Cpap for extended wilderness camping?

I copied this from someones post on another thread.

"
Technical Notes:
- The Z1 (and Z2) are designed as 15VDC devices with a min voltage of 11.8VDC (before it shuts down) and a max voltage of 16.5VDC
- Max amperage = 2A
- Power uses a 2.1mm x 5.5mm plug
- The Z2 has the same specifications as the Z1, only the fan motor is quieter and the electronics were redesigned to incorporate improvements they have discovered. (For example, in the Z1 if the internal battery dies and the machine cannot store data, it throws a Fault 33 and shuts down the machine. In the improved Z2 design if that happens the machine continues working but just won't store data)
"

This tells me it should run 12vdc. I'm curious to know the real answer of 12v vs 15v.

I have a power supply that allows me to adjust the voltage. My Z2 Auto runs at 11.8vdc and any lower than that it will shut off after running for a minute. I tested from 16vdc down 12vdc and noticed the motor runs slower as you turn down the voltage which also decreases the pressure at the mask a little.

Also if you are running on 12vdc and using the Z Breathe exhale relief at a setting 3 there is quite a delay in response before the machine changes pressure. The motor is noticeably less responsive and slower at 12vdc. If you used the Z-Breathe at setting 3 than I think you would want to run the machine closer to 15vdc. When I set the Z-Breathe to a setting of 1 than the exhale relief response seems to stay the same no matter the voltage.

As far as noise goes I noticed differences depending on the Z-Breathe setting. 1 is the quietest, 2 is more whiny and 3 it starts to chirp along with the whine.

The post at this link below is somewhat outdated but may be helpful.

https://crateinc.com/cpap-in-the-outdoo ... Ad0zAPzCOo

I have used a 300 Ah LiFePo battery that weighs about 15lbs (not waterproof but the pelican case is) with some luck. I think my folding solar panel is 60 watts at 22.4% efficiency, monocrystalline. The manufacturer of all this Aspect Solar is long out of business.

There are some issues. One is the battery management system is broken (out of the box, all units ever made) and I haven’t had time to design another (a little beyond my skill set, but achievable).

This setup is great for car camping for two nights in very sunny locations. We are always rolling the dice on cloudy weather though. So it’s hard to call this a reliable situation. If you are in a car you can charge off of the cigarette adapter as you roll down the road, that helps a lot.

I use a Resmed Aircurve 10 BiPAP machine at 10/4.8 with (sometimes) a little heat on the hose and minimal humidity.

The really impressive thing about LiFePo is that there is zero parasitic drain. I literally came back to my battery after two years of pandemic etc and found that it was full! It also might perform more reliably in cold weather?

I hope that someone makes a travel BiPaP. I guess they consume too much energy or the market is too small? Anyone know why they aren’t available in travel size?

Thanks for the input on this subject. I have no idea on travel bilevel machines. The industry seems to always lag behind what some of us want. I did consider LiFePo4 batteries for a while. They are a good compromise between the light lithium batteries and lead acid batteries. Personally I'm going to give the lightweight LiPo batteries a try. Those are supposed to be more rugged and safer than other Lithium ion batteries. Cost is higher of course.

I've since learned that the cigarette lighter car adapter cord that they sell for the z1 & z2 is intended to charge the Power Shell battery pack not to run the machine. I should ask Breas directly about running the machine on a lower battery voltage.

Sustained vs cranking voltage?
I have always seen that in reference to amps.

chunkyfrog wrote: ↑

Tue May 03, 2022 10:11 pm

Sustained vs cranking voltage?
I have always seen that in reference to amps.

Yes amps is what you normally read about. Although when you have a load on a battery the voltage can drop some. Maybe that's what they are referring to. I think on vehicles the voltage can drop quite a bit when cranking the engine which is probably why they list those specifications. I've never checked that personally so not certain.

I noticed when monitoring the voltage going to my Z2 machine that the voltage would vary slightly with the difference in pressures from the exhale relief. The voltage would change slightly as the motor ramped up and down with each inhale and exhale. The amperage or current will also change with the speed of the motor.

Rob K wrote: ↑

Tue May 03, 2022 9:12 pm

I've since learned that the cigarette lighter car adapter cord that they sell for the z1 & z2 is intended to charge the battery pack not to run the machine. I should ask Breas directly about running the machine on a lower battery voltage.

I can definitively state the "car cord" will not charge the battery on my Z1. The battery is 15V, and something higher than 15 is needed to charge it. This is above what most automotive alternators will deliver. The car cord will run the CPAP for a while if the car battery is good.

stevenal wrote: ↑

Wed May 04, 2022 10:21 am

Rob K wrote: ↑

Tue May 03, 2022 9:12 pm

I've since learned that the cigarette lighter car adapter cord that they sell for the z1 & z2 is intended to charge the battery pack not to run the machine. I should ask Breas directly about running the machine on a lower battery voltage.

