Do I REALLY need solar?

[Thunder Dan]

I was thinking about what I really need. I will be urban stealth camping, and I can charge my laptop at work, and my phone too. The only thing I absolutely cannot go without is my CPAP machine. It runs on DC power, and I can get a cigarette lighter plug for it for about $15. 80 watts = 6.67 amps @ 12 volts. 8 hours a night = 54 amp hours. The cigarette lighter on my truck stays live even when the vehicle is completely turned off and the key is out of the ignition.

I know a starter battery is designed to deliver a lot of power for a short time, and a deep cycle battery is designed to deliver a lower amount of power over a longer period. But, is there a battery out there that will deliver enough to run my CPAP for 8 hours and still have enough juice to start the truck in the morning, and get charged up by my alternator? The alternator is either 105 or 145 amps, I am not sure. I will look at it when it is light outside.

But if there is a battery that can do that, it seems to me that would be the most simple thing, without even messing with solar. I imagine at some point in the future I will get solar anyway (after I save some money from not having a mortgage). But for now, is this something that sounds feasible?

 

[highdesertranger]

so how many amp/hrs is your battery rated at? how long will you drive it everyday after using those 54ah? it seems to me that you will be taking your battery down to about 50% of capacity, it would take hours of driving everyday to recharge your battery to 100%. that's not even mentioning other draws like listening to your radio or recharge your phone/lap top. highdesertranger

 

[SternWake]

The 6.67 amps might only be when the dehumidifier is used on the Cpap, it could be 1/3 of that without it.

The alternator rating does not have much to do with how fast the battery recharges.  It can affect the charge time to 80% State of charge(SOC), but once this ~80% SOC is reached, the battery limits how much it can accept.  Generally from 80% to 100% requires ~4 hours NO MATTER how powerful the charging source might be, and those 4 hours is when the voltage regulator allows 14.4 to 14.8v for those 4 hours.

Most Vehicles will not do this. and as a result, 80 to 100% can take 6 hours or 8 hours of driving.

You can of course Cycle the battery anyway, and drive for a hour each day and get near the 80% range, but the battery will not last very long without ever getting back up near that 100% range.  Cycling from 50 to 80% day after day is very hard on a Lead acid battery, it needs to get to 100% every so many cycles or it loses capacity quickly

And if you only have 100 AH of battery, and IF you do need 50AH to power the cpap for 8 hours, and can only get the battery back upto 80%, then on night two you will cycle the  battery down to 30%, and this is *very* hard on a lead acid battery.  night 3 and you wont be able to start the engine and the Cpap would likely not run for the full 8 hours

So in your case, the solar is verging on Mandatory, unless you can run an extension cord to your vehicle when at work and run a battery charger.

Another consideration,  is the pesky Peukert effect.  A 100 AH battery earns that capacity rating by powering a 5 amp load for 20 hours before falling to 10.5v, which is considered 100% discharged.  Loads over 5 amps will not allow this battery to provide a total of 100Ah of capacity, but some number less, and this can be considerably less, and just gets worse as the battery ages and sulfates, and in your usage it will age quickly.  Also the battery must be fully charged at the start of this and without those 4 hours held at absorption voltage, your battery is not going to be starting the discharge in the happy  fully charged zone.

Now you could do the battery warranty thing often, but after one replacement you will start paying a prorated warranty replacement, and these can approach the price of a new battery.

If you are not hooking up a secondary battery system, then get yourself a larger jumper pack similar to this, as You will be needing to jump start yourself often.
http://www.amazon.com/Jump-N-Carry-JNC660-1700-12-Volt-Starter/dp/B000JFJLP6

Same rules apply for the battery inside this unit. 4 hours minimum to 100% charged and it wants to live at 100% SOC,, or it will lose capacity quickly.  The batteries inside these are nothing special, usually just a 12/18 or perhaps 22Ah cheapo chinese AGM battery, so you could do the same thing with jumper cables to such a battery for less$$ and less convenience:

http://www.amazon.com/EnerSys-Genes...=UTF8&qid=1462080504&sr=1-7&keywords=18Ah+AGM

 

[akrvbob]

To me it's a no-brainer, free electricity--FOR THE REST OF MY LIFE!! Totally silent, virtually maintenance free, no extra wear and tear on the engine or alternator, no noise, no gas.

And it's cheap!!

To me the only valid question is why in the world would you even debate it? It's FREE electricity, for the REST OF Your LIFE!!!
Bob

 

[highdesertranger]

Bob has a good point. I was going to bring up the free electricity part(after initial investment). highdesertranger

 

[wagoneer]

nobody needs solar, it's just nice to have.

 

[WheelEstate USA]

You can set up the basic solar for right at $300.
I recommend the Renogy 100W starter kit and a Walmart marine battery just to get you going.

