CPAP Charging off grid

[zimdavid]

I have a 2021 Transend 240 ML trailer with a factory installed 100 w Furrion panel, 25 A MPPT charge solar controller. Does this just charge the tongue battery? Can I use this to run 2 Capp machines while off grid

[Country Campers]

I have a 2021 Transend 240 ML trailer with a factory installed 100 w Furrion panel, 25 A MPPT charge solar controller. Does this just charge the tongue battery? Can I use this to run 2 Capp machines while off grid

Yes that system will only charge the tongue battery , the only battery for the RV unless you have added a second battery. I am not sure if the dealer installed battery , usually a general deep cycle battery , will run the 2 CPAPP machines over night , this will be determined by the amperage draw of the CPAPP machines. Also have you confirmed that the solar system and charger are actually charging the battery? The reason I ask is because some have found that their dealer did not wire the charge controller to the battery circuit.

Brian

[howson]

I have a 2021 Transend 240 ML trailer with a factory installed 100 w Furrion panel, 25 A MPPT charge solar controller. Does this just charge the tongue battery? Can I use this to run 2 Capp machines while off grid

Hi zimdavid. I noted this was your first post, so please check out the Welcome Letter to New Members https://gdrvowners.com/forum/main-fo...to-new-members when you get a chance.

To your question: yes, the solar panel's purpose is to charge the battery. That's the primary purpose for any solar setup! (There are minor exceptions but not important at this point.)

When it comes to running the CPAP machines, the answer is "it depends". How much power does the CPAP draw over the course of 8 hours? What type of battery (or batteries) is in your trailer?

Your 240ML has a 12V refrigerator, right? Keeping the battery bank at a sufficient charge to maintain the refrigerator is, IMHO, priority #1. I suspect that even with the solar panel you'll need a supplementary way to recharge the battery if off-grid for any length of time.

There's a ton more to discuss, but it depends on how deep you want to go with this topic. If you want more information, feel free to ask more questions.

Howard

[zimdavid]

Thanks I'll check on your comments and questions tomorrow.

[Yoda]

I have a 2021 Transend 240 ML trailer with a factory installed 100 w Furrion panel, 25 A MPPT charge solar controller. Does this just charge the tongue battery? Can I use this to run 2 Capp machines while off grid

You will need 2 battery's . I run 2 CPAP's off of the 12v system using the 12v power cords that you can get from your CPAP supplier. Even with my 2-12V deep cycle battery's and my 160W solar I will pull the battery's down to about 70 to 75% charge overnight and running nothing else, With your fridge in the picture its going to be iffy, You might need a generator to help charge the system back up in the day.

I did a write up on how I wired in my CPAP power. Use the search feature here.

Hope this helps

[zimdavid]

CPAP is a Resmed Air Sense 10 24V 3.74 A

Trailer battery is a Interstate Marine 24M-XHD CCA 800, MCA 1000 RC 135

[howson]

CPAP is a Resmed Air Sense 10 24V 3.74 A

Trailer battery is a Interstate Marine 24M-XHD CCA 800, MCA 1000 RC 135

From scanning the User Guide for that model CPAP at https://www.resmed.com/us/dam/docume...e_amer_eng.pdf it appears your machines will only run off a 120vAC to 24vDC converter. Your trailer does not have an inverter (a device that changes DC to AC) so you won't be able to use these machines "off grid" without modifications to your trailer.

Even if your trailer had an inverter, the 53W typical consumption of each CPAP means that each one (if it could run off of 12v) would consume power at a rate of ~4.5 amps per hour (aH). (53W divided by 12v = 4.5 amps). Two of these machines = 9aH. I can't tell the aH capacity of your battery, but since you'll be consuming ~72aH over 8 hours with two machines running...there's no doubt more battery power is required. As a comparison, a top-of-the-line Battle Born LifePO4 battery has 100aH. 100% of it's charge is useable, so even one of those would be 3/4 consumed in 8 hours. We haven't even factored in the refrigerator or furnace yet!

