# Math Wiz's and Deep Cycle Battery help for hunt



## stillhunterman (Feb 15, 2009)

*Math Wiz's and Deep Cycle Battery help*

Need a little help with battery usage (deep cycle). My son has recently been diagnosed with sleep apnea, pretty bad from what the doc says. Soooo, he is going to be using the machine to keep him breathing at night. It pulls 7amps when in full operational mode, 4 if the humidifier is turned off. We will be tenting it on the deer hunt in october and I have to come up with a mode of power for the gizmo. I know a small generator will do the job, but neither of us want to hear it run for 7 hrs if possible, though that may be our only choice.

Was thinking about a deep cycle battery. If we pull 7 amps, anyone know how to calculate how long the battery will run the machine? We could charge it up during the day I suppose, or when we get back to camp. Any ideas out there? Thanks for any advice/help on the subject! 

Disclaimer: I know this relates to hunting, but hey, a deep cycle battery is used for trolling motors! :mrgreen:


----------



## stillhunterman (Feb 15, 2009)

Need a little help with battery usage (deep cycle). My son has recently been diagnosed with sleep apnea, pretty bad from what the doc says. Soooo, he is going to be using the machine to keep him breathing at night. It pulls 7amps when in full operational mode, 4 if the humidifier is turned off. We will be tenting it on the deer hunt in october and I have to come up with a mode of power for the gizmo. I know a small generator will do the job, but neither of us want to hear it run for 7 hrs if possible, though that may be our only choice.

Was thinking about a deep cycle battery. If we pull 7 amps, anyone know how to calculate how long the battery will run the machine? We could charge it up during the day I suppose, or when we get back to camp. Any ideas out there? Thanks for any advice/help on the subject! Hope you all have memorable hunts this year!


----------



## k2muskie (Oct 6, 2007)

Well I'm for sure no mafffppphhhttt wiz but maybe this link will help you out a titch especially if you peel back the onion as it refers to deep cycle batteries used for like jazzie carts etc. Sorry I can't provide the math on this I rely on cheat sheets such as what this link shows as I purchased some items in preparation for the hard deck season that will require a deep cycle battery. :mrgreen: :mrgreen:

http://www.batteryspec.com/html/SLA-Rep ... eries.html


----------



## Critter (Mar 20, 2010)

Here is a calculator for you. Just put in the amps and voltage and it will give you the information that you are looking for. Now when you go to purchase a battery or do a little bit more figuring you need to consider the temperature of where the battery is going to be at.

As for a generator the Honda's are the quietest ones out there and I believe that it is the EU line. They purr instead of sounding like a lawn mower.

http://www.lifelinebatteries.com/marinesizing.php


----------



## Huge29 (Sep 17, 2007)

my trailer with twin 6 volt golf cart batteries would run my dads cpap machine for two nights and still have about 50% even with lights, fridge, etc fwiw.


----------



## Flyfish4thrills (Jan 2, 2008)

*Re: Math Wiz's and Deep Cycle Battery help*

First off, you'll need an inverter between the battery and the cpap machine. That will be around $100. With it drawing 7amps, it will use 840 watts (plan on 1000 watts or 1kw) (7ampsx120v=840). 
Assuming it draws 840 watts continuously, and you have a 12v battery as the power source, that is 840watts/12v = 70amps. Therefore, if you have a 220 Amp Hour battery, it would last 220/70 = 3 hours. Put 2 identical batteries in parallel and you would get 6 hours.

Here is how you calculate it (in greater detail): http://www.batteryweb.com/pdf/inverter_ ... ng_faq.pdf

Here is a good primer on batteries: http://www.windsun.com/Batteries/Battery_FAQ.htm

Here is an article on parallel battery setup http://batteryuniversity.com/learn/arti ... igurations and here: http://otherpower.com/otherpower_battery_wiring.html

Look in the back of the manual for the specifications. It should say the size of inverter needed. Here is an example of one that only uses 1.8amps (manual says it needs a 300Watt inverter.). See page 9 http://www.somnitech.com/_PDF/SleepStyl ... Manual.pdf

Personally, I would purchase a small gas inverter if you have the money as they are very quiet and efficient, or if it isn't life or death, go without for the small camp trip.

