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0-30V 0-3A power supply

Cyparagon

Cyparagon

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whaddaya mean unknown? :confused: There are two modes, constant voltage and constant current. Set current to an appropriate value, set voltage to 4.2. It charges at the current you've set until the power supply is at 4.2V. Then it switches to constant voltage.
 
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BShanahan14rulz

BShanahan14rulz

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I think what Brenner is trying to say is that ____fire companies lie about specs. OEMs have real specs that you can use as a starting point when calculating what current to set your power supply to, and therefore are safer to charge with a PSU. Obviously, charging with a PSU is the best way to charge known, unprotected, single cells if the user knows what they are doing.

Other things to take into account are how many cycles you have put that cell through, how old it is, what its internal resistance is, has it ever accidentally been dead-shorted, etc.



Kind of like when you buy a <5mW laser from ebay. at levels below 5mW, total radiated power in the beam is low enough that your natural blink reflex will block the beam before it has a chance to cause damage to your retina. This doesn't mean that you can wave around any laser labeled <5mW all willy-nilly, for all you know it may be outputting 80mW.
 
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Brenner

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BShanahan14rulz said:
I think what Brenner is trying to say is that ____fire companies lie about specs. OEMs have real specs that you can use as a starting point when calculating what current to set your power supply to, and therefore are safer to charge with a PSU. Obviously, charging with a PSU is the best way to charge known, unprotected, single cells if the user knows what they are doing.

Other things to take into account are how many cycles you have put that cell through, how old it is, what its internal resistance is, has it ever accidentally been dead-shorted, etc.



Kind of like when you buy a <5mW laser from ebay. at levels below 5mW, total radiated power in the beam is low enough that your natural blink reflex will block the beam before it has a chance to cause damage to your retina. This doesn't mean that you can wave around any laser labeled <5mW all willy-nilly, for all you know it may be outputting 80mW.
Click to expand...

Exactly.

Trying to help people who do not know much about this "charging li-ion with PSU" idea.

Poster above you with his advice to "Set current to whatever" would probably get much "better" response, and sent to learn basics at CPF .

Unbelievable. Not a bit of responsibility.
 
Cyparagon

Cyparagon

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Oh calm down :tired: I didn't mean it literally. I've changed it to read "an appropriate value."
 
Cyparagon

Cyparagon

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I bought this 30V 5A supply last week. Voltage looks good on the scope, but the current regulation is unacceptable. They claim <2mA rms in the users guide, but this is what I measure with it set to 400mA across a typical test load of 3 diodes and a 1ohm resistor:

YH305D.png


And this was at a measly 0.4A load! These things only get worse at higher current. That first spike is ~55mA rms and the rest is ~18mA rms. This piece of junk is going back to the seller.
 
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Blord

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I am not familiar with scopes. Do you mean the current overshoot the first spike at 455mA if you set it at 400mA ?

I always connect the diodes when all knobs are turned to zero and short the terminals. After the connection I turn the dials to the desire values. I don't know if my psu is good at regulations.
 
tsteele93

tsteele93

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Cyparagon said:
I bought this 30V 5A supply last week. Voltage looks good on the scope, but the current regulation is unacceptable. They claim <2mA rms in the users guide, but this is what I measure with it set to 400mA across a typical test load of 3 diodes and a 1ohm resistor:

YH305D.png


And this was at a measly 0.4A load! These things only get worse at higher current. That first spike is ~55mA rms and the rest is ~18mA rms. This piece of junk is going back to the seller.
Click to expand...


Ugh, that is the one I bought. How did you test it?
 
vk2fro

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That supply may be ok on loads with input capacitors, and that arent current sensetive, but thanks for warning me cyparagon. I'll get a different brand, and bust out my scope and check before powering anything sensitive with it.

(could you imagine the horror of using one to test modulation input on say a 1 watt green module, and popping the laser 15 minutes after its out of the box?)

I think tsteele93 meant, "how did you set up the scope to see that".

From memory he did it with a one shot setting, input triggered or something. I to am not familiar with these fancy digital scopes, but I really should buy myself one of those Rigols. My Hitachi V212 is the size of a PC case.

I think EEV blog on u-tube has a scope tutorial.
 
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tsteele93

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vk2fro said:
That supply may be ok on loads with input capacitors, and that arent current sensetive, but thanks for warning me cyparagon. I'll get a different brand, and bust out my scope and check before powering anything sensitive with it.

(could you imagine the horror of using one to test modulation input on say a 1 watt green module, and popping the laser 15 minutes after its out of the box?)

I think tsteele93 meant, "how did you set up the scope to see that".

From memory he did it with a one shot setting, input triggered or something. I to am not familiar with these fancy digital scopes, but I really should buy myself one of those Rigols. My Hitachi V212 is the size of a PC case.

I think EEV blog on u-tube has a scope tutorial.
Click to expand...

Thank you. :)
 
tsteele93

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My main use will be providing Voltage to the driver, connected to a dummy load to set the driver current. Since I won't be using it to send current directly to the diode do I need to be as concerned?
 
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Cyparagon

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Voltage looks fine on the scope on mine. It might be different under heavy load, and there is certainly the possibility that mine is defective. The seller still hasn't replied. However, it takes a (comparatively) ridiculously long time to come up to voltage - sometimes as long as 500ms.
 
Kizdawg

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So in CC mode the voltage reading will go up as it is providing current and when it reaches it's max it will switch into cv? Also anyone that can sell me high current leads for the psu at a decent price I'm interested.
 
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