My camping battery kit and a charging question

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lenscap
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Location: Oregon

My camping battery kit and a charging question

Post by lenscap » Fri Jan 19, 2018 10:09 am

After reading through many posts about which battery is right for my use, I purchased the following;

https://www.amazon.com/gp/product/B00G8 ... UTF8&psc=1

https://www.amazon.com/gp/product/B00G8 ... UTF8&psc=1

https://www.amazon.com/gp/product/B0009 ... UTF8&psc=1

https://www.amazon.com/gp/product/B0057 ... UTF8&psc=1

https://www.amazon.com/Power-Cord-Phili ... +12v+cable

I am car camping for a couple of nights in a row, and this kit has worked flawlessly so far. But now I am considering planning a week long trip with no access to AC to recharge. Looking at all the solar options out there, I am still confused as to how many watts I should need to keep my battery charged (and still have reserve). My guess at this point is that a 50W panel might be enough, 100W definitely. Sharing your experience with particular units will be greatly appreciated.

My camping will be both in the desert southwest and Pacific Northwest, regardless I don't use humidifier when camping. Using my 1.5 amp charger takes on average 3.5 hours to fully charge after one night of use.

freetimecreations
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Re: My camping battery kit and a charging question

Post by freetimecreations » Fri Jan 19, 2018 12:19 pm

Formula
DC watts to amps
current (A) watts (W) volts (V):
A = W / V

Example uses 13 volts

AC 1.5 amp charger =19.5 Watts, because 1.5 amps times 13 volts = 19.5
50 watt solar panel puts out 3.8 amps an hour because 50 watts divided by 13 volts = 3.8

Variable are less sun in Northwest. Fixed vs free standing panel.

50 watt panel but add 20% more = 75 watts

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Last edited by freetimecreations on Tue Feb 19, 2019 4:44 pm, edited 2 times in total.

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CapnLoki
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Re: My camping battery kit and a charging question

Post by CapnLoki » Sat Jan 20, 2018 5:10 am

lenscap wrote:...

I am car camping for a couple of nights in a row, and this kit has worked flawlessly so far. But now I am considering planning a week long trip with no access to AC to recharge. Looking at all the solar options out there, I am still confused as to how many watts I should need to keep my battery charged (and still have reserve). My guess at this point is that a 50W panel might be enough, 100W definitely. Sharing your experience with particular units will be greatly appreciated.

My camping will be both in the desert southwest and Pacific Northwest, regardless I don't use humidifier when camping. Using my 1.5 amp charger takes on average 3.5 hours to fully charge after one night of use.
Sorry about the delay, I'm travelling right now.

The equipment looks fine - I'm not that familiar with the charger but it looks similar to BatteryTender. The battery is 50 Amp-hours, larger than the 35 AH I often recommend. With the DreamStation you can roughly figure 5 amp-hours a night without humidity - high pressure or altitude could raise that. So the 50AH battery might run for a week with a 20-30% reserve.

Solar power is hard to figure because much depends on how "open" your view of the sun is. In a canyon or forest, you might only get a tiny amount of sun. Calculations start with the "sun factor" which depends on location and season. A factor of "3" means you can expect 3 hours of sun, so a 100 watt panel might be expected to generate 300 watt-hours, or about 25 amp-hours, assuming its not shaded and you have "average" sun. The pacific north west is about 3, but the desert is 6 or 7, so you get almost continuous sun. Of course, you can expect a lot of reliable sun in the desert, but could easily be "blacked out" by clouds in the North West.

The other factor is that the large battery will, when depleted somewhat, accept a lot of current fast. If you had a tiny, one night battery it would not accept the large output from the 100 watt panel, but your battery will gobble it up. However, after one night it is only 10% depleted, so it will not accept much. Also, it is possible that a 100 watt panel would need a regulator to avoid overcharging the battery - it depends on the output voltage of the panel. Small panels are sometimes thought of as "self regulating" because the output is too low to hurt a battery, but especially in the desert a panel will be running full tilt. Make sure the wiring and fuses are up to snuff.

So back to your question: your battery might actually cover a one week trip, so anything you collect with solar is gravy. Your use is 5 AH or 60 Watt-hours a night (I guess) so even the 50 watt panel will recover that if it gets good sun. There's a fair chance you could return with a fully charged battery.

