On planning work on my boat.. I am intending on running a 12 volt system as per normal.. but I will need at least one 24v connection for laptop charging. I will be running two batteries for the amp hours.. but I am trying to figure out how to get 24 volts for a single line and the rest to have 12 without either melting wires or putting 24 through the whole system?
The trucks use 24v.. but some of their accessories are 12v... what am I missing?
Run your 12v stuff in parallel. Run your 24v stuff off a series wire. You can run a series/parallel setup off two batteries as long as you don't create a direct short when you wire it.
Quick dirty diagram.
Diagram deleted because I berkeleyed up.
Disregard this. It's wrong.
Just use a power inverter for 110 and charge the computer that way?
Thread closed
I'm gonna have to give you a Fail, there, Toyman. And a battery explosion, which is generally considered A Bad Thing.
Kenny has The Win.
mad_machine wrote: ... what am I missing?
A DC/DC converter. It will have a more stable and consistant output than the serries/parallel set up in that drawing, but the 110v AC inverter will do the same and be more useful.
Dr. Hess wrote: I'm gonna have to give you a Fail, there, Toyman. And a battery explosion, which is generally considered A Bad Thing. Kenny has The Win.
E36 M3! You're right. Big fail on my part. That's a short.
Deleted the diagram.
I sat down and redrew it. You will only be able to run the 12v stuff is off one battery if you want a 24 volts. The other option is a 12v to 24v converter.
I can deal with that. I just did not want to run an inverter to bring power up to 120.. than the laptop's powersupply to drop it down to a useable level. Just seemed like I would wind up wasting too much energy as heat
What do you need a laptop on a boat for anyways? The most efficient system is going to be a dedicated DC-DC you can build your own if handy with a soldering iron.
well.. I am planning on some long term cruising.. as in 6 to 8 weeks come next winter... I might want to log onto GRM
What are the wattage requirements of the laptop in question? If not given on on the power supply, multiply volts by amps for watts.
I have not bought it yet.. that is later on the list
Also, poking around on amazon (searching; automotive laptop power supply) seems to indicate at least some laptops have 12 V input power supplies available. That's probably the easiest most effective option.
For example http://www.amazon.com/PWR-Satellite-Pa3468u-1aca-Adp-75sb-Notebook/dp/B002VANJ4Q/ref=sr_1_16?ie=UTF8&qid=1373512444&sr=8-16&keywords=automotive+laptop+power+supply
Now that makes life a lot easier
It would also appear Kensington makes a universal one.
Yeah inverters are inefficient (even more so when used to power an AC to DC adapter like a...charger of pretty much any kind) but potentially more useful. If the only thing you need anything but 12v for is a laptop charger, then just get a cig. socket charger for your laptop. These use a DC to DC converter (much more efficient) or sometimes are even just wired straight in as some laptops charge from 12v.
In reply to Toyman01:
not to be a punk.... but you failed again: that is a 24v to 12v converter... and I don't think you can run the boat (except a laptop) off that one converter... you know alternator and starter and all that engine stuff.....
GameboyRMH wrote: Yeah inverters are inefficient (even more so when used to power an AC to DC adapter like a...charger of pretty much any kind) but potentially more useful. If the only thing you need anything but 12v for is a laptop charger, then just get a cig. socket charger for your laptop. These use a DC to DC converter (much more efficient) or sometimes are even just wired straight in as some laptops charge from 12v.
That is the plan now. Having seen that there are DC to DC converters makes this much easier.
As for my boat, there will not be a gas or diesel engine aboard, I will be running a Torqueedo Electric outboard for those times I need an engine. When I take her cruising, I will mount a solar panel on the stern rails for battery charging. The idea is to be as self sufficient as possible aside from food and water.. and even food can be caught when underway
Interesting, don't skimp on batteries then, consider 4 or even more rather than just 2. Some boats have wind turbines on them to aid charging when anchored, could help when it's cloudy.
Toyman, are you trying to kill him? 
I've never heard of the torqueedo, interesting stuff. I wonder how hard it would be to use the motor as a generator from tidal current when at anchor, like regenerative braking. Really, any time water is moving around the boat either under sail or on the hook or dock, there is a huge opportunity there
GameboyRMH wrote: Interesting, don't skimp on batteries then, consider 4 or even more rather than just 2. Some boats have wind turbines on them to aid charging when anchored, could help when it's cloudy.
The idea is efficency. LED navigation and interior lights will cut down on the amp hours needed. The Torqueedo has it's own battery pack that can move a 1.5 ton boat (like mine) for 20 nautical miles at about a knot and a half over 10 hours... the faster you go, the less distance and time you get.
The biggest powerhogs will be charging up the motor and laptop and running whatever radio and navigation gear I have going when underway
mad_machine wrote: The Torqueedo has it's own battery pack that can move a 1.5 ton boat (like mine) for 20 nautical miles at about a knot and a half over 10 hours...
I'm having trouble with this math 1.5 knots for 10 hours = 20 nautical miles?
Cool project. I've been playing with solar and aux batteries in the Westfalia, but deleting the gas motor is not a good choice in that vehicle. Still, it's fun to think of maximizing efficiency.
I didn't know them little wind mills on boats made power, cool. I have a solar powered ventilation fan a boater was throwing away, the battery shorted and the thing wouldn't work. Fixed now. I also have a 40W solar battery charger thingy that goes into the cig lighter. I was thinking about taking the solar charger and charging up a dry cell 12V battery I have when camping, then run LED lights off of that. I'm not sure how much that stupid little solar charger will charge the battery though. Neat project and good luck.
benzbaronDaryn wrote: I was thinking about taking the solar charger and charging up a dry cell 12V battery I have when camping, then run LED lights off of that. I'm not sure how much that stupid little solar charger will charge the battery though.
It'll work, just the little solar charger won't charge it up very fast. But then LED lights shouldn't discharge it very fast.
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