The Teac tv drops the battery voltage from 13.3 to 12.4 when switched on at the set, should it drop nearly 1 volt? It has always been connected via 12v socket. Only the tv, vast box etc do not drop the voltage at all when turned on individually.
Thanks for all and any help
Bas
Mike Harding said
03:28 PM Aug 20, 2021
TVs are moderately power hungry and yours may be drawing 50W or so - about 4A at 12V. The fact that this is dropping the battery voltage by 1V suggests your battery is old and tired and may not be long for this world :(
Bas + Eve said
03:44 PM Aug 20, 2021
We have 3x130ah batteries 12 months old. Nothing else we have drops the voltage by 1 volt as soon as you switch it on, Vast box included. Its got me knackered.
Corndoggy said
04:00 PM Aug 20, 2021
What's the wattage/amperage of your vast box. It probably is less than your TV so won't draw as much current and less voltage drop. Take it this is not a new TV so has the voltage drop just started to happen?
Mike Harding said
05:30 PM Aug 20, 2021
Bas + Eve wrote:
We have 3x130ah batteries 12 months old.
It would have been helpful to have included that information in your original post.
Perhaps your batteries are not being properly charged? Other than that I have no idea.
Bas + Eve said
06:34 PM Aug 20, 2021
The tele is around 5 years old. I noticed when I changed the lead which has a digital voltage read out. When the power is switched on at the socket there is no change, but when the tv is turned on..voltage 1v drop and flashes low voltage. I read up the TEAC power consumption and it says 90w which seems high to our other Akai tv at 50
w. However having said that we have never had any problems in those 5 years.
Corndoggy said
07:36 PM Aug 20, 2021
Get your hands on a multimeter and check the voltage at the battery terminals with tv on and off. Try connecting the TV to an outlet as close to the batteries as you can. So this lead is a new gadget that your using?
Bas + Eve said
08:44 PM Aug 20, 2021
No the gadget is not new, have used it many times. We are camped up in the Outback so will have plenty of time to investigate. I will swap TVs and see if that makes any difference. The batteries are fully charged floating at around 14.5v. The days are hot and clear.
msg said
01:01 AM Aug 21, 2021
My small Teac TV on or off made no difference to the volts. (according to the meter)
kgarnett said
09:47 AM Aug 21, 2021
It seems to me that there is some excessive resistance in the cabling between the battery terminals and the TV.
If the TV is truly rated at 90W then at 13V it would draw 90/13 = 6.92A or if only say 45W it would draw 45/13 = 3.46A.
Now if there is a voltage drop of 0.9V between the battery terminals and the TV then in case of 90W then the resistance of the interconnection must be 0.9/6.92 = 0.13ohms or in the case of 45W the resistance must be 0.9/3.46 = 0.26 ohms.
In either case it is not a very high resistance but sufficient to cause a noticeable voltage drop (0.9V) . I believe you should look closely at the interconnecting cable and all connectors between the battery and the TV including fuses, fuse holders etc and the TV power socket and fuse.
I am aware of some minor assumptions that would affect the accuracy of the calculations, but the general thrust of the result is accurate.
Just a thought !
-- Edited by kgarnett on Saturday 21st of August 2021 11:06:51 AM
-- Edited by kgarnett on Saturday 21st of August 2021 11:57:17 AM
TVs are moderately power hungry and yours may be drawing 50W or so - about 4A at 12V. The fact that this is dropping the battery voltage by 1V suggests your battery is old and tired and may not be long for this world :(
It would have been helpful to have included that information in your original post.
Perhaps your batteries are not being properly charged? Other than that I have no idea.
It seems to me that there is some excessive resistance in the cabling between the battery terminals and the TV.
If the TV is truly rated at 90W then at 13V it would draw 90/13 = 6.92A or if only say 45W it would draw 45/13 = 3.46A.
Now if there is a voltage drop of 0.9V between the battery terminals and the TV then in case of 90W then the resistance of the interconnection must be 0.9/6.92 = 0.13ohms or in the case of 45W the resistance must be 0.9/3.46 = 0.26 ohms.
In either case it is not a very high resistance but sufficient to cause a noticeable voltage drop (0.9V) .
I believe you should look closely at the interconnecting cable and all connectors between the battery and the TV including fuses, fuse holders etc and the TV power socket and fuse.
I am aware of some minor assumptions that would affect the accuracy of the calculations, but the general thrust of the result is accurate.
Just a thought !
-- Edited by kgarnett on Saturday 21st of August 2021 11:06:51 AM
-- Edited by kgarnett on Saturday 21st of August 2021 11:57:17 AM