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Choosing a Battery thread: http://www.cpaptalk.com/viewtopic/t1140 ... ttery.html

lenscap
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Re: My camping battery kit and a charging question

Post by lenscap » Sat Jan 20, 2018 3:42 pm

Thank you freetimecreations and CapnLoki ! I appreciate your help!

I will use the panel free-standing, and I'm thinking a foldable panel is best for me since space is limited under my pickup's canopy. A quick search on Amazon leads me to this: http://www.amazon.com/Dokio-Monocrystal ... +panel+kit The reviews are mostly great, it folds for traveling, and by the numbers it should be enough for my needs, plus it comes with a controller. The low price doesn't hurt either. I'm gonna order this one, and I'll report back if it does the trick or not.

Thanks again!

USMCVet
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Re: My camping battery kit and a charging question

Post by USMCVet » Sat Jan 20, 2018 11:59 pm

Just make sure panel is waterproof so you can leave it out and not worry about rain

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CapnLoki
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Re: My camping battery kit and a charging question

Post by CapnLoki » Sun Jan 21, 2018 8:25 am

USMCVet wrote:Just make sure panel is waterproof so you can leave it out and not worry about rain
Its hard to believe that a product that can only be used outside, and has to stay out for an extended period to be useful, would not be to some degree weatherproof. That said, there are comments that say the canvas edging might not stand up to long term exposure. I didn't see any way to tie it down, which would be very useful, if not necessary, for unattended use. So I eagerly await a review of the performance and build quality.

One point of concern is a comment that the cable from the panel to the controller is short, and the cable from the controller to the battery is long. This means that the controller must be left outdoors, and there's a long run to the battery which creates a voltage drop that fights against the controller. It would be much better to have a long run to the controller which would be near the battery so its both protected and getting accurate voltage readings from the battery.

All in all this looks like a reasonable system at a very good price. The reviews are generally positive, and I be very interested in the results.

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Machine: DreamStation Auto CPAP Machine
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Humidifier: DreamStation Heated Humidifier
Additional Comments: Pressure 9-20, average ~9.5; often use battery power while off-grid
Hark, how hard he fetches breath . . .  Act II, Scene IV, King Henry IV Part I, William Shakespeare
Choosing a Battery thread: http://www.cpaptalk.com/viewtopic/t1140 ... ttery.html

Rob K
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Re: My camping battery kit and a charging question

Post by Rob K » Mon Jan 22, 2018 4:31 pm

A bigger battery or multiple batteries are an option also so you don't have to worry about recharging until you get home.

I did a bunch of research trying to figure out a solar panel and battery system. The answer wasn't clear and time was running short for my wilderness car camping trip. Undecided I just tossed my 79Ah trolling motor battery in the Jeep and took that camping with me and would see how far that would get me. With my Resperonics cpap set to a pressure of 10, humidifier off and using my Airfit P10 mask I ended up getting 9 nights which took the battery down to 50% charge. Can't remember for sure, but I believe I used it around 7-8 hours per night. I didn't have to recharge the battery at all on a 10 day camping trip.

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Machine: AirCurve™ 10 VAuto BiLevel Machine with HumidAir™ Heated Humidifier
Mask: AirFit™ N10 Nasal CPAP Mask with Headgear
Additional Comments: Resmed F10 Mask for colds. When camping on battery power I use P10 mask and PR 560p machine.
Last edited by Rob K on Tue Jan 23, 2018 5:47 pm, edited 1 time in total.

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Goofproof
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Re: My camping battery kit and a charging question

Post by Goofproof » Mon Jan 22, 2018 6:46 pm

K.I.S.S., works again. What about a nice 110 volt 10 to 15 amp battery charger, using a 110 volt inverter attached to your vehicle, to boost it back up if needed, if you were driving the cigar lighter would work only maybe slower. As long as you are driving anyway the added cost of fuel would be little. Jim
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CapnLoki
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Re: My camping battery kit and a charging question

Post by CapnLoki » Tue Jan 23, 2018 4:52 pm

Goofproof wrote:K.I.S.S., works again. What about a nice 110 volt 10 to 15 amp battery charger, using a 110 volt inverter attached to your vehicle, to boost it back up if needed, if you were driving the cigar lighter would work only maybe slower. As long as you are driving anyway the added cost of fuel would be little. Jim
I've been thinking about this approach - is it silly to add an extra, inefficient device or elegant simplicity. However, there's one got'cha to be considered: many accessory plugs (as cigarette sockets are now called) are fused at 10 Amps. To get 10 amps charging through both an inverter and charger you'd have to start with over 20 Amps, and that would quite possibly blow the fuse. It might be better to rig the battery directly to the alternator, by jumpering to the car's battery. That would allow full charging as long as you rev'd slightly to make sure the alternator "turns on."

