New Battery and Amp-Hour Data

Thanks. It fits. The two quick connector plugs from the two brands look exactly alike.

Hello All,

I am brand new to this forum and have not had much time to explore all the topics, but I am a Mechanical Engineer by degree and Software & Circuits Engineer by job title for the Military. I am also a huge DIY person.
That being said,

I have been looking into batteries for my respironics CPAP by philips, and the price point is incredibly high...
Because of my background with electronic circuits and microprocessors, etc... I think it is about time that someone comes out with a reasonably priced UPS Battery pack, that will actually last a long time...(For a decent price)

So anyway, I have been picking up bits of data on power consumption little by little here and there for CPAP machines... And honestly there is no standard due to the fact that every user is different and probably has more or less Apnea per night than another user... So I have started to compile a list for correlation and trying to find the redundant patterns as well as the best algorithms to compile and utilize the data...
Basically I am trying to extrapolate and interpolate from the results that I can find online... so far it is not a large list, mostly due to the fact of so many CPAPs on the market and data spread all over the web... And due to the feature usage like the pressure and humidification level, there are quite some obstacles to figure it all out,... but the first post of this Data was very helpful.
It made several things very clear... If you are not a math person, here is what it meant...
NOTHING IS LINEAR!!!

Even with the same user and the same settings, the power usage varies alot... So... To make a battery to fit everyone's needs is not really possible, since every user is going to use different settings and additionally have more or less Apneas per night causing the machine to compensate, and therfore change its power usage.... (Sometimes Wildly)...

It would only make sense to buy the battery you actually need, or the battery that you think you will need...
Then of course there are people like me who want to be prepared for the worse case scenario...

So, Even thought I am brand new here, I am hoping to get some feedback from the Techies and Even the NON Technical People, who want to contribute....
Basically it boils down to nightly usage (hours, ampHours,wattHours&Voltages, or anything else.... but always including the machine type and its voltage "requirements") without the AC-to-DC Voltage conversion, it can be quite difficult to figure out some of the unknown variables... If you have a "Kill-A-Watt" device or something to monitor power consumption,... that is amazing even in AC current, because it tells you the VA and Watts... as well as the power factor...

If you are interested in having a long lasting UPS for much less than what the medical device companies charge for such a thing... please contribute to my data, and help me create plans for backup batteries on a budget for the everyday person, who cannot afford a $600 battery from philips... Or even a $300 version from Freedom Medical(low Power for the price anyway.. )... aftermarket battery...

I am hoping to get some good feed back from everyone where possible...
Honestly, I am going to do this either way, but I do not use very much pressure (4cmH2O), so my battery needs may be much less that others, but as I see this MADNESS in the Market, I want to help everyone out... And I know that most people are around 8+ cmH2O..... Usually on the higher side like 10-14...), but with enough data points the extrapolate from, I am quite sure I can get you in the ballpark for power consumption based on your levels of usage....

My goal is to create a UPS backup for the everyday user, who would like the comfort (at home or AWAY) that the CPAP will continuously work even during a power outage...
(Because I am a prepper... NOW.... and if you want the long story read the bottom...)
So, I have studies the designs of pass through chargers and TRUE UPS devices and realized there is a huge difference... The battery compositions and what that means for Voltage, Amperage and Wattage... Battery chemistry, Discharge Compatibility, Charge Comparisons, and so much more...
Who knew there was so much involved with a simple battery...(Mind Boggling)

A secondary goal is to create a somewhat long term battery, for unusual circumstances.. (my only example that hits home was from Hurricane Katrina back in 2005 when we did not have power for weeks and were completely reliant on the fuel brought in by family members for our generators to provide minimal power, for DeepChestFreezers and AirConditioning@night)...notably many had it worse, however in the deep south those without A/C at night in one form or another, did not sleep much at all... (I know I was lucky to have an out of state getaway)... And now considering the fact that I have this crazy Apnea...(I'm not sure how I could function after another event like that.. and We had over 8 feet of water in our home, survived on Government MRE food, and things I never would have imagined..), but dont get me wrong... I know many people have never experienced such things and others have experiences even worse... but to that end, I have basically come up with a few codes and self builds that could help with those people who suffer with Sleep Apnea...