Look on Amazon, find their kit, and call Renogy direct...they will match the Amazon price, saving you a few bucks. The reason I say to call them is you will get the kit in about 2 days...quicker than Amazon and still free shipping.
While you wait for that, run over to Wally's and get the $100 marine battery.
Granted, this isn't the best battery but it should last you a year or maybe more. The charge controller is their cheapo on but it will get the job done and you can upgrade/expand later down the road.
I started out this way and know several others who have, so I know it will work. In 3 or 4 days from the time you order you will be independently powered and pretty much worry free. You'll even have enough power to run some led lights and keep your laptop and phone charged without wondering if your rig will crank in the morning.

Here's the kit...
http://www.amazon.com/gp/aw/d/B00BF...+solar+kit&dpPl=1&dpID=51tMu4DA-EL&ref=plSrch

Here's Renogy's number...
(909)287-7100
Tell sales the price you saw on Amazon after they give their quote. Ships on FedX.

 

[WheelEstate USA]

Also...while at Wally's, they have a fairly heavy ciggy/USB combo (black plasic) for about 10 bucks.
You will most likely have some extra cable left over from the solar install to wire that guy. If not, Home Depot and Lowes has what's called landscape cable in 12G by the foot...tuff stuff...looks like lamp cord, only heavier. 

Good luck and enjoy the freedom of solar

 

[GotSmart]

The CPAP will not run with humidifier on 12 volt. (most of them)  I found that out when buying my conversion cord.

 

[Thunder Dan]

Sounds like a resounding YES, I do need solar. I will check into bindi&us' suggestion. Thanks everyone!

 

[Gypsy Jane]

I've run Wal-Mart deep cycle batteries in motorhomes for years, and had no complaints.
You may eventually want to wire your deep cycle battery to charge from the alternator, with an isolator, in case of extended crappy weather.
Check out marine power packs - battery boxes with built in ciggy plugs. One model has usb also.

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[wagoneer]

Many get along just fine with no solar I did for many years (before I knew about solar like it was a govt. secret) in the 70's. But now that I have a simple but good system just can't see going without. It's just not installed yet.

 

[Canine]

I don't understand the appeal of buying a kit for $150 when you can buy the panel and controller separate on e bay for $125.You are going to want at least 2 panels sooner or later so might as well get em now.

 

[66788]

nobody needs solar, it's just nice to have.

I would NOT van dwell without electricity.   I also use a CPAP, charge my devices, use lights, run fans etc.

I would not say "Nobody needs solar."

 

[WheelEstate USA]

Bob D...Many of use Renogy because they have a quality panel with a strong frame and great customer service. Their panels are known to hold up to use we submit them to on and off road. 

There's plenty of cheaper panels out there that are crap and would never stand up in mobile use. This is one of those cases of getting what you pay for.
Renogy stands behind their products, as we saw with the faulty flex panels. They not only quit selling them, but made all of the buyers whole. Any company that does that gets my vote.

And they ship fast and free, which many of the cheaper ones do not. Shipping can be costly.

Buy them where you like but till I see better, I will go with Renogy.

 

[Canine]

I'm not knocking Renogy panels.The last 4 panels that I bought last year are Renogy.The point I was making is that you can buy the items separate and save money.However,In checking kits on ebay,I found a 100 watt Renogy kit for $140 with free shipping.This is about as cheap as you can buy the parts separate.Of the 24 panels I've ordered,I've only sent 1 order of 4 back.Damned if I can remember the name of them,but the quality was obviously terrible.I plan to buy a Renogy mppt controller this fall for comparison purposes to see if I gain any charging amps.

 

[GotSmart]

I'm not knocking Renogy panels.The last 4 panels that I bought last year are Renogy.The point I was making is that you can buy the items separate and save money.However,In checking kits on ebay,I found a 100 watt Renogy kit for $140 with free shipping.This is about as cheap as you can buy the parts separate.Of the 24 panels I've ordered,I've only sent 1 order of 4 back.Damned if I can remember the name of them,but the quality was obviously terrible.I plan to buy a Renogy mppt controller this fall for comparison purposes to see if I gain any charging amps.

When ordering panels, ask for open box.  

Renogy has the rights for ebay and Amazon, so the store will definitely match the price or beat it as they do not have to pay the % to the resale services.

 

[Gypsy Jane]

As to why would anyone pay more for a kit? Until I'm experienced and knowledgeable in solar, a kit has parts that I know are compatible. I hate those second and third trips to the store. And until I get a day-stretcher, what saves me time is a good thing.

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[WheelEstate USA]

The 100W kit and Wally marine battery is a good way to start and learn more about solar and what you really need.
As time goes on, you will find yourself expanding and going to more refined equipment based on needs and education.

Just don't start out thinking you can run high power inverter and household appliances with the basic kit.

 

[Gypsy Jane]

Nope. Electronics and a fan, it's all I need in the van.

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