Battery: "deep cycle" vs "general purpose"

When to pick up a battery and charger in preparation for camping. I was going to get a Duracell 12-35J, which is a deep cycle battery, but instead got a 12-35C, which is "general purpose". They're both AGM.

Does it really matter? Deep cycle is more what I wanted, but "general purpose" AGM still isn't a starting battery, and I can't really see any difference looking on the web.

(I know that we shouldn't use "starting" batteries, but this is definitely not a starting battery. It seems like it's probably used in wheelchairs, conventionally.)

dh37 wrote: ↑

Sat May 22, 2021 12:53 pm

(I know that we shouldn't use "starting" batteries, but this is definitely not a starting battery. It seems like it's probably used in wheelchairs, conventionally.)

No, deep cycle batteries are recommended for wheelchairs and mobility scooters. Duracell says,

Count on deep cycle batteries to have 40% more cycles (or better!)
than general purpose batteries in the same application.

https://www.batteriesplus.com/psdoc/doc ... atalog.pdf

That said, how many nights per year do you plan on using the battery? How many nights must it work before recharging? Which model CPAP machine are you using when camping? What are your pressure settings and average pressure? Are you using an inverter or converter? Will you be using a heated humifier?

ChicagoGranny wrote: ↑

Sat May 22, 2021 2:03 pm

That said, how many nights per year do you plan on using the battery? How many nights must it work before recharging? Which model CPAP machine are you using when camping? What are your pressure settings and average pressure? Are you using an inverter or converter? Will you be using a heated humifier?

I'm using my AirSense10; I only have one CPAP machine. (Which leads to a different question: do most people have an extra one on hand in case their main one breaks, or do they assume the medical device provider can expedite shipment of a replacement?)

I already bought the ResMed converter. I plan on turning the humifier off, as well as the ClimateAir heated hose. I looked at my pressure in OSCAR, and assuming 10 of the standard units should be more than enough (once in a while the pressure is > 10, but usually it's below 10). Looking at the forum posts, as well as the ResMed battery document, I should be fine with 12 AH/night. Two nights of camping ==> 35 AH should be more than enough. (I also got the 1.25 A Battery Tender.)

dh37 wrote: ↑

Sat May 22, 2021 3:09 pm

I'm using my AirSense10; I only have one CPAP machine. (Which leads to a different question: do most people have an extra one on hand in case their main one breaks, or do they assume the medical device provider can expedite shipment of a replacement?)

Since I'm 6 years into this CPAP thing I have my old machine as spare. But I do have another of same model brand new in box picked up at rock bottom price when it was on sale for like 1/2 price few years back. When you have your prescription in hand and some disposable income you have that flexibility.

dh37 wrote: ↑

Sat May 22, 2021 3:09 pm

I already bought the ResMed converter. I plan on turning the humifier off, as well as the ClimateAir heated hose. I looked at my pressure in OSCAR, and assuming 10 of the standard units should be more than enough (once in a while the pressure is > 10, but usually it's below 10). Looking at the forum posts, as well as the ResMed battery document, I should be fine with 12 AH/night. Two nights of camping ==> 35 AH should be more than enough. (I also got the 1.25 A Battery Tender.)

I can't tell the difference between these batteries excepting the terminals and the model number. What makes one a deep cycle and the other not I am curious to know. I can get about two nights off a 120 Watt hour battery with a different machine but that's using up 100% of that 120 watt hours. I think you're more towards the 4-6 nights range with this battery and your pressure. Try not use more than 80% of its to preserve its lifespan. As always YMMV

dh37 wrote: ↑

Sat May 22, 2021 3:09 pm

I already bought the ResMed converter. I plan on turning the humifier off, as well as the ClimateAir heated hose. I looked at my pressure in OSCAR, and assuming 10 of the standard units should be more than enough (once in a while the pressure is > 10, but usually it's below 10). Looking at the forum posts, as well as the ResMed battery document, I should be fine with 12 AH/night. Two nights of camping ==> 35 AH should be more than enough. (I also got the 1.25 A Battery Tender.)

That's a good scenario, and I would expect the battery to last five years if properly maintained. Next time, get the deep cycle which has thicker plates than the general purpose.

You can make an estimate of how many hours your battery will run your CPAP without recharging by using this guide - https://document.resmed.com/en-us/docum ... lo_eng.pdf It would be a good idea to subtract 10 to 15% for a general purpose battery.

dh37 wrote: ↑

Sat May 22, 2021 3:09 pm

(Which leads to a different question: do most people have an extra one on hand in case their main one breaks, or do they assume the medical device provider can expedite shipment of a replacement?)

Keep a backup at home. Even a new machine can fail at the end of a long, tiring day as you get in bed. Murphy's law says the machine will fail on the first night of a three-day weekend when your DME is closed. Backup masks and hoses are also a good idea.

Backup machines should be used occasionally for a night. I use mine about once or twice a month for hour-long afternoon naps.

Thanks for the advice, folks. I'll try to return this battery and get the similar-but-deep-cycle one in it's place. If not, lesson learned. (I had to kind of rush things because the camping trip is next weekend.)

amenite wrote: ↑

Sat May 22, 2021 4:44 pm

I can't tell the difference between these batteries excepting the terminals and the model number. What makes one a deep cycle and the other not I am curious to know.

Yeah, exactly. The catalog lists one as general purpose and one as deep cycle, but the only obvious difference is the terminals. Can't find any really detailed specs anywhere.

dh37 wrote: ↑

Sat May 22, 2021 12:53 pm

When to pick up a battery and charger in preparation for camping. I was going to get a Duracell 12-35J, which is a deep cycle battery, but instead got a 12-35C, which is "general purpose". They're both AGM.

Looks to me that the only real difference between the two batteries is the terminal type. I wouldn't worry about it.

palerider wrote: ↑

Sat May 22, 2021 7:54 pm

Looks to me that the only real difference between the two batteries is the terminal type. I wouldn't worry about it.

Yeah, I had that thought.