sourcing batteries for Transcend, preferably generic

[bunter]

hi all,
after a successful hiking holiday with a hired portable Transcend machine, where we were staying in villages each night and I had access to power (in Japan), we are now planning for 2016 another hiking holiday, but this time in remote areas where the huts have no services, and there may even be some camping (in New Zealand).

I've already booked the hire machine for the next holiday, but I need to source a couple of batteries.

I would really like to find some generic batteries that meet the specs for the CPAP machine. The prices of the branded ones are frightful!

Has anyone done this, and can give me some pointers?
How do I describe the power needs of the machine to a battery-shop person?

I have read some reviews that the named brand batteries don't necessarily give you the running time that they promise - even if you don't have heating or humidifying on. Is there something better than the named brand batteries?

Since I (and hopefully a couple of my kind companions - they don't want me to snore either) will be carrying the machine and batteries, I want to minimise the weight.

Is there better runtime-per-kg in the bigger batteries or the smaller ones?

any advice or direction appreciated

many thanks

[Terry]

Is there a number on the batteries?

[otrpu]

I know nothing about CPAP machine batteries. But, I don't drive and use a Mobility Scooter and Public Transportation to get around. Scooter uses two 12v 18Ah deep cycle batteries. Found a great "Deal" on Sears Batts. 20% less cost than original batts, that lasted 6 months. I contacted Sears CS yesterday requesting warranty replacement of the "Bargain" Batts". After only 3 months service.

I drove OTR three years. Diesel PU required two batts. I purchased WallyWorld batts. They only lasted a year, but had much longer warranty. Got free replacement batts every year. Loved WallyWorld. . .only place to get batts, tires, and oil changes on Sunday. I decided if I bought cheap. . .buy two. . .they're gonna break. JMHO

Cheers,
otrpu

[Terry]

I checked the battery they sell, and it's not just a battery, it's a battery pack, which is a plastic case that contains a number of actual batteries and possibly some electronics.

I'm not sure what to tell you since it looks like their large battery pack is still only good for one overnight, so you would need multiple packs.

They have a solar charger for it, but it takes 12 hours to charge, and this is probably in ideal conditions.

If you'll be near a vehicle, they have a cord that plugs into the 12v outlet, which will power and recharge the unit.

[justMongo]

Batteries questions for backup or camping come up frequently.
For backup in home, sealed, deep-cycle lead-acid batteries are often preferred.
Lugging an SLA battery on ones back is tough -- lead is heavy.

Lithium Ion batteries offer the best power to weight ratio.
You are likley stuck with a battery pack built for the unit; and you will need a charging system: solar, or AC mains when available.

Runtime per kg is roughly the same for a given battery chemistry. You gain an advantage when using a battery chemistry like LiIon that has a higher energy per kilogram.

Best wishes on your adventure.

[Tacoma Droner]

The Transcend battery, especially the P8, is very cool. Yes, a bit spendy, but there's nothing special about the technology. It's a plain jane lithium-ion battery rated at 14.4 volts with a storage capacity of about 5.2 amp hours. The tricky part to using a generic lithium-ion battery is the connector on the end of the cord. You have to get one that will fit the machine. Duh! I think you'll discover that lithium-ion prices, even when you go generic, are going to be on par with the Transcend brand name. Not gonna save that much.

One word of warning--there are plenty of websites hawking lithium-iron-polymer (LiFePo) batteries for CPAP use. LiFePo's are super lightweight and the pricing is good, way less than lithium-ion on both counts, but the amp-hours specs are very suspicious. I've been thinking about buying a LiFePo just for the hell of it and trying it out at home just so I can get some real-life experience before taking it with me out into the backcountry. Last thing I want is some over-hyped battery that quits on me before I was expecting it to! Also, I've heard the LifePo's are not reliable when it's cold out. Don't know if that's true, but would want to test it out before that big snowshoe camping trip.

[bunter]

The Transcend battery, especially the P8, is very cool. Yes, a bit spendy, but there's nothing special about the technology. It's a plain jane lithium-ion battery rated at 14.4 volts with a storage capacity of about 5.2 amp hours. The tricky part to using a generic lithium-ion battery is the connector on the end of the cord. You have to get one that will fit the machine. Duh! I think you'll discover that lithium-ion prices, even when you go generic, are going to be on par with the Transcend brand name. Not gonna save that much.

