Why doesn't use voltage doublers or multipliers insted of DC-DC boost converters?

Thread Starter

Htin Aung

Joined May 29, 2016
36
Hello my dearest technicians,

Today I wonder, what is the difference between using of DC-DC step up boost converters and voltage doublers/voltage multipliers.Now I'm trying to make my own 2x15W portable bluetooth speaker using some modules and components what I have.Things all I have to use is Tda7297 amp,18650 charging modules, some li ion batteries and some components.1626342407088.jpg

1626342407102.jpg

1626343401946.jpg
I wanna charge my speaker with 5v Li-ion battery charging module. So the power in my speaker will 4.22V Max .It is ok with Bluetooth receiver module.
But Tda7297 amp needs 12V. So I decided to use my DC-DC step up module it supports 1.5-28V and adjustable linear output of 2-28V. And I also have a 5V to 12V converter USB cable what i used for my old router with mobile powerbank.
1626342407075.jpg

1626342407060.jpg

After all, recently I seen a video from ElectroBOOM (A man always playing with High Voltage).
He uses diodes and capacitors to double or multiplies the input voltage.
So I got an Idea to think, why I'm not using voltage multipliers or doublers for my Mini amp or is it possible.
And I found that Tda7297 has wide suppliable voltage range.
Building a circuit like this is more simple and low-cost.(as I think)
Finally I decided to ask on AAC .
Can Voltage doublers and multipliers were use as power supply?

Thank u so much.
 

Attachments

Yaakov

Joined Jan 27, 2019
3,736
Voltage multipliers operate with AC. DC to DC converters use DC and by making it AC or interrupting it, allow it to be raised in voltage, then convert it back to DC.

You would have to create AC from the DC first, so why would you want to use something not optimized to the purpose?
 

Dodgydave

Joined Jun 22, 2012
10,085
Dc to Dc conversion is ok to step up for using small batteries, but it comes at a cost of extra current from the batteries to provide the higher voltage. Voltage doublers are used in AC circuits and again the current will be lower than normal.
 

BobTPH

Joined Jun 5, 2013
4,030
Getting 30W from a single 18650 would be 8A and the battery would last probably last 15 minutes, if it was even capable of that current.

Since you are going tho need multiple cells anyway, your most efficient solution is to put them in a series / parallel arrangement giving you 12 V directly. 3 in series gives you 11.1 V which is probably good enough.

Bob
 

Thread Starter

Htin Aung

Joined May 29, 2016
36
Getting 30W from a single 18650 would be 8A and the battery would last probably last 15 minutes, if it was even capable of that current.

Since you are going tho need multiple cells anyway, your most efficient solution is to put them in a series / parallel arrangement giving you 12 V directly. 3 in series gives you 11.1 V which is probably good enough.

Bob
Thank you so much sir.
Then, fully charged li ion battery gives around 4.22V and if i connect 3 cells in series, It's total charged voltage would around 12.6V.( just as my result)
And my 12V power supply gives 12.4V at free of any load.
So, Is it safe for 3 cells in series to charge without any BMS? I think fully charged voltage is 12.66V and charger gives only 12.4V means my batteries may never fully charged so it may never over charge my batteries and my batteries will safe without any BMS protection board. Coz I wanna use it to charge my drill machine's battery as it's original charger was damaged.I wanna know is it safe or not.
I got battery explosion when I was young because of charging 3 18650s in series with 1000w inverter.
I didn't know It's charging output is around 14.6V and explosion burned down my uncle's shop.
Lesson is expensive. So I never dare to play like that anymore.


Thank you so much.
 

Deleted member 115935

Joined Dec 31, 1969
0
Thank you so much sir.
Then, fully charged li ion battery gives around 4.22V and if i connect 3 cells in series, It's total charged voltage would around 12.6V.( just as my result)
And my 12V power supply gives 12.4V at free of any load.
So, Is it safe for 3 cells in series to charge without any BMS? I think fully charged voltage is 12.66V and charger gives only 12.4V means my batteries may never fully charged so it may never over charge my batteries and my batteries will safe without any BMS protection board. Coz I wanna use it to charge my drill machine's battery as it's original charger was damaged.I wanna know is it safe or not.
I got battery explosion when I was young because of charging 3 18650s in series with 1000w inverter.
I didn't know It's charging output is around 14.6V and explosion burned down my uncle's shop.
Lesson is expensive. So I never dare to play like that anymore.


Thank you so much.

strong suggestion then

dont.


Li Ion batteries are VERY intolerant and dangerous when charged / discharged wrong
 

BobTPH

Joined Jun 5, 2013
4,030
Get s commercial 11.1V battery and appropriate charger. If the likes of Apple, Samsung, and Boeing can’t make a proper charger, neither can you.

Bob.
 
Top