I have a Lepai LP-2020A+ amplifier still waiting for me to install the
ceiling speakers in our kitchen.

It has a bullet(?)/barrel(?) connector in the back, standard wall wart
input, for 12V 2A. I have a PSU for it and everything works nicely. Drives
standard HiFi speakers very nicely considering the price.

I am contemplating using this in our caravan (next problem is choosing
speakers) which has a 12V leisure battery.

Apart from finding a suitable lead, in line switch and a fuse, is there
anything else I should consider before fitting this?

Running off 12V looks the obvious way to go because it should work on and
off mains power.

Cheers


Dave R

--
AMD FX-6300 in GA-990X-Gaming SLI-CF running Windows 7 Pro x64

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This email has been checked for viruses by Avast antivirus software.
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On 20 Mar 2017 12:28:55 GMT, David wrote:

I have a Lepai LP-2020A+ amplifier still waiting for me to install the
ceiling speakers in our kitchen.

It has a bullet(?)/barrel(?) connector in the back, standard wall wart
input, for 12V 2A. I have a PSU for it and everything works nicely. Drives
standard HiFi speakers very nicely considering the price.

I am contemplating using this in our caravan (next problem is choosing
speakers) which has a 12V leisure battery.

Apart from finding a suitable lead, in line switch and a fuse, is there
anything else I should consider before fitting this?

Running off 12V looks the obvious way to go because it should work on and
off mains power.

Cheers


Dave R

A 12v vehcle battery is more like 13.8v when it's being charged by the
alternator. It will still probely be OK, but to be sure you could put
two diodes in series with the supply that will drop the voltage about
1.2v
--

Graham.
%Profound_observation%

On Monday, 20 March 2017 12:28:59 UTC, David WE Roberts (Google) wrote:
I have a Lepai LP-2020A+ amplifier still waiting for me to install the
ceiling speakers in our kitchen.

It has a bullet(?)/barrel(?) connector in the back, standard wall wart
input, for 12V 2A. I have a PSU for it and everything works nicely. Drives
standard HiFi speakers very nicely considering the price.

I am contemplating using this in our caravan (next problem is choosing
speakers) which has a 12V leisure battery.

Apart from finding a suitable lead, in line switch and a fuse, is there
anything else I should consider before fitting this?

Running off 12V looks the obvious way to go because it should work on and
off mains power.

Cheers


Dave R

Vehicle electrics produce huge voltage spikes in some circumstances. It's unlikely that a cheap Chinese amp has any protection against them. Its odds of survival would be improved if the leisure battery it runs from were always disconnected from the car during starting. Some cars do that.


NT

On 20/03/2017 14:37, wrote:
On Monday, 20 March 2017 12:28:59 UTC, David WE Roberts (Google) wrote:
I have a Lepai LP-2020A+ amplifier still waiting for me to install the
ceiling speakers in our kitchen.

It has a bullet(?)/barrel(?) connector in the back, standard wall wart
input, for 12V 2A. I have a PSU for it and everything works nicely. Drives
standard HiFi speakers very nicely considering the price.

I am contemplating using this in our caravan (next problem is choosing
speakers) which has a 12V leisure battery.

Apart from finding a suitable lead, in line switch and a fuse, is there
anything else I should consider before fitting this?

Running off 12V looks the obvious way to go because it should work on and
off mains power.

Cheers


Dave R

Vehicle electrics produce huge voltage spikes in some circumstances. It's unlikely that a cheap Chinese amp has any protection against them. Its odds of survival would be improved if the leisure battery it runs from were always disconnected from the car during starting. Some cars do that.


NT


Couple of diodes and a big choke filter might help, available wildly
overpriced from all good ICE emporiums

On Monday, 20 March 2017 15:01:32 UTC, Lee wrote:
On 20/03/2017 14:37, tabbypurr wrote:
On Monday, 20 March 2017 12:28:59 UTC, David WE Roberts (Google) wrote:
I have a Lepai LP-2020A+ amplifier still waiting for me to install the
ceiling speakers in our kitchen.

