280AH dongguan lighting cells top balance.

[Watch Me Build]

Got these hooked up for a top balance. How long do you think it will take?

It's set at 3.45 for the first push. But it seems like as it goes on it's pushing less than 3.45 to them. I started doing them individually last night because I didn't have bus bars, and as it went on the amperage was dropping and when I tested the voltage at the outputs of the power supply it would keep getting lower. Not by a ton... But when it dropped to 1.7 amps it was around 3.40v. then I'd bump it back up to 3.45 on the multimeter, and the amps would crawl over 2 again.

This pack has been going for about 10 minutes and it already dropped to 3.44v at the outputs.


Is this standard? Or is it just a cheap power supply that I will have to keep messing with?

(Sorry for the newbish nature of this.)

 

[RCinFLA]

Test the voltage at battery terminals That is what matters. If you have too much difference ( greater then 0.02v) in voltage between battery terminals and power supply terminals then leads are too small gauge. The more current you push the more lead voltage drop.

 

[Watch Me Build]

Test the voltage at battery terminals That is what matters. If you have too much difference ( greater then 0.02v) in voltage between battery terminals and power supply terminals then leads are too small gauge. The more current you push the more lead voltage drop.

It's now 3.35 on the alligator clips hooked to the battery and 3.43 right at the outputs. It was definitely 3.45 at the outputs when I started this.

So can I just up the voltage and use the readings I'm getting at the clips for now until I get thicker guage leads?

And does this explain why the voltage at the outputs would continue to slowly drop as the amperage drops? Sorry. I'm trying to wrap my head around it, but I'm still confused.

 

[Watch Me Build]

Wait... Nevermind. Ive been up for a very long time... That 3.35 was at the clips while hooked to the battery... so basically I was just testing what the battery is charged to.

When I hook directly to the power leads on the clips the voltages match. It's sending the right amount through the leads with no loss...

Sorry for the mix-up.

But it does still seem to be slowly outputting less as the amps wind down. I bumped it up a bit to get it back to 3.45, and will post pics as the amperage drops

 

[Luthj]

Set the power supply to 3.5V or so with nothing connected to it. Set the current to max. You want to be in constant voltage mode if the power supply has one. Then connect the cells. The votlage will drop to whatever the equilibrium is for the cell at your PSUs rated current. When the voltage hits the setpoint, the current will taper to zero.

As a note, working with batteries when sleep deprived is a recipe for an expensive mistake. Personal experience talking here.

 

[Watch Me Build]

Set the power supply to 3.5V or so with nothing connected to it. Set the current to max. You want to be in constant voltage mode if the power supply has one. Then connect the cells. The votlage will drop to whatever the equilibrium is for the cell at your PSUs rated current. When the voltage hits the setpoint, the current will taper to zero.

As a note, working with batteries when sleep deprived is a recipe for an expensive mistake. Personal experience talking here.

I believe I'm in constant voltage mode. The voltage LED is lit, and the current knob doesn't seem to do anything unless turned all the way to the left to switch it to current mode.

The instructions were complete garbage, and absolutely zero help. But from what I've seen on people's YouTube videos, I think I have this set correctly.