battery backup recommendations as10/as11

[Crimson Nape]

robbob2112 - You stated that you didn't see an A10 ASV listed. All A10's used the same hardware, and in theory, should have the same power draw. The difference of A10 models is the firmware. You could always use the S9 VPAP Adapt listing. It is the S9 ASV name. There is slight difference in power draw.

- Red

[robbob2112]

Ok, I played with chatGPT a lot more and here is what I came up with -
using 3 amps as max draw for the standard pap
The full 90watts of the ASV minus 20% I figure they built in there for safety.

2 phillips simplygo o2 concentrators set on max (2L continuous)

A 48V 100Ah LiFePO4 (included 48v 10amp charger )
https://www.currentconnected.com/product...k-battery/

buck converter 48v to 12v for the concentrators
https://www.amazon.com/Valefod-Step-Down...0BFJ6VRX1/

buck converter 48v to 24v for the asv ... (not sure what the as11 takes yet so a few assumptions)
https://www.amazon.com/gp/product/B089LRQM9Z


ChatGPT says it will run everything with heaters for 11.25hours.

These products combined currently cost about $1688.

Now, in future I intend to expand the battery capacity greatly and add solar on the roof. I could go cheaper on the battery but anything with that many watt hours capacity is within a couple hundred bucks.

What I am considering is this - I can use two of them in the master closet with the hardware above and 3 of them down by the furnace to power it for 37 hours.
https://www.currentconnected.com/product...ttery-kit/

[Crimson Nape]

Just make sure that this device can be connected full time to a power source. Brands like the Jackery can not be connected full time to AC power. Yours looks like it might be able to.

- Red

[robbob2112]

it can be depending on the charger... I may go with the chargeverter listed on the same site verse the included 10 amp chargers..   More reading to so but at least I have my basic battery size.  The battery is very nice in that you can open it up and replace individual cells if needed and the software will tell you which cell is having issues.  The concentrators draw a bunch of power and I have batteries for them, but a total of 7 batteries = 6 hours run time at 2L cont.  Pitty you cant use pulse output with a cpap.

redoing my calculations using 67watts per pap and 120watts per concentrator - the 48v 100ah battery will support the rig for 23 hours... so 2 days of sleep.

Use the other 4 batteries with a manual transfer switch and I can run the fridge, freezer, gas water heater, well, gas furnace, bedroom power, and media server for about 24 hours.


I asked chatGPT for a breakout of how much power a cpap alone needs for 12 hours of run time  - here is what it spit out - might be useful for others just interested in a cpap backup - this is with the heater and tube on


If the CPAP draws 5.6A at 12V:  (using airsense + humidifier and tubing from the doc you posted)  - this just verifies what is in the chart - a 68ah battery is good 

1. **Power Requirement of the CPAP:**
\[ Power (W) = Voltage (V) \times Current (I) \]
\[ Power = 12V \times 5.6A = 67.2W \]

2. **Energy Requirement for 12 Hours:**
\[ Energy (Wh) = Power (W) \times Time (hours) \]
\[ Energy = 67.2W \times 12 hours = 806.4Wh \]

3. **Convert this energy requirement to amp-hours at 12V:**
\[ Capacity (Ah) = \frac{Energy (Wh)}{Voltage (V)} \]
\[ Capacity = \frac{806.4Wh}{12V} = 67.2Ah \]

So, at 12V, you would need a 67.2Ah battery to run the CPAP machine (drawing 5.6A) for 12 hours.





P.S. sorry if I hijacked the thread with my rambling out loud.

[samsam71]

I can tell you from real world testing on my AS11 at 9.4-12.4cm with humidifer (4) and heated tube 26c
It's averaging about 2.6Ah consumption on a LiFO4 using a direct DC12-24v power adaptor instead of std AC mains power adaptor.
You could probably add an extra 1Ah loss if you ran it through an inverter.

[robbob2112]

Well, Just waiting on the final part to arrive on Monday to start assembly of my backup battery - 

Li Time - 12v 200ah plus battery (2560Wh capacity) - black friday sale for $539 - (Tear down video says they are grade A prismatic cells inside)
Expert Power 2000w Pure sine wave inverter/charger -- BF - $439

Crimpers (Temco TH0005), cable ends, 2/0 cable (pure copper welding wire), shunt, disconnect, Battery disconnect switch, and last but not least a Type T 200A fuse and mounting block - $400ish

Overkill - YES - $1300ish - but I want to be able to run the TV and/or a fridge from it as well depending on outage length  - and I get to play with large cables and crimpers

The crimpers will be reused when I do the DIY solar thing next year so they are worth the extra $$ verse the cheap ones that don't do the crimps correctly.  And you need to do the crimps correctly at 100+ amps of draw or you have a hot spot and fire hazard.  I could have layed everything out and just ordered the cables I needed to length but I added a few guesses up and it is cheaper to do them myself.

