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12v TV won't work.

8.8K views 13 replies 9 participants last post by  sergeant  
#1 ·
We have a panasonic 12v TV which has always worked ok on hookup. We recently tried the TV on battery and it kept turning itself off during tuning. On reading the manual it was because there was insufficient charge in the battery. We had two batteries, linked and reasonably charged, so why did the TV fail? Any ideas?
 
#4 ·
Am I right in thinking that you've just connected direct to the TV where an external 12V power supply goes?

In that case, the TV is used to getting a nice clean 12 volts dc +/- not very much. Your leisure battery could be anywhere between 13 volts and less than 10 volts. Improving the wiring would certainly help, but there's no guarantee it would continue to work once the battery voltage started dropping.

A 'proper' vehicle TV is designed to use the sort of dc supply found in a van / car, and so will work better in that situation. Ours works fine on the manufacturer's wiring.

Gerald



 
#5 ·
I also had exactly the same problem and agree with the comments above. Most motorhomes have 12V socket wires that are far too thin. This results in a voltage drop betweem battery and socket. I disconnected the original wiring to my 12V socket and fitted new thicker cable direct to leisure battery, via a new in line fuse of course.

Trevor
 
#7 ·
thicker cable

We also have this TV and regularly experienced it switching off after 30 minutes of viewing on a fresh battery in our caravan. When ever we arrived somewhere, the first thing we did autotune - because this seemed to need even more juice. Was cured by running some thick solid core ring main cable from the battery, fused, directly to the 12v socket by the tv.

I'm now coverting a sprinter van into a race home and just had an argument with the local motorfactors sales desk about using 4mm multistrand to cable up the 12v sockets in the van. He insisted that we should be using 2.5mm but I insisted on the 4mm because of previous voltage drop issues. He just shook his head and took my cash.

Guy
 
#9 ·
You can get DC to DC convertors which will stabilise the supply voltage to the right level that the TV requires but might be better to run it off 12V to 230V invertor. We tried first with the Ring 75W one but it kept cutting out. Better to get a good 150W invertor but be sure to unplug it when not in use. the standby current may be small but it all helps to drain the batteries.

Richard
 
#10 ·
Re: thicker cable

monkeyrig said:
....... Was cured by running some thick solid core ring main cable from the battery, fused, directly to the 12v socket by the tv.

Guy
Just in case you are not aware solid cable should not be used in a van its against the wiring regs. Only flexible multistrand. Agree with you about 4mm though

Regards Frank
 
#11 ·
howdy

DABurleigh said:
Guy,

Welcome to MHF!

Intrigued by the username and avatar .....

Dave
Hat tip back at you Dave

Avatar is Elvis and Mookie - two huskies from my 3 dog team

MonkeyRig is what goes behind the dogs.

Cheers Frank about the regs - first advice got about the caravan a few years ago was to fit the thickest shortest thing you could you find... which now I understand that the word 'multistrand' was missing somewhere within that. It was a new van and the dealer was no help on the matter.

motorhome is exclusively mutlistrand :wink:

Guy
 
#13 ·
Thanks everyone for your replies. The question now is - a) does Ed do a bit of rewiring direct from the battery which will undoubtedly solve the problem or b) do we treat ourselves to one of those luverly flat screen jobbies from the NEC (and probably have to do the wiring anyway) I'll have to check the biscuit tin to see how the wind blows. 8O
 
#14 ·
Hi all, As i said in an earlier post a lot of the problem is tha fact that a lot of 12v tv's are not true 12v tv's but require 12.8 to 13.2 to function correctly. These are the ones that everyone has problems with. When buying a 12v tv read the spec sheet first to ensure it is a true 12v tv, Steve