camping

[madfin]

Could you give me more information on your system. I am scheduled to raft the Grand Canyon next summer and need to figure out a system that will last 21 days. How high are your settings? Mine is 11. What kind of battery do you use? How much solar energy will I need to generate? Do you need any other electrical equipment such as to regulate overcharging, etc? Thanks for you help.

[mrhyak]

Could you give me more information on your system. I am scheduled to raft the Grand Canyon next summer and need to figure out a system that will last 21 days.

I assume your question is directed at me - First of all congrats on the Canyon Permit, I've been down the river 3 times and it never ceases to please. It sounds like you're doing a private 18 day trip, with 3 days travel. My system with the battery pack and solar panel has been down the river twice now, powering a friends older respironics unit and it has done fine. The system uses a 24AH battery (AH stands for Ampere Hour, the number of amps available in an hour. For most batteries, this is given as over a 20 hour period.) and one of my 20watt solar panels. The pressure setting was 10CMH2O, and I believe the current draw was 1.5amps. I have built the gel cell battery into an ammo can with a push to test meter and watertight connectors so the solar panel remains connected all day. Because my panels have both blocking and bypass diodes, I connect them directly to the battery without a charge controller. A charge controller will waste a little bit of power, and with only a 20 watt panel, I need all of the power possible. Overcharging in this case is not an issue. Now that I need CPAP I'm working on some upgrades and when they're done I will do a post, maybe with a few pics. My friend and rafting buddy is bummed because now he needs to buy his own setup, after using mine for years. I'm planning a trip in Idaho near the end of the month so I need to get it done and tested in time. BTW, one of the links on this topic is to someone who also ran the river, but it appears they did a commercial trip (11day?) and did not worry about recharging.

[madfin]

Thanks for responding. Yes, I am doing a private trip down the Grand Canyon. I did it once before, but that was before CPAP. We've had our permit on file since 1988 and finally it is our turn. Why do you not use larger marine dry cell batteries? You can buy 100 amp hour batteries that are not too heavy to load in a raft. I was thinking that I would need two of them plus a solar panel. Also is your solar panel a flexible marine panel or a rigid panel? Please send me the results of your upgrades. My e-mail is madfin66@hotmail.com. Thanks again. Brian

[mrhyak]

I use the smaller batteries because I already lug two much weight. If you want to lug around 100 AH of battery - go for it. The more power, the less you will rely on recharging. You don't say what machine your using - I've currently got a remstar pro but hope to get a PB420g for travel as they use less power. If you have to use an inverter, you will need that 100AH and then some. Do this simple calc - Amp Load * Hours/night * 2 = min AH battery size. If your unit draws 2 amps and your usage is 7 hours then you need a minimum of 28 AH, since rule of thumb is to only draw down the battery by 1/2. For recharge via solar, a simple rule of thumb is to get a panel with as many watts as you need AH by above calculation, in this case 28 watts - all of this assumes we are talking 12 volts. I prefer flexible panels because they are much easier to strap on to the raft. You don't need to increase your solar panel watts if you decide on a bigger battery, since all you need is to replace what you use. If we start talking about winter, then double the solar panel size. Jim

[madfin]

I use a remstar plus with C-flex. How much less power does a pb420g use? Also does C-flex cost or save power? Thanks. Brian