Anyway, I have talked enough for this post... And if you want more details, just message me. I am pretty much an open book, at least CPAP considering...

Hope Everyone is Safe,
Bye,
J

Alternatively, spend $70 on a 35ah scooter battery, $50 on a battery tender, a few bucks on a box, and whatever for the 12V cord on your cpap, and just go to sleep.

J_CPAP_Guy_Mech_Eng wrote: ↑

Thu Jul 23, 2020 12:15 am

Hello All,

I am brand new to this forum and have not had much time to explore all the topics, but I am a Mechanical Engineer by degree and Software & Circuits Engineer by job title for the Military. I am also a huge DIY person.
That being said,

I have been looking into batteries for my respironics CPAP by philips, and the price point is incredibly high...
Because of my background with electronic circuits and microprocessors, etc... I think it is about time that someone comes out with a reasonably priced UPS Battery pack, that will actually last a long time...(For a decent price)

So anyway, I have been picking up bits of data on power consumption little by little here and there for CPAP machines... And honestly there is no standard due to the fact that every user is different and probably has more or less Apnea per night than another user... So I have started to compile a list for correlation and trying to find the redundant patterns as well as the best algorithms to compile and utilize the data...
Basically I am trying to extrapolate and interpolate from the results that I can find online... so far it is not a large list, mostly due to the fact of so many CPAPs on the market and data spread all over the web... And due to the feature usage like the pressure and humidification level, there are quite some obstacles to figure it all out,... but the first post of this Data was very helpful.
It made several things very clear... If you are not a math person, here is what it meant...
NOTHING IS LINEAR!!!

Even with the same user and the same settings, the power usage varies alot... So... To make a battery to fit everyone's needs is not really possible, since every user is going to use different settings and additionally have more or less Apneas per night causing the machine to compensate, and therfore change its power usage.... (Sometimes Wildly)...

It would only make sense to buy the battery you actually need, or the battery that you think you will need...
Then of course there are people like me who want to be prepared for the worse case scenario...

So, Even thought I am brand new here, I am hoping to get some feedback from the Techies and Even the NON Technical People, who want to contribute....
Basically it boils down to nightly usage (hours, ampHours,wattHours&Voltages, or anything else.... but always including the machine type and its voltage "requirements") without the AC-to-DC Voltage conversion, it can be quite difficult to figure out some of the unknown variables... If you have a "Kill-A-Watt" device or something to monitor power consumption,... that is amazing even in AC current, because it tells you the VA and Watts... as well as the power factor...

If you are interested in having a long lasting UPS for much less than what the medical device companies charge for such a thing... please contribute to my data, and help me create plans for backup batteries on a budget for the everyday person, who cannot afford a $600 battery from philips... Or even a $300 version from Freedom Medical(low Power for the price anyway.. )... aftermarket battery...

I am hoping to get some good feed back from everyone where possible...
Honestly, I am going to do this either way, but I do not use very much pressure (4cmH2O), so my battery needs may be much less that others, but as I see this MADNESS in the Market, I want to help everyone out... And I know that most people are around 8+ cmH2O..... Usually on the higher side like 10-14...), but with enough data points the extrapolate from, I am quite sure I can get you in the ballpark for power consumption based on your levels of usage....

My goal is to create a UPS backup for the everyday user, who would like the comfort (at home or AWAY) that the CPAP will continuously work even during a power outage...
(Because I am a prepper... NOW.... and if you want the long story read the bottom...)
So, I have studies the designs of pass through chargers and TRUE UPS devices and realized there is a huge difference... The battery compositions and what that means for Voltage, Amperage and Wattage... Battery chemistry, Discharge Compatibility, Charge Comparisons, and so much more...
Who knew there was so much involved with a simple battery...(Mind Boggling)

