Charging a back up battery

[Hawthorne]

I have the DC power cord.

I have no idea what a "smart charger" is. Is it part of the battery or do you buy it separately too?

Is it the Respironics Battery pack that you have or are you planning to buy that one? I wasn't clear on that.

[nobody]

A smart charger will be able to sense when the battery is done charging and turn itself off so the battery doesn't get overcharged. Most of them are like that, but you'd want to be sure before you left it plugged in on your battery. No I do not have the Respironics battery pack and don't have any intention of buying it. It was much cheaper to buy a separate battery, charger and cords.

I have the DC power cord.

I have no idea what a "smart charger" is. Is it part of the battery or do you buy it separately too?

Is it the Respironics Battery pack that you have or are you planning to buy that one? I wasn't clear on that.

[billbolton]

The use of an inverter just adds to the power consumed and thus increases the required size of the battery pack.

Contemporary inverters are 90%+ efficent, so an inverter per se doesn't add very much to the battery capacity required.

On the whole, DC heating systems are less efficient that AC heating systems, so its quite possible that in terms of energy usage it is pretty much a zero sum one way or the other.

Any heated humidifier, whether DC powered or AC powered, will use several times the energy used by a flow generator, so it is the use of a heated humidifier of any type that has a very significant impact on battery capacity requirements.

The advantage of a DC for humidifier for battery use is that the cost of an inverter is avoided, but the disadvantage for AC use is the need for an external power pack to provide DC to the flow genator+humidifier.

Cheers,

Bill

[builta]

I have the Respironics Battery Pack and have had it for a couple of years now. I have never had to use it. Everytime a power outage type storm brews up, I top off the charge and have it ready. It's availabe at cpap.com for $299 I believe.

So far that is all I have ever done with it.

I am following this thread, knowing virtually nothing about batteries but feeling better having something ready.

I have 2 questions.

Builta- you say that the M Series with an integrated heated humdifier will work from your battery with some level of heat in the humdidfier. I have the M Series Auto A-flex. I use the FP stand alone humidifier with it but have the Intregrated heated humidfier set up with my backup M Series Pro. Do you know if both the machine and the integrated humidifier would work with that battery? It would be on DC power of course since I have adapter cord.

El Pap - you said you are going to purchase that Duracell unit. You said you are going to leave it plugged in, in the laundry room until and if you need it. That sounds good to me.
Do you know if I can leave my Respironics battery pack plugged in all the time like that?

If you 2 or any one else on this thread knows the answers to my questions, Help!

Thanks

Hi Hawthorne,

I want to address your question regarding the Heated Humidifier.

I don't own a Fisher & Paykel Heated Humidifier, but I can give you a general thought here. If the power cord that you plug into the F&P HH is a direct connection from the wall outlet to the humidifier base (without any power brick in between) then it is a fair bet that it runs on AC. So, to run both the F&P stand-alone Heated Humidifier and either of the M Series XPAPs you would need an inverter (probably one of those "True Sine Wave" types) for the humidifier and a 12 volt connection (or just plug the Respironics power brick into the same inverter).

To use the Respironics M Series integrated M Series HH and one of the M Series XPAPs you can most likely run both directly from the single 12 Volt DC feed. You plug the 12 volt cigarette type adaptor into the 12 volt supply (you may need to hook up the battery connector to the battery) off of the Battery and then plug the other end into the humidifier and then connect the humidifier's extra 12 Volt DC cord into the XPAP (very similar to how you would normally hook up the unit to the power brick).

Hawthorne--I don't think, based on your earlier posts, that this applies to you but, based on my limited research, there are exceptions to my previous comments that I will try to cover briefly here. There are other forum members who are much more familiar with these units and I am confident that they will correct and I hopefully excuse my generalities. Some of the Respironics units have an "extra attachment" that is installed onto the power brick. You can tell because there is one connection from the wall outlet to the power brick, but there are 2 additional cords coming out of the power brick one from the opposite end of the power brick and one "kind of" from the side of the unit. This side outlet is a AC outlet and it is used to connect directly from the power brick to the humidifier and the other connector connects to the XPAP. Other ones, like the older Respironics XPAP "tank style" units, have different connections and voltages and power supplies. If you don't know for sure what form of electricity AC-vs-DC and what exact voltage your XPAP unit and Heated Humidifier uses, then post your specific unit and humidifier information to the forum (and I advise you to post it to the general forum and not directly to me, as there are others with much better unit specific information) and someone will be able to provide specific feedback--you may need to use an inverter for the Heated humidifier or both humidifier and XPAP or maybe not.