It has a bullet(?)/barrel(?) connector in the back, standard wall wart
input, for 12V 2A. I have a PSU for it and everything works nicely. Drives
standard HiFi speakers very nicely considering the price.

I am contemplating using this in our caravan (next problem is choosing
speakers) which has a 12V leisure battery.

Apart from finding a suitable lead, in line switch and a fuse, is there
anything else I should consider before fitting this?

Running off 12V looks the obvious way to go because it should work on and
off mains power.

Cheers


Dave R

Vehicle electrics produce huge voltage spikes in some circumstances. It's unlikely that a cheap Chinese amp has any protection against them. Its odds of survival would be improved if the leisure battery it runs from were always disconnected from the car during starting. Some cars do that.


NT


Couple of diodes and a big choke filter might help, available wildly
overpriced from all good ICE emporiums

A big choke is a great way to produce spikes fatal to silicon.


NT

On 20/03/17 14:37, wrote:
On Monday, 20 March 2017 12:28:59 UTC, David WE Roberts (Google) wrote:
I have a Lepai LP-2020A+ amplifier still waiting for me to install the
ceiling speakers in our kitchen.

It has a bullet(?)/barrel(?) connector in the back, standard wall wart
input, for 12V 2A. I have a PSU for it and everything works nicely. Drives
standard HiFi speakers very nicely considering the price.

I am contemplating using this in our caravan (next problem is choosing
speakers) which has a 12V leisure battery.

Apart from finding a suitable lead, in line switch and a fuse, is there
anything else I should consider before fitting this?

Running off 12V looks the obvious way to go because it should work on and
off mains power.

Cheers


Dave R

Vehicle electrics produce huge voltage spikes in some circumstances. It's unlikely that a cheap Chinese amp has any protection against them. Its odds of survival would be improved if the leisure battery it runs from were always disconnected from the car during starting. Some cars do that.

No, they don't any more.

The cheap chinese amp will almost certainly use a overvoltage enabled
chipset designed specifically for car use - its the biggest market for a
20W off 12V system after all - and will not be harmed, and of course if
you are really bothered just put a ****ing capacitor across the supply.




NT



--
There is something fascinating about science. One gets such wholesale
returns of conjecture out of such a trifling investment of fact.

Mark Twain

On Monday, 20 March 2017 15:13:00 UTC, The Natural Philosopher wrote:
On 20/03/17 14:37, tabbypurr wrote:
On Monday, 20 March 2017 12:28:59 UTC, David WE Roberts (Google) wrote:
I have a Lepai LP-2020A+ amplifier still waiting for me to install the
ceiling speakers in our kitchen.

It has a bullet(?)/barrel(?) connector in the back, standard wall wart
input, for 12V 2A. I have a PSU for it and everything works nicely. Drives
standard HiFi speakers very nicely considering the price.

I am contemplating using this in our caravan (next problem is choosing
speakers) which has a 12V leisure battery.

Apart from finding a suitable lead, in line switch and a fuse, is there
anything else I should consider before fitting this?

Running off 12V looks the obvious way to go because it should work on and
off mains power.

Cheers


Dave R

Vehicle electrics produce huge voltage spikes in some circumstances. It's unlikely that a cheap Chinese amp has any protection against them. Its odds of survival would be improved if the leisure battery it runs from were always disconnected from the car during starting. Some cars do that.

No, they don't any more.

The astra certainly disconnects during starting. Old cars are likely not to..

The cheap chinese amp will almost certainly use a overvoltage enabled
chipset designed specifically for car use - its the biggest market for a
20W off 12V system after all - and will not be harmed, and of course if
you are really bothered just put a ****ing capacitor across the supply.

There's already a huge lead acid one on the supply.


NT

In article ,
wrote:
On Monday, 20 March 2017 12:28:59 UTC, David WE Roberts (Google) wrote:
I have a Lepai LP-2020A+ amplifier still waiting for me to install the
ceiling speakers in our kitchen.

It has a bullet(?)/barrel(?) connector in the back, standard wall wart
input, for 12V 2A. I have a PSU for it and everything works nicely. Drives
standard HiFi speakers very nicely considering the price.

