loading

charge a battery while using it?

https://www.instructables.com/id/Ammo-box-speakers-2/
hi, i'm looking for a way to charge a 12v deep cycle lead acid battery while powering an amplifier from the battery. Can i literally just attach the battery charger to the battery as well as the amplifier as long as the connections to the amplifier and charger do not touch? or is it not that simple? 
The instructable linked above is what i what to implement it into. Any help will be appreciated! 



sort by: active | newest | oldest
rickharris3 years ago
Quite a lot of articles have constant chargers attached with the battery acting as a buffer - The comments about noise should be heeded though.

If the supply is not large enough to drive the amp the current will come from the battery - in time the battery will go flat!

If the supply can drive the amp then the current will come from the supply. so you don't need the battery!

This system is only of use to avoid the necessity of re connecting the battery every time your finished.
WillERoberts (author)  rickharris3 years ago
could i just put a charge controller in between my battery and amp? or would that still allow electrical noise through?
My main reason for wanting to do this is so i do not have to disconnect the battery to charge it. With my current set up i can run the amp directly from the mains (with a 12v supply) while i disconnect the battery to charge it. But if i could remove the need for disconnection that would be all the better.
Sorry there is no way to change reality just for your fervent desires.

This is the only way to use the battery ..... BUT IT WILL UPSET THE AMP.
CHARGE-BATT-AMP.bmp
WillERoberts (author)  iceng3 years ago
what do you mean upset the amp? My amp can supposedly take upto 15v which is more than the charger gives so shouldn't it be fine?
I guess you should try it for your own experience.
A charger gives more then 15v ..... it gives RIPPLE.
The Ripple makes your amplifier believe it ( the Ripple )
is part of your signal and dutifully amplifies it.

Also if your starting with discharged battery ( it happens )
the ripple voltage dropping lower then turns off the balanced
input stage or puts it into a nonlinear gain then turns it back on
at 120 cps causing speaker braking Pops in addition to rumbling hum.

See the pics outlining this pulsing DC which is fine for a battery
BUT Horrible for amplifiers.
ripple1.bmpripple2.gif
WillERoberts (author)  iceng3 years ago
The charger I use is a cheap DC charger which gives a pretty constant 14.4v, so although there is some 'ripple' the current it is pretty consistant at 500mA.
I'll do what you suggest and try it for myself. It will probably be a couple of weeks before i try it but i'll post my findings here when i get back from holiday.
Thanks for your quick replies!

(if the ripple is too large could i just use a current controller between the amp and power supply?)
See ICENG's reply
iceng3 years ago
Most battery chargers create electronic noise that will drive your amp sound crazy with
AC hum ripple and other amplifier induced electronic pops and thumps that could
damage expensive speakers..

A battery alone has the very smoothest DC power available ( that is wonderful for amps ! ).

YES .... If you can build a HiFi Power Supply that has voltage control
( not a simple charger ) then you could charge the battery at the same time as using it
to run your amplifier.

BUT .... That makes no real sense,  when you could run your amp directly
from that expensive HiFi Power Supply ! !

A


WillERoberts (author)  iceng3 years ago
could i just put a charge controller in between my battery and amp? or would that still allow electrical noise through?
My main reason for wanting to do this is so i do not have to disconnect the battery to charge it. With my current set up i can run the amp directly from the mains (with a 12v supply) while i disconnect the battery to charge it. But if i could remove the need for disconnection that would be all the better.
samaddon3 years ago
No. you can't attach directly cause it will have bad affect the battery!