DC-DC (12v to 15v or 19v) adapters

demonboy

demonboy

Well-Known Member
Joined
11 Oct 2004
Messages
2,237
Location
Indonesia
www.youtube.com
Been recommended a website that specialises in DC to DC power conversion. I'm running a laptop that only needs 19v so I was considering a DC adapter rather than running it through an inverter (I assume an inverter is a greater drain on the battery bank).

The website/manufacturer is iGo. Does anyone have any experience with these kind of products, or recommend anything cheaper?
 
Maplins do a very reasonably priced Laptop convertor supplying a range of voltages at 3 amps. Runs my Dell just fine of 12 volts.

Used to run through an invertor, but you are right that it is a heavier drain on the battery.
 
Check the wattage....

DC-DC adaptors work very well, but you need to ensure you get one with a high enough power rating for your laptop. Modern laptops are quite power-hungry! If you get an adaptor with a 120watt rating (like the Maplin one) you should be OK.
 
One point that you must bear in mind .....

Power consumption of Notebook PC is deoendent on what you ask it to do .... If you like to call up charts from CD and not have on Hard disk - then you will draw a lot more power. If you run most things from a USB caddy Hard disk as I do - that draws power. If you run a USB connected GPS with power via the USB as my eTrex does when connected to my later Notebook ..... they ALL draw power.

What happens then is whatever power supply you use other than original power pack on mains, you will draw from the Notebook battery as well ...

eg : My notebook will run for 4 days using about 8 - 10 hours per day till battery gives up (Notebook battery not boats !!)

But if I run all data etc. from internal hard drive, connect eTrex to 12v power and use the serial connector .... no CD's etc. Then I have no trouble and do not run out of power ..... as long as boat battery is charged of course.

I am not trying to worry you at all - just pointing out that careful use of PC facilities and add-ons to extend battery life and useage time .....

(I do have to admit that my Domestic Battery is not in the best flush of youth - which does not help !!!)

Yes the Maplins DC - DC machine is good .... I have the White Knight Adaptor ... £29 I think it was ... now they have cheaper I think .... and more choice.
 
Thanks Nigel, some useful food for thought. I was aware of some of the variations in power consumption but it's interesting what you say about using the notebook battery as well as the boat's.
 
Hi demonboy,

One of the problems with the Maplin's units is that they don't do them for the later Dell's apparently. I have an Inspiron 8600 and can't find anything in Maplin's catalogue that has the correct plug, indeed in the FAQ's section they specifically exclude several Dell models.

Anybody else know differently or who can give details of one that will work? I can't even seem to source a Dell one, even though someone (I think Lemain) mentioned they had one on a similar thread a while ago.

Oh, sorry to hang off your thread demonboy!
 
I found out the hard way !

Steve .... Albin Vega owner was with me and my Notebook just went off. I thought OK - its gone into Stby .... but no the battery was flat. I left it off and connected and it charged up again over a period.
I first of all thought it was a fault - but thinking about it and adding up the items I had hanging of the Notebook - it became obvious what had happened. I had exceeded the adaptor rating, it couldn't supply all that wattage - so Notebook battery compensated - draining that ever so slowly. Later trips out on boat - I reduced the items connected and had much better battery life ....

I will be changing my Domestic battery as well next time back - so both added together should mean a better situation ...

I do add that if you have a real good boat battery - then that will help greatly ... my domestic probably doesn't deliver so well when called on ...
 
Thanks sailorgirl!

I've looked at this site before but can see nothing that is suitable for the 8600c. I've emailed them now, so hopefully they will be able to point me to something I've missed!!
 
I have used a number of the buck converters, including the generic one shown by Tome (comes under alot of different brand names that one), with no problems. I find it is best to select an oversized one capacity wise though especially if your notebook does not have efficient power management.

You may likely find that your notebook will run straight off your boat's 12v supply too and this has been mentioned as a possibility before (I think including by Nigel whose comments encouraged me to explore it further). I had wondered about how widely possible this was (my previous notebooks would run off 12v although 18v plus charger ones). However, I have just got a new notebook which came with a complete maintenance manual (wonderful, how to completely dismantle, even down to the individual screw sizes and types). In that, even though the computer is an 18.5v charger one, the battery voltage is specified as 11.1v ie the cells in the battery pack are arranged in series of 3 (3x 3.7v Li-Ion cells in series) and the series banks paralleled ie the machine normally runs on 11.1v and I suspect this is the usual case for 6 cell battery packs and probably also so for 9 cell ones.

We have a permanently installed invertor on board (quasi sine wave), and all computers, notebooks and desktops, I have tried run fine on that too. I think people tend to overemphasise the efficiency gain of using a 12 volt buck convertor over a good invertor but, of course, the most efficient is to run the notebook straight off the boats 12v supply.

{Edit: Have entered in the above the exact voltage for the battery and the cell arrangement in it from the maintenance manual).

John
 
Many thanks for that demonboy. I'll have to check that the 'tips' they mention will fit the Dell, but it certainly looks like the answer.

Cheers Jerry
 
Hi demonboy,

Looked into the iGo stuff more closely, but whilst the ones they recommend will power the laptop, they won't charge the battery at the same time apparently. They recommend the Dell branded one if one wants to do both.

I already have inverters aboard to charge the batteries so might go this route, but would prefer to use one unit to do both, so will try and source a 'Dell' brand one.

Thanks for the link anyway.
 
I use one of those Maplin jobs for my monitor, but it does work on the laptop. However, I now use a trust AC/DC-DC adaptor fromPC world that cost me a fortune (£75), but it does convert any power supply AC or DC into pretty much output- my Sony wasn't listed, but it works fine (so far...)- god knows how it works out the voltage needed! Mind you, I did see Maplin have something like this for £20 now. Aaaagh.
BTW... 40 hours on a notebook battery? How on earth do you manage that? Just over 3 hours is the best listed in the specs on the market I think. Or is that a high consumption pen and paper notebook?
Jem.
 
battery time ...

Quote :>BTW... 40 hours on a notebook battery? How on earth do you manage that? Just over 3 hours is the best listed in the specs on the market I think<

I think you misunderstood ... a) it was me that mentioned 4 days at 8 - 10 hrs per day, b) it was while plugged into dc-dc converter and boat battery.

The statement was made to illustrate that when the adaptor does not supply all the wattage req'd for all the bits and bobs such as CD drive, caddy HDD, etc. etc. - the notebook battery also gives power to add to the adaptors ... Thus you have notebook battery discharging at very slow rate ... not the usual slam-dunk couple of hours if lucky. So again --- the adaptorf is providing majority of power required, with battery giving the balance ....

Disconnect peripherals, stop reading charts from cd's etc. and adaptor will then power all and have a chance to also start charging notebook battery ....

OK ..... /forums/images/graemlins/tongue.gif
 
You must log in or register to reply here.

Share this page

Top