amp hours

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amp hours

Postby onebrucewayne » Wed May 18, 2016 10:47 pm

Greetings

Here is my first and not my last question... I have a 12 volt 35 amp hour bat deep cycle. I also have a 400 watt invert. I need to run an oxygen generator 24/7. It is 110 v 290 watts and 3 amp machine. I have looked at the charts and I have read and re-read until my eyes hurt and I don't trust myself and only half of what I read. Is this going to suffice for a two day period? My TD is wired for 110, but I also would like to be free of pay sites every once in a while.

Any help is much appreciated

BruceWayne

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Re: amp hours

Postby Graniterich » Wed May 18, 2016 11:02 pm

A 120 290 Watt device will draw three amps, you have 17 usable amps . On all the time,six hour's worth. How about solar?
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Re: amp hours

Postby yrock87 » Wed May 18, 2016 11:03 pm

I don't think so. Your oxygenation consumes 3 amp am hour on 110v(actually 120 in the us). Convert that to 12v and you will use 30 amps an hour! Another way to look at it is it takes 290 watts to run. Watts don't care if they are ac/dc, 120v,240v, 12v or 1.5v AA batteries. Watts are watts. Now to get 290 watts at 120v takes (290w/120v=2.41amps) or a bit under 3 amps for your AC house plug . However if you want to run off of DC you get (290w/12v=24.11amps.) 24.1 amps to run. If you o ly have a 35 amp hour battery then you will get just over an hour of run time. Likely less if you add the inefficiency of the inverter (80% efficient).

Sorry but you will either need A. A much larger battery; B. a generator; C. A more efficient oxygdnater; or perhaps come combo of the three that will let you run of a largeish battery overnight and then run the generator in the am and pm to recharge.

Hope this helps.
Last edited by yrock87 on Wed May 18, 2016 11:04 pm, edited 1 time in total.
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Re: amp hours

Postby vigilant1 » Wed May 18, 2016 11:03 pm

onebrucewayne wrote:I have a 12 volt 35 amp hour bat deep cycle. I also have a 400 watt invert. I need to run an oxygen generator 24/7. It is 110 v 290 watts and 3 amp machine. . . . Is this going to suffice for a two day period?


Bruce,
Sorry, but it doesn't look good. Your machine draws approx 290 watts, your battery has 420 watt-hours available (12 volts x 35 amp-hours = 420 watt/hours). That would allow you to run the machine for about an hour and 15 minutes. But in reality these batteries can't be drawn down below about 50% if they are to have a long life, and there will be other losses in the conversion from 12V to 120VAC (that's why inverters get warm--wasted electricity). So you''d either need many more batteries or some other approach. Maybe pressurized O2 bottles would be more practical?

Mark
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Re: amp hours

Postby vigilant1 » Thu May 19, 2016 11:05 am

Graniterich wrote:How about solar?

Sorry, not practical.
1) The unit still needs to run at night, so we still have the need to store up 290 watts x 10 hours of darkness = 2900 watt/hours of electricity = about five Group 27 batteries (drawn down to 50% of capacity).
2) Solar panels put out about 9 watts/sq ft in direct sun. Just to run the unit in the daytime with full sun would require a panel size of 32 sq ft. Now, add in the panels needed in the early morning and afternoon when sun angles are low, the panels needed to store up juice for the coming night, etc and you've got about three times that much sq ft (i.e. the same size as two-three sheets of plywood).
3) This needs to run all the time, without fail--clouds/rain, fog, etc. So double (at a minimum) all of the above (including batteries) to have enough production capacity and storage to get through non-optimum periods.

I think compressed oxygen will be the most dependable, practical approach
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Re: amp hours

Postby onebrucewayne » Thu May 19, 2016 2:24 pm

Thank you

Thank you Very much to all that responded to my post. Good thing I did not trust myself on this topic. Good answers fellow teardropers. At least I can use the bat for my 12 v lighting system and charging the phone.

I guess it's shore power for me then, I do have a generator but as you know - Off after 9 pm.

Compressed air and a small o2 producing back pack let me walk around unhitched from my 110 house machine. You can only have adventures as far as your tube will let you go.

I am not giving up, just rethinking all the options.

Have fun camping

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Re: amp hours

Postby pchast » Thu May 19, 2016 10:07 pm

Lets explore that back pack unit. Can it run continuously? And how long... What kind of battery does it use?
Can it be supplied from the camper battery or just recharged. Is its output enough if you are resting/sleeping?
:thinking:
You may have an alternative there for at least occasional use.
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Re: amp hours

Postby Dale M. » Fri May 20, 2016 9:49 am

Just keep in mind for anything in future, if you are running inverter any 120V AC device you are powering is going to draw 10X on 12V DC side so if device is drawing 3 amps at 120V AC you can do simplify calculations by knowing load on DC side is going to 10x or in this case 30 Amp... Its rough estimation but it gets you there when shopping ...

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Re: amp hours

Postby onebrucewayne » Fri May 20, 2016 9:25 pm

Very helpful all

My back pack seems to be the way to go here. It states on the back 12v and 4 amp max. link follows:

http://www.oxygenconcentratorstore.com/ ... freestyle/

It lasts 2 hrs for me unplugged from any power source. With the waist battery pack it will last an additional 3 hours. IT also has a plug for the cig lighter in the vehicle as well as the TD. This device is not meant for a sleeping aide. When you stop breathing at night ( and everybody does ) it gives off a horrendous beeping alarm that must be addressed. Imagine that when you're sleeping. I suppose I will give that a try in the house first and then garage camping over night just to see how it works.

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Re: amp hours

Postby onebrucewayne » Wed May 25, 2016 5:55 pm

greetings once again

My air supplier delivered my tanks the other day, small enough to wear on my back or carry. This is every month.

While discussing the problem with a friend of mine the respiratory specialist commented, I can set you up with 2 m90 tanks and you would be good for two nights. Just call it in.

Okay problem solved

Each tank is about 20 hours of compressed o2. I'm so ready to hit the camp sites.

Thanks to all

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Re: amp hours

Postby PKCSPT » Wed May 25, 2016 10:25 pm

onebrucewayne wrote:greetings once again

While discussing the problem with a friend of mine the respiratory specialist commented, I can set you up with 2 m90 tanks and you would be good for two nights. Just call it in.

Okay problem solved

Each tank is about 20 hours of compressed o2. I'm so ready to hit the camp sites.

Thanks to all

BruceWayne

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Re: amp hours

Postby yrock87 » Wed May 25, 2016 11:18 pm

Glad to hear you are in good shape. Jus take sure you have a vent cracked to let the excess oxygen vent.
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