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Author Topic: Using laptop over night  (Read 2519 times)

Wink

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Using laptop over night
« on: May 13, 2018, 04:52:41 PM »
Hello,

I am changing my batteries and solar pannel to work fully remotely from the van. I might need to have the laptop plugged up to 14h a day (a macbook pro, 80w). Sometime overnight.

I am wondering if 2 gel batteries (200ah) and a 120w solar pannel would be enough.

When I'm asking profesionnals, they always want to sell me those very expense Lithium batteries. It might be overkill for a single laptop.

What do you think ?

Camper_Dan

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Re: Using laptop over night
« Reply #1 on: May 14, 2018, 01:31:59 AM »
Greetings and Welcome!

I use junkyard batteries these days, they're cheap and just as good as expensive ones.  I have also ditched solar and just charge my house battery while driving, or via a generator if I'm not doing enough driving.  Solar is too unreliable and finicky, and parking in the sun during the summer is a dumb idea.  Park in the shade and forget about solar.

If you  insist on solar, you want a minimum of 200 watts of solar for every 100 amps of batttery capacity, and more is always better.

You don't want to leave your laptop plugged in all the time, you only want to plug it in to charge it, and then use the laptop battery when you're using it.  Mine takes a little under an hour to charge, and is good for 7-8 hours on a charge.  If I'm using it while I'm charging it, it can take twice as long to charge.

If your laptop battery(s) are bad, get some new ones, and get an extra set as well, that way you can have an extra set charged and ready to swap in as needed.

As for solar, an isolator is a whole lot cheaper, and the only people who like solar are also using an isolator to charge their battery(s) while driving.  They're giving credit to the solar, when it's the isolator keeping their batteries charged.  Solar or not, only a dummy would do it without a generator and an isolator.  Just charging while driving keeps my batteries charged 99% of the time, the only time I need my generator is if I'm stationary for over a week, which is very rare.  Even when I'm boondocking I usually go shopping at least once a week, and my ice chest needs a new block of ice once a week.

I stick with lead acid deep cycle batteries, so I can add water as needed.  I just replaced my almost 7 year old (with me), $15, 110ah deep cycle junkyard battery with a $18 deep cycle junkyard battery that the date code says is under 3 months old.  They had half a dozen deep cycles to choose from.  Solar kills batteries prematurely too, so that's another reason to stay away from solar.  Batteries like a high amp charge initially, which tapers off as it gets fully charged, solar delivers a low charge that then ramps up, before tapering off.  Bad news for battery life.  When I had solar, my pair of $350 battteries were only lasting 8-10 months because of that poor charging method.  They were also AGM (Gel) so I couldn't top them off every few months.

Both solar and lithium are also both fire hazards, and the simpler you can keep your system the better.  Spaghetti wiring is NEVER a good thing.

I also tend to charge everything including my laptop while I'm driving, via a 1 to 4 ciggy lighter splitter plugged into the dash, that way I get a free charge on everything, without going through my house battery.  Sometimes I'll also charge my laptop while I'm in a restaurant, library, or anywhere I can plug it in and maybe work too.  In other words charge your laptop with someone elses power whenever it's convenient.

If your laptop's 80 watts, that's only about 7 amps per charge.  That's about 7 charges on a 100ah battery, without going below 50%, twice that if you have 200ah worth of batteries, and you're not using it for anything else, but you're probably going to want a fan and some lighting as well.

Cheers!
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Wink

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Re: Using laptop over night
« Reply #2 on: May 14, 2018, 04:36:13 PM »
That's Dan for that long and complete answer. You rock.

I'm surprised of what you say about lead batteries. I currently have 2x100ah fully charged with an isolator, plugging my laptop get them down to 11.5v within 15 minutes.

Sure I use a crap 12/220v convertor which probably double my consumption. Getting a proper 12v laptop charger will be my next move, but it won't be enough.

7 charges on a single 100ah lead battery, I would love that ! Considering how cheap that is.

Driving every day is not an option. My lifestyle involve long period of dedicated work before I move on to the next spot.


Camper_Dan

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Re: Using laptop over night
« Reply #3 on: May 15, 2018, 12:30:26 AM »
Greetings!

Yes, the car cords are much more efficient!

Are the lead acid batteries you have now deep cycle?  How have you been charging them?  Not all isolators are created equal either, and your wiring  also makes a huge difference.  I am actually using a relay, instead of an isolator because that's what the battery shop recommended, but I call it an isolator for clarity of what I'm talking about.  The wires running from my starting battery to the relay, and then to my house battery are the same size as those originally running to my starter.

Have you checked  the water level in your batteries?  How old are they, and have you checked their state of charge?  You can get a load test performed at most battery shops.  Have you tried charging your house batteries up fully using a house style battery charger?  If one battery is weak, it can also be draining the other one.

Your inverter may also be a part of your problem, it might not be working as it should, and I always recommend not using an inverter for anything, since so many things are available in 12 volt models these days.

11.5 volts is discharging the batteries lower than they should ever be discharged, so they may be toast.  I have battery protectors on mine so they never go below 12 volt state of charge.   This protects the batteries and ensures a long life for them. 

A generator and a house style battery charger work well for me, that gives me shore power if I absolutely need it, and battery charging if I need it too.  Another popular choice is home made generators consisting of a gas engine hooked up to a car alternator.  I got my cheapo 3500 watt no name generator for $99, and my battery charger for $29.  I added a $17 super quiet muffler to the generator, and you can't hardly hear it running.  Mine runs for about 8 hours on a gallon of gas, and if I'm using only it to charge my house battery, it only takes about a half an hour once a week.  Of course I don't require too much battery power.  Normally driving 15-20 minutes every few days keeps my house battery topped off.  About the only things I use my house battery for are charging my laptop, and a fan.  In the winter sometimes I use a 12v electric blanket, and in the summer I sometimes use a swamp cooler.  My lanterns have their own solar panels built in, and so does my bug zapper, my radio, and a battery charger for AA/AAA/C/D/9v batteries.  So I just sit them in a window and they charge themselves.  I also put a spray bottle and one black painted water jug where the sun can get to them for solar heated hot water.  If necessary, I can also heat water on my stove.

If you're going to be in remote areas, make sure you have your own toilet and shower too.  Having my own really improved my life, even though I am mainly a city camper.  There's no feeling quite as good as being totally self sufficient, and having your own toilet and shower is a huge step in the right direction.

We'll work on getting you an awesome system up an running.

Cheers!

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