(I reserve the right to have made a mistake......someone can back me up on these numbers if they are nice but I'm pretty sure about them).


----------



## stillhunterman (Feb 15, 2009)

Thanks so much for the info, it's much appreciated. This will take some thought since money will be an issue... Thanks again guys and gal! ;-)


----------



## Bears Butt (Sep 12, 2007)

My older brother has been taking his cpap machine on our hunts for the past 5 years. I just talked to him and this is what he said.
He bought a pretty good deep cycle battery from Auto Zone, makes sure it's charged max before the hunt. He runs the cpap every night and the battery will last him 3 nights without being charged. We usually hit the rack about 10 p.m. and rise at 5 a.m. (7 hours run time each night).
He says he likes to top the charge off each morning while we are having coffee, but if he doesn't have his generator or doesn't want to run it, the battery will last 3 full nights.
Also, he said to make sure you have the equipment to run the cpap off a battery. It requires a cigarette type plug in to connect to the battery. When he first went to camp planning on using it, he didn't have all the connections and ended up turning the generator on all night and sleeping in the camper with the cpap plugged into household current.
For what all of this is worth.


----------



## Huge29 (Sep 17, 2007)

BB's post just reminded me that before using the trailer batteries he used the smallest car battery known to man, not even a deep cycle battery, the Honda group size 51. it also worked for at least two nights using a 700 watt inverter, so even the smallest deep cycle (group 24, 12" battery) should easily last 3-4 nights. Good luck!


----------



## stillhunterman (Feb 15, 2009)

Some great info, thanks a lot everyone! I'm sure I can get something going with this info!


----------



## DallanC (Jan 13, 2009)

I dont know that a battery will hold up all that well.

I'd just recommend a Honda EU1000 generator vs the weight and hassle of a battery. Small enough to pack in, VERY quiet, just stick it 100ft away from the tent and chain it to a tree, then run an extension cord back to the tent. Done. They have a built-in fuel pump so you can modify a spare cap to run a line into a larger gas can for extended periods of running.

I had a EU1000 I just sold that only had 8 hours on it... it was a steal. I run a pair of EU2000's now for my trailer.


-DallanC


----------



## fishnlv (Sep 14, 2012)

If you look closer you will see your cpap machine is already probably a 12 volt and has a converter to 110 for house current. I have a phillips resperonics unit that I think is most common. The humidifier half uses much more current the the air pump. I disconnect it and leave it home. I take mine in the camp trailer all the time and have a standard marine walmart type 27, a few days is no problem. To get the converter cord go to an online place called THE CPAP SHOP call them on the phone. They sell excellent quality stuff and will make sure you get what you need. Camping with mine is no problem what so ever. good luck,


----------



## Huge29 (Sep 17, 2007)

Welcome to the forum fishnlv! I could not figure out why you were so mad talking about this guy's crap machine, but then realized it was a P not an R. Welcome!


----------



## stillhunterman (Feb 15, 2009)

fishnlv said:


> If you look closer you will see your cpap machine is already probably a 12 volt and has a converter to 110 for house current. I have a phillips resperonics unit that I think is most common. The humidifier half uses much more current the the air pump. I disconnect it and leave it home. I take mine in the camp trailer all the time and have a standard marine walmart type 27, a few days is no problem. To get the converter cord go to an online place called THE CPAP SHOP call them on the phone. They sell excellent quality stuff and will make sure you get what you need. Camping with mine is no problem what so ever. good luck,


Thanks much fishnlv! Good info there, will check it out. Gotta love this forum, lots of good folks! Welcome!


----------