I am contemplating using this in our caravan (next problem is choosing
speakers) which has a 12V leisure battery.

Apart from finding a suitable lead, in line switch and a fuse, is
there anything else I should consider before fitting this?

Running off 12V looks the obvious way to go because it should work on
and off mains power.

Cheers


Dave R

Vehicle electrics produce huge voltage spikes in some circumstances.
It's unlikely that a cheap Chinese amp has any protection against them.
Its odds of survival would be improved if the leisure battery it runs
from were always disconnected from the car during starting. Some cars do
that.


Would this amp in a caravan be in use when the car engine is started or
running?

--
*Ambition is a poor excuse for not having enough sense to be lazy *

Dave Plowman London SW
To e-mail, change noise into sound.

On 20/03/17 15:38, wrote:
On Monday, 20 March 2017 15:13:00 UTC, The Natural Philosopher wrote:
On 20/03/17 14:37, tabbypurr wrote:
On Monday, 20 March 2017 12:28:59 UTC, David WE Roberts (Google) wrote:
I have a Lepai LP-2020A+ amplifier still waiting for me to install the
ceiling speakers in our kitchen.

It has a bullet(?)/barrel(?) connector in the back, standard wall wart
input, for 12V 2A. I have a PSU for it and everything works nicely. Drives
standard HiFi speakers very nicely considering the price.

I am contemplating using this in our caravan (next problem is choosing
speakers) which has a 12V leisure battery.

Apart from finding a suitable lead, in line switch and a fuse, is there
anything else I should consider before fitting this?

Running off 12V looks the obvious way to go because it should work on and
off mains power.

Cheers


Dave R

Vehicle electrics produce huge voltage spikes in some circumstances. It's unlikely that a cheap Chinese amp has any protection against them. Its odds of survival would be improved if the leisure battery it runs from were always disconnected from the car during starting. Some cars do that.

No, they don't any more.

The astra certainly disconnects during starting. Old cars are likely not to..

The cheap chinese amp will almost certainly use a overvoltage enabled
chipset designed specifically for car use - its the biggest market for a
20W off 12V system after all - and will not be harmed, and of course if
you are really bothered just put a ****ing capacitor across the supply.

There's already a huge lead acid one on the supply.


Well exactly. But it hasn't the low internal resistance of a big cap


NT



--
Ideas are more powerful than guns. We would not let our enemies have
guns, why should we let them have ideas?

Josef Stalin

Dave Plowman (News) wrote:

Would this amp in a caravan be in use when the car engine is started or
running?

Modern caravan electrics disconnect all except the caravan
battery and fridge (if fitted) once the car ignition feed is
live.

https://caravanchronicles.files.wordpress.com/2012/07/caravan-wiring-13-pin.jpg

Chris
--
Chris J Dixon Nottingham UK


Plant amazing Acers.

On Mon, 20 Mar 2017 16:06:04 -0000, The Natural Philosopher wrote:

On 20/03/17 15:38, wrote:
On Monday, 20 March 2017 15:13:00 UTC, The Natural Philosopher wrote:
On 20/03/17 14:37, tabbypurr wrote:
On Monday, 20 March 2017 12:28:59 UTC, David WE Roberts (Google) wrote:
I have a Lepai LP-2020A+ amplifier still waiting for me to install the
ceiling speakers in our kitchen.

It has a bullet(?)/barrel(?) connector in the back, standard wall wart
input, for 12V 2A. I have a PSU for it and everything works nicely. Drives
standard HiFi speakers very nicely considering the price.

I am contemplating using this in our caravan (next problem is choosing
speakers) which has a 12V leisure battery.

Apart from finding a suitable lead, in line switch and a fuse, is there
anything else I should consider before fitting this?

Running off 12V looks the obvious way to go because it should work on and
off mains power.

Cheers


Dave R

Vehicle electrics produce huge voltage spikes in some circumstances. It's unlikely that a cheap Chinese amp has any protection against them. Its odds of survival would be improved if the leisure battery it runs from were always disconnected from the car during starting. Some cars do that.

