Running Sierra sound with lithium ion???

P

paul delany

Registered
Country flag
Hi folks I'm moving to battery power, my problem is I'm feeding the left and right track imputs on my Sierra board with the crest receiver motor +and motor - pcb pads In order to give the Sierra a reference voltage, but?? As Greg said in his post anything above 12v and the sound chips are over heating, tried to use a variable resistor set for 30 ohms but varies too much,, and help appreciated please.
 
paul delany said:
Hi folks I'm moving to battery power, my problem is I'm feeding the left and right track imputs on my Sierra board with the crest receiver motor +and motor - pcb pads In order to give the Sierra a reference voltage, but?? As Greg said in his post anything above 12v and the sound chips are over heating, tried to use a variable resistor set for 30 ohms but varies too much,, and help appreciated please.
Click to expand...
A "buck converter" would be you best bet.
This one is adjustable and take wide range of input voltages.

 
GAP said:
A "buck converter" would be you best bet.
This one is adjustable and take wide range of input voltages.

Click to expand...
Hi OK, I need some explanation here as I thought I understood the Sierra board basics? How is the motor v output over stressing the sound chips? What am I missing? The start up voltage for a shay motor is roughly 9 volts? What am I missing here?
 
paul delany said:
Hi OK, I need some explanation here as I thought I understood the Sierra board basics? How is the motor v output over stressing the sound chips? What am I missing? The start up voltage for a shay motor is roughly 9 volts? What am I missing here?
Click to expand...
 

Attachments

  • IMG_20221120_152505.jpg
    IMG_20221120_152505.jpg
    289.2 KB · Views: 0
Track voltage is 14.5 or what ever, motor + and motor - are feeding my Sierra track pickup imputs, so why is it over driving the sound processor S??
 
The simple answer would be to use a '3S' rather than a '4S' battery pack..

That way you would not exceed the 12V limit of the sound card.

Your motor is fed a PWM signal. - The full 14.5V but switched on and off, for different amounts of time (mark-space ratio) it is this that controls the motor speed.

PhilP
 
PhilP said:
The simple answer would be to use a '3S' rather than a '4S' battery pack..

That way you would not exceed the 12V limit of the sound card.

Your motor is fed a PWM signal. - The full 14.5V but switched on and off, for different amounts of time (mark-space ratio) it is this that controls the motor speed.

PhilP
Click to expand...
Hi Philip wow I didint know that at all, so I can't step down the voltage to 12 v with a 5 watt 30 ohm resistor then?
 
paul delany said:
Hi Philip wow I didint know that at all, so I can't step down the voltage to 12 v with a 5 watt 30 ohm resistor then?
Click to expand...
No, because the voltage across the resistor will depend on the current flowing through it, so will vary, rather than being a constant value.

As the load on the motor varies, the current will change through the resistor (which is fixed) so the voltage will vary.

PhilP
 
PhilP said:
No, because the voltage across the resistor will depend on the current flowing through it, so will vary, rather than being a constant value.

As the load on the motor varies, the current will change through the resistor (which is fixed) so the voltage will vary.

PhilP
Click to expand...
Hi PhilP I'm greatful for you explaining the finer detail, 30 years ago I worked in a r+d lab with access to ossiloscopes etc, I didint know that the motor voltage was a pulsed one, so I guess il leave the motor voltage feed disconnected from the Sierra imputs and have no sense voltage and just be happy with the chuff sound affect.
 
paul delany said:
Hi PhilP I'm greatful for you explaining the finer detail, 30 years ago I worked in a r+d lab with access to ossiloscopes etc, I didint know that the motor voltage was a pulsed one, so I guess il leave the motor voltage feed disconnected from the Sierra imputs and have no sense voltage and just be happy with the chuff sound affect.
Click to expand...
Or, a dc - dc buck converter at the initial pwr imput.
 
I used a similar converter in a tram that had a Lithium Ion 4S battery producing up to 16V when fully charged. My 12V ESC did not like that, so the converter keeps it happy. The tram is quite slow though!
 
Fred2179G said:
I used a similar converter in a tram that had a Lithium Ion 4S battery producing up to 16V when fully charged. My 12V ESC did not like that, so the converter keeps it happy. The tram is quite slow though!
Click to expand...
Hi, I'm going to go with some buck converters I'm assuming the best way to adjust them for bang on 12 volts would be under load with a small motor???
 
Fred2179G said:
I used a similar converter in a tram that had a Lithium Ion 4S battery producing up to 16V when fully charged. My 12V ESC did not like that, so the converter keeps it happy. The tram is quite slow though!
Click to expand...
hi fred what dc converter did you use i cant find any 14.8 to 12v converters
 
www.ebay.com

Mini DC-DC Buck Step-down Converter Adjustable Power Module 3.3V 3V 5V 9V 12V 3A | eBay

3A run for about 20 seconds into the chip to protect against overheating, can be cooled by the chip cooling work in 3A current. Output ripple: 20mV (12V to 5V 3A). Output Current: 3A (Max). Connected to the car battery without the need for switching, can be connected to the cigarette lighter...
www.ebay.com

Paul,, we may have confused you with the talk about fixed voltages. The one I used had a fixed output but a variable input. Like this one on US eBay.
 
paul delany said:
hi Greg i cant find a converter to convert 14.8 to 12volts
Click to expand...
Hi Fred so.
I fitted a dc/dc converter board, LM 2596 , I then set the output voltage to 11.2 volts while the pcb had a load on it, I fiited to the electronics on my shay,, frustratingly, the motor output feed to the sencing part of the Sierra board is still causing the sound chips to overheat, even when I adjusted the final output voltage supplying the crest receiver with 9 volts.

So I'm giving up and doing away with the Sierra sensing voltage completely.
I don't know why the Sierra is overheating??, when I remove the motor sense feed wire, the Sierra performs fine.

I'm confused now
 
You must log in or register to reply here.
Back
Top Bottom