This brings up another possible issue: some newer cars use an energy saving regulator that keeps the alternator "off" unless it determines that there really is a load. You might have to do something like turning on the lights to force the alternator "on."

As noted before, the best way is to simple have a large enough battery (or extra batteries) to last for the trip.

_________________
Machine: DreamStation Auto CPAP Machine
Mask: Quattro™ Air Full Face Mask with Headgear
Humidifier: DreamStation Heated Humidifier
Additional Comments: Pressure 9-20, average ~9.5; often use battery power while off-grid
Hark, how hard he fetches breath . . .  Act II, Scene IV, King Henry IV Part I, William Shakespeare
Choosing a Battery thread: http://www.cpaptalk.com/viewtopic/t1140 ... ttery.html

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Goofproof
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Re: My camping battery kit and a charging question

Post by Goofproof » Tue Jan 23, 2018 6:12 pm

CapnLoki wrote:
Goofproof wrote:K.I.S.S., works again. What about a nice 110 volt 10 to 15 amp battery charger, using a 110 volt inverter attached to your vehicle, to boost it back up if needed, if you were driving the cigar lighter would work only maybe slower. As long as you are driving anyway the added cost of fuel would be little. Jim
I've been thinking about this approach - is it silly to add an extra, inefficient device or elegant simplicity. However, there's one got'cha to be considered: many accessory plugs (as cigarette sockets are now called) are fused at 10 Amps. To get 10 amps charging through both an inverter and charger you'd have to start with over 20 Amps, and that would quite possibly blow the fuse. It might be better to rig the battery directly to the alternator, by jumpering to the car's battery. That would allow full charging as long as you rev'd slightly to make sure the alternator "turns on."

This brings up another possible issue: some newer cars use an energy saving regulator that keeps the alternator "off" unless it determines that there really is a load. You might have to do something like turning on the lights to force the alternator "on."

As noted before, the best way is to simple have a large enough battery (or extra batteries) to last for the trip.
The Inverter is hooked directly to the battery, (Fused and switched). The charger plugs into the Inverter, and charges the battery. The Cigar Lighter isn't used , except on it's own, as a second charging option, giving two options to recharge. Jim

The inverter - charger probably will recharge the faster, than the cig lighter.
Use data to optimize your xPAP treatment!

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freetimecreations
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Re: My camping battery kit and a charging question

Post by freetimecreations » Tue Jan 23, 2018 7:13 pm

Rob K wrote:A bigger battery or multiple batteries are an option also so you don't have to worry about recharging until you get home.

I did a bunch of research trying to figure out a solar panel and battery system. The answer wasn't clear and time was running short for my wilderness car camping trip. Undecided I just tossed my 79Ah trolling motor battery in the Jeep and took that camping with me and would see how far that would get me. With my Resperonics cpap set to a pressure of 10, humidifier off and using my Airfit P10 mask I ended up getting 9 nights which took the battery down to 50% charge. Can't remember for sure, but I believe I used it around 7-8 hours per night. I didn't have to recharge the battery at all on a 10 day camping trip.
A second battery is a good approach. Don't have to worry about dead car battery. Get a sealed deep cycle (not marine) battery in case it tips over. These are designed to discharge down to 50%.

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lenscap
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Re: My camping battery kit and a charging question

Post by lenscap » Tue Jan 23, 2018 7:15 pm

I've been thinking about this approach - is it silly to add an extra, inefficient device or elegant simplicity. However, there's one got'cha to be considered: many accessory plugs (as cigarette sockets are now called) are fused at 10 Amps. To get 10 amps charging through both an inverter and charger you'd have to start with over 20 Amps, and that would quite possibly blow the fuse. It might be better to rig the battery directly to the alternator, by jumpering to the car's battery. That would allow full charging as long as you rev'd slightly to make sure the alternator "turns on."

