltage varies from 12 volts (discharged) to 14.4 volts (charging).  Your CPAP machine documentation probably says it takes 12 volts plus or minus a half volt or a quarter volt.  It may just say 12 volts with no tolerance.  That's what's on the sticker in the first picture.  

Somebody might suggest a link to a device that would regulate and shut down before the battery is dead that avoids the double 20% loss.  That could increase your run time from 4 hours to 5.  Directly connecting the CPAP to the battery or cigarette lighter outlet is likely to kill the CPAP.  

Meanwhile, daily discharging your starter battery to the point where the inverter shuts off will lead to early death of the starter battery.  Plan on it.  Have jumper cables and someone you can call or a AAA membership.

 

[John61CT]

You need

1. A deep cycling battery bank

​The best battery value by far is Duracell (actually Deka/East Penn) FLA deep cycle golf cart batteries, 2x6V, around $200 per 200+AH pair from BatteriesPlus or Sam's Club


2. A way to charge them back up daily.

Solar is a good one.

Driving hours every day or running a genny is meh, bank won't last as long.

Plugging into shore power is best.

There is no cheaper shortcuts to these two above.


3. A 12V to 12V stabilizer may help you save the inefficiency of an inverter + transformer, but won't solve the bigger problem, marginal impact.

 

[Trebor English]

On Amazon I found a thing that might work.  It plugs in to a cigarette lighter and provides output at various voltages including 12.  It is only good for two amps.  Your CPAP could take 5 amps or 6.67 amps according to the stickers.  Without the humidifier it could be that 2 amps is enough.  Do you have a multimeter that you could use to measure what your CPAP uses?

https://www.amazon.com/CyberPower-CPUDC1U2000-Universal-Adapter-2000mA/dp/B00ELGA23E

It probably won't shut off with low voltage to protect your battery.

 

[Jacksonricher]

I will be buying a multimeter.
So should I be looking at buying:

✓Two 6v 200 amp hour batteries
OR
✓Two 6v 100 amp hour batteries

Then a charging source. I am thinking of buying a 100w portable panel I can put outside everyday. I have a high top and no idea if the top can carry a solar panel or two.

I know there is more equipment needed to do the job, just taking it one step at a time. My brain is sluggishy.

And will those TWO 6v batteries
be wired parallel or in series?

 

[Trebor English]

You can get good value with a pair of 6 volt golf cart batteries in series.  That will be about 200 to 220 amp hours.  Cheap ones will cost between $180 and $200 for a pair.  These should give good service life at low cost.

For about $100 you can get a 100 amp hour 12 volt marine battery from Walmart.  If the golf cart batteries are too expensive this should work.  Your CPAP may be at the limit for one of these.

A 100 watt portable panel won't be enough if your CPAP uses 5 amps 8 hours, 40 amp hours.  Without the humidifier, depending on your pressure setting, it might be enough to replace just what your CPAP uses.  

On Amazon search for "200 watt foldable solar" to see what they have.  It's about $270.  A 100 watt is about $150.  Rigid 100 watt panels are about $100.  

At Harbor Freight sometimes the multimeter is free with a coupon.  You should be looking in the $10 price range.  You will need to measure 12 to 20 volts and up to 10 amps DC and 120 volts AC.

 

[Jacksonricher]

Thank you Trebor. That gives me options for now. That way I can save and add or whatever I need. Right now I just need to get my Cpap running.

 

[Trebor English]

Thank you Trebor. That gives me options for now. That way I can save and add or whatever I need. Right now I just need to get my Cpap running.

Do you have any shore power plug in options?

 

[John61CT]

Again you need a proper deep cycling battery bank, nothing from Walmart will be as good as the Duracell FLA golf cart batteries, 2x6V in series gives you 200+AH for around $200 per pair

Buy from from BatteriesPlus or Sam's Club.

Also look locally for Trojan T-105, but will be a bit pricier.

Solar, need 200W minimum unless you drive a lot every day or have access to shore power.

Does either apply to your situation?

 

[Jacksonricher]

No shore power and I will not be driving everyday.

Thank you John

 

[Jacksonricher]

Ok, so I get the solar panels, get the batteries then what else besides wires will I need?

What's a low cost controller? Or whatever I need

I am making progress here, starting to understand for the first time this stuff thanks to you guys. I appreciate it very much.

 

[Jacksonricher]

I found this on Amazon and wondered if this will work plus the batteries. There is some mounting hardware and connectors also that I would buy shown here too.

https://www.amazon.com/Renogy-Monoc...ocphy=9031994&hvtargid=pla-318232541946&psc=1

 

[Jacksonricher]

The Battery:
John, Is this what I would need, two of these? I am getting lost in the amp hours part now( 215AH at 20 hour rate)

https://www.batteriesplus.com/produ...tcipucZ85I2n6hc9zpHiUDoJWDdS2HNQaAo4dEALw_wcB

Thank you

 

[DLTooley]

I draw less than one amp without a humidifier, a direct 12v connector cable will also help. I’ve never had issues with varying voltages.

Especially if you are not driving daily you will have issues with your starter battery. A single Walmart deep cycle will run your cpap. A 50 watt solar panel will do the job, but a 100 watt is better if you can afford it.

 

[John61CT]

The Battery:
John, Is this what I would need, two of these? I am getting lost in the amp hours part now( 215AH at 20 hour rate)

https://www.batteriesplus.com/produ...tcipucZ85I2n6hc9zpHiUDoJWDdS2HNQaAo4dEALw_wcB

Thank you

Yes there's also one slightly bigger, either will do, just make sure you get FLA not sealed for value and longevity.

Your cost $/AH/yr will be a small fraction of getting a 12V big box batt.

 

[tx2sturgis]

Because this is a medical device, and reliability is important, you might want to call your medical doctor or schedule an appointment with whoever provides care for your sleep apnea, and get a recommendation for, and/or a trial for, a portable battery-powered c-pap. 

Tell them you need a 'travel c-pap'. It might even be covered by your insurance.

There are many of them on the market, most use some sort of rechargeable battery, and some even have a solar panel option.