As Bill Bolton has stated in this thread and this other other thread viewtopic.php?t=40540 from which I paraphrase and intermingle my own thoughts here, the types of inverters that you may need and power consumption of those inverters and how they compare to 12 volt DC consumption is complicated. You need to know how much power your unit consumes and then size the "Off Grid" power solution accordingly. If you will use a 12 Volt Lead acid Battery--like a Deep Discharge Lead Acid Battery (In order of increasing cost--Wet Cell [read that conventional], Gel type [read this like most -but not all UPS units] or AGM [Absorbed Glass Mat, read this as the new spill proof batteries-like the one that "nobody'' has and posted the photo of])--you need to size the battery for at least double the capacity that you need. Please see the sited thread for estimates of battery size and consumption. It is clear that the "Big Power User" is the Heated Humidifier. So, if you can manage without using the heated humidifier, maybe you can use it in pass over mode, you can use a smaller battery solution.

There are many different battery solutions, battery types, power capacities, different levels of simplicity-vs-complexity, portability, travel restrictions and prices. No single battery solution will be right for everyone or every situation. Research both the electrical requirements of your specific XPAP (and, if you plan to use it, your Heated Humidifier also), how portable the different types of solutions are, how much they cost, how much they weigh and if you are comfortable with all of the different connections and maintenance needed for the different solutions.

--------------------------------------------------------------
Billbolton wrote:
Contemporary inverters are 90%+ efficent, so an inverter per se doesn't add very much to the battery capacity required.

On the whole, DC heating systems are less efficient that AC heating systems, so its quite possible that in terms of energy usage it is pretty much a zero sum one way or the other.

Any heated humidifier, whether DC powered or AC powered, will use several times the energy used by a flow generator, so it is the use of a heated humidifier of any type that has a very significant impact on battery capacity requirements.

The advantage of a DC for humidifier for battery use is that the cost of an inverter is avoided, but the disadvantage for AC use is the need for an external power pack to provide DC to the flow genator+humidifier.
end quote--------------------------------------------------

Bill, I do not consider it energy efficient to use an inverter to convert 12 volt DC into AC to supply power to a power brick that converts power back to 12 volt DC (reference my M-Series XPAP and integrated M Series Humidifier--both of which are direct 12 volt DC devices). Power conversion efficiency is not a simply 90+% type answer, it depends on many factors. Power conversion devices can and do vary from Peak efficiency to lower efficiencies--sometimes much lower efficiencies. The M Series Power Bricks are AC to DC inverters--and I'll bet that they have efficiency issues of their own. But I'll bet that AC powered units convert at least some of the power into DC "inside the box." It is generally a question of where do you put the weight (and heat) of the inverter. I grant you that there is tangent discussion on all of this but I think that it is Off Topic.

I think the actual comparison of power consumed and its comparison to different settings for pressure and heated humidifier setting along with the interaction of power inverter, power bricks, internal electronics and other factors would make for a rather interesting, complex and extensive project (or even energy conservation research paper/thesis/white paper). For someone else!

That said, for me, the Respironics M Series XPAP and integrated M Series Heated Humidifier is pretty darn convenient to use when I am "off grid"--due to power outage or camping. My personal solution will be a 75 to 100 Amp Hour (type 27 or 31) AGM Lead Acid Battery. I will store the battery in a task designed marine style battery box and charge the battery with both a bulk three stage charger and then float the battery with a "quiet" maintenance type "pulse desulfating" long term AGM tuned trickle charger. I will take the battery with me when camping or place it next to my bed when not camping. I will not take either the XPAP or Battery when I go for overnight hikes. I figure that I will easily be able to last several nights "off grid" between recharges.

[builta]

The use of an inverter just adds to the power consumed and thus increases the required size of the battery pack.

Contemporary inverters are 90%+ efficent, so an inverter per se doesn't add very much to the battery capacity required.

On the whole, DC heating systems are less efficient that AC heating systems, so its quite possible that in terms of energy usage it is pretty much a zero sum one way or the other.

Any heated humidifier, whether DC powered or AC powered, will use several times the energy used by a flow generator, so it is the use of a heated humidifier of any type that has a very significant impact on battery capacity requirements.

The advantage of a DC for humidifier for battery use is that the cost of an inverter is avoided, but the disadvantage for AC use is the need for an external power pack to provide DC to the flow genator+humidifier.

Cheers,

Bill

Bill, Please see my previous post. There is a note to you in there. But, I had problems with the quote syntax. Anyway please see previous post. I'm interested in your comments--although we may need a different thread.--Peace Brother

[Hawthorne]

Builta - thanks so much for taking time to explain all that to me! I do appreciate it but all the "battery jargon" is simply above my head.

