18vdc Aux System Using Golf Cart Batteries?

[Ragtime]

Hi all, I've been poking around in the forums reading about how best to power a laptop aboard. I know my laptop runs on 19 volts, and I'd say 18 volts is close enough to run it, plus I can charge my 18 volt power tools off an 18 volt system, and it seems like an 18 volt system should be attainable by putting a 6 volt golf cart battery in series with a 12 volt car/marine battery. Plus, two 6 volt golf cart batteries in parallel should be able to charge off the same systems that charge my current 12 volt system.

So, I envision a 2 marine battery(12v) and 2 golf cart battery(6v) system that will allow me to power my 18v appliances(computer, drill etc) with an auxillary 18v line, yet with minimal changes to the 12v infrastructure of my boat because of the ability to charge the two 6v batteries(when in parallel connection) with my 12v charging system, and because the "main line" will still be 12v.


My question: How do I wire the 4 batteries together to make it all work(without playing battery musical chair)!
@#*

[edsailing]

Sounds like a complicated and expensive solution to a problem we all have - I just bought a small inverter (70w) for less than $20.

[GordMay]

Originally Posted by Ragtime

...yet with minimal changes to the 12v infrastructure of my boat because of the ability to charge the two 6v batteries(when in parallel connection) with my 12v charging system, and because the "main line" will still be 12v.

My question: How do I wire the 4 batteries together to make it all work(without playing battery musical chair)!

Greetings and welcome aboard Ragtime.

You don't.
It would be a wiring & switching nightmare.
You don't want to combine differing types (voltage) of batteries (you could use identical 6V batteries to achieve the same, but still a bad idea, IMHO).

[btrayfors]

I agree. It would be a nightmare, and wouldn't work anyway.

Your 18V tools are charged with 115VAC chargers. You can't hook an 18V battery directly to a large 18V source to charge it. Aside from the problems of controlling amperage flow, 18V isn't enough to charge an 18V battery...it needs considerably more.

As Gord says, combining different types of batteries isn't a great idea, either.

I'd suggest you look into a small inverter to charge your 18V appliances via 115VAC.

There are dedicated laptop devices designed to run them from 12V (e.g., car) systems. One of the better ones is made by Lind. These are relatively efficient and will allow you to charge the laptop's internal battery, not just run the laptop.

Bill

[Caribsailors]

Check the data on your computers battery, I doubt it is rated for 18 volts.

All of mine have ranged from 10.5v to 12v. I've always thought about experimenting with the battery removed, and wiring the laptop into the 12v system.

Haven't yet, the $20 inverters still working

Cheers

[solarjames]

My computer programer friend has been running ibm thinkpad laptops for years with them wired directly to 12volts, even know the laptop is a 17 volt model. He has not had any problems. I would not make an 18 volt bank

[garymcg]

Originally Posted by Ragtime

Hi all, I've been poking around in the forums reading about how best to power a laptop aboard. I know my laptop runs on 19 volts, and I'd say 18 volts is close enough to run it, plus I can charge my 18 volt power tools off an 18 volt system, and it seems like an 18 volt system should be attainable by putting a 6 volt golf cart battery in series with a 12 volt car/marine battery. Plus, two 6 volt golf cart batteries in parallel should be able to charge off the same systems that charge my current 12 volt system.

So, I envision a 2 marine battery(12v) and 2 golf cart battery(6v) system that will allow me to power my 18v appliances(computer, drill etc) with an auxillary 18v line, yet with minimal changes to the 12v infrastructure of my boat because of the ability to charge the two 6v batteries(when in parallel connection) with my 12v charging system, and because the "main line" will still be 12v.


My question: How do I wire the 4 batteries together to make it all work(without playing battery musical chair)!
@#*

Just buy a 12v car adapter for your laptop (they're cheap on ebay), cut the cigarette lighter plug off the end, and wire that directly into your 12v panel, problem solved and everything is at the proper voltage. Best not to go reinventing the wheel when it comes to electrical systems.