[Equipment] Battery backup

[AlanE]

Interesting idea. If you search for BOX-24-31 you can find battery boxes fairly cheap. They seem large enough to hold an AGM and a 'battery tender' device. Also Battery Tender has a 5-Watt solar panel with a controller built into it for around $60us. That should be good to recharge the battery.

[foss]

Hi AlanE,

I use a 5 watt solar panel to charge a battery I use to supply low power (QRP) amateur radio rigs. QRP is radio operation at 5 watts or less. A 5 watt panel is unlikely to keep up with the needs of an xPAP. Even without the humidifier or the hose heater turned on, it would require much more than 5 watts. It would charge the battery but probably too slowly to completely recharge the battery in one day's sunlight.

Jeff

[AlanE]

Amateur Extra here

The solar panel is not to keep up with xPAP since you have no sun at night. But in an extended power outage it would help charge the battery when you have no other option. I would just get a 100 watt panel. In fact I'm looking to get 3 to put on the roof for powering ham gear.

[foss]

Last night....

I ran off the 55 amp hour Powercell AGM battery for 9 hours and 15 minutes. The ResMed A10 Autosense settings were for auto humidity and auto for heated ClimateAir hose. About 2/3 of the water in the humidity tank was consumed. The air conditioner for my apartment was set to 75 degrees fahrenheit. The indicated pressure for the evening was 10.9, also set to auto. The beginning voltage on the battery was 13.25 and the voltage reading this morning was 12.75. Based upon the voltage readings, the battery could easily supply two nights or more of usage at the above Autosense settings. Without the humidity and hose heater turned on, it could easily operate the machine for several nights. I am using the ResMed DC converter that is designed to plug into the cigarette lighter in a car (or other 12 volt supply). The converter is very efficient at converting the voltage to the proper 24 volts required by the A10, much more efficient than an inverter (12 volts DC to 120 volts AC) and then using the ResMed 120 volt power supply. I am sure that makes a considerable difference. I have tried using inverters with my amateur radio equipment and get relatively poor battery life compared to 12 volts direct without the need to operate off 120 volts AC.

I will provide more information as I develop data. I hope to post an article in the Wiki as I have more data.

Thanks, Jeff

[parkerdt]

Great Stuff! Keep us updated as you learn more, please.

thanks!
Dave

Last night....

I ran off the 55 amp hour Powercell AGM battery for 9 hours and 15 minutes. The ResMed A10 Autosense settings were for auto humidity and auto for heated ClimateAir hose. About 2/3 of the water in the humidity tank was consumed. The air conditioner for my apartment was set to 75 degrees fahrenheit. The indicated pressure for the evening was 10.9, also set to auto. The beginning voltage on the battery was 13.25 and the voltage reading this morning was 12.75. Based upon the voltage readings, the battery could easily supply two nights or more of usage at the above Autosense settings. Without the humidity and hose heater turned on, it could easily operate the machine for several nights. I am using the ResMed DC converter that is designed to plug into the cigarette lighter in a car (or other 12 volt supply). The converter is very efficient at converting the voltage to the proper 24 volts required by the A10, much more efficient than an inverter (12 volts DC to 120 volts AC) and then using the ResMed 120 volt power supply. I am sure that makes a considerable difference. I have tried using inverters with my amateur radio equipment and get relatively poor battery life compared to 12 volts direct without the need to operate off 120 volts AC.

I will provide more information as I develop data. I hope to post an article in the Wiki as I have more data.

Thanks, Jeff

[PaulaO2]

So I need a minimum of 55ah. Probably aim for 100.

I'm having problems finding a way to recharge the battery after using it. Solar is good but only if you have enough panels and wattage. But if I only use a few volts, then maybe it won't need that much to get it back up to full.

And yes! I keep deep cycle AGM batteries for my ham gear, too. Extra ticket. I don't have an active shack right now but use HTs in the truck. I had it set up better then the OL wrecked it and I had to remove it all prior to it being repaired. Then she wrecked it again before I could get it all back in and I just never got up the nerve to finish.

[parkerdt]

I'm just not a do-it-yourself guy when it comes to electricity, and especially when it comes to important medical equipment. I hope one of our vendors, someday, will offer a plug and play battery/tender kit as has been discussed. I thin 100 Ah would be great, and I'd consider 200 Ah. Solar charging is not make or break for me as our house is quite shady. Being able to charge from a portable back-up generator without perfect regulation would be great. Unfortunately, I am, so far, a market of one.

Dave

[foss]

I am an extra class as well. I wasn't suggesting that a 5 watt charger would ever keep up with an xPAP machine. Someone had mentioned a 5 watt solar panel. I use a 5 watt panel with my QRP radios and it does well with backup batteries for night use. (A set of AA lithium batteries works well and charge easily from the 5 watt panel.) My NC40A only draws about 15 ma on receive and a little over 125 ma on transmit. My Elecraft K2 sn 155 needs a little more but not a lot.

I hope we meet on the bands some day,
73, de Jeff

[OMyMyOHellYes]

I have seen something in the radio world and I would think about doing something like this if ever I was in a situation where short term power failures were common:

1. Get a 13.8V (12V) power supply to hook to household 110 AC outlet
2. Get a Super PWRgate from West Mountain Radio
3. Get a battery (35, 55, 75, 100, heck even 200 AH if that's what your fancy runs towards.)
4. Resmed users only - get the Resmed DC power supply.

Hook all that up and run the xPAP from the PWRgate. It serves as a charger when the battery is not supplying power so it will always keep the battery topped off (don't know if its Al Gore Rhythm is as good as the Battery Tender's - might require investigation) . It switches to the power supply, which is fed from wall socket, when power is running and fails over to the battery when the wall socket power supply goes down. Being from West Mountain Radio, it uses PowerPole connectors. (YAY PowerPoles! PowerPoles - an addiction unto itself for folks that use 12V DC power.)

It would be a bit clunky, but it would accomplish what a lot of folks seem to want. Kind of a dedicated homebrew DC output UPS (avoiding that inverter waste) - one that is scalable for xPAP use. And you can put whatever size battery or bank of batteries needed to get you a full night of blissful, heated humidification.

Radioactive xPAPers know where to go looking for this. If anyone wants specific direction, PM me and I can send links.

OMMOHY

[parkerdt]

OK, say for a 100 AH battery:

How big a charger? Brief look online, and I don't see one with power poles output. Would like to make this as straightforward as possible... Guess us ResMed folks would also need a power poles to cigarette lighter adapter to plug the 12-24 V converter into. And it appears you would have some question about eh PWRgate as a long term trickle charger?

thanks!
Dave