Perhaps others here, like Yoda , can share their first-hand experience with trailer-friendly (12vDC) CPAP machines. And consider upgrading your batteries. TucsonJim has an excellent primer here: https://gdrvowners.com/forum/operati...ithium-battery

Howard

[Yoda]

CPAP is a Resmed Air Sense 10 24V 3.74 A

Trailer battery is a Interstate Marine 24M-XHD CCA 800, MCA 1000 RC 135

Every CPAP made can be operated off of a 12V power plug. You just needs the adapter

https://www.1800cpap.com/resmed-s9-s...verter-24v-90w

https://www.amazon.com/Replacement-C...ag=googhydr-20

https://www.amazon.com/Resmed-37297-.../dp/B0721T72ML

https://www.directhomemedical.com/re...ower-cord.html

https://www.thecpapshop.com/dc-power...ense-10-series

https://www.cpapxchange.com/dc-power...ne-resmed.html



Give your supply house a call - they will have one, Ask for a DC to DC adapter power cord that plugs into a 12V power point - (think old cigarette lighter) 12V power port.

Hope this helps - Keith

[howson]

Every CPAP made can be operated off of a 12V power plug. You just needs the adapter

Thanks, Keith--obviously I'm not very knowledgeable about these CPAPs. The OP should be aware that regardless of the voltage source, according to the manual the typical consumption is 57 watts (which doesn't change just because a different adapter is used) so your input that more batteries are needed is accurate.

[Yoda]

Thanks, Keith--obviously I'm not very knowledgeable about these CPAPs. The OP should be aware that regardless of the voltage source, according to the manual the typical consumption is 57 watts (which doesn't change just because a different adapter is used) so your input that more batteries are needed is accurate.

I have been through about 4 differant brands in my life so far. They are all power hungry -especially if the heater function is turned on.

zimdavid There is another possible option. Some brands offer a separate portable battery bag. They are very pricey If I remember correctly. It has a Lithium battery, fast charger and cables - but for the price you could easily get 2 more battery's. There are some neat battery trays for the front of your trailer with from 2 to 4 battery capacity. With the pass through under your bed it would be simple to wire in a couple of power point plugs.

Here is my install on my 5th wheel - yours would be simpler. https://gdrvowners.com/forum/operati...wer-in-bedroom

Hope this helps

[Brian S]

I have an older ResMed S9 CPAP machine. The power cord contains a 120 volt to 24 volt power supply. I have plugged mine into a watt meter and it draws just under 20 watts even with the Humidifier on. I will be getting the newer AirSense 10 unit for this season, but ResMed is not able to give me any operating wattage on it. My plan is to change my current 12 volt deep cycle battery to two 6 volt golf cart batteries in series. I will also install a 1000 watt inverter in the front pass through and run a 120 volt outlet to the bedside. I am thinking the batteries should last at least the whole night, if not several depending on water pump and lights usage. If need be, I will get a portable 100 watt solar panel and charge controller for my batteries.

Any thoughts or ideas on this plan? Math is not my strong suit and I am trying to figure my total Ahr draw. The 6 volt batteries are 235 Ahr each, so i am assuming i will have about 115 to 117 Ahrs if i take them down to 50 %?

[howson]

Brian S

A constant 20W drain (20 watts per hour) will consume about ~2 amp hours (aH) from the batteries (20W/12V). Over a typical 10 hour period that's ~20aH. That does not account for power drawn from the batteries for the furnace, refrigerator, and any other 12v appliance that's going to drain power.

So it looks like (on paper) that the 6V golf cart battery setup will work just fine, but run those 6v batteries to depletion due to an oversight and their ability to hold and dispense a charge will rapidly decrease. If you're considering new batteries, give the lithium alternatives a hard look.

LifePO4 batteries (lithium) have a high initial price, but their long-term cost has been proven to be less. There are multiple YouTube videos and blog websites you can search for that spell out the benefits. Of course there's more usable power, too. Back-of-the-napkin configuration: a single100aH Battle Born (or equivalent), a compatible charger, battery monitor and a small generator is a setup that may meet your needs. Go with two 100aH Battle Borns and you'll almost double the usable available power available to use (versus the golf cart batteries).

If you go with the golf cart batteries, at minimum get a quality battery monitor: https://gdrvowners.com/forum/operati...-do-i-need-one

TucsonJim has an excellent primer on batteries in the Reference Material section if you haven't seen it: https://gdrvowners.com/forum/operati...ithium-battery

Guest (Jim) and Yoda (Keith)?