I have posted about batteries and UPS many times in the past but, so far, the light bulb has not come on!!

If it's like most other things, one of these days, with a certain phrasing in a post,I will, all of a sudden - get it!!

I almost always use my humidifiers in passover mode so that is no problem. I did not intend to try the F & P standalone humidifier with a battery setup. It does have a separate AC plug but, in passover mode, even that would work in a power outage.

Until "the light dawns" ,I will just keep doing as I am doing - topping off the battery charge whenever there is the possibility of a power outage. Then it is ready to hook up during the night should the power fail. The Respironics battery is supposed to have a 6 month shelf life on a full charge so I expect it would have enough charge for one night if I needed it and had not topped it off but it happens within a 6 month time period. With my 90% pressure it says on the cpap.com site that I can get probably 24 hours from a full charge. That's without heated humidity of course. In passover mode, the humidifier is not drawing any power so I am fine there.

Fortunately we don't have many all night power outages but one never knows.

Thanks again!!

[builta]

Builta - thanks so much for taking time to explain all that to me! I do appreciate it but all the "battery jargon" is simply above my head.

I have posted about batteries and UPS many times in the past but, so far, the light bulb has not come on!!

If it's like most other things, one of these days, with a certain phrasing in a post,I will, all of a sudden - get it!!

I almost always use my humidifiers in passover mode so that is no problem. I did not intend to try the F & P standalone humidifier with a battery setup. It does have a separate AC plug but, in passover mode, even that would work in a power outage.

Until "the light dawns" ,I will just keep doing as I am doing - topping off the battery charge whenever there is the possibility of a power outage. Then it is ready to hook up during the night should the power fail. The Respironics battery is supposed to have a 6 month shelf life on a full charge so I expect it would have enough charge for one night if I needed it and had not topped it off but it happens within a 6 month time period. With my 90% pressure it says on the cpap.com site that I can get probably 24 hours from a full charge. That's without heated humidity of course. In passover mode, the humidifier is not drawing any power so I am fine there.

Fortunately we don't have many all night power outages but one never knows.

Thanks again!!

Hi,

Sorry that I went over your head. I felt obligated for various reasons.

Look at your battery backup paperwork and see if it tells you what type of battery is built into your unit. This will change based on when the unit was manufactured. This is relatively important because different types of batteries ""like to be charged and stored differently" to prolong their long term life and their ability to hold and release power. Just because the literature says that the unit can go 6 months between recharging, that doesn't mean that it is best for the battery's life to do that.

I would look for something that indicates "Lithium," "Lithium Ion," "Gel," "Spill proof," "AGM," "Nichel Metal Hidride," "NiM," "Lead Acid." Let us know what it says.

I guess that the most important thing to remember is that it is likely that over time the battery will loose its ability to hold and deliver power (usually in the 3-5 year time frame--maybe sooner if they used or charged/not charged in what the battery industry refers to as an "abusive" manor.) This is true for basically every battery system out there. So, finding one that works for you and if possible allows you to change the batteries out after they age and learning how to properly use, charge and maintain the battery system is good for the pocket book.

I personally want a battery system that I can just for multiple applications that way I get more "Utility" out of the battery investment before it's life is used up. I have an RV and will switch out the batteries between my RV and House for increased utility. So, it will be sized for the RV. That will give me long run times on my BiPAP and Heated Humidifier but boy, it is a heavy battery. Not what I would suggest would be ideal for others. But, it is good in my circumstances. For business travel I will travel without backup. I tend to do a lot of air travel (several times a week and often internationally in 4 to 6 month bursts) and will only travel light and easy. The security and airline restrictions and rolling change cause unexpected delays or other difficulties--just too many different requirements and I hate missing the plane.

[Hawthorne]

It is a "sealed lead-acid battery". Says something about a "12V, 2.3A switch mode charger designed to effectively charge sealed lead-acid batteries while protecting the batteries from overcharging. (I have the charger).

It says- A universal voltage input of 100-240 ". "Reverse polarity and short circuit protection".
A charge time of 10 hours on a completely drained battery. Less if there is still power in the battery when charging begins. A shelf life of 6-9 months when not in use.

The little manual says-
BATTERY PACK
Power- 14.4AH (depending upon prescription pressure and breathing patterns).
Fuse- Mini 15 A Littlefuse or equivilent. A couple of spare fuses came with it. It looks to me like the fuse is for the charger- according to the documentation.