One word of warning--there are plenty of websites hawking lithium-iron-polymer (LiFePo) batteries for CPAP use. LiFePo's are super lightweight and the pricing is good, way less than lithium-ion on both counts, but the amp-hours specs are very suspicious. I've been thinking about buying a LiFePo just for the hell of it and trying it out at home just so I can get some real-life experience before taking it with me out into the backcountry. Last thing I want is some over-hyped battery that quits on me before I was expecting it to! Also, I've heard the LifePo's are not reliable when it's cold out. Don't know if that's true, but would want to test it out before that big snowshoe camping trip.

many thanks - this is very helpful.
And a cheaper, lighter option might be worth buying and trying asap since I am facing having to buy two or three for the hiking. (multiple days away from anything including vehicles.) if it works it would be good to know.
hhhmmm, I wonder how I could simulate a night in the snow???
cheers

[pl99]

I'm wondering if power tool batteries can be adapted to power the Transcend. At Home Depot, I see a 2-pack of 18V, 4AH Lithium batteries for US$99. They match the voltage on Transcend's AC adaptor and exceed the amperage shown (1.67A). The P8 on the other hand is $250-300 each. I realize I'll have to attach a plug somehow, get the polarity right, etc. And as Tacoma mentioned, the P8 is only 14.4V. And, the P8 seems to be lighter. But do people see an obvious flaw in what I'm thinking?

[ger365]

I'm wondering if power tool batteries can be adapted to power the Transcend. At Home Depot, I see a 2-pack of 18V, 4AH Lithium batteries for US$99. They match the voltage on Transcend's AC adaptor and exceed the amperage shown (1.67A). The P8 on the other hand is $250-300 each. I realize I'll have to attach a plug somehow, get the polarity right, etc. And as Tacoma mentioned, the P8 is only 14.4V. And, the P8 seems to be lighter. But do people see an obvious flaw in what I'm thinking?

I love the idea...
But, ignoring limiting devises to protect the devises...one shows max. draw and the other max. capability. So high current draw may give you 2 hrs per battery...lower settings on blower will give more time. ALL of them "fudge" on the specs...
There are now solar backpacks to charge electronics great for cell phones...but I wouldn't put my life in their hands.
So does the P8 do 6-8 hrs?
Wish someone could send me schematics for the converters so I study them and maybe give others a cheaper way of doing 12/24 volt...
I am the first to admit I'm not the brightest bulb in the chandler...

[pl99]

Thank you!

Another idea is to use power banks that are designed for running / charging laptops.

(This forum just blocked my link, so please look for B011BGPUSI on Amazon.)
This battery is 32Ah (vs 5.2Ah for Transcend's PS8 battery), and includes a bunch of laptop plugs. Hopefully one of them fits my CPAP? If so, does that mean I can go backpacking for a whole week!?
The top review is from a CPAP user!

There's a slew of very similar battery products out there. Just look up "power bank for laptops."

I'm not sure what I'd set the voltage to. My AC adaptor says 18V 1.67A, but the PS8 battery is reportedly 14.4V. I can't find device voltage on the device itself or in the documentation.

I'm wondering if power tool batteries can be adapted to power the Transcend. At Home Depot, I see a 2-pack of 18V, 4AH Lithium batteries for US$99. They match the voltage on Transcend's AC adaptor and exceed the amperage shown (1.67A). The P8 on the other hand is $250-300 each. I realize I'll have to attach a plug somehow, get the polarity right, etc. And as Tacoma mentioned, the P8 is only 14.4V. And, the P8 seems to be lighter. But do people see an obvious flaw in what I'm thinking?

I love the idea...
But, ignoring limiting devises to protect the devises...one shows max. draw and the other max. capability. So high current draw may give you 2 hrs per battery...lower settings on blower will give more time. ALL of them "fudge" on the specs...
There are now solar backpacks to charge electronics great for cell phones...but I wouldn't put my life in their hands.
So does the P8 do 6-8 hrs?
Wish someone could send me schematics for the converters so I study them and maybe give others a cheaper way of doing 12/24 volt...
I am the first to admit I'm not the brightest bulb in the chandler...