At 12v 2000w is 166amps.  YIKES!! -- that is why the super sized cable.

The type T fuse - there is a very long topic on fuses over on the diysolar website - but the 200ah lifepo4 battery has a short circuit current of around 7000amps ..... crazy .... So it requires a fast blow fuse attached directly to the positive terminal.  Go without is and accidentally slip with a screw driver or wire and there will be smoke and molten metal flying around and possibly a fire.  

The major point on fuses seems to be the interupt voltage - so if something is arcing at 7000amps it needs to be able to cut the power - standard small fuses will melt and the current keeps flowing through a plasma arc until something else melts and stops it.

Lifepo4 batteries are the bomb when it comes to capacity per pound but they can be far more dangerous than a standard car battery.

Once I get everything layed out and connected I'll have to find either a plastic or metal case to put it all in.  Metal for fire hazard or plastic as insulation for shock hazard.  Everything will be shrink wrapped and covered so the shock hazard is minimal.

Robert


I could have gone with a simple charger and a simple pure sine inverter that were separate and just switched between them with a 2 position battery switch and it would have been cheaper but I couldn't have left it online all the time.  With this inverter I can switch it to prefer battery power and it will use it down to 40% then charge it up again.  I figure a week a month

[UnicornRider]

Keep us  updated, I am looking at starting with something for camping to also cover for power outage.
Then advance to whole house. 

[robbob2112]

Will do, 

I can post links to the various items on amazon if you want.

If you want to start learning about all the various items to do with whole home power start with 


https://diysolarforum.com/


And youtube videos by Will Prowse..... there are others out there, some are good and some are burn your house down bad.  I have a background in electronics repair from my Navy days and have done some electrical work in the past.  I still have Soooo much to learn so I can do it right, pass inspection to tie to the grid and be safe.

Robert

[HappySailor]

Hi Robbob2112,

I suppose you have a good reason to use 12v and that you have already ordered everything. So this is for everybody else I suppose.

For this kind of power usage, and because you go from 12v to mains voltage for everything, I would have gone for at least a 24v system, while a 48v system would be even better. The current goes down a lot, so less losses in the wires, thinner wires, cheaper, less weight.

The only reason for the 12v would be if you need that 12v for other heavy uses.

Cheers,

Charan

[robbob2112]

You are correct, it is 12v for a reason.  
My two biggest draws in an outage will be the O2 concetrators and they run from 12v using the included bricks.  And I plan to buy a 12v brick for the cpap and run it from that.

At 24v I could have used a 12v buck converter to cut down the voltage and run the concentrators from that but with more waste than if I had done a boost converter to 24v for the cpap. 


But that leads into a whole different topic - Voltage stability - at 24v I can run a direct cable to the cpap but the charger puts out 28.4~29.2 to charge the battery and when it is nearly discharged it puts out only about 20v.  That seems a pretty wide range to expect the internal circuitry on the CPAP to be able to compensate for.  So I would then need a buck/boost/stabilizer/voltage regulator to make sure what actually hit the CPAP was exactly 24vdc with little to no ripple on it.  I've seen on here where others just use the cable and call it good but I wanted something that would function more like a UPS so I wasn't constantly having to switch to charge, then battery separately and disconnecting the CPAP all the time.


Were I camping the separate charger/inverter boxes would have been fine, but this is stationary in the bedroom and not intended to move around.  If you just run the inverter on the battery for a few lights and the cpap from the battery for camping with no charger attached I think it would be just fine to run 24v.  For that use they have a variety of 100amp disconnect plugs from anderson power to let you switch from one to the other easily.  You could also skip some of the fusing and switching I am going to use because it is in my house and I rather not have anything melt.


Note - the inverter is 45lbs and the battery is a bit less - pretty heavy duty to try hauling around to camp.  

One other consideration - idle power consuption on the inverter/charger - the one I bought consumes 60watts at idle.  So also not good for camping


Better to just haul a charged battery and if you think you will use it all in the time you camp a MPPT and solar panel to hook to it to keep it topped up.  But then you are back to stabilizing the voltage to the PAP unless you disconnect it while charging from solar.  And if you get into all that one of the off the shelf solar generator units might make more sense even though it costs more.



For all those reasons I decided 12v was just the simplest way to go.  And things like that are why I have been lost in the DIY solar forum for weeks.