DIY Dell Car charger

[ratdude747]

I am thinking of making a homebrew car adapter for my 2 dell latitudes. After seeing how expensive they are pre-made, I wonder if I can save $$ by doing it myself.

they both are PA-10/12 compatible, meaning they work with the barrel plugged 60W/90W units.

I happen to have a steel project box (found brand new at goodwill for $2) that may be oversized but will work.

I think I can get the cord for the laptop end on ebay (with plug). I know I can get the cigarette lighter plug and cord

I would like at least some advice and preferably some guidance in designing the circuitry to make it happen.

my questions are:

1. should I aim for a 60W unit or a 90W unit? or one in between? I think 60W since my math says I will need at least 5A to do that (not including waste heat, etc.)

2. I know that these units have a wattage indicator pin. how exactly does the pin function? I tried probing a 60W and a 90W adapter but came up short on a conclusion.

3. Is this even a worthwhile project? or would it be a better deal to save up for a new 9 cell battery for my d630?

[shovenose]

Re: DIY Dell Car charger

I would go for one of those universal car adapter things with interchangable plugs and variable voltage.
That way you can run any laptop in your car in the future.

[ratdude747]

Re: DIY Dell Car charger

I would go for one of those universal car adapter things with interchangable plugs and variable voltage.
That way you can run any laptop in your car in the future.

they are pricey (well good ones, anyway)... if they were not then this thread would not exist.

[shovenose]

Re: DIY Dell Car charger

They're less than $20. That's probably about how much it's going to cost for parts to make your own.

[ratdude747]

Re: DIY Dell Car charger

They're less than $20. That's probably about how much it's going to cost for parts to make your own.

have some proof? last I checked they were going for $60+.

and by good, I mean good, not chinese no-name.

[shovenose]

Re: DIY Dell Car charger

Sorry, I seem to have missed that part about wanting a good one

[brethin]

Re: DIY Dell Car charger

100w Car inverter will run you under $20 and work better than anything you can build for anything close to that price.

[ratdude747]

Re: DIY Dell Car charger

100w Car inverter will run you under $20 and work better than anything you can build for anything close to that price.

I had one, my (retail) $20 unit bombed itself... even after a recap, it bombed those caps as well. and it was only a 70W (I used a 60W brick)

my understanding was that if you wanted a good (not a fire hazard) power inverter, you had to pay $$$ for it...

[joshnz]

Re: DIY Dell Car charger

what is the voltage it needs i'm guessing 19 volts?

[ratdude747]

Re: DIY Dell Car charger

what is the voltage it needs i'm guessing 19 volts?

19.5v

[joshnz]

Re: DIY Dell Car charger

hmmm I'm thinking can't be that hard to make something.

1. 50/60hz push pull inverter with a full wave rectifier with a feed back circuit or regulator.

2. switchmode step up supply more efficient.

[smason]

Re: DIY Dell Car charger

I've been using the same inverter for 15 years, never a problem. It's one of the original Statpower units. Much simpler than building one for mobile use.

[Evil Lurker]

Re: DIY Dell Car charger

100w car inverter will run you under $20 and work better than anything you can build for anything close to that price.

+1

[ratdude747]

Re: DIY Dell Car charger

+1

so you really want me to bomb my car?

seriously, all of the $20 inverters I saw were garbage... I know that my 70W Vector unit folded when given a 60W dell PA-12 and a D400... I recapped it but I was told by KC8ADU that it was a fire hazard and I could have killed my laptop with it.

I am looking for long term solutions... not short term time bombs.

[c_hegge]

Re: DIY Dell Car charger

I would just go for a better battery or a good in car inverter, simply because if you get it wrong you can say good bye to your laptop.

[ratdude747]

Re: DIY Dell Car charger

I would just go for a better battery or a good in car inverter, simply because if you get it wrong you can say good bye to your laptop.

no, that is why you test with a multimeter (digital and analog).

but my battery has been wonky lately... so i may go the battery route for that reason.

[NxB]

Re: DIY Dell Car charger

Lol, my $20 harbor freight inverter ran a few different laptops just fine.

[ratdude747]

Re: DIY Dell Car charger

Lol, my $20 harbor freight inverter ran a few different laptops just fine.

luck is never a good reason to do something. if you cannot find a lovical reason, don't do it.

I have this thing still:

https://www.badcaps.net/forum/showth...ght=vector+70W

but i don't want to burn down the car or the laptop.

[weirdlookinguy]

Re: DIY Dell Car charger

You're overthinking this. $60 isn't that much if it's something you really need (I'm talking about the universal car adapter).

The homebrew solution will be extremely clunky and a pain in the ass to plug in every time you want to use it which means you'll use it less. When all is said and done I'd be willing to put down money that the total for a homebrew will come close to or exceed the cost of a real universal adapter.

If you want to make the homebrew as a fun side project (you are an EE major after all), go for it. But if it's for practical purposes then just buy the real thing and carry on with life. Shit like this is not worth stressing about.

[ratdude747]

Re: DIY Dell Car charger

it was both a side project and a pratical project.