What battery to buy

[Papsmagee]

I have a dilemma. I've been using two 6-volt deep cycle marine batteries for 3 years because we dry camp most of the time. Paired with them is a 200-watt solar panel mounted on the roof. I also have a 2000 Watt inverter installed for my new Springdale 202QB TT. I need the inverter to run my CPAP at night. Just got back from 3 night trip boon docking up the Rogue River in Oregon and drained my batteries down to 11.2 amps the last night camping. Batteries were around 13 when we went to bed. This seems to have drained to far too fast from past experience. Could the batteries need to be replaced?

Should I consider lithium-ion battery? Do you have experience with this type of battery?

Thanks.

Papsmagee
2022 Springdale 202 QB
2015 Tundra 4WD 5.7L V8

[flybouy]

A 200 watt solar panel may not be enough to replenish what you are using, especially if your not in full direct sunlight. I don’t have or use a CPAP but have read that if you are using the heared air function it takes a lot more power.

[chuckster57]

If you have the ability to run a gen during the day, you might want to consider a battery pack if one is available for your cpap.

What else is on when your running your machine? 200 watts of solar isn’t a lot when you try to recover all the energy you used.

[Papsmagee]

During the night the only thing running is the CPAP, the refrigerator, and the water pump. I stopped by the dealer this morning and talked to one of the mechanics about this. Like you, he doesn't use a CPAP, but suspects that I need to be sure the batteries are fully charged before bed. Of course, this is a bit of a challenge in itself because if they are low - say 12.1 or 12.2 - the solar won't help and the generator is off limits after 7 PM in most campgrounds, isn't it?

So, then, one other option is Lithium-ion. It's a lot of $$, but stronger and longer charge from what I have been reading online.

More exploring needed!

Thanks.

Papsmagee

[gkainz]

I always use a DC cord for my CPAP - if your particular unit has one available - to avoid running an inverter and reduce the inefficiency that introduces. I also make sure I shut off the heated humidifier.

[mikec557]

Originally Posted by Papsmagee

During the night the only thing running is the CPAP, the refrigerator, and the water pump. I stopped by the dealer this morning and talked to one of the mechanics about this. Like you, he doesn't use a CPAP, but suspects that I need to be sure the batteries are fully charged before bed. Of course, this is a bit of a challenge in itself because if they are low - say 12.1 or 12.2 - the solar won't help and the generator is off limits after 7 PM in most campgrounds, isn't it?

So, then, one other option is Lithium-ion. It's a lot of $$, but stronger and longer charge from what I have been reading online.

More exploring needed!

Thanks.

Papsmagee

Just a couple thoughts. In your first post, near the end, you twice said AMPS, I have to assume you meant VOLTS.

I've used a CPAP for a few years while camping. We've had lead acid batteries and lithium iron (not ion, that's a different kind of lithium for other than RVs), and we have usually had about 300 watts of solar panels. I say all that just to establish my experience.

1. Using an my 120vac power supply through an Inverter to run my CPAP uses about twice as much battery power as using the 12v power supply for my ResMed AirSense 10. The CPAP uses 24v, so the 12v power supply still has to change the 12v to 24v. But it still uses less battery power than the 120vac power supply running through an inverter.

2. I leave the heated water/humidifier ON, just like at home. I sleep better with it on. To be clear, this is NOT the "heated hose". I don't have one and never used one. But I believe it draws a lot more power than the humidifier.

3a. Assuming two 6v, 225 amp hour, batteries in parallel. This would give you 12v 225ah battery bank. Using only 50% of your ah in order to prolong your battery life, you can use 112ah between charging each day.

3b. I think you would benefit from having a battery monitor, that would show you actual usage, and actual state of charge. There are cheaper ones, but I always recommend the Victron Smart Shunt ($130 on Amazon). It's easy to use and it Bluetooth to your phone for easy monitoring.

Once you can monitor the draw on your batteries you can tell if they're getting old/weak, how much any particular electrical device draws, and how full your battery is once the sun's gone down.

Just some food for thought.

[pasayten]

You could also look into having a separate battery pack for your CPAP...

https://www.jackery.com/products/exp...-power-station


1000watt-hr of power... 12vdc or 120vac... and charge it during the day via 12vdc or 120vac. CPAP usually use 30-60 watts/hr... At 60 would give you a good 15 hours of use.

Takes the worry and load off of your trailer system. :-)

We use ours for our laptops/phones and other equipment as needed and don't want to tax our trailer system during the night.

[mikec557]

Originally Posted by pasayten

You could also look into having a separate battery pack for your CPAP...

1000watt-hr of power... 12vdc or 120vac... and charge it during the day via 12vdc or 120vac. CPAP usually use 30-60 watts/hr... At 60 would give you a good 15 hours of use...

I use a ResMed and have done a lot of testing using a EcoFlow River Pro 720Wh. I think the manufacturers give a misleading idea that the unit's rating is the "usable" amount of power. In my example, 720Wh.

The internal batteries in almost all of these units the internal batteries are in the range of 20-26vdc. That means they have to either INvert or CONvert to provide 12vdc or 120vac, and including 5v USB. There's not only the inefficiency of that process, some will will make 5 & 12 volt even if all you want is one of those. And I think some have those turned on when all you want is 120vac.

I think the idea is still good. Just don't buy one too small thinking you'll get to use the name plate rating.