Wizard
We live in the country, in a small cabin off the electricity grid on petrol/lpg generated 12 volt power. My deep cycle bank of batteries are getting old and don't charge higher than about 12.2 volts. That's ok because my LED cabin lights run quite happily on much lower voltage and my own MSI brand laptop will run through the PowerTechPlus DC adaptor when batteries run down to around 11 volts.
The problem is my daughters Apple Mac laptop that we had to purchase through her school. there is no Power Tech Plus adaptor plug to suit this laptop, and I haven't been able to find any other brand of DC to DC adaptor to suit it from electronic shops such as Jaycar or computer specialists either.
So we have to power her Mac via a 150watt invertor.Aside from being power hungry, the invertor cuts out when battery voltage drops to about 12.1 volts, so I have to power it with a small 12 volt car battery that needs to be charged daily after each nights use (she's on it from 4.30 to around 11.00 pm each school day). This is manageable on school days because I charge the battery in the car I take her to School in (about 60km round trip). What is difficult to cope with is the current 2 week School term holidays. The lazy good for nothing teenage sodhardly leaves her room and spends most of the day and night on her laptop. I struggle to keep her supplied with batteries during these periods so I really need to find a solution to 'losing' the invertor and powering her Mac through a DC adaptor.The Macs power requirement is 16.5 volts.
Bill.
Master
The
Apple don't allow third party vendors to use the MagSafe connector in their products, so until recently the only way to get a 12v charger for a Mac laptop was to cannibalise a stock MAc charger and build your own from scratch. If you want to go down that route, I can probably come up with plans for you. However if you just want to buy something, then this guy sells adaptor kits, albeit for a nice chunk of cash...
Mikegyver's Store
Look up SolarGorilla. They do a ciggy socket to magsafe adaptor. It's a bit exxy thanks to the Apple gouge, but should give you a platform to work from.
Master
I stand corrected - looks like somebody's started churning them out. Found these on eBay
Car Charger for Apple MacBook Pro Magsafe A1222, 85W | eBay
$40 - seems like a good deal to me.
Just be aware, the 45W adapter is for the Macbook Air ONLY. You'll need the 60W or 85W for anything else.
Wizard
I'm not very electronically minded, but it would appear that the chargers linked to are just an invertor and charger built in to a single unit,with over and under voltage protection, I would still need to keep my deep cycle batteries over 12.1 volts.
I might get hold of another mag safe power lead, measure the polarity on the 4 pin wires and splice the wires to my spare Power Tech Plus DC to DC adaptor.
Bill.
ChatterBox
Realistically the only way to increase voltage is to use an transformer, which means you are really just creating an inverter. You can decrease DC voltage easily, but increasing is not so easy.... So yes, most 12v DC chargers for an Apple laptop (19V) will in some shape or form be an inverter. It's just a matter of how effectively and efficiently they can integrate it into a single device.Originally Posted by wagoo
ChatterBox
The thing about DC is that you can't use a transformer to change the voltage. Getting a bit technical a transformer works on AC because the sinusiodal wave form is the relative motion needed to make a current ( magnetic field,
Conductor and relative motion)
So either an inverter or a separate small solar system to power your daughters computer. If you want to go down that path Bee Utey is going to send me his secondhand regulator if you want it pm me and him and you can have it as you need it more than I do. If you know how to get a couple of 35w solar panels to you from Queensland I will give you them. They are second hand but still work fine. Then all you need is a battery and wire it up.
Otherwise I have a use for it all
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