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.
AMD FX-6300 in GA-990X-Gaming SLI-CF running Windows 7 Pro x64
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
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!
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 email@example.com London SW
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 Tuesday, 21 March 2017 10:53:11 UTC, Capitol wrote:
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 , and they may last anywhere from
40ms to 400ms.
There are diagrams explaining it all.
On Monday, 20 March 2017 12:28:59 UTC, David WE Roberts (Google) wrote:
Vehicle electrics produce huge voltage spikes in some circumstances. It's u
nlikely 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 alwa
ys disconnected from the car during starting. Some cars do that.
's unlikely that a cheap Chinese amp has any protection against them. Its o
dds of survival would be improved if the leisure battery it runs from were
always disconnected from the car during starting. Some cars do that.
A big choke is a great way to produce spikes fatal to silicon.
On 20/03/2017 14:37, firstname.lastname@example.org wrote:
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.
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