A secondary goal is to create a somewhat long term battery, for unusual circumstances.. (my only example that hits home was from Hurricane Katrina back in 2005 when we did not have power for weeks and were completely reliant on the fuel brought in by family members for our generators to provide minimal power, for DeepChestFreezers and AirConditioning@night)...notably many had it worse, however in the deep south those without A/C at night in one form or another, did not sleep much at all... (I know I was lucky to have an out of state getaway)... And now considering the fact that I have this crazy Apnea...(I'm not sure how I could function after another event like that.. and We had over 8 feet of water in our home, survived on Government MRE food, and things I never would have imagined..), but dont get me wrong... I know many people have never experienced such things and others have experiences even worse... but to that end, I have basically come up with a few codes and self builds that could help with those people who suffer with Sleep Apnea...


Anyway, I have talked enough for this post... And if you want more details, just message me. I am pretty much an open book, at least CPAP considering...

Hope Everyone is Safe,
Bye,
J

For about almost everything you need to know on powering a XPAP on battery, it's here: viewtopic/t114012/Choosing-a-Battery.html ! It does require reading to get the knowledge. The choices of what people need comes from what they want to do with it, and economics along with knowledge how things work.

Questions to ask are needs:

Power needed to run the XPAP the way you plan to run it.
How many days you want it to power the load without charging.
Whether overall Cost or Easy of use are needed.
Portable or fixed location.
Power needed, 12 Volt or 24 Volt. I think the right time to chose this would be when you buy your XPAP, however many don't, there are workarounds for 24 volt off of 12 volt power with a loss in efficiency.

There are probably many more things to consider, it's not cut and dried, a system of trade-offs. That's not counting the many solutions out there.
Lead Acid or Lith Ion, all have their quirks, and types each with their own needs, it's not just a bottle of electricity. Jim

More power is always better!

Goofproof wrote: ↑

Thu Jul 23, 2020 1:18 pm

Power needed, 12 Volt or 24 Volt. I think the right time to chose this would be when you buy your XPAP, however many don't, there are workarounds for 24 volt off of 12 volt power with a loss in efficiency.

Warning: Electronics knowledge ahead. Abandon hope of understanding if you lacking a basic grounding (could not resist)

The 12 to 24v thing is true, but as you say there are workaround. The loss of a *good* buck or boost converter is far less than the loss of an inverter, for example. Some of them achieve 90%+ efficiency.

It would not be impossible to design a battery that provided 12V using 2 batteries in parallel, or 24v with the two in series. Easy change that could be done electronically, then no loss in efficiency. The 24V units tend to require about half the current (amps) as the 12V, as would make sense.

BUT (there's at least one, always) the real determination of how much current is needed is the humidifier. If you're going camping, or designing a ready-to-use but not always-on solution, then the easier answer is to turn the humidifier off when on battery.

But a true UPS would mean not waking me up just because power went out, and that means the humidifier is going to run.

On my series 60 at about 15cm with humidity setting in the middle, it would draw almost 4 amps at start, and then between 2 and 3 amps as you used it.

I have not measured the Resmed (at 24v) yet, but I think it'll be about half.

Battery technology is a big problem. Most batteries are least happy remaining fully charged. Li-Ion technology would be a poor choice without custom electronics that limited the state of charge to 70-80% tops. For true long life you'd limit the bottom too, but in this case I say use it until the batteries are depleted (using a BMS). A Lead Acid battery is better ... a tender would keep it safely topped off without too much impact on lifetime. The problem with Lead Acid batteries is they don't like being fully discharged, and doing so can kill the battery, if not reduce it's capacity.

Lots to think about...

I’m new to the site so forgive me if I make a transgression.

I went without my CPAP for all night two weeks ago due to a storm outage. Without my CPAP it was miserable. I slept upright in a recliner (without being reclined) to minimize the Apnea. When the power came back on I resisted taking a nap to catch up and instead went to sleep an hour early.

The next day I started investigating a battery backup. My first reaction was that it was highway robbery for a backup battery. $300, and it would only last one night. Several years ago we were without power for four days. So one night isn’t going to cut it.

