My battery backup setup

[surferdude2]

OMyMyOHellYes, I'll be changing makes on my next purchase. This smacks of poor design. I also hear more complaints about the Aircurve 10 than the S9 ever had so it looks like they're slipping.

Dude

[Marthajoy7]

Thank you for the scope. Picture is worth more than 10,000 words. I appreciate your help as I am waiting for parts to arrive. I just remembered that a simple way to drop 5v to about 3.3 volts would be to stick a few diodes forward biased on the 5v line. If I remember correctly, each forward junction drops voltage 0.6 volts. current is small so even signal diodes would work. So if it looks as if I do need to get to ~ 3 volts, that 3 diodes might do the trick.
Can you tell me where in the circuit the scope measurements were taken?
Had a bit of confusion as to the scope scaling. Also horizontal time frame.

I have an idea of what the data stream is. When you go for a sleep study, they have a means of getting real time data recorded for the pulmonary doctor. My guess is that is comes off the power supply and some program is used to convert it into a graph. Would be nice to know they hook up for a sleep study, but probably of little help while one is sleeping. Or one Led would be about right. But when data stream was happening might blink a lot, but then maybe not as at 0.5ma I do not think there is enough current to turn one on.

[Perchas]

Welcome to the forum: ve7ltd, Marthajoy7, and Perchas

I found that using a single 47K between 24V and the center pin yielded exactly what I needed - about 1.8V on the startup.

I have run this setup on two machines, and used it for 6 nights hooked to a 250aH 12V battery in my trailer. Worked fine every time.

Great find, ve7ltd!

I will test the 47k ohm resistor scheme over the allowable input voltage range of the A10 on my three units.

Thanks, it's a pleasure to chat with you.

You can try test the 47k ohm resistor scheme down the allowable input voltage range of the A10 ?

Down to 12 V and testing.

[Marthajoy7]

Something else I just thought of that we need to test, especially with reducing voltage. Dies the air pressure remain the same. I understand that measuring is not hard. Basically, just water in a tube and see how many cm the water moves up the tube. tjink I need to see how much water is used as to me the weight of the water would factor into it. But should be able to test. Not good if the pressures cannot be counted on
ok. I found instructions on this site:

http://www.apneaboard.com/forums/Thread-...ew-dollars

I would like to make something that does not take up so much room. Use a couple of elbows so the tubes can be almost side by side, and maybe made so caps can be put on both ends, so the fluid can be stored in the tubing. PEX tubing should do fine and I have a crimper from having to work on our mobile home. I can see making something that would fit on 2 or 3 feet of 1x2 or 1x3.

[ve7ltd]

My Airsense S10 operates until the voltage drops below 20.3V, then it shuts down. It will not run at 12V. I did not try to exceed 24V. I did these tests with a variable voltage 28V power supply.

This was with a 47K resistor between the + of the power feed the sense pin. This drops the sense voltage to 1.71V @ 20V input. It will not power up again until the voltage exceeded 22.4V. This differential is likely to ensure that the unit does not cycle on and off continually on a dead battery.

Dave

[Marthajoy7]

Posted by ve7ltd - Today 08:53 PM
My Airsense S10 operates until the voltage drops below 20.3V, then it shuts down. It will not run at 12V. I did not try to exceed 24V. I did these tests with a variable voltage 28V power supply.

This was with a 47K resistor between the + of the power feed the sense pin. This drops the sense voltage to 1.71V @ 20V input. It will not power up again until the voltage exceeded 22.4V. This differential is likely to ensure that the unit does not cycle on and off continually on a dead battery.

Dave

...- . --... .-.. - -..

Wondering if power down was from sense line voltage dropping below threshold or just not enough power left. What I think they are saying; The sense line still in operating voltage because they are using a regulator in the sense circuit. Then lower the main power because this is the way Resmed's power supplies work.
I am really surprised that Resmed uses a regulator on every type of supply they make for just the sense line. I plan on hooking up a 5 volt regulator that sells for ~ $2 on ebay. I expect the resistance will be a little over 6 k ohms when tested. But it would function the same as Resmed's power supplies. But mine will have the ability to charge phones and other usb devices. Like my oximeter.