CHARGER
Input rating- Nominal 90-264 VAC/47-63Hz
Nominal Voltage rating - 12V
Charging Voltage -14.7V
Charging Current - 2.3A
Auto Adapter fuse -3A
Maximum output power - 35W
Temperature range - -10 C to 40 C.
Safety Conforms to EN 60601-1

I think I got all those numbers right!!

Any help??

I would not take it when I travel. I don't camp or RV. It is strictly for home use in a longer term (several hours to several days ) power outage. I might take it for extended stay somewhere power might be iffy. That would be only if I were driving. It weighs about 13 lbs.

[nobody]

It is a "sealed lead-acid battery". Says something about a "12V, 2.3A switch mode charger designed to effectively charge sealed lead-acid batteries while protecting the batteries from overcharging. (I have the charger).

It should be fine to leave it plugged in with that.

[builta]

It is a "sealed lead-acid battery". Says something about a "12V, 2.3A switch mode charger designed to effectively charge sealed lead-acid batteries while protecting the batteries from overcharging. (I have the charger).

It says- A universal voltage input of 100-240 ". "Reverse polarity and short circuit protection".
A charge time of 10 hours on a completely drained battery. Less if there is still power in the battery when charging begins. A shelf life of 6-9 months when not in use.

The little manual says-
BATTERY PACK
Power- 14.4AH (depending upon prescription pressure and breathing patterns).
Fuse- Mini 15 A Littlefuse or equivilent. A couple of spare fuses came with it. It looks to me like the fuse is for the charger- according to the documentation.

CHARGER
Input rating- Nominal 90-264 VAC/47-63Hz
Nominal Voltage rating - 12V
Charging Voltage -14.7V
Charging Current - 2.3A
Auto Adapter fuse -3A
Maximum output power - 35W
Temperature range - -10 C to 40 C.
Safety Conforms to EN 60601-1

I think I got all those numbers right!!

Any help??

I would not take it when I travel. I don't camp or RV. It is strictly for home use in a longer term (several hours to several days ) power outage. I might take it for extended stay somewhere power might be iffy. That would be only if I were driving. It weighs about 13 lbs.

Hi,

I think that you can relax. You have a good back up system for your XPAP.

A Sealed Lead acid battery is a good save type of Lead acid battery. I suspect that it is a AGM type rather then a Gel type, but I don't know for sure. An AGM type battery is the most forgiving of the typically available lead acid batteries. Your charger is a "Multi Stage" charger--this is good.

Note--The only thing that I cannot determine is if your charger has a "float setting" which would lower the voltage to about 13.5 volt DC. If it has a float setting then leaving it plugged in all the time will not hurt the battery--but I cannot recommend this to you without knowing about the "Float setting" that I just mentioned. Too bad you cannot find this information in you paperwork. It is not listed in the Respironics web site either. Maybe someone else in the forum has this information. You could test for this but, I'm not sure if you are comfortable around electricity, mechanically inclined and have a volt meter.

I would suggest that as a minumim you should recharge your battery pack at least once a month to keep it topped off. I know that the literature said that it can be store for up to 6-9 months but, more frequent charging will help prolong battery life in storage. I think that the little bit of extra energy that you use to frequently recharge it is worth the extended battery life. If you forget to charge it for a month or two no big issue but, if you forget to charge it for a year or two that is a different type of story.

Here is a good (read this as not too "techy") FAQ for Lead Acid Batteries:
http://www.windsun.com/Batteries/Battery_FAQ.htm

[Hawthorne]

Thanks for all the help in understanding the battery backup I have! I'm understanding it much more, thanks to this thread.

Builta - that link you gave me is just great and not too "techy"! The FAQ section really helped as well. I'm now planning to top off the charge every month ( when I change the white filter in my cpap machine) rather than leave it plugged in all the time. If I forget once in a while I still feel I have backup available. I am thinking I don't want it plugged in all the time. Also, I am not comfortable enough to test for that float setting, which I am not sure I have. I checked again but did not see that at all in the documentation.

Thanks again all!!

[billbolton]

Power conversion efficiency is not a simply 90+% type answer, it depends on many factors.

Power conversion from low voltage DC to mains voltage AC is a fairly straightforward technology nowadays, and achieving power conversion efficencies of 90%+ using readily available design approaches has been discussed previously here.... and right now I don't have time to go through it all again, but a few minutes with the search facility should turn it up.

Cheers,

Bill (MIEEE)

[builta]

Hi Hawthorne,

I'm glad the the information that we provided was helpful. Again I think, that your backup unit is a good balance of function and ease of use for your particulare needs.