This brings up another possible issue: some newer cars use an energy saving regulator that keeps the alternator "off" unless it determines that there really is a load. You might have to do something like turning on the lights to force the alternator "on."

As noted before, the best way is to simple have a large enough battery (or extra batteries) to last for the trip.
I'm in the elegant simplicity camp. I love the idea of solar, I feel like I'm sticking' it to the man by getting power from the sun and not PGE. The reality is that this will be my first learning experience with solar and I'm stoked just for that! It may turn out that the hassle factor is a turn off, or it may not be efficient enough. I'll be happy if I can just keep it charged enough to go the whole week off grid, and without using the truck's battery. I don't wanna try to charge off my accessory plug, don't want to worry about blowing fuses, I like simplicity and less worry.

The solar panel kit arrives tomorrow, but here in Portland, OR, there is rain forecast everyday for the next week. I'll do a test in sunlight the first chance I get, but it may be awhile.

Thanks for all the good info !

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CapnLoki
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Re: My camping battery kit and a charging question

Post by CapnLoki » Wed Jan 24, 2018 7:40 am

freetimecreations wrote:... Get a sealed deep cycle (not marine) battery in case it tips over. These are designed to discharge down to 50%.
Small point, though important for those pushing the limits on AGM batteries. Although staying above the 50% point is good practice if you want to maximize battery life, you can go down to 20% without seriously damaging the battery. The cost is shown in this spec sheet from UBG (for the 18AH AGM, but similar to all):
http://files.upgi.com:8086/UPGFileServi ... heet/D5745
the chart Cycle Life vs Depth of Discharge shows that at 50% discharge you might get about 500 cycles, but at full discharge its under 200. Actually, like most specs this is optimistic so you might want to cut it in half. And what they call "100% Depth of DIscharge" is about 11.75 volts, which is not not quite the same as "dead." But my point is that if you go camping a few times a year, and most batteries will "die of natural causes" in 6 to 10 years, then 50 cycles might be plenty.

On the other hand, if you cycle your batteries daily (as I do during the summer on the boat) then you would want to strictly observe the 50% rule. I get about 6 years (about 500 cycles) from my primary house bank of flooded batteries (never below 50%) and maybe 7-8 years from my AGM starting batteries, which are almost never discharged more than a few percent.

Lots of other tidbits in the sheet, like the battery should be charged up every 4 to 6 months - more in hot temperatures - and at least once a year to prevent damage.

_________________
Machine: DreamStation Auto CPAP Machine
Mask: Quattro™ Air Full Face Mask with Headgear
Humidifier: DreamStation Heated Humidifier
Additional Comments: Pressure 9-20, average ~9.5; often use battery power while off-grid
Hark, how hard he fetches breath . . .  Act II, Scene IV, King Henry IV Part I, William Shakespeare
Choosing a Battery thread: http://www.cpaptalk.com/viewtopic/t1140 ... ttery.html

Rob K
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Re: My camping battery kit and a charging question

Post by Rob K » Wed Jan 24, 2018 10:06 pm

freetimecreations wrote:
Rob K wrote:A bigger battery or multiple batteries are an option also so you don't have to worry about recharging until you get home.

I did a bunch of research trying to figure out a solar panel and battery system. The answer wasn't clear and time was running short for my wilderness car camping trip. Undecided I just tossed my 79Ah trolling motor battery in the Jeep and took that camping with me and would see how far that would get me. With my Resperonics cpap set to a pressure of 10, humidifier off and using my Airfit P10 mask I ended up getting 9 nights which took the battery down to 50% charge. Can't remember for sure, but I believe I used it around 7-8 hours per night. I didn't have to recharge the battery at all on a 10 day camping trip.
A second battery is a good approach. Don't have to worry about dead car battery. Get a sealed deep cycle (not marine) battery in case it tips over. These are designed to discharge down to 50%.
Not sure if this is directed toward me or the OP. My trolling motor battery is a 79AH AGM. It is sealed against spillage. Your advise is spot on.

_________________
Machine: AirCurve™ 10 VAuto BiLevel Machine with HumidAir™ Heated Humidifier
Mask: AirFit™ N10 Nasal CPAP Mask with Headgear
Additional Comments: Resmed F10 Mask for colds. When camping on battery power I use P10 mask and PR 560p machine.