I began searching the Internet looking for a solution and ran across a thread in another forum that directed me here.

So here is what I’m thinking of doing. Buy two lead acid batteries with a large enough capacity to run my Airsense Autoset for three of four nights. I haven’t figured out the size, but I’m guessing a couple of group 24 batteries might be required. Funny thing is I have an associates degree in electronics, but haven’t used it in over 20 years and the knowledge seems to have escaped me. Anyway, I transgress. I would hook the batteries in series to obtain the 24 volts. Then I would connect a 24 volt charger across the batteries to keep them topped off and power the CPAP, while I have utility power. Then when the power goes off, the batteries would power the machine. No loss of pressure, so unless I sensed the loss of the ceiling fan, or my stupid security system alarms for no utility, I would stay in blissful sleep.

So tell me what I’m missing. Why wouldn’t this work? I figure the cost to be about $200 and I get three or four nights backup instead of one.

Not much.

You'll want the batteries in some kind of container because they are acidic. I recommend agm batteries because in theory they are less likely to leak. The container must NOT be air tight, or hydrogen can build up. No indoor Hindenburgs please.

The charger must be a tender, so as not to overcharge.

And you'll need the Resmed power cable.

khauser wrote: ↑

Fri Jul 24, 2020 8:44 pm

Not much.

You'll want the batteries in some kind of container because they are acidic. I recommend agm batteries because in theory they are less likely to leak. The container must NOT be air tight, or hydrogen can build up. No indoor Hindenburgs please.

The charger must be a tender, so as not to overcharge.

And you'll need the Resmed power cable.

Thanks for the response. I was planning on using AGM batteries, and I’ve been struggling with the container. I’m sure the CEO isn’t going to want this ugly thing in her bedroom so I need to dress it up as much as possible. I had not thought through to the connection, but willlook at that as well.

Ejones0310 wrote: ↑

Sat Jul 25, 2020 8:30 am

khauser wrote: ↑

Fri Jul 24, 2020 8:44 pm

Not much.

You'll want the batteries in some kind of container because they are acidic. I recommend agm batteries because in theory they are less likely to leak. The container must NOT be air tight, or hydrogen can build up. No indoor Hindenburgs please.

The charger must be a tender, so as not to overcharge.

And you'll need the Resmed power cable.

Thanks for the response. I was planning on using AGM batteries, and I’ve been struggling with the container. I’m sure the CEO isn’t going to want this ugly thing in her bedroom so I need to dress it up as much as possible. I had not thought through to the connection, but willlook at that as well.

Under a XPAP table, out of sight, out of mind all you have to see is the power cord to the machine. Put it in a battery box, they don't look bad. Jim

I've did a lot of reading on the topic of a battery backup for my CPAP machine. I got a lot of information from you folks here and this is what I did. I have an old RemStar M series which there is no battery backup available even if I was willing to spend 3-5 hundred (Canadian Dollars) which I'm NOT lol

The first thing I did was order a "Shielded D.C. Power Cord" that would work with my machine. I got mine here: $52.75 CAD
https://www.google.com/search?q=Item+%2 ... e&ie=UTF-8

Next I took a chance a bought a small battery (that if it wasn't big enough, it fits perfectly in my lawn tractor) In my area we rarely get power outages that last more than a few hours, so I took a risk that this smaller battery would do fine, and it DID <smile> I bought this lead acid battery for $48.99 from here: https://www.canadiantire.ca/en/pdp/moto ... 2050p.html

Lastly I purchased a "Battery Tender Junior" for $49.99 from here: https://www.canadiantire.ca/en/pdp/batt ... 1940p.html

I'm all in @ $151.73 CAD. You Americans should get these items a lot cheaper than I did.

I also took a chance that this little .75 amp charger/maintainer wouldn't be able to keep up because I really had no positive idea how much power my machine drew.

Well I hooked everything no trouble and let my machine run for a 24 hour test, I don't use the humidifier and I'm set at 18-19. Well, not only did this little battery keep my machine running for 24 hours straight, that little charger is supposed to have a flashing green light when the battery is at 80% full. I was amazed that after 24 hours the charger light was still solid green meaning fully or at least above 80% charged.

