raftergirl said:
Here's another alternative. I was given this link by another rafter who uses CPAP. These batteries might be a good compromise. Not quite as expensive as the Li Ion, but much lighter and slightly smaller than my Deep Cycle AGM. 6.6 lb. for the 12V20A vs mine at 13 lb. Another plus is that they are much better suited to being discharged below 50% vs the AGM batteries, and they have a much longer lifetime of charging. I might think about one of these in the 12A version (3 lb.) for my kayak touring where I definitely need a smaller & lighter battery. Perhaps I'll replace all my AGM with these in the future????
http://store.starkpower.com/Energy-Stor ... _c_21.html
I'll admit my ignorance right up front...I've been following the various backup power posts with the hope of finding just the right set up that would work for me at home however, I get glassy eyed with some of the technical jargon. To put it plainly, I get that a higher amp hour back up source will last longer than lower amp hour ones. I also get that there are many options with varying amounts of effort/skill needed to build them: back up unit from CPAP.com, deep cycle marine battery, lithium ion battery, car jump starter, UPS etc. TOO Many Options have my head spinning and I don't want to solder, weld, wire, or otherwise construct my back up power solution. My ultimate set up would last more than a few days (I live in earthquake country), be easy to set up (keep those "caution! make sure you have your positive/negative cables in the right place lest you blow up your CPAP machine and who knows what else" warnings to a minimum), be safe indoors, and be cost efficient. Think plug and play...not a lot to ask, right?
I currently have a new model Duracell DR600PWR 18Ah powerpack bedside and I've purchased the Shielded DC Cord for PR System One 60 Series Machines and the Respironics, 12volt DC Battery Adapter Cable with Battery Clips so that I have the option of hooking up to a deep cycle battery in the future. Aside from hooking the CPAP up directly to the deep cycle battery, does it make sense to pigtail (is that the right word?) the Duracell powerpack via the built in jumper cables to the deep cycle battery for charging/longer CPAP run time in the event of a long term power outage? My thought is this solution will give me several different options if it will work. I'll have the powerpack to use directly with my CPAP for short term use (it has a single DC and 2 AC outlets plus 2 USB ports which can also be used with other electronic devices), and then I can charge the powerpack using the deep cycle battery and use each separately as well as pigtail the two together for a longer term electrical source. Does this make sense and will it work as I describe?
If it works what about the safety of having the Lithium Iron Phosphate battery stored next to my bed vs. a lead acid battery and the issue with gasses emanating/acid spilling from it. Per the StarkPower website "LiFePO4 contains no poisonous lead, no acid, and does not create gasses during charge, as traditional Lead-Acid batteries do." Does this mean a battery box used to seal a deep cycle battery is not necessary with a LiFePO4? Are there any concerns regarding LiFePO4 batteries to be aware of? What are the trade offs between the two types of batteries besides initial cost, battery weight and potential poisonous gasses? The website (see link above) makes the LiFePO4 sound great compared to lead acid batteries but how much of that is advertising or can these features be considered fact?
If I buy a 12Ah battery and I'm only powering my PRS1 560 without the humidifier (Pressure: APAP 9.0 min/15 max) how many hours can I expect from the different configurations of this setup assuming the source is fully charged (sorry, math is not my strong suit)?
CPAP connected to powerpack standalone via AC?
CPAP connected to powerpack standalone via DC?
CPAP connected via 12volt DC Battery Adapter Cable with Battery Clips to lead acid deep cycle battery
CPAP connected via 12volt DC Battery Adapter Cable with Battery Clips to LiFePO4
CPAP connected to powerpack via DC and powerpack is pigtailed to lead acid deep cycle battery
CPAP connected to powerpack via DC and powerpack is pigtailed to LiFePO4
How many times can the powerpack be recharged via the deep cycle and then used standalone? How long will it take to recharge the powerpack?
Depending on the answers I may want to go with the 20Ah...
I'd appreciate any feedback so that I know what to get when I make my next back up power purchases.
Thanks!
d
p.s. I was able to get the Duracell DR600PWR 18Ah powerpack delivered to my home for $120 (coupons helped!) and I found the Sears JumpStart Platinum Portable Power 22Ah 1150 model that has been mentioned several times on other threads for a reduced price of $80 (plus tax) but you'd need to pick it up from a Sears store near you AND the item would need to be in stock.