Originally Posted by elind
I'm thinking that I will use a jump start battery pack that has a 12 volt or 120 inverter for my CPAP when overnighting at Walmart. That way if the CPAP draws down the battery it's only the battery pack dead. It also moves around with the CPAP where it's needed.
Well... I think you are going to be EXTREMELY disappointed over time with that approach despite its' attractiveness.
1. The quick start battery packs are made to deliver SHORT jolts of high current to start a car. This means lots of thin plates .. and not much DEEP CYCLE capacity.
2. Using a "starting " battery continuously in deep cycle application will cut battery life by OVER 50%... most likely by 2/3.
3. The run time you get per charge on the pack...will not take you though the night AND you risk going below 12.2V ...or going flat which is really damaging to a battery.
4. Using the inverter mode rather than the 12V mode costs at least 15% of your battery power in conversion loss in a small inverter.
5. You need a conventional true deep cycle battery (wet or AGM) with amp hours of close to 100 which means a group 27 or 31 and around 60-65 lbs in a wet battery. That's a lot to carry around!
Anyway...good luck & think it through ...or at least buy it somewhere you can take it back to for a while if unhappy.