After what I've observed in my situation, I could definitely sleep 10-12 hours on battery power. I'm not sure at this point if I'm going to run on AC or DC power full time? If I decide on AC, I will keep everything hooked up to the battery/charger and if the power does go out, all I'll have to do is switch the power plugs in the back of the machine and go back to sleep.

After finding a bit info here and other sites, I was able to satisfy my particular situation. I registered here so I could pass on my experiences with the forum in the hopes it will be of help to someone. Thanks: Dave Ontario Canada

Thanks for this very useful information!

I bought one of those hobby meters as well and ran a test on my AirSense 10 at my normal settings including humidifier and heated hose, pressure average 9, humidity 3/8, tube temp 80.

It used about 17.1 Ah per 8 hours.

So I figure I could get just about two nights out of the U1 Weize 12V 35AH battery, maybe with turning off the heated hose to be safe.

J_CPAP_Guy_Mech_Eng wrote: ↑

Thu Jul 23, 2020 12:15 am

...Basically it boils down to nightly usage (hours, ampHours,wattHours&Voltages, or anything else.... but always including the machine type and its voltage "requirements")...

I am clueless about electrical stuff, likely from getting shocked several times that freaked me out as a child, once as a toddler when I got my little hands on bobby pins and with plugs at eye level well you guessed it, another when my idiotic step-father wired the front door handle for Halloween night, etc. so I am leary . I have a GoalZero Escape battery (since discontinued with no equivalent replacement) that has to be recharged frequently so it's dying . During power outages, I just plug my ResMed S9 into it, reset to a narrow pressure range, hit Start, and go back to sleep -- I do not use the humidifier. I have been looking at this https://smile.amazon.com/gp/product/B07 ... AIWF&psc=1 but $250 with their discount and no solar recharge option it is both pricey and not ideal. Power outages in the Atlanta, GA area are usually just hours long, a few have lasted overnight, but with our penchant for ice storms, there is always the potential for multiple nights, so...

ResMed S9, no humidifier, pressure ranges from 10-17 tho I re-set the range to current average to 1 above whatever my 7 day average has been (I keep track on paper so I know the number) -- this is usually like 13-14 unless congestion is horrible and pressure would be like 16-17. I would like 4-5 nights without re-charge and the option to plug into house power as well as solar just in case. I usually sleep 8.25 hours. Do you need the info on my solar panels? I've never needed to use them and they are old, purchased 2009 or 2010 when I bought the Escape battery. I will see if I can find the data on my S9, I never throw away that sort of info but I have no idea where it might be, the only thing I sorta remember is 90W.

Hi J_CPAP_Guy_Mech_Eng,

Just posted this on another thread. Use a modular set up with two Half-U1 20AH AGM batteries and a solar panel. One battery easily supports two nights of use without recharging. Went a week with two batteries and 30 watt solar panel (summer time near a beach so lots of sunlight hours) running CPAP, a fan and charging phones. Basic set-up with one battery can be achieved for $75 -80. Details below.

Hope this helps you in your quest.

Post by Lane101 » Mon Jan 04, 2021 11:26 am
Hi SevenDay,

I've built a modular battery back up for my Respironics CPAP using Half U1 size 20 amp hour (AH) sealed lead acid absorbed glass mat (AGM) batteries that weight roughly 12 lb. each. At 10cm of pressure one of these easily powers my CPAP for two nights of camping (roughly 5 AH per night) with power to spare for charging cell phones (safe to use up to 80% of an AGM battery's capacity or 16 out of 20AH). To run your Airsense 10 on a 12 volt DC battery you will need either the ResMed DC Converter or a 120v power Inverter since the ResMed runs on 24volts DC or 120 volts AC. The converter is available on the following link:

https://www.cpap.com/productpage/resmed ... 0-machines

Note that my setup only runs my CPAP, not the humidifier. Running the humidifier will require a multiple of the battery capacity and may exceed the current capacity of the various components used in my set up. Also the ResMed converter looks like it includes a 12V socket adapter with alligator clips. Don't recommend using alligator clips as a primary connection due to the heightened risk of a short circuit on the exposed connectors.