No, they don't any more.

The astra certainly disconnects during starting. Old cars are likely not to..

The cheap chinese amp will almost certainly use a overvoltage enabled
chipset designed specifically for car use - its the biggest market for a
20W off 12V system after all - and will not be harmed, and of course if
you are really bothered just put a ****ing capacitor across the supply.

There's already a huge lead acid one on the supply.

Well exactly. But it hasn't the low internal resistance of a big cap

It's pretty damn low - how many amps do you get off it to run the starter for example? Caps only need to be used where a large amp is a long way from the battery, and the amp dips the voltage due to losses in the cable.

--
"The most dangerous thing in the world is to try to leap a chasm in two jumps" -- David Lloyd George, former UK Prime Minister

On Mon, 20 Mar 2017 16:24:45 -0000, Chris J Dixon wrote:

Dave Plowman (News) wrote:

Would this amp in a caravan be in use when the car engine is started or
running?

Modern caravan electrics disconnect all except the caravan
battery and fridge (if fitted) once the car ignition feed is
live.

https://caravanchronicles.files.wordpress.com/2012/07/caravan-wiring-13-pin.jpg

That would be very stupid. So you start your car as the battery is getting low, and can't use the lights to see in the caravan, watch TV, etc, etc?

--
"A life without danger is a life not worth living" -- Moist von Lipwig

On Monday, 20 March 2017 16:06:07 UTC, The Natural Philosopher wrote:
On 20/03/17 15:38, tabbypurr wrote:
On Monday, 20 March 2017 15:13:00 UTC, The Natural Philosopher wrote:
On 20/03/17 14:37, tabbypurr wrote:
On Monday, 20 March 2017 12:28:59 UTC, David WE Roberts (Google) wrote:
I have a Lepai LP-2020A+ amplifier still waiting for me to install the
ceiling speakers in our kitchen.

It has a bullet(?)/barrel(?) connector in the back, standard wall wart
input, for 12V 2A. I have a PSU for it and everything works nicely. Drives
standard HiFi speakers very nicely considering the price.

I am contemplating using this in our caravan (next problem is choosing
speakers) which has a 12V leisure battery.

Apart from finding a suitable lead, in line switch and a fuse, is there
anything else I should consider before fitting this?

Running off 12V looks the obvious way to go because it should work on and
off mains power.

Cheers


Dave R

Vehicle electrics produce huge voltage spikes in some circumstances. It's unlikely that a cheap Chinese amp has any protection against them. Its odds of survival would be improved if the leisure battery it runs from were always disconnected from the car during starting. Some cars do that.

No, they don't any more.

The astra certainly disconnects during starting. Old cars are likely not to..

The cheap chinese amp will almost certainly use a overvoltage enabled
chipset designed specifically for car use - its the biggest market for a
20W off 12V system after all - and will not be harmed, and of course if
you are really bothered just put a ****ing capacitor across the supply..

There's already a huge lead acid one on the supply.


Well exactly. But it hasn't the low internal resistance of a big cap

A big electrolytic cap is never going to kill massive spikes on the 12v line. With additional filtering one can.


NT

On 20/03/17 17:46, wrote:

A big electrolytic cap is never going to kill massive spikes on the 12v line. With additional filtering one can.



A big electrolytic is 'additional filtering' dear.

NT



--
How fortunate for governments that the people they administer don't think.

Adolf Hitler

On Monday, 20 March 2017 21:15:03 UTC, The Natural Philosopher wrote:
On 20/03/17 17:46, tabbypurr wrote:

A big electrolytic cap is never going to kill massive spikes on the 12v line. With additional filtering one can.



A big electrolytic is 'additional filtering' dear.

I'm glad you've worked that out. And hopelessly ineffective against a 50A inductive source. What a pointless brainless discussion.

On 20/03/2017 12:57, Graham. wrote:
On 20 Mar 2017 12:28:55 GMT, David wrote:

I have a Lepai LP-2020A+ amplifier still waiting for me to install the
ceiling speakers in our kitchen.

