12v Accessory socket problem

[Anseo]

Many of you will know that me and electricity are not well acquainted friends, I will try my best to explain my little dilemma :blink:

I took the12v car vacuum cleaner and plugged it into one of the two 12v accessory sockets within the caravan. The caravan was on EHU at the time, caravan is a Bailey Pegasus GT65 Ancona.

Upon plugging in the vac the vac motor turned for half a second or less, then nothing, I thought that a fuse may have blown, tried the vac in the other 12v accessory outlet, this time I did not hear the motor in the vac start, but had the 'impression' that there was another 'trip'.

I take vac to the car and plug it in and it works fine, I notice that 12v accessory socket in car is marked 1.5 amps, 12 v accessory socket in the caravan is marked 6 amps.

I cannot find the fuse(s) related to 12 v accessory socket in the caravan distribution board, I plugged the TV into one of the 12v accessory outlets using the 12v connector, no power supply to TV

Any help on this please, thank you.

Anseo

 

[Woodentop]

The relevant fuse will be one of the stack in the front of the power box under a seat. It is clearly marked. The likelihood is that it will be one fuse for both outlets. My Peg 462 (2010) has a 10A (red) fuse.

The most likely reason that the fuse blew is starting current on the vac, and/or the vac draws more current that you thought. It might be rated, say, 3A but on start for a very short time it could pull several times that and hence the fuse blows.

 

[Craigyoung]

Hi ,
It'll be the fuse more than likely , we bought a travel kettle a few years ago so we could use it on 12v whilst in the euro tunnel on way to France but upon trying it out in the caravan whist hooked on the drive we blew the fuse also , i had to ring the Ropers where we got it from so they could tell me which fuse it was . Even though something can be used in a 12v socket , check the wattage . It could be possibly marked auxillary . Best off buying a small plug in vacuum . Hope you get sorted .

Craig

 

[VicMallows]

The fact that the caravan was on EHU means that the voltage will have been around 13.8v, or maybe higher on some systems. This will mean the initial surge current will be quite a lot higher than when on a static 12v supply. (The vac will work a lot better at the higher voltage too!). Even so, a correctly rated fuse (probably 10A) should not blow. Most likely reason is that someone has at some stage replaced the fuse with lower rated one....we all do it if it is the only fuse we have to hand ....and then forget to replace it! (Also, a fuse which has been operating close to its limit over a long period can 'age' so that it fails at a lower than rated current).

I don't think your car outlet is rated at 1.5A .... that would be far too low to power a cigar lighter. 15A is much more likely.

 

[Craigyoung]

Thats why i carry a small tub with a few of each fuse just incase ! Kept handy beside the +firstaid box and torch !! In the swift that we have now if a fuse blows a little red indicator illuminates so you know which one to change as I found out not long ago when the radio was not working which was also linked to the 12 volt sockets .

Craig

 

[Anseo]

Thanks for the helpful replies folks.

VicMallows, I checked the 12v outlet in the car, you are correct, the outlet is marked as "MAX 15A", my bad

Have not had time to check out the fuseslocation as yet, will get round to it.

If the fuse is actually 10 amp,would there be any risks in uprating it to a 15amp fuse (assuming that the vac continues to blow a 10amp fuse), I just bought this vac for car and caravan use, not sure if I can get one with lower power consumption that would actually suck up anything

Thanks,
Anseo

 

[VicMallows]

If the fuse is actually 10 amp,would there be any risks in uprating it to a 15amp fuse (assuming that the vac continues to blow a 10amp fuse)

In practical terms, NO. However I doubt very much if your vac would blow either a 10A or 15A fuse. Fuses (unlike MCB's) typically tolerate a short-term overload up to double their rated current.

 

[Anseo]

The 10amp fuse had blown, now replaced.

Not on EHU at the moment so did not check the vacuum cleaner in the 12v outlet whilst on EHU.

12v outlets working OK now, so am happy with that at this time.

Thanks for all your help folks.

Anseo is

 

[Craigyoung]

Hi
the chances are if you put it back into the 12 volt socket it may blow the fuse again as the wattage may be too high for the caravan ? We just bought a cheap plug in one I think from Amazon plugs in doesn't blow nothing .