I believe what the other persons suggestion would have been a 12 volt supply with a 20K resistor to bring the sense line voltage back up.

Does that help?

He seems to be saying that there is a zener diode on the Motor circuit? That lowers the voltage for the motors to below that voltage, So if you are not running humidity or heated tube, You might get better efficiency by using just one battery. But that is why I am saying a pressure check should also be done if that works, just to make sure the motors have the same amount of power.

[Perchas]

My Airsense S10 operates until the voltage drops below 20.3V, then it shuts down. It will not run at 12V. I did not try to exceed 24V. I did these tests with a variable voltage 28V power supply.

This was with a 47K resistor between the + of the power feed the sense pin. This drops the sense voltage to 1.71V @ 20V input. It will not power up again until the voltage exceeded 22.4V. This differential is likely to ensure that the unit does not cycle on and off continually on a dead battery.

Dave

Thanks to Martha with the message telegraphy, I discovered who you are, the author of IRPL, congratulations.

I will send you an email with a link to YouTube, I was news for technological event in Discovery, Spain TV, TV Australia, etc. Twelve years ago ........

. .- ....- .- . -.-- --..-- / --... ...--

.

[Marthajoy7]

Thanks to Martha with the message telegraphy, I discovered who you are, the author of IRPL, congratulations.

I will send you an email with a link to YouTube, I was news for technological event in Discovery, Spain TV, TV Australia, etc. Twelve years ago ........SmileSmileSmile

. .- ....- .- . -.-- --..-- / --... ...-- ia4ax, / 73

Sorry, that is not me.
Just a now disabled old lady whom used to use amateur radio.
Have not used morse code in decades, but thought I could figure it out. Funny how I remember ancient things, but as forgetful on immediate events.

[sdb7802]

Ran tests successfully on my three A10s using Dave's 47k ohm resistor to 24 volts on the center pin. At 24 volts, the value can range between 31k and 55k. All machines work down to about 20 volts and require 22.3 volts to restart.

Also, ran tests successfully with 5 volts through a 6.8k ohm resistor on the center pin. At 5 volts, the resistor can range between 4.7k and 9.8k.

None of the machines will run on 12 volts with any of the center pin scenarios mentioned so far. I think the motor is designed for 24 volts nominal.

Thanks to Dave, Martha, and Perchas for some fresh good ideas!

[Marthajoy7]

Thank you so much. Taking the range of resistance that the device works finding the middle at 7225. Puts the closest common available resistance as 7.5k with 6.8k being next closest.
So it is coming together, using anderson gray power connectors on each battery when directly connecting to individual batteries, and XLR connectors when connecting to mobility devices for power.
pos and neg input wires from usb converter found on ebay for just over $2.
Will split usb output cable and tie - on converter output to neg lead.
Positive 5v goes to a 7.5k res and to center pin.
Positive 24 volts ties to 10 amp fuse positive input on usb converter and inner connector.
Negative 24v lead ties to negative input on usb connector, neg 5v usb output, and outer connector on 7.4mm connector

In regards to oscope display.
If I am reading the scope correctly? The sense line resting voltage seems to be almost 13volts.
During power up, your lable of 1.8volts to me looks like 6 volts on the scope. Also it looks like when data is going on it is almost going to ground. So almost 13 volts is being sunk through the 47k ohm resistor. Need to look at how much power is being dissipated by the resistor. Ok, power lost is low about 0.003 watts. Trying to think this out. Could just go with 47K off of 24v and just have converters for charging devices. I have been told that the data we are seeing is probably inner device communication. Different parts talking to each other. Have we looked at any of the data on the sd card while using in the 47k ohm mode to make sure sd card data is recording as normal?

What I do not know yet.. Is usb 5volt output negative the same as power input negative. Hopefully they are not isolated from each other.