At a guess they are on the same power wire & it is not big enough to handle the draw. The old setup in my Fiat Ducato that is now completely stripped out was like that, 1 wire from fuse ran all the way around the van, if you turned on more a couple of things the wire just wasn't able to handle the amount of draw needed to run them.
Hence 1 of the reasons that we have completely started again with a blank canvas.

Hi;

    Wolly's right. The cableing not handeling the current draw. It could also be that the house battery may be flat and need charging, Battery size may be to small OR the battery is old and needs replceing . Also the television would have a low voltage cut out and once the battery voltage has droped below the cut off point the set would shut down.

The water pump would draw quiet a few amps ( 10~15 Amps is not uncommon ) and cause the television to shut down and /or the caravan house lighting to pulse as when the water pump is running and battery voltage is low,  the current draw would be even higher and then the battery voltage would be even lower and the pump motor would slow down ( and the load on the motor decrease ) . This would then cause the battery voltage to increase (due to the load decreaseing ) and the motor would then try and increase in speed and the load would then increase .And then the battery voltage then would take a nother dive. This voltage fluxuation is what causes the lights to flicker. If left in this state the pump would eventualy stall and could cause the motor to burn out. Most water pumps would have some type of fuse installed BUT at the lower voltage the fuse may not fail.

 

The bit that is concerning is Copper1 said in the "new van" surely the manufacturers wouldn't run 1 wire for tv & fan, 1 for pump & lights, how much does a few extra mtrs of wire cost really.
I expected it with mine for it was a cheap, cheap, cheap install & I knew that when i bought it.

-- Edited by Woolly on Monday 27th of January 2014 04:29:08 PM

Copper do you have a MultiMeter? Stick the probes over the Battery terminals and have a helper turn stuff on a bit at a time or one at a time.

Keep an eye on the reading it should stay within specs ie a 12V battery should not drop below 11 - 11.5 V. If so then add up the power used by the devices
that were turned on and make sure they don't overload the battery rating.

Sometimes it is possible that manufacturers overlook the requirements of low voltage circuits in recreational equipment because it comes under auto electrical.

Anyhow I'm guessing here that either the batteries are under charged / insufficient rating or the wiring is too small for the current used. Keep in mind the ideal
12V wire size is around 8mm dia. I bet you yours is not that thick.

Another thought is maybe it's the dreaded EMF problem. When the TV goes off do you mean powers off or does it just lose the signal? Fans and pumps
are electric motors which produce large EMF (electromagnetic fields) which can and do disturb tiny TV signals. In RV's you can take to the bank that no manufacturer
of electrical gear shields them, why should they there are no or very weak regulations for 12Vdc equipment.

Good luck mate.

I am with Cloak on this EMF problem ,I have a simler problem with my tele switch on a certain light witch is LED off goes the television ,and  Copper 1 new van may have LED lights.

lance C

Hi all, and rocklizard;

                              Ok I'll try and make this a bit clearer for you . I used work in the electronic field and while i know what i'm talking about, trying to put that in to text, well lets say it's not one of my strong points , so this time I'll try and keep it simple.....

The basic 12 Volt television running off your house battery will draw about 4 ~ 5 amps and a bit more if the set has a DVD player installed. So we have a medium sort of load?.

As the load of a 12 Volt water pump that is fitted into your average  caravan the draw would be in the order of 10 ~15 Amps, mine is fitted with a 15 Amp. Some of the higher pressure pumps the current draw is a lot higher, Some of the pressure pumps that farmers use to do a bit of spraying of chemicals,water based, well a 30 Amp fuse is fitted, small tankers fitted onto a small trailer etc.

Now depending on what type of battery that you have and there are many differant types out there the open ternimal voltage ( no load ) and nothing connected to the battery , should have a voltage of about 13.7 odd volts for a full charged battery and you only have to drop a couple of volts ( 11.5 ~ 10.5 ) and the battery would be basicly flat. At this lower voltage the battery could supply the current that  the television would require, but when it come to trying to run the water pump as well as the television the battery voltage is 'pulled' even lower, television shuts down and the water pump would pulsate.

This pulsating would cause the battery voltage to rise and fall a fair bit and this rise and fall in voltage causes the lights to change in intensity ( brightness ). This is not realy a problem with a fully charged battery as the battery has the capacity to handle the load at the time, but if the battery is on the way out or 1/2 flat or even under sized for the job. This is why many caravans have two or more heavy duty battery fitted and the common size appears to be 100 A/H.

On a side note, a bus that i have been looking at and had been converted in to mobil home had a total of 8 x 12 volt batterys fitted and each battery was 200 A/H so we had a total of 1600 A/H . Also this mobil home had 720 Watts of solar panels fitted to the roof.

One of the biggest problems with 12 Volts is the capacity of the battery and also the size of the wireing, not a problem if you only have a few led lights, but a problem if you just want to run your television, But a real big problem if you are trying to start and run a 12 volt water pump. Start current would be a lot more amps than what the pump draws once the motor is running. Same as a car, it takes a lot more fuel to reach a speed of 100 Kms than it takes to maintain that speed.

How old are the battery and if you could beg /borrow a muilty meter and check the battery votage, like what ' cloak' has asked you to do. 

I you are haveing problem with television recieption when you are running the water pump, the problem could be the antenna system in your caravan be the problem , and this is a real can of worms here, or the water pump is puting out hash ( on to the 12 wiring ) and the television internal power supply and/ or the digital tuner may not like the dirty voltage been feed to it

 

 

 

 

 

 

 

 

 

      

Thanks everyone for your input. Rockylizard Mate sorry if I confused you but my missus say's I am bad and my typing is  SH#T  anyway Nelly hit the nail on the head it is a new van only a few months old so will get it looked at, and you would think the battery's would be top notch. But I thought in the short term as I am away in Tassie, I might be able to do a shonky repair or quick fix .

 

 

 

Thanks again everyone for your input and yes I have a multimeter so will do a few checks.

First thing I would check would be earth wiring.

Hello All

I had a similiar problem.   The problem was the batteries.   They showed fully charged, but when the load came on, they would collapse, resulting in all 12volt equipment going kaput.

Check the battery condition, ie, do a load test first before heading off in other directions.

Happy caravanning

Mate

Keep it on the check list.   One would hope the lecki did a load test.

Cheers

Quite often the reason that RFI and EMI becomes a problem is poor aerial connections which cause a weak signal that the interference can easily overcome. Fix the aerial and the troubles go away. There are numerous cheap ferrite clip on filters that may also help to reduce line interference.

I agree with what has been said about RFI and EMI, however some DC motors can produce reactive sparking at the commutators and that will cause this problem every time. We have a small DC fan that can not be used when the TV is on due to that. Mind you all other considerations including ferrite TVI filters etc have been employed. This induction can be in the order of 1KV a 240V AC motor can induce a 10KV spark... food for thought?