Craig

 

[Anseo]

Hi Craig,

The vac did not blow the 10amp fuse when plugged into the 12v accessory outlet(s).

I will try the vac again when on EHU and see what happens.

Checked my battery voltage yesterday (off EHU) and it was showing 13v, on EHU the control panel in the caravan shows 13.8v, don't know if that is enough to make a difference and cause the 10amp fuse to blow.

I will connect the caravan to EHU later today ( if it stops raining ).

I am reluctant to buy a 230v vac as
a) I am Scottish (read- tight as 2 coats of paint).
b) If off grid then the 12v vac is the only option, short of carrying a generator :lol: .

 

[Craigyoung]

Hi
Well if you're going off the grid , point taken about wanting the 12 volt system working otherwise a dustpan and brush is the other cheap option !! ha ha !!
Good luck

 

[Dustydog]

Hi
Well if you're going off the grid , point taken about wanting the 12 volt system working otherwise a dustpan and brush is the other cheap option !! ha ha !!
Good luck

Quite right Craig. You can't beat a good scrubber
Anseo.
What's you vac wattage rating?
It is not uncommon for the 12v plug and or socket to short internally causing a fuse to blow.
May be worth checking their wiring.

 

[Anseo]

Anseo.
What's you vac wattage rating?
It is not uncommon for the 12v plug and or socket to short internally causing a fuse to blow.
May be worth checking their wiring.

Hi Sir Sir Dustydog ,

Sorry for the late reply.

Sir Dustydog, label on the appliance shows 120w.

Thanks,
Anseo

 

[Dustydog]

Anseo.
What's you vac wattage rating?
It is not uncommon for the 12v plug and or socket to short internally causing a fuse to blow.
May be worth checking their wiring.

Hi Sir Sir Dustydog ,

Sorry for the late reply.

Sir Dustydog, label on the appliance shows 120w.

Thanks,
Anseo

Sir Haggis.
I'd check the plug and socket wiring for a loose wire causing a short.
Have you tried the cleaner on the car socket?

 

[Anseo]

Dustydog, the vac works fine when used in the car, I have not checked the socket wiring as yet.

Cheers,
Anseo

 

[Craigyoung]

But have you tried it again in the caravan yet on the 12v ?? :huh:

C.

 

[glenno]

If its 120watt then at 12v its pulling 10amps. If the voltage is 13.8v (on EHU) then the draw is 8.7amps. Pretty close to the 10amp capacity of the fuse in that circuit - and that fuse might be supplying other items such as radio or tv antenna.

Best not to use that vac in the van unless you have a good supply of fuses.

Don't put a higher amp fuse in - that's not a good thing to do.

 

[ProfJohnL]

If its 120watt then at 12v its pulling 10amps. If the voltage is 13.8v (on EHU) then the draw is 8.7amps. Pretty close to the 10amp capacity of the fuse in that circuit - and that fuse might be supplying other items such as radio or tv antenna.

Best not to use that vac in the van unless you have a good supply of fuses.

Don't put a higher amp fuse in - that's not a good thing to do.

Hold on there! You have an error in your basic volts amps and watts. Most appliances are not constant wattage (including 12v dc vacuum cleaners) The wattage will vary depending on the supply voltage.

An appliance is given a rated wattage at a specified voltage, so from that you can calculate the current at that voltage, but what essentially defines the current is the resistance of the appliance. Now I fully appreciate that a motor is not a constant resistance device, but for the purposes of this post a 120W device running at 12V will consume 10A and that gives an equivalent resistance of 1.2Ohms

If you increase the supply voltage across a resistance the current goes up in this case 13.8V /1.2Ohms = 11.5Amps which in turn produces a wattage of 159W!

In practice it is not quite that simple becasue motors are not constant resistance devices, but the same general principle applies, increase a supply voltage and the current will increase also. This is good enough for this type of situation.

If a power socket in a car is rated at 10A (at 12V) that socket should be capable of supplying 10A without blowing a fuse, Equally as the 12 supply in a car can often reach 14.4V when the alternator is charging, most fuses should withstand a nominal 12V 10A load being fed with 14.4V and producing a current of 12A without rupturing.

