WARNING to CPAP Users: PREPARE for the Unexpected - When the power goes out

[JVinNE]

Was the guy lying to me? I really don't know anything about the stuff IAm all new to it.

[GWild]

The WM saleperson is likely similar to a Home Depot salesperson: knowledgeable about stock, but not an expert -- I doubt he was intentionally misleading you. Batteries are not as simple as you'd expect, and it is very easy to be misinformed.

I think the charger you purchased has a voltage meter built in... that'd be an easy first look at voltages. If the WM charger provides more than 14.1 volts during absorption phase, then you are risking early Gel battery failure (in a nutshell, once the electrolyte boils the surface area of the plate contact is permanently compromised - think of bubbles forming in a gel - unlike in fluids, they don't go away).

From memory: for gelled battery float maintenance Absorption should be limited to under 14.1 volts, Float under 13.5 (some say 13.8 and 13.2 are the magic numbers - check your battery spec sheet).

Or you can buy a reasonable Digital Multi Meter for about $150 on Amazon. I find 4 1/2 digits best, but anything that measures True RMS and has at least a 5000 count display is usable. Meters are not a good place to be bargain hunting... over a short time the cheap models degrade in very bad ways. And a good DMM comes in handy for a lot of things around the house.

More on gelled lead-acid batteries: search wiki for "VRLA battery" - it may expose a few of the common myths about the benefits of AGM/GEL technologies over 'good' wet cells.

[SuperSleeper]

I just got back from the Marine store. I bought a west-marine--15-amp-automatic-battery-charger-with-engine-start-timer--14982045
and a west-marine--gel-deep-cycle-marine-gel-battery, with 97 amp hours at 12v--P015020365

As long as you might be considering going back to the vender, it looks like to me that the model number you listed (if you look on West Marine's website) is the P015020365 model... (look at the list of model numbers on their web page).

According to that list, model P015020365 [on the bottom] is the 31.6 amp hour version for $159.99, not the 97 amp hour version, which they list for $414.99.

If you paid $159.99, you probably got the 31.6 amp-hour version.

[JVinNE]

I just got back from the Marine store. I bought a west-marine--15-amp-automatic-battery-charger-with-engine-start-timer--14982045
and a west-marine--gel-deep-cycle-marine-gel-battery, with 97 amp hours at 12v--P015020365

As long as you might be considering going back to the vender, it looks like to me that the model number you listed (if you look on West Marine's website) is the P015020365 model... (look at the list of model numbers on their web page).

According to that list, model P015020365 [on the bottom] is the 31.6 amp hour version for $159.99, not the 97 amp hour version, which they list for $414.99.

If you paid $159.99, you probably got the 31.6 amp-hour version.

Paid $414.99

[SuperSleeper]

Paid $414.99

Good, that's their listed price for the 97 amp-hour version. But the model number you posted (15020365) was for the 31.6 amp-hour one (according to their own website). I wanted you to be aware of that, in case they tried to switch it on you or something. The 97 amp-hour version is model number 15020399.

[JVinNE]

Paid $414.99

Good, that's their listed price for the 97 amp-hour version. But the model number you posted (15020365) was for the 31.6 amp-hour one (according to their own website). I wanted you to be aware of that, in case they tried to switch it on you or something. The 97 amp-hour version is model number 15020399.

SuperSleeper, may I ask you a favor? Would you take a look at West Marine online; the store is close, and I can just go there in person. Please advise me on which battery tender and meter to purchase. I am completely new to all of this, a little scared, and going through a lot of stress right now. Please help me. Thank you.

[SuperSleeper]

SuperSleeper, may I ask you a favor? Would you take a look at West Marine online; the store is close, and I can just go there in person. Please advise me on which battery tender and meter to purchase. I am completely new to all of this, a little scared, and going through a lot of stress right now. Please help me. Thank you.

Someone may correct me here, but I don't think you need a really expensive charger for your 12 volt battery. I have purchased a BatteryMINDer from Amazon and was very happy with the way it worked. Just do an Amazon search for "BatteryMINDer Charger/Maintainer/Desulfator System - Model# 1500" Sells for around $50 or so, plus tax & shipping. It has a color-coded light system to let you know what's going on with your battery.

If you think you need a meter, you can purchase any inexpensive 12 volt meter to test the battery as well. I purchased a cheapie for about $20 off Amazon - they work fine for a rough estimate of your battery's charge, as long as after the charging period, you remove the charger, and just let the battery sit idle by itself (with nothing attached to it at all) for about a day, then turn on your cheapie volt meter, turn it to the 12-volt setting (important to do this first) and put the red lead onto the battery's positive terminal and the black lead onto the negative terminal, Then read what it says on the meter. You'll probably want your battery to read at a minimum somewhere above 12.7 volts, but the higher the better.

But really, if you use a trickle charger like the BatteryMINDer, you'll be fine without the need to worry about checking the charge, as at those low trickle-charge amperages (this one charges at 1.5 amps), and with the BatteryMINDer's protective circuitry, you can leave it on pretty much all the time (plugged in) and not have to worry about over-charging your battery.

But keep in mind that you always want to completely disconnect the charger from the battery if you're going to use the battery to power your CPAP machine. Leaving the charger hooked up while you power your CPAP will likely damage your CPAP.

Hopefully GWild and others can chime in, but that's my basic thoughts on what you need. You don't need to over-spend to keep your battery charged up. And trickle chargers are better for the battery anyway, as larger chargers can damage the battery. It's safer to go with a small, 1-2 amp trickle charger in other words.

On West Marine's website, they probably have something like the BatteryMINDer, but I couldn't find one for a decent price when I searched their site. Amazon's going to get you a better price anyway, and you pay a bit more for 2-day shipping to get it faster if need be.

Just my thoughts.

[parkerdt]

Anyone have experience and comments good or bad with using a computer grade UPS as a backup supply for CPAP power? I have several APC BackUPS 1500s that I am not using for computer gear....

Currently, I do have my machine protected by a good surge protector, but that is it. As the thunderstorm tonight reminded me, we do lose power here, and while I have an emergency generator, it is not the whole-house auto start type.

thanks,
Dave

[Sleepster]

Anyone have experience and comments good or bad with using a computer grade UPS as a backup supply for CPAP power?

I use one and it works great. But with the humidifier on it will last only a few hours. It lets me sleep through every power outage we've had in the last three years.

For longer outages I have the cables I'll need to run off my car's battery.

[JVinNE]

Supersleeper, I took the 15 amp charger back to the marine store, and I bought a 1.5 amp, 12 volt battery trickle charger/tender, at the auto parts store. I also purchased the proper cable for my machine from a DME shop. Might buy second battery and tender soon. The things are as heavy as f*ck, but it is comforting to have one/them.