So, you bought a new 12 Volt PAP back-up battery.

Why did it fail fresh out of the box?

12 Volt PAP back-up battery

Imagine this:

You are a happy PAP user. You happen to live in an area where power outages happen occasionally. Thankfully the order of your  back-up power source for PAP devices finally arrived. And you’re feeling confident of a night’s sleep, no matter what.

Then, the lights go out.

You grab your recent purchase with confidence and hook that back-up battery to your PAP. It starts, you start to relax, congratulating yourself for being prepared.

An hour into your sleep, your PAP shuts down and the power hasn’t come back on. The battery refuses to work even though the voltage indicator shows some power remaining.

Now what?

Good sense tells you when the power returns, to complain to the company who sold you the battery.

But, hold on.

Before you, do consider this:

Most back up batteries come with a near 40-50% charge out of the box, typically.

With a battery coming out of the box, it is technically is dead at a 40-50% charge. What this means is the use of a battery at a 40-50% or less charge cannot maintain 12 volts.

The solution?

Your new battery needs a full charge before its first use.

Reason: New batteries are actually damaged by low charge states (when in use) by a process called sulfation.

Sulfation is when an acid battery is deprived of a full charge.


Lithium batteries are a different story however…

Lithium batteries won’t be as testy. But they do come with their own care and charge requirements. Read the material provided with your back up battery if it is lithium. Lithium batteries are better and more reliable on a charge level less than 100%. Here is a chart below about storing lithium batteries when they are not in use. One piece of advice is to store your lithium battery at 40% charge remaining. But once it is out of the box for the first time, it is always a good idea to charge it fully before its first use.

The take home lesson?

Charge that new PAP battery after you buy it and definitely before you actually need it.

Here’s to your successful sleep no matter what the situation!



Call 1.877.430.2727 for help.

Written and Edited by Bill Bistak B Sc.,SEO/SEM Spc, CRT

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  1. I came up with a brilliant idea. I have a hoveround in trying not to use, and i was thinking about using the deep cell batteries. Thanks..


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