Filament fuses do suffer wear, and if one has continually been operated at close to its limit, it may fail with time, or if the is only a marginal excess current. and or vibration.

 

[Anseo]

Craigyoung:
I have tested the vac in the caravan 12v system and it worked OK, but I was not on EHU at the time, I will get round to testing on EHU this weekend.

glenno:
I have a plentiful supply of fuses :lol:
I'd prefer not to uprate the fuse and if it does blow when on EHU then I can make a point of switching off EHU for the small amount of time I will be using the vac, not a big deal considering how little the vac is used.

Prof:
You have me wondering what fuse rating is used in the car 12v accessory socket, I must check that out also (the vac works fine in the car.).

Thanks all.

 

[Craigyoung]

The fuse rating is a chance to be higher in the car as when our kettle blew the fuse in the caravan I checked it in the car to see if it was problem on the kettle that had gone but as soon as I put it in on the car it worked straight away ? As it happened we never did use that kettle it was meant to be for when we were in the Eurotunnel crossing and then driving through France to plug in and boil whilst on the move but that didn't happen !!!

Craig

 

[ProfJohnL]

Prof:
You have me wondering what fuse rating is used in the car 12v accessory socket, I must check that out also (the vac works fine in the car.).

Thanks all.

You will have to check the car manufacturers wiring diagram, but fuse that feeds the socket may not be dedicated to the socket, it may be shared with some other functions. Its rather like a domestic 13A socket, the socket it's self does not have a dedicated fuse or MCB, but it will usually be on a shared (ring) circuit and protected by a 32A MCB. It is the appliance manufacturers responsibility to fit a fused plug, which should carry the correct size of fuse.

In theory a 13A socket could provide a full 32A if a plug with short circuited fuse were inserted. And the same situation could arise with a cars 12V socket.

It is a characteristic of DC motors (as used in 12 Vacuum cleaners) that when you first connect power to the motor it is stationary, and the motor will pass more current that they are rated for, for the fraction of a second it takes to spin up the motor up. Once it is turning it naturally starts to generate a back E.M.F. which opposes the supply current and it will settle down to its specified rating. IN a car they're may be sufficient extra current capacity to meet the primary surge without blowing the sockets supply fuse, but in a caravan the socket may a have a dedicated fuse, and that may possibly be ruptured by the motors primary surge.

 

[chrisn7]

I experienced a similar problem to this when hooking up a tyre pump. This is what I discovered:
- the car accessory sockets (BMW) are fused at 20 amps, so no issue there.
- the factory van accessory socket is fused at 5 amps
- an extension cable I bought to run form the car was also fused at 5 amps

Now the extension cable was no cheapo, of high quality and the cable size allowed me to up the fuse to 10 amps which solved the pump issue temporarily.
Subsequently, I installed separate sockets for my tyre pump in a hatches near the wheels, individually fused at 10 amps from the van battery. No further issues.

 

[Anseo]

Today I tried the vac in the 12v caravan accessory sock whilst on EHU, the 10A fuse immediately blew.

So, it seems that whilst on EHU, using the vac is a no-no.

Had lots of help on here, thanks all.

Anseo

 

[Anseo]

I experienced a similar problem to this when hooking up a tyre pump. This is what I discovered:
- the car accessory sockets (BMW) are fused at 20 amps, so no issue there.
- the factory van accessory socket is fused at 5 amps
- an extension cable I bought to run form the car was also fused at 5 amps

Now the extension cable was no cheapo, of high quality and the cable size allowed me to up the fuse to 10 amps which solved the pump issue temporarily.
Subsequently, I installed separate sockets for my tyre pump in a hatches near the wheels, individually fused at 10 amps from the van battery. No further issues.

I will bear that in mind re the tyre pump chrisn7.

I might just fit an additional 12v accessory socket in the battery compartment, probably direct to the battery terminals with an inline 15A fuse, unless you good folks advise otherwise.

P.S. the existing external 12v accessory socket is rated at 6amps.

 

[Craigyoung]

Did someone mention dustpan and brush ?!?!
Sorry !