It has a bullet(?)/barrel(?) connector in the back, standard wall wart
input, for 12V 2A. I have a PSU for it and everything works nicely. Drives
standard HiFi speakers very nicely considering the price.

I am contemplating using this in our caravan (next problem is choosing
speakers) which has a 12V leisure battery.

Apart from finding a suitable lead, in line switch and a fuse, is there
anything else I should consider before fitting this?

Running off 12V looks the obvious way to go because it should work on and
off mains power.

I've used a lot of AV equipment that has been supplied with a 12V psu,
in motorhomes, using the motorhome's 12V supply. I've never had a
problem either with voltage or interference, as far as I can recall.

But do get the polarity right!

Bill

In article ,
Bill Wright wrote:
I've used a lot of AV equipment that has been supplied with a 12V psu,
in motorhomes, using the motorhome's 12V supply. I've never had a
problem either with voltage or interference, as far as I can recall.

Must admit this problem with large spikes many seem to mention isn't
something I've seen in practice. I've added quite a bit of home designed
and built electronics to the old Rover without taking any precautions
against this - just normal smoothing. And non of it has failed.

--
*Horn broken. - Watch for finger.

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) wrote:
In article ,
Bill Wright wrote:
I've used a lot of AV equipment that has been supplied with a 12V psu,
in motorhomes, using the motorhome's 12V supply. I've never had a
problem either with voltage or interference, as far as I can recall.

Must admit this problem with large spikes many seem to mention isn't
something I've seen in practice. I've added quite a bit of home designed
and built electronics to the old Rover without taking any precautions
against this - just normal smoothing. And non of it has failed.


The only times I can recall high voltage spikes on a 12/24V system was
on buses and milk floats around 1960. The bell coil on the bus used
enough current to produce 200V spikes which destroyed the Germanium
diodes in the alternator. On the milk floats, the back emf from the
motors had the same effect on Germanium transistors. I've never seen a
problem after 1970.

On 21/03/17 10:53, Capitol wrote:
Dave Plowman (News) wrote:
In article ,
Bill Wright wrote:
I've used a lot of AV equipment that has been supplied with a 12V psu,
in motorhomes, using the motorhome's 12V supply. I've never had a
problem either with voltage or interference, as far as I can recall.

Must admit this problem with large spikes many seem to mention isn't
something I've seen in practice. I've added quite a bit of home designed
and built electronics to the old Rover without taking any precautions
against this - just normal smoothing. And non of it has failed.


The only times I can recall high voltage spikes on a 12/24V system
was on buses and milk floats around 1960. The bell coil on the bus used
enough current to produce 200V spikes which destroyed the Germanium
diodes in the alternator. On the milk floats, the back emf from the
motors had the same effect on Germanium transistors. I've never seen a
problem after 1970.

And of course cars are stuffed full of electronics these days.

I looked up the spec of a popular 20W IC audio amp designed for car use.
40V spikes its designed to handle


--
Gun Control: The law that ensures that only criminals have guns.

On Tuesday, 21 March 2017 10:53:11 UTC, Capitol wrote:
Dave Plowman (News) wrote:
In article ,
Bill Wright wrote:
I've used a lot of AV equipment that has been supplied with a 12V psu,
in motorhomes, using the motorhome's 12V supply. I've never had a
problem either with voltage or interference, as far as I can recall.

Must admit this problem with large spikes many seem to mention isn't
something I've seen in practice. I've added quite a bit of home designed
and built electronics to the old Rover without taking any precautions
against this - just normal smoothing. And non of it has failed.


The only times I can recall high voltage spikes on a 12/24V system was
on buses and milk floats around 1960. The bell coil on the bus used
enough current to produce 200V spikes which destroyed the Germanium
diodes in the alternator. On the milk floats, the back emf from the
motors had the same effect on Germanium transistors. I've never seen a
problem after 1970.

Suppression of Transients in an Automotive Environment 1999 by Littelfuse has a very different take on it.
Independent studies by the Society of Automotive Engineers
(SAE) have shown that voltage spikes from 25V to 125V can
easily be generated [1], and they may last anywhere from
40ms to 400ms.
There are diagrams explaining it all.


