12v Charging Electronics on the Water or Road

In the past and in general on the boat, we’ve always relied on inverters to convert the D/C battery current to the A/C necessary for all the important things like charging my camera batteries, powering the laptop and, most importantly, making coffee.  However converting from the batteries 12v current to A/C wastes amps.

Although the wasted energy varies depending on how much is needed and the inverter used, it’s my understanding that a good average is 15% wasted.  Doesn’t sound like a lot, but every amp counts when you’re operating with limited power resources such as on my boat… or now in my travel trailer.

So I’ve been trying to figure out how to power stuff directly from D/C (i.e. batteries), i.e. 12v – like your car cigarette lighter.   It’s relatively easy to charge a phone from a 12v outlet, and I’ve figured out how to power my IPad via 12V, but the laptop was a challenge.  Luckily John K, a CC reader, posted a comment introducing an Apple 12V power charger (be careful to make sure you get the adapter if your MacBook Air is post 2012!).

In my research, I found that since laptops are all over the map when it comes to power requirements, it’s necessary to find a 12v power cord that matches your specific laptop.  For example, my MacBook Air requires 45 watts, but my recently deceased MacBook Pro required 60 watts — both are 13″ displays.  Must be something to do with the solid state design of the Air, but regardless, you cannot just find a 12v plug and assume it will power your laptop or computer.  And that’s before you even start to think about the connection on the laptop end!

I finally found a 12V power connection that works with the MacBook Air — with an adapter for the post-2012 models.  It’s not cheap, but it’s less expensive than Dell’s version of a 12v power connection for David’s Dell Inspiron (at 90 watts, btw).  Here’s the info:

1.  12V 14.5v 45 watt power connector for my MacBook Air (also available for pre-2012 MacBook Air).   This looks much like the regular Mac power cord for A/C, but so far it works well in the trailer, and I’m sure it will work equally well on sv Winterlude.  Here’s the link to MarineBeam.com.

2.  12V 90 watt power connector for David’s Dell Inspiron (that also runs our Nobeltec Odyssey navigation software underway) … directly from Dell — the more questions I asked, the more confused I got, so I figure it’s best to buy it directly from Dell.  They asked for the Serial Number and model number of his computer to match us up with the right 12v power source.  I supposed it’s possible to fry sensitive electronics with the wrong 12v power cord?  Here’s the link:  Dell 90 watt Auto-Air Converter for Select Laptops

Unfortunately, I’m still stuck with either a small inverter or our main boat inverter to power things like the coffee pot and my camera battery charger.  We’re in the process of buying a new one for the trailer, but haven’t decided which one yet, here are some possibilities.

Anyone have a recommendation on a small inverter?  Are the USB ports necessary or even useful?  How much power – our small one on the boat is 300 watts, but I notice you can get alot more watts these days for not much money.  The two small inverters we have aboard the boat are both very noisy and tend to overheat quickly – plus they’re 10+ years old.  Anyone have a recommendation for a small inverter that would allow me to charge my camera battery?  I figure the coffee pot is going to require either a manual approach during quiet hours (see Java Dilemma) or our Honda 2000 generator.  So I’m not concerned with big items, just little stuff.

Please leave comments and let us know your solutions and how you like them.  THANKS! Cheers!  Jan