You will also need 12volt Adapter Plug cigarette lighter type socket that can be attached to the batter with an in-line fuse on the positive terminal. My set-up uses the NOCO-GC018 with a 7.5AH fuse (reduced from the 15AH that comes with the adapter). The ResMed DC converter will plug directly into this. I place the battery in the bottom section of a plastic Harbor Freight Ammo Box and then place the box in a soft side tool bag for transport and storage.

With a converter or inverter you will likely only achieve 70 - 80 % power efficiency meaning that to deliver 5 AH per night the 6 to 7AH will be drained from the battery. Additionally your power requirements will also vary per your actual prescription pressure. If you require pressure that is much higher than 10cm a second battery may be needed (my preference for a modular approach per details below as we use this for camping) or a full U1 size, that typically has a 35AH capacity (may be fine for your needs if just used at home for power failures), can be used. With the full U1 size there are plastic battery boxes available instead of the ammo can. Full U1 size may also be preferred if you run 2 machines on one battery as a higher current draw in excess of 5% of a battery's specified capacity (e.g. 1AH for a 20AH battery) will result in less overall available battery capacity (battery spec sheets provide detailed info on this).

This type of half U1 battery runs at about $40 on Amazon with the other components (12volt adapter socket, ammo can, tool bag and electrical tape) running around $30+/-. You will also need a charger for the battery that runs from $10 to $40 depending on charge rate/features. The ResMed DC converter is the most expensive item at $70 to $80. A 120v modified sine wave inverter will run around half that cost though you need to confirm that you AirSense can run on this type of power output.

Note that you need to ensure that all exposed connections are well wrapped in electrical tape to minimize chances of an accidental electrical short.

My current set up is more complex than the above to provide lots of usage flexibility and the addition of a solar panel for longer camping trips. Just one battery is needed for a 2 night weekend camp out and with the second battery and my solar panel we camped for an entire week running my CPAP and a fan at night while also charging cell phones as needed.

Details on my battery set up and the setup of Bbergin76 (he used a 35ah battery) from an earlier post (from same thread you were provided earlier) on the following link: viewtopic/t114012/Choosing-a-Battery.ht ... &start=180 are pasted below as follows:

Lane101 wrote: ↑
Fri Jun 14, 2019 1:45 pm
Hi Bbergin 76,

The ExpertPower 12200 battery terminals work well with O-Ring adapter connectors; mine are hooked up that way. Just screw the connectors on. Note that my battery packs use o-ring connectors that are smaller than those on the Deltran (custom spliced 12 awg wire with Anderson Pole connectors on the other end) for both of my battery packs. The M5 bolts on the 1200 battery are 5mm across while the Deltran connectors are 3/8" (approx. 9.5 mm). You will need to check if a wider washer to hold the connectors securely. Once connected any exposed connections should be covered with electrical tape for added safety. Be careful when connecting wires to the battery terminal. A battery of this size can generate over 200 amps in a short circuit (even more for a full U1 size). I typically keep one terminal covered with electrical tape when making direct to battery connections. If you to the multiple battery route (one U1 and a second half-U1 size) you should by an extra Deltran SAE/O-ring connector so you don't have to deal with exposed terminals while camping.

Note, if you are referring the the Mighty Max U1 35ah battery the O-rings should also work. You may need to purchase connection hardware for this one (nuts, bolts and locknut washers). Again need to match hardware size to O-rings and battery terminals. One of my original half-U1 batteries had terminals like this.

U1 is a battery size. The Exp12200 and similar 18 - 22 amp hour batteries are often referred to as Half-U1 size. Note that while the Exp12200 specifications allow charging at up to 6 amps per hour it is more optimal to keep the charging rate below 4 amps/hour (referred to as .2 of Capacity or "C"). Would recommend the 3 amp charger as ideal if you also have a separate U1 battery.

