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paulz
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# Posted: 19 Jun 2018 06:16pm - Edited by: paulz
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I read, here I think, that some 18v laptops will run on 12. Neither of my dead battery laptops will, with or without battery. My hope was/ is to leave one at the cabin, which is 12v only.
Next I tried a 6v sla battery in series with my truck battery, that worked but my solar only does 12v. Then I got the bright idea of putting a 5v usb charger in series with the truck battery. That didn't work. I even tried 24v with two truck batteries on my old junker laptop and it worked but I'm afraid to try it with the good one. That would allow me to charge them in parallel and swtch to series. Or I could get two 6vs and charge in series. Or just use an inverter and the 110v power supply. Or buy a new laptop battery and shuffle it back and forth from home to charge.
Or there might be a better option that my non- electronic brain is missing?
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ICC
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# Posted: 19 Jun 2018 10:12pm - Edited by: ICC
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I dunno if there would be many laptops that would work if given a 12 volt input voltage. My reasoning is that all rechargeable lithium battery powered devices need to have circuitry to shut them down once the voltage falls to a certain value. A device that operates off a nominal 18 volt battery will probably be set to shut down at something like 14volts or so. That is to protect the battery; two things that will kill a lithium battery quickly is to be charged to too high a voltage as well as being run down to too low a voltage.
Whether or not 24 volts is safe is hard to say. Depends on how the laptops internal circuitry is designed. I would hate to guess wrong on something I did not want to break. It might also run for a while and then too much heat from too high a voltage may toast something.
How much is a new battery? As long as it is one of the older removable types shuttling it back and forth may work if that gives enough run time. Alternatively, an inverter to recharge off the 12 volt battery using the 120 VAC charger may be best. As long as the laptop charger does not mind the squarish wave from a cheap inverter... some chargers will run a bit warm.
? Rig up a power cord from an 18 volt tool battery??
OR you can exercise your experimental nature and get a boost converter.  Something like this, depending on how many watts you need at 18 volts. That particular one can deliver about 28 watts at 18 vdc from a 12 vdc input. That is according to the advertised specs. Some of the Chinese sellers have not heard of truth in advertising.  A heat sink may be required but the stated efficiency is over 90% so maybe not. Here's another that is appealing as it has a built in display.
Those require some soldering skills, and a box, whatever, to keep it safe from accidental shorts.
I have not used either item myself. I make no specific recommendations - it is just an idea with some examples. Nor have I bought from that ebay seller. Gearbest is a Chinese seller I have used for assorted things. Mostly good results from them but I would definitely use Paypal for any purchases.
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creeky
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# Posted: 20 Jun 2018 10:15am
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DC/DC buck/boost converters would be my suggestion. They're cheap. Even the programmable ones. I would watch I don't stress my battery with too high/low a voltage.
Be interesting how this turns out.
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buckybuck
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# Posted: 20 Jun 2018 10:25am
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Why do you need a laptop at the cabin? Just wondering; might be less hassle to go with an iPad or Android tablet, along with a cheap Bluetooth keyboard if keyboarding is a necessity. Lots of options for charging via USB port.
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razmichael
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# Posted: 20 Jun 2018 11:02am
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As much fun as building/using a buck converter or some other put together device (and I fully admit I would be tempted), I go along with ICC's comment to just get an inexpensive 9but decent quality) inverter. less than $100 bucks - highly unlikely you need pure sine wave - and you have the inverter for any other small things you might need. My cabin is wired 12V but some 120 off a 1800w modified sine wave (that I only turn on when needed). No issues using this to charge my Surface Pro or wife's laptop when needed. We rarely use these at the cabin but my work sometimes requires it so I'd rather be able to spend a weekend at the cabin and do some work than stay at home!
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paulz
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# Posted: 20 Jun 2018 11:02am
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Thanks guys. I'll look into the boost converters but what has me confused right now is the battery for this laptop says 11.1v but the specs and a/c adapter are 19v, is there a second battery somewhere?
I have a Kindle fire at the cabin, and my cell phone. Problem number one is my old fat fumble fingers make too many mistakes on little keypads. I tried an admittedly small bluetooth keyboard and wasn't much better. I'm from the old IBM windows desktop age and also find android harder to deal with. These are not insurmountable problems of course, just thought it would be nice to have a large screen, keyboard and windows once in awhile.
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ICC
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# Posted: 20 Jun 2018 01:56pm - Edited by: ICC
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If the battery states 11.1 volts it should run on 12 volts DC from any other source. The charger output is higher because like all batteries you need a higher voltage to push the energy into the battery. The higher the faster the recharge. Also more heat so there is a limit.
If you are keyboarding a lot a real keyboard is the best, IMO. But I have found some nice little stylus things that make it a little easier than fingers ob phone size screens. I have better luck on my 8.4" tablet.
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paulz
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# Posted: 20 Jun 2018 08:43pm
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Here is the replacement battery for my laptop, 11.1v, and the power supply, 19v. I cut the wire at the output side of the power supply (and test for polarity and voltage, it was 19 something, then jumpered to a fully charged car battery. Wouldn't boot up. The laptop battery has about a half dozen terminals, no idea how one would jumper there. There must be some circuitry inside, maybe I'll crack it open.
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paulz
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# Posted: 20 Jun 2018 09:55pm - Edited by: paulz
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Here's an explanation of 19v power supply and 11v batteries in laptops. Actually several explanations..
https://www.quora.com/How-does-a-laptop-run-on-both-11v-from-a-battery-and-19v-from-a -charger
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paulz
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# Posted: 20 Jun 2018 10:21pm
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So I gather from the above link that it will run on 11 (or hopefully 12) volts if I can replace the battery with jumpers. I opened up the old battery, sure enough there is a circuit board and several wires running to it. The one black on in the photo was just taped to the side of one battery, a thermal thing? Not sure about the blue wire on the other battery. Harrumph, never easy..
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paulz
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# Posted: 20 Jun 2018 10:33pm
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Ew
http://batteryuniversity.com/learn/article/how_to_repair_a_laptop_battery
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paulz
Member
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# Posted: 22 Jun 2018 08:52pm
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Gave up on the battery port, ordered a boost converter. More to follow.
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paulz
Member
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# Posted: 26 Jun 2018 05:50pm
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Up and running on the $5 boost converter I bought online. Will report back any changes. Thanks all!
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