Sanwu 2.1 ch 2x50w+100w hiss noise (boombox)

[NotExist]

noise could be from boost converter if cheap crappy or just noise one. i have one of these, seams to be very good. no noise i can hear.
Sure Electronics' webstore 300W BOOST Converter for CAR Audio - TL494

i thought sanwu was a good brand. i got 30w tpa3110 boards from them. maybe try a YJ 2.1 board? There stuff tends to be good Yuan Jing Audio
check forum reviews too. i have there tpa3116 black and smd boards.

looks like ya using lead acid battery charger not a lithium one! i have this for my 12v lifepo. cost me around or under £15 but prices have shot though the roof!
BQ24650 lithium | eBay

The solar charger cutoff at low voltage is 19v
And the high overcharge voltage is 25.4v, really close to the max recomend voltage of 25.2v to this batteries.

Also in addition there is protection board on the left corner of the picture, may be its bms, but not sure, any way its there also for over charge and discharge protection.
Its rated at 19v cutoff and 25.2v cutoff.

The main charging method is wall charger for this kind of batteries.
After use i just take them out and change 8 at a time, Have 2 chargers.

And to charge lithium batteries, don't you need a very regulated power supply? In other words, it's not like lead acid where you gradually raise the battery voltage?

I'm not sure about that, but it's what I've always understood. I suppose it's solvable by adding a voltage regulator to your charging circuit.

About the boost board, its not a boost, its a buck, to lower the voltage to 12v, for intex pump and cooling solution.
The amplifier doesn't connected to it.

 

[cacao ambiance]

with lithium its not just the voltage but the current and a special err charging curve/maths for lithium
Charging Lithium-Ion Batteries – Battery University
Understanding RC LiPo Batteries

 

[Th3 uN1Qu3]

That charger will be perfectly fine for a Lithium pack unless he connects a really high powered solar panel, the charge current is limited to what the panel can deliver. A solar panel powerful enough to deliver enough energy to destroy those lithium cells won't even fit his build.