Absolutely stick with AGM batteries for camping. They are the safest lead-acid type battery and the only type that does not vent gasses unless damaged or overcharged. Both Gel and flooded lead-acid require venting (source Battery University @ batteryuniversity.com). AGM is the only type I would use indoors or in a tent. Also, you can use 80% of an AGM battery's capacity versus a max of 50% of a flooded batter without damaging it.

P.S. Regarding Goofproof's comment. It is correct, we are seeking to protect both the device and the wiring from a current overload and one size often doesn't fit all. In your specific case, for charging with a Deltran Battery Tender (3 amp or less) and use of a Dreamstation, a 7.5 amp should protect both the CPAP, charger and wires given that it is the specified/provided fuse for the Deltran and below the 8 amps provided in the Dreamstation DC connector.

Good example of Goofproof's point is my set up (more complex with an inverter and solar power) where I use a 15 amp fuse on a 12 awg main battery connector with lower capacity fuses for the various items (bespoke Anderson pole connector for each that plugs into the main battery cable) in my modular system including:

- 5 amp fuse for my CPAP machines - 18 awg with barrel connector for CPAP with Anderson connectors for battery connection
- 7.5 amp fuse for the 3 amp Deltran charger - use the connector provided by Deltran, cut off the O-rings and spliced on the Anderson connectors
- 5 amp fuse for the solar panel wire (cable connects to solar charge controller)
- 7.5 amp fuse on my NOCO cigarette lighter socket (use to charge phones with a USB charger in the socket and to run our air mattress inflater)
- no additional fuse for the 400 watt inverter - 15 amp main cable fuse is more than sufficient as I want to cap the power draw to 180 watts given the size of my batteries. Also the inverter has its own fuses.

My system evolved over time. Started with just an 18 awg barrel connector cable for my CPAP with just a 5 amp fuse and one battery. Bought a second to camp more that 2 -3 nights. Later added an inverter that also had USB chargers that required the separate 12 awg cable to support it. Added the solar panel last year to support a week long camping trip to Assateague Island. Converted to Anderson pole connectors with the addition of the solar panel and also added the NOCO cigarette lighter adapter at the same time. Sounds like you don't require this level of complexity for your needs.

Hi Lane,

Sorry to resurrect on old post here. I've built my 35Ah battery for my wife's CPAP and its working well in testing, now I am looking to build a smaller 20Ah battery to be able to recharge electronics and blow up our air mattresses. This is what I am looking at and was wondering of your input.

Battery: https://www.amazon.com/ExpertPower-EXP1 ... way&sr=8-1
Connector: https://www.amazon.com/NOCO-GC018-Adapt ... ive&sr=1-1 Should I look to use a smaller fuse than the 15A that it comes with?
Inverter: https://www.amazon.com/Ampeak-400W-Powe ... way&sr=8-3 to be able to connect various electronics for charging.

Could it really be that simple, or am I missing something? I would of course get a box to be able to contain the battery.


Hi Bbergin76,

The three components you list are exactly the items currently in our modular system and with the caveats below they have all worked well since they were acquired as upgrades/replacements for our 2018 Assateague Island trip mentioned earlier. Comments as follows:

1) ExpertPower 12200 20ah battery: Bought our first one last year right before our Assateague trip and it has worked well. Arrived fully charged reading 13.1 volts with no load and, based on usage, appears to deliver stated amp hour capacity. Second replacement battery delivered this year arrived in similar condition and did well in an initial load test. Based on experience and generally good reviews would recommend the battery. Also at $40 on Amazon it's priced well. One year after purchase the first battery is still doing well. Note that in the off-season we top off the charge every couple of months and additionally cycle the batteries (use only 20% of capacity) if not used for 4 months to prevent sulfation. We have 5 other lower capacity (7 and 8 amp hour) ExpertPower batteries as replacements for our PC UPS and Verizon Fios backup that have also worked well - so far for up to 2 and a half years. Good ratings on Amazon also support this.

