Discharging on CellPro 4s

[must289pwr]

I have looked through the manual and I have not been able to find any info on discharging batteries with the Cellpro 4s. It has a storage mode where it charges to 50% but, as far as I can tell, no way to get it there from a charged cell. I tried putting a battery that was about 80% on in storage mode and it just beeps as if its done charging.

Does this charger not have a discharge mode or am I just missing something all together.

[marchambault]

It doesn't discharge ...

[must289pwr]

thought so .. thanks for the confirmation.

[TheBum]

The problem with chargers that discharge is that the discharge current has to go one of two places:

1. Into the power supply, which is OK if you're running the charger off a battery and bad if you're running it off an AC power supply.

2. Burned off as heat.

I think the discharge mode is what killed my first Maxpro X6 charger.

You're better off just buying four 100 ohm, 10W resistors from Radio Shack (2 packages of 2 resistors each for a total of $4) and wiring them in parallel across the battery power contacts. You can discharge two 3S packs in series or a 6S pack at around 1A (or one 3S pack at around 500mA) and stay well within the power rating of the resistors. If you're worried about over-discharge, some sort of voltage alarm could be employed, or if you don't mind checking from time to time, just hook up a voltmeter.

[marchambault]

Originally Posted by TheBum

The problem with chargers that discharge is that the discharge current has to go one of two places:

1. Into the power supply, which is OK if you're running the charger off a battery and bad if you're running it off an AC power supply.

I've never seen a charger that will put the power back into the power supply. Power supplies (especially switching power supplies) are one way operations, they can't take power back.

Discharge dissipates the power as heat.

[TheBum]

Originally Posted by marchambault

I've never seen a charger that will put the power back into the power supply. Power supplies (especially switching power supplies) are one way operations, they can't take power back.

I don't remember where I read it, but somebody actually reported a charger that would take the current from the battery being discharged and feed it back into the power source, which would have to be a large battery itself. I thought it sounded like a pretty bad idea.

[RC Accessory]

Originally Posted by TheBum

The problem with chargers that discharge is that the discharge current has to go one of two places:

1. Into the power supply, which is OK if you're running the charger off a battery and bad if you're running it off an AC power supply.

2. Burned off as heat.

I think the discharge mode is what killed my first Maxpro X6 charger.

You're better off just buying four 100 ohm, 10W resistors from Radio Shack (2 packages of 2 resistors each for a total of $4) and wiring them in parallel across the battery power contacts. You can discharge two 3S packs in series or a 6S pack at around 1A (or one 3S pack at around 500mA) and stay well within the power rating of the resistors. If you're worried about over-discharge, some sort of voltage alarm could be employed, or if you don't mind checking from time to time, just hook up a voltmeter.

1). Never heard of such a thing.

2). More than likely the MOSFET was not designed to handle the current or heat that the discharged pack was giving out.

[TheBum]

Originally Posted by RC Accessory

2). More than likely the MOSFET was not designed to handle the current or heat that the discharged pack was giving out.

I know one of the surface mount capacitors broke and the broken end was popped up at about a 45 degree angle.