Howard

[Yoda]

I have an older ResMed S9 CPAP machine. The power cord contains a 120 volt to 24 volt power supply. I have plugged mine into a watt meter and it draws just under 20 watts even with the Humidifier on. I will be getting the newer AirSense 10 unit for this season, but ResMed is not able to give me any operating wattage on it. My plan is to change my current 12 volt deep cycle battery to two 6 volt golf cart batteries in series. I will also install a 1000 watt inverter in the front pass through and run a 120 volt outlet to the bedside. I am thinking the batteries should last at least the whole night, if not several depending on water pump and lights usage. If need be, I will get a portable 100 watt solar panel and charge controller for my batteries.

Any thoughts or ideas on this plan? Math is not my strong suit and I am trying to figure my total Ahr draw. The 6 volt batteries are 235 Ahr each, so i am assuming i will have about 115 to 117 Ahrs if i take them down to 50 %?

Brian - you don't need an inverter(unless you want one) to run your CPAP. See post #8 above and consider getting a 12v power adapter cord from your CPAP supplier and wiring in a 12V power plug. Link in post #10. Below is a picture of the typical 12v adapter cord. Just don't run the CPAP humidifier/heater and you will be fine. When you order your new unit ask that they include the 12V power cord/adapter. Every make of CPAP out there has this 12v adapter available. They may call it a car adapter.


Hope this helps
Keith

[Guest]

Brian S

A constant 20W drain (20 watts per hour) will consume about ~2 amp hours (aH) from the batteries (20W/12V). Over a typical 10 hour period that's ~20aH. That does not account for power drawn from the batteries for the furnace, refrigerator, and any other 12v appliance that's going to drain power.

So it looks like (on paper) that the 6V golf cart battery setup will work just fine, but run those 6v batteries to depletion due to an oversight and their ability to hold and dispense a charge will rapidly decrease. If you're considering new batteries, give the lithium alternatives a hard look.

LifePO4 batteries (lithium) have a high initial price, but their long-term cost has been proven to be less. There are multiple YouTube videos and blog websites you can search for that spell out the benefits. Of course there's more usable power, too. Back-of-the-napkin configuration: a single100aH Battle Born (or equivalent), a compatible charger, battery monitor and a small generator is a setup that may meet your needs. Go with two 100aH Battle Borns and you'll almost double the usable available power available to use (versus the golf cart batteries).

If you go with the golf cart batteries, at minimum get a quality battery monitor: https://gdrvowners.com/forum/operati...-do-i-need-one

TucsonJim has an excellent primer on batteries in the Reference Material section if you haven't seen it: https://gdrvowners.com/forum/operati...ithium-battery

Guest (Jim) and Yoda (Keith)?

Howard

howson Howard,

I agree that a lithium battery(s) is by far the best option. The issue I had with my OEM flooded lead acid battery was to listen to the generator 4 hours/day since this battery type will only accept 10amps. So discharging a FLA battery to 50% with heat on only during sleeping with the 75ah battery would give me around 37 ah to charge the next morning. As a result, the battery had to be charged every 9 hours for almost 4 hours. Painful! Charging at 10 amps while other items are running resulted in two two hour charge intervals daily while listening to chitty chitty bang bang.

Now take my 100ah lithium battery from AIMS. I can run my rig with heat on and use approximately 45% of its capacity in 24hrs. Since the dedicated lithium charger will put out 60 amps, the battery will fully charge while running the generator each morning to operate a coffee pot. So roughly 40 minutes or so later and the battery is fully charged. I cannot state what amperage two 6v batteries will accept but they will not come close to a lithium battery that can take up to 1C which is 100amps if you wished to push it this hard. Most of us us 0.5C to increase battery longevity.

Hope this helps.

Jim

[Brian S]

Thanks Guys for all the great information! I know the Lithium is probably the best route to go ultimately, but the batteries alone are going to be over $1200 each here in Canada! Then i need to change the charger and everything as well. I think the 1000 watt inverter will be overkill too, but I think using it at 100 watts or less at a time will prolong its life too. I am also going to install a 12 volt battery monitor to keep an eye on the battery levels.
Boondocking is something totally new to us! We have always used full hook-ups in the past. Our new 2600RB will be a whole new experience this year and since we don't really know how it will go, this is a first step for us.
As for the CPAP machine, the 20 watts was at 120 volts, not 12 volts. Won't that make a big difference? Also, my machine runs on 24 volts, not 12 volts, so i am not sure how a car charger would work? My power cord steps the 120 volts AC down to 24 volts DC.
I also have a 3000 watt inverter generator that is also new this year. I had a 1200 watt open frame generator in the past, but never used it for the RV. I was going to....until we got the 3000 watt unit.