MRC 989 - Dischager rate won't go above .22 amp

[ANGRY-ALIEN]

Hi guys... I'm having a little challenge with my 989... For some reason, it won't go above .22 amp when I'm trying to discharge 16 cells....
the discharge rate is set to 1.2 amps now (been using this rate for a year now), but the 989 refuses to discharge at this rate.

Any ideas why this may be happening?

Alien

[sikeston34m]

Originally Posted by ANGRY-ALIEN

Hi guys... I'm having a little challenge with my 989... For some reason, it won't go above .22 amp when I'm trying to discharge 16 cells....
the discharge rate is set to 1.2 amps now (been using this rate for a year now), but the 989 refuses to discharge at this rate.

Any ideas why this may be happening?

Alien

I use the same charger.

Did it just stop discharging at 1.2 amps?

Hmmm...............There are FET's mounted to a large heat sink inside that do the discharging duties.

The heat sink has a large thermistor mounted onboard to protect from over heating. There is also a fan that cools the heat sink during discharging.

Sounds like your fan might have quit. Check it out.

My fan first got noisey, then got quiet. LOL The fan had locked up, so I replaced the fan. Good as new again.

[ANGRY-ALIEN]

Well... I'm not sure the fan is problem... it does kick in at 139° internal during 'Charge mode'... and it does sound healthy... I also just remember it won't go over 5 amps too for
'Charge mode' even if I set it for 6.... Could it be the Fets? or could it be something bigger?

[sikeston34m]

Originally Posted by ANGRY-ALIEN

Well... I'm not sure the fan is problem... it does kick in at 139° internal during 'Charge mode'... and it does sound healthy... I also just remember it won't go over 5 amps too for
'Charge mode' even if I set it for 6.... Could it be the Fets? or could it be something bigger?

I'm not talking about the power supply fan. I'm talking about the fan inside the charge unit itself.

The charge unit limits it's charge amperage to the capability of the power supply. They are matched. Think of it in watts of output.

The larger the voltage of the pack, the lesser the amps that it will charge at.

I'm sure it will charge at 10 amps if you're only charging one pack, but put them both on in series, and it's going to limit you.

[ANGRY-ALIEN]

Yeah... I was referring to the charger fan and not the power supply's... the MRC power supply packed in for a few months now.... I am using a HP DPS-600PB B 575W POWER SUPPLY

I understand the concept of current draw when Charging, but does that principle still apply to discharging as well?

[suicideneil]

I believe it does, though the manual/ spec sheet should answer that question in more detail.

[sikeston34m]

Originally Posted by ANGRY-ALIEN

I understand the concept of current draw when Charging, but does that principle still apply to discharging as well?

Yes, it does.

That looks like a pretty hefty Power Supply. cool

[ANGRY-ALIEN]

Originally Posted by suicideneil

I believe it does, though the manual/ spec sheet should answer that question in more detail.

The manual really only speaks to heat generated from high amp discharges... nothing about current draw from the power supply.

Originally Posted by sikeston34m

Yes, it does.

That looks like a pretty hefty Power Supply. cool

Yeah... but I really can't get the full potential from them... I'm current running them on 110V source and 220... so the watt output is a little lower than advertised...
even hooking up 2 of them in series or parallel (which not a safe thing to do), still won't provide enough power to satisfy the needs of the charger.