2) NOCO GC018: This has worked will for us as noted earlier. Note that the 15 amp fuse that comes with it is too high for 16 awg wire and needs to be replaced with a lower capacity fuse. See the June 16th review by sandygee for this item (full disclosure that the review is mine and this is our family account under my wife's online name). When we stripped the wires to attach the Anderson connectors we discovered something other than 100% copper wire (see review pictures). Normally a 10 amp fuse would be fine for 16awg wire, we used a 7.5 amp fuse in case this is aluminum. We currently use this adapter to inflate our air mattresses (12 volt inflater that does not require an inverter) and charge phones (with a 5 volt cigarette lighter charger) when camping.

3) Ampeak 400watt inverter: Has performed well for us since purchased last year. Overkill with a 20 ah battery but we wanted the extra capacity should we want to use in on our auto in an emergency. You really don't want to draw more than 5 amps (60 watts) from a 20 ah (battery will last about 3 hours before dropping below 11 volts when new). At 12 amps (144 watts) the battery will only last an hour.

If you plan on staying at or below 5 amps you may be able to use the cigarette lighter adapter that comes with the Ampeak and the NOCO GC018 with a 7.5 amp fuse. Per CapnLoki keep some spares in case a power spike blows the fuse. With 50% extra fuse capacity there should be minimal nuisance fuse blows. Test it out with your planned power loads to ensure that there isn't an excessive voltage drop or initial voltage spike that blows your NOCO fuse.

We converted to 12 awg wire from our battery to minimize DC voltage drop in addition to providing a 20 amp current capacity for additional safety margin with a 15 amp fuse. When we first build our camping power supplies years back we found that our prior inverter (Harbor Freight) would kick in with a low voltage alarm with smaller 18 gauge wire/barrel connectors that ran my CPAP and could theoretically handle the amps required for the desired inverter use. Have had no issues with the 12 gauge auto zip wire we currently use direct to the inverter.

One additional note, we replaced the two 35 amp fuses that come installed in the Ampeak with 25 amp fuses for better protection in emergency use as we don't expect to use full unit capacity. With our battery pack the 15 amp fuse on wire that connects to the Ampeak will blow long before the inverter fuses ever come into play. See my June 4th, 2018 review for the Ampeak on Amazon under sandygee for additional perspective. Only complaint was that the fan kicks in at lower power usage than expected (60 watt test). Still much better than the older inverter this replaced. Fan did not kick in for our AC current ZZZPap machine, that I use at home, when tested. The externally mounted user replaceable fuses are a big plus for this unit as many inverters at this price point have fuses that are soldered in and not user replaceable.

You have a variety of options to house a battery of this size. We place our half-U1 size 20ah batteries in the bottom half of an inexpensive plastic ammo box or Rubbermaid 3.25"x 9"X 2" vinyl/rubber drawer organizer that in turn is placed in a 12 inch tool bag that is easy to carry. Wanted something hard protecting the battery base and bag has space for a charger and or inverter plus cables. Within the bag all metal connections are covered with heat shrink tubing and/or electrical tape so there is nothing exposed to an accidental short circuit. Just unzip the bag and pull out the battery wire. We use this bag for one of our 20ah batteries:
https://www.amazon.com/Husky-Inch-Contr ... 0778&psc=1
Can often find it at Home Depot for less. The draw organizer in one battery pack is from Target and the ammo box bottom from Harbor Freight (typically $3.99 with coupon). Just remove the top. Other types of soft side bags/small backpack may work. In the case of your 35 ah battery just get a U1 battery box.

Got the idea for a soft side container from the now discontinued Respironics Battery Pack. See the link below at cpap.com that has a picture of the opened pack with a taped lead acid agm battery:
https://www.cpap.com/productpage/respir ... -cable-kit
By the way, the detailed specs on this show a 14.4 amp hour capacity - 80% of an 18 amp hour Half-U1 size battery that was likely used. Validated a lot of my design on these specs including the fuses. This uses a main 15 amp fuse on the battery with either a 3, 5 or 7 amp fuse on the CPAP machine cord based on specific device specifications.


Feel free to reach out with any additional questions.