I can definitively state the "car cord" will not charge the battery on my Z1. The battery is 15V, and something higher than 15 is needed to charge it. This is above what most automotive alternators will deliver. The car cord will run the CPAP for a while if the car battery is good.

Thanks for pointing that out. I'm meant say the cord is to charge the Power Shell battery. I'll go back and edit that so people aren't confused.


The cigarette car adapter is made for charging the battery through the Power Shell not for running the machine. There's likely a 12v to 15v boost circuit in the Power Shell. This is the advertisement for the adapter that says it's intended use is for charging the battery:
"12V DC Adapter for Z1 & Z2

The DC Power Cord for Z1 / Z2 CPAP Machines is used to charge the Extended Life Battery Battery through the PowerShell with a 12 Volt battery source (cigarette lighter style plug) such as in a car. The peg end of the cord plugs into the PowerShell. The other end of the cord ends in a power/cigarette lighter outlet. This DC Power Cord can be used with a power outlet in a vehicle or a stand alone battery power source."

Here's the definitive answer on voltage requirements right from the manufacturer:


Hi ROB,
​
The Z2 unit will not run off of 12V DC. The unit needs to run off of 14.4-15V. Anything 30W + of power capability and 110V AC will run the unit. Please let me know if you have any further questions. Have a wonderful day and take care.

Best Regards,

Brandy Wright
Customer Support Specialist
Breas Medical, Inc

Rob K wrote: ↑

Wed May 04, 2022 4:00 pm

stevenal wrote: ↑

Wed May 04, 2022 10:21 am

Rob K wrote: ↑

Tue May 03, 2022 9:12 pm

I've since learned that the cigarette lighter car adapter cord that they sell for the z1 & z2 is intended to charge the battery pack not to run the machine. I should ask Breas directly about running the machine on a lower battery voltage.

I can definitively state the "car cord" will not charge the battery on my Z1. The battery is 15V, and something higher than 15 is needed to charge it. This is above what most automotive alternators will deliver. The car cord will run the CPAP for a while if the car battery is good.

Thanks for pointing that out. I'm meant say the cord is to charge the Power Shell battery. I'll go back and edit that so people aren't confused.


The cigarette car adapter is made for charging the battery through the Power Shell not for running the machine. There's likely a 12v to 15v boost circuit in the Power Shell. This is the advertisement for the adapter that says it's intended use is for charging the battery:
"12V DC Adapter for Z1 & Z2

The DC Power Cord for Z1 / Z2 CPAP Machines is used to charge the Extended Life Battery Battery through the PowerShell with a 12 Volt battery source (cigarette lighter style plug) such as in a car. The peg end of the cord plugs into the PowerShell. The other end of the cord ends in a power/cigarette lighter outlet. This DC Power Cord can be used with a power outlet in a vehicle or a stand alone battery power source."

I was speaking of the Power Shell battery. I even had my Power Shell upgraded to work with the new larger battery. It won't charge either the new or the old. It does run the Z1 if I remove it from the Power Shell.

It appears Breas no longer sells the 12v car adapter cable as an accessory but I see their cables or the equivalent for sale in a lot of places. There is a lot of conflicting information on what that cord is designed to do depending on who is selling it. Most places say that cord is used to charge the power shell battery. Some places say it's to charge the battery and run the machine. Breas customers service says the machine does not run on 12vdc, so why would they even have made the 12v cord to begin with. Pretty insane misinformation.

From what you describe it's just a cord to supply 12v to the machine to run it. Like you say 12v won't charge the battery, so if yours does not charge the battery than there obviously is no booster in the power shell.

I'll ask Breas and see what they say about that cord. They were being sold when the company was HDM. Part number HD60-6030. Breas is now telling me the machine does not run on 12v even though I know it will since I tested it.

Here's another response from Breas about the 12v car adapter cable and the Power Shell. They say the cables purpose is to charge the Power Shell battery. They didn't say if there was a 12v to 15v boost circuit in the Power Shell but they did say it will charge the battery with a 12v input to the power shell. Maybe the vehicle has to be running so you get a higher voltage from the alternator which charges the car battery at around 14vdc give or take. I just measured my two Jeeps. With the key turned to accessory there is only 11.7vdc a the cig socket on both vehicles, which is not enough to run the machine and possibly not going to charge the battery either. I know the machine will run for a minute before it shuts down at 11.7vdc. With the vehicle running there is 13.6vdc at the socket on one vehicle and 14.3vdc on the other one. It probably takes several hours to charge the battery from the car is my guess and my guess is the vehicle is supposed to be running.

