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1.5 Amp Fuse keeps blowing in my car

I have a GPS set up in my car - Basically I use a power outlet in the
dash similar to a cigarette lighter with a splitter to feed 2 12V
items items. My setup includes an HP Ipaq that has a 5 amp fuse -
never blows a fuse into 1 side of the splitter. The other side for
about 5 months I plugged in my GPS Bluetooth receiver - It recently
keeps blowing the 1.5 amp fuse. I even bought a new charger. I can the
take the charger whcih similar to a cell phone charger and put it into
another vehicle & it will not blow the fuse. My GPS receiver requires
the 1.5 AMP fuse. I would imagine there is something in the circuitry
of my vehicle causing it to blow 1.5 Amp 250V fast acting fuse - is
there anything I can put on the circuit to ro stop this ????
 
M

martin griffith

Jan 1, 1970
0
On 11 Mar 2007 16:36:09 -0700, in sci.electronics.design
I have a GPS set up in my car - Basically I use a power outlet in the
dash similar to a cigarette lighter with a splitter to feed 2 12V
items items. My setup includes an HP Ipaq that has a 5 amp fuse -
never blows a fuse into 1 side of the splitter. The other side for
about 5 months I plugged in my GPS Bluetooth receiver - It recently
keeps blowing the 1.5 amp fuse. I even bought a new charger. I can the
take the charger whcih similar to a cell phone charger and put it into
another vehicle & it will not blow the fuse. My GPS receiver requires
the 1.5 AMP fuse. I would imagine there is something in the circuitry
of my vehicle causing it to blow 1.5 Amp 250V fast acting fuse - is
there anything I can put on the circuit to ro stop this ????

You could possibly measure the current, or is that a bit technical?


martin
 
You could possibly measure the current, or is that a bit technical?

martin

With a little direction I can do it - I have 3 meters bascially your
39.95 type but I'm sure I can do it - what do I set my meter to when
you say measure the current -

Thanks
 
N

no_one

Jan 1, 1970
0
With a little direction I can do it - I have 3 meters bascially your
39.95 type but I'm sure I can do it - what do I set my meter to when
you say measure the current -

Thanks

put in a 3 amp fuse. The splitter seems to be able to handle it and you
won't be plagued with nuisance blowouts. If the GPS is truly failed it will
blow the 3 and you will need to troubleshoot the GPS unit. Otherwise the
upstream wiring should be just fine.
many people seem to believe that fuses are to protect the load device when
they are really to keep the upstream wiring from burning up.
 
put in a 3 amp fuse. The splitter seems to be able to handle it and you
won't be plagued with nuisance blowouts. If the GPS is truly failed it will
blow the 3 and you will need to troubleshoot the GPS unit. Otherwise the
upstream wiring should be just fine.
many people seem to believe that fuses are to protect the load device when
they are really to keep the upstream wiring from burning up.- Hide quoted text -

- Show quoted text -

Actually what I failed to mention was I plug the charger in to the 12V
power outlet without plugging the other end into the GPS and it blows
the fuse - it has something to do with the power source in my car not
the GPS unit - in other vehicles it does not blow the fuse

Thanks
 
P

Paul E. Schoen

Jan 1, 1970
0
Actually what I failed to mention was I plug the charger in to the 12V
power outlet without plugging the other end into the GPS and it blows
the fuse - it has something to do with the power source in my car not
the GPS unit - in other vehicles it does not blow the fuse

Thanks

It seems like the charger is causing a momentary surge, possibly because of
a capacitor charging up. The vehicle that does not cause a problem may have
some sort of series resistance or inductance that limits this surge. It
would be difficult to measure this surge without a storage scope or peak
reading meter. You should be able to use, perhaps, a 1 amp slow blow fuse.
You could also add maybe a 1 ohm resistor in series, or a hash choke. There
are also surge limiting thermistors that start at a couple of ohms and then
drop to about 1/10 that when they get hot.

Paul
 
It seems like the charger is causing a momentary surge, possibly because of
a capacitor charging up. The vehicle that does not cause a problem may have
some sort of series resistance or inductance that limits this surge. It
would be difficult to measure this surge without a storage scope or peak
reading meter. You should be able to use, perhaps, a 1 amp slow blow fuse.
You could also add maybe a 1 ohm resistor in series, or a hash choke. There
are also surge limiting thermistors that start at a couple of ohms and then
drop to about 1/10 that when they get hot.