NT

In article ,
wrote:
On Tuesday, 21 March 2017 10:53:11 UTC, Capitol wrote:
Dave Plowman (News) wrote:
In article ,
Bill Wright wrote:
I've used a lot of AV equipment that has been supplied with a 12V
psu, in motorhomes, using the motorhome's 12V supply. I've never
had a problem either with voltage or interference, as far as I can
recall.

Must admit this problem with large spikes many seem to mention isn't
something I've seen in practice. I've added quite a bit of home
designed and built electronics to the old Rover without taking any
precautions against this - just normal smoothing. And non of it has
failed.


The only times I can recall high voltage spikes on a 12/24V system
was on buses and milk floats around 1960. The bell coil on the bus
used enough current to produce 200V spikes which destroyed the
Germanium diodes in the alternator. On the milk floats, the back emf
from the motors had the same effect on Germanium transistors. I've
never seen a problem after 1970.

Suppression of Transients in an Automotive Environment 1999 by
Littelfuse has a very different take on it. Independent studies by the
Society of Automotive Engineers (SAE) have shown that voltage spikes
from 25V to 125V can easily be generated [1], and they may last anywhere
from 40ms to 400ms. There are diagrams explaining it all.


Interesting. I've never seen a say 5v regulator that can cope with 125v.
60v is common for automotive rated ones.

--
*Pride is what we have. Vanity is what others have.

Dave Plowman London SW
To e-mail, change noise into sound.

Does the output use a bridge system, ie no common earth to speakers, if so
be very careful with installing the cables and speakers.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"David" wrote in message
...
I have a Lepai LP-2020A+ amplifier still waiting for me to install the
ceiling speakers in our kitchen.

It has a bullet(?)/barrel(?) connector in the back, standard wall wart
input, for 12V 2A. I have a PSU for it and everything works nicely. Drives
standard HiFi speakers very nicely considering the price.

I am contemplating using this in our caravan (next problem is choosing
speakers) which has a 12V leisure battery.

Apart from finding a suitable lead, in line switch and a fuse, is there
anything else I should consider before fitting this?

Running off 12V looks the obvious way to go because it should work on and
off mains power.

Cheers


Dave R

--
AMD FX-6300 in GA-990X-Gaming SLI-CF running Windows 7 Pro x64

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

On 20/03/2017 14:37, wrote:
On Monday, 20 March 2017 12:28:59 UTC, David WE Roberts (Google) wrote:
I have a Lepai LP-2020A+ amplifier still waiting for me to install the
ceiling speakers in our kitchen.

It has a bullet(?)/barrel(?) connector in the back, standard wall wart
input, for 12V 2A. I have a PSU for it and everything works nicely. Drives
standard HiFi speakers very nicely considering the price.

I am contemplating using this in our caravan (next problem is choosing
speakers) which has a 12V leisure battery.

Apart from finding a suitable lead, in line switch and a fuse, is there
anything else I should consider before fitting this?

Running off 12V looks the obvious way to go because it should work on and
off mains power.

Cheers


Dave R

Vehicle electrics produce huge voltage spikes in some circumstances. It's unlikely that a cheap Chinese amp has any protection against them. Its odds of survival would be improved if the leisure battery it runs from were always disconnected from the car during starting. Some cars do that.


NT


Modern control units in motorhomes/caravans isolate the supplies to
things like amps* (assuming their are correctly installed) while the
vehicle ignition is on. Therefore, the amp shouldn't 'see' any spikes
etc on the charging supply from the vehicle.

The control units have either integral or external 'smart' chargers
which, with the leisure batteries, supply a pretty clean DC supply.

*only a few 'dumb' items are allowed to be powered, to comply with the
regs. For example, in mine (a motorhome) a couple of lights and the
fridge in the rear. In a caravan, you would only need the fridge.




--

Suspect someone is claiming a benefit under false pretences? Incapacity
Benefit or Personal Independence Payment when they don't need it? They
are depriving those in real need!

https://www.gov.uk/report-benefit-fraud