"Hi Rob,
​
That DC Cable was only meant to charge the PowerShell battery. We no longer sell it because patients and distributors thought it was able to be used to run the Z1/Z2 as well and it cannot. That DC cable only puts out 12V which is enough to charge the powershell battery, but the Z1/Z2 units need 14.4-15V to run. We stopped selling it a couple of years ago partially because of that confusion. The PowerShell only needs 12V to charge the battery but its output is 15V.
​
Let me know if you have any further questions. Have a wonderful day and take care.

Best Regards,

Brandy Wright
Customer Support Specialist
Breas Medical, Inc

I got this 6ft hose that packs down to 10" to go with the Z2. It doesn't seem real sturdy but some people reviewing it said it lasted a number of years for them. It appears to be vinyl tubing with a spring inside and hard plastic ends. Cleaning it looks like a challenge so might have to replace it more often. I won't be using it a lot anyway so it should last a number of years for me.

So the new hose fits tightly on everything I own but not the Z2. It is loose and does not stay on the Z2 hose adapter or the muffler. The fittings on the Z2 are like a mm smaller than everything else. The new hose ends are hard plastic so they need an exact fit to whatever your connecting it to. I ended up having to put a few raps of clear tape around the Z2 fittings so the hose end snugged down tight. The hose needs to have rubber ends not hard plastic. On the bright side the machine is much quieter with this hose and I'm very happy about that. Should be able to run a higher pressure now with less noise and get more zzzzz's.

Edit: I've since tested the original 4ft hose which is the most noisy, a standard 6ft non heated hose which was quieter and the 6ft packable hose and it is the quietest of the three.

https://www.amazon.com/dp/B01B5DHJ5O?ps ... ct_details

Back to the 12v vs 15V question about the Z2 CPAP.

I was able to run my new Z2 from the cigarette port on a Renogy GP-14 battery for 2.5 nights. I measured the following at 7CM pressure:
Friday: 7 hours. Voltage 12.33. 19 watt-hours used
Saturday: 7 hours, voltage 11.93, used 20 watt-hours
Sunday: 4 hours until it quit running at 11.83 volts having used 13 watt-hours.
The pressure never felt quite right, and it is clear that the machine was not functioning perfectly.

So I charged up the GP-14 and tried running the Z2 from the DC-out 5.5mm port at 12 volts. Renogy tells me this is the recommended way to power a CPAP. However that conflicts with Breas saying the Z2 is not made to run on 12V. I went ahead and tried it anyway since I did not yet have a 15V USB-C PD trigger cable. I connected 5.5mm cable direct from the battery (Renogy GP-14) to the Z2. I was able to sleep 9 nights. 2 hours into night 10 the battery stopped delivering power. The Z2 consumed a bit less than 23 watt-hours per night on average. I slept 8 hours a night. Really not a bad experience but not the same as at 15V.

About the battery. The Renogy GP-14 is a 72000 amp-hour (266 watt-hour) battery pack. It can deliver "12 volts" through a cigarette lighter port. It has a separate regulated DC power port (a 5.5x2.1 mm plug) that can deliver 12, 16.5, 20 or 24 volts. It can deliver USC-C PD at 5,9,12,15 or 20 volts. It can also be used to power USB 5v devices like cell phones. See it at https://www.amazon.com/dp/B0791WDZTW

One of the GP-14 review images on Amazon is from someone running a Z2 at 12V from the DC port as I did.

It's too bad the Renogy's DC port can't deliver 15 volts as that would be the ideal way to power the Z2 CPAP from this battery (the Z2 would not turn on at 16.5V). It's a beast at 3+ pounds but it has the largest capacity of any of the backpack-suitable power packs I found. I would prefer to skip the cigarette lighter port and the Qi wireless charging. It also has a built-in flashlight which I don't need. Without these extras the package would be smaller and weigh less.

Next steps:

I now have a 15V USB-C PD trigger cable from jacobparts that seems popular with people on this forum. I am going to try it out with a different battery for a few days and then will see how many nights I can get from the GP-14 with USB-C PD at 15 volts.

The other battery I am trying next is a Nitecore NB2000 which is about a quarter the capacity of the Renogy. However is is super light -- 11 oz. Four NB2000s would be a bit more capacity than the GP-14 without the extra stuff I don't need.

I also need to evaluate solar charging. If I can get a solar panel to charge my battery I can carry a lighter battery but the solar panels are not light and I don't know if hanging it from my backpack will expose the panel to enough sun to recharge a night's power consumption in a day of hiking. Worried about hiking in the trees and rainy days.