Paul- Hide quoted text -

- Show quoted text -

I will try both - 2 questions - Can I use a 1.5 Amp slow blow or did
you recommend a 1 AMP slow blow instead of 1.5 for a reason. Also when
you say in series can I simply put a 1 ohm resistor on the + positive
side of the female power outlet the charger plugs into

Thanks
 
P

Paul E. Schoen

Jan 1, 1970
0
I will try both - 2 questions - Can I use a 1.5 Amp slow blow or did
you recommend a 1 AMP slow blow instead of 1.5 for a reason. Also when
you say in series can I simply put a 1 ohm resistor on the + positive
side of the female power outlet the charger plugs into

Thanks

The 1 amp gives a better safety margin, but 1.5 amps should be OK. The
wiring will be protected in either case.

The resistor would go between the 12 VDC source and the outlet. The fuse
would also be in series. If you disconnect either the fuse or the resistor,
the circuit will be open.

Also, make sure the power plug does not somehow short out the connector as
it is being inserted. Especially if it is not a standard type connector for
12 V power.

Good luck,

Paul
 
H

Homer J Simpson

Jan 1, 1970
0
I would imagine there is something in the circuitry
of my vehicle causing it to blow 1.5 Amp 250V fast acting fuse - is
there anything I can put on the circuit to ro stop this ????

A slow blow fuse?



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..
..
..

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The 1 amp gives a better safety margin, but 1.5 amps should be OK. The
wiring will be protected in either case.

The resistor would go between the 12 VDC source and the outlet. The fuse
would also be in series. If you disconnect either the fuse or the resistor,
the circuit will be open.

Also, make sure the power plug does not somehow short out the connector as
it is being inserted. Especially if it is not a standard type connector for
12 V power.

Good luck,

Paul- Hide quoted text -

- Show quoted text -

Paul thanks for your time & help

I will try both
 
P

Paul Hovnanian P.E.

Jan 1, 1970
0
With a little direction I can do it - I have 3 meters bascially your
39.95 type but I'm sure I can do it - what do I set my meter to when
you say measure the current -

That might not be very helpful. Your meter might be able to measure the
steady state draw of this charger. But I suspect that what is blowing
your fast acting fuse is the charging current of a capacitor in its
input stage. You'd need an oscilloscope to see that.

Try replacing the 1.5 A fast acting fuse with a slow blow type (same
rating).
 
E

Eeyore

Jan 1, 1970
0
I have a GPS set up in my car - Basically I use a power outlet in the
dash similar to a cigarette lighter with a splitter to feed 2 12V
items items. My setup includes an HP Ipaq that has a 5 amp fuse -
never blows a fuse into 1 side of the splitter. The other side for
about 5 months I plugged in my GPS Bluetooth receiver - It recently
keeps blowing the 1.5 amp fuse. I even bought a new charger. I can the
take the charger whcih similar to a cell phone charger and put it into
another vehicle & it will not blow the fuse. My GPS receiver requires
the 1.5 AMP fuse. I would imagine there is something in the circuitry
of my vehicle causing it to blow 1.5 Amp 250V fast acting fuse - is
there anything I can put on the circuit to ro stop this ????

If the fuse blows it's because the current is too high !

What's the spec of the GPS receiver ? What model even ?

Graham
 
E

Eeyore

Jan 1, 1970
0
martin said:
On 11 Mar 2007 16:36:09 -0700, in sci.electronics.design


You could possibly measure the current, or is that a bit technical?

My thoughts entirely.

Graham
 
W

w_tom

Jan 1, 1970
0
Paul thanks for your time & help

I will try both

Better is to cure the 'power on' surge with a component called an
'inrush current limiter'. It starts with higher resistance, then
resistance goes lower. Inrush current limiters are standard and
plentiful for 120 volt appliances (that have lower current draw).
They may be harder to find for your higher current. If not an inrush
current limiter, then Paul Hovnanian's slo-blo fuse recommendation is
a better solution.

Also a warning. Some 12 volt plugs short out (therefore blow any
fuse) when put in some 12 volt auto power receptacles.
 
C

colin

Jan 1, 1970
0
I have a GPS set up in my car - Basically I use a power outlet in the
dash similar to a cigarette lighter with a splitter to feed 2 12V
items items. My setup includes an HP Ipaq that has a 5 amp fuse -
never blows a fuse into 1 side of the splitter. The other side for
about 5 months I plugged in my GPS Bluetooth receiver - It recently
keeps blowing the 1.5 amp fuse. I even bought a new charger. I can the
take the charger whcih similar to a cell phone charger and put it into
another vehicle & it will not blow the fuse. My GPS receiver requires
the 1.5 AMP fuse. I would imagine there is something in the circuitry
of my vehicle causing it to blow 1.5 Amp 250V fast acting fuse - is
there anything I can put on the circuit to ro stop this ????

reminds me of a myth on mythbusters about someone replacing a blown fuse
with a bullet ....

Colin =^.^=
 
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