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surfer21
1st January 2010, 07:45 PM
My 7" GPS unit from ebay seems to charge ok from the 240v adapter and the red light shows on unit when its connected to charger....however ive tried the car charger and no red light and does not charge as it went dead while driving.
I checked the output at the end which plugs into gps unit and there was 12v but it wont power the gps unit?????
Anybody else had this issue?

Nicko
1st January 2010, 10:43 PM
If the car charger has a mini USB it should only be 5 volts DC

vaku8tr
2nd January 2010, 04:19 AM
may sound silly but check fuse in the charger [cigarette plug end] Had same problem .fuse blown

Les Addison
3rd January 2010, 11:18 AM
I had a similar problem, have it plugged in turned on, wiggle the the wire that goes into the mini usb plug. Had two cables go this way. Les

surfer21
3rd January 2010, 12:04 PM
Its a round plug and it has power at the end but will not make a connection when plugged into unit

Les Addison
4th January 2010, 03:49 PM
Test cigarette circuit with lighter, should glow red. If 240 V charger works, problem will be a connection or fault in the 12v charger cable. Les

LaurieM
4th January 2010, 08:54 PM
OK. If it's a round plug it's likely putting out 15, 16, 17 or 18 volts.

They all have a slightly different sized plug. Won't contact in the wrong sized plughole.

There may or may not be an over voltage cut-out.

But then it could be putting out 12 volts.

You need to get your books out for both the GPS and the power outlet. If the voltages don't match, then it won't work.

Best wishes.

mlenser
5th January 2010, 08:58 AM
I checked the output at the end which plugs into gps unit and there was 12v but it wont power the gps unit?????I understood this to mean that he has 12v at the gps end of the car charger lead? I would guess that its a bad connection in the cable that fails under load.
i.e. the voltage drops to low when under load?

I would have guessed that surfer21 has measured the output from the working wall charger to confirm the gps needs 12v dc?

festy
5th January 2010, 09:22 AM
did the car charger come with the gps, or purchased separately?
Has it ever worked?

LaurieM
5th January 2010, 11:45 AM
I would have guessed that surfer21 has measured the output from the working wall charger to confirm the gps needs 12v dc?
Well, I was guessing he may not have. That's why I explained the different size round plugs.

It will be enlightening to hear from the OP. Without confirming the voltage requirement, it's a guessing game, huh! Ah well. :rolleyes

raider
21st November 2010, 07:17 PM
so we know the 240v pack charges the gps in a socket on the gps...and its a round plug type
and the indication is red led display when 240v plug is the charging input...

so for laughs and giggles...with multi meter what is the output
volts from 240v charging unit or does it say on the unit..

input240v ===ac/2amp
output 5v==== dc/1.5amp
+inner
-outer

cause that would mean its a 5v required

if it says
output 12v l=====dc/1.5amp

then the unit needs 12v

HIGHLY UNLIKELY ...

same result is you test it with a meter..

now if the car plug does not match what the 240unit is doing..
as in 240 in and 12v or 4v out

and your car plug is 12v in and out..and it needs 5v
the stepdown rectifer in the plug has gone!
throw the cig out and geta new one..

what you must remeber is 12v cig are not really ment for recharge
there ment for boosting and some just running!

so your better with a inverter and feeding it 240v to 5v
often because it can handle it..
supply and recharge

but not allot of units do both on v5 from 12v or 5v from 240v

you could get a better version of 12v to 5v that is higher current in amps to match the 240v output dc in amps
so the cig lighter might put out 5v but at 600watt
the 240v unit puts it poutat say 1.5 amp
so find a 12v to 5v that does it at 2amps

anyway....thats the full answer i guess..

hope that helps ya...

many thanks raider :) :welcome

cuvier100
21st November 2010, 08:33 PM
The 7" Ebay GPS units require a 12 volt dc supply.

I suspect that the the contact on the cigarette lighter socket is poor. Do you smoke? Try it in another car.

Mike

festy
22nd November 2010, 09:44 AM
so for laughs and giggles...with multi meter what is the output
volts from 240v charging unit or does it say on the unit..

input240v ===ac/2amp
output 5v==== dc/1.5amp
+inner
-outer

Even a dodgy Chinese plug pack should have better than 4% efficiency ;)
Did you mean 0.2 amps?



now if the car plug does not match what the 240unit is doing..
as in 240 in and 12v or 4v out

and your car plug is 12v in and out..and it needs 5v
the stepdown rectifer in the plug has gone!
throw the cig out and geta new one..

I assume you mean the stepdown (buck) regulator?
Rectifiers don't step down (if anything, they sort of step up!), their purpose is to convert AC to DC. Voltage level manipulation is a different kettle of fish...



what you must remeber is 12v cig are not really ment for recharge
there ment for boosting and some just running!

Some 12v->5v DC-DC adapters are only designed to supply 500ma - they're mainly the USB style ones, as the USB2.0 "high power" class definition only calls for 500ma. There's plenty available that will deliver multiple amps though, and they don't know/care whether you're running or charging your device.



so your better with a inverter and feeding it 240v to 5v
often because it can handle it..
supply and recharge

Nooo!!!!!!! apart from the added zap dangers of increased voltage, there's the DC->AC->DC conversion and the 12v->240v->5v voltage shenanigans that are very, very wasteful from a power perspective.

An inverter will draw considerably more power from the 12v side to run a 5v output than a DC-DC converter.
Inverters just aren't efficient, specially at such low power. An inverter designed to supply say 120w will have an efficiency around the 80-90% level when supplying 100w+, but at <10w would be in the 60% area (don't quote me on the exact numbers, but pretty sure the ballpark is right).

If the inverter has an "auto start" feature like most smaller ones, it may not even start up with such a small load present.
My old 300w MSW inverter won't run a phone charger without something else connected as well.

Also, a 12v->5v DC-DC converter capable of supplying 1.5a is a lot cheaper than an inverter, and smaller too! I built a 5a @ 5v one a while ago for a grand total of $4.



you could get a better version of 12v to 5v that is higher current in amps to match the 240v output dc in amps
so the cig lighter might put out 5v but at 600watt
the 240v unit puts it poutat say 1.5 amp
so find a 12v to 5v that does it at 2amps


600w @5v would require cables roughly the size of jumper leads, you're talking 120 amps there!
I can't see where you got the 600w figure from though?

Anyway, it's only the 240v adapter's output current you're interested in - in your example that's 1.5a @ 5v. That's a whopping 7.5 watts. No need to go larger than the 240v adapter's output of 1.5a if that one does the job.

But, none of this is relevant if the GPSr takes a 12v input ;)

madhat
22nd November 2010, 11:44 AM
i have to be carefull when using examples to make them absolute...and factual ...sorry if that upset festy
i was tring to get accross what i stated below...


the theme here was ....
test the cig lighter and its supply
if not good
make a new one...seperate..which is in fact better for inverter
and free up the cig lighter..
clutter wise..
test the production of 240 and cig lighter for same output and pol.

a small inverter would do...and if the now defunked cig lighter burnt out lets find out why..
1) badly made
2) poor fittings
3) bad car cig lighter
4) underdone for the job

and fix it...


thanks raider :)
:welcome

madhat
22nd November 2010, 11:52 AM
my son and i both saw the post...and i told him what i thought...
he gave rough copy ...example..
and posted a reply
under his log on...

he and i agreed on the problem...

i saying now...on behalf of raider..my son...the above points i think are more important...
but i take your point...perhaps examples should be techical correct

just to explain why i answered festy....

:)madhat

:hatoff