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        Discussion Cannot discharge 1cell NiMH

#1 n808 Oct 07, 2012 05:07 PM

Cannot discharge 1cell NiMH
 
I am trying to cycle my glow driver's single NiMH cell, but PL6 refuses to discharge, error code "Pack < 3V". Yes, of course, it's a single cell. I am unable to figure out how to change this. I have tried both trickle and fast NiMH presets.

What am I doing wrong?

F/w 1.10

#2 Tim Marks Oct 07, 2012 06:24 PM

Quote:

Originally Posted by n808 (Post 22938822)
I am trying to cycle my glow driver's single NiMH cell, but PL6 refuses to discharge, error code "Pack < 3V". Yes, of course, it's a single cell. I am unable to figure out how to change this. I have tried both trickle and fast NiMH presets.

What am I doing wrong?

F/w 1.10

Hi:

You are not doing anything wrong. Due to the design of the internal discharge circuit, the output battery has to be > 3V in order to use internal discharge. What you can do is turn on Regenerative Discharge, hook up a Pb battery to the PL6 input for power, and then use Regenerative Discharge to discharge a single Ni cell. You might ask yourself why this limitation? Of course if one utilizes a FET for discharge operations, it is possible to support < 3V, but we use a high quality bipolar transistor for this purpose. The voltage drop is higher across the transistor junction, and this is why there is the 3V limitation. But the benefits are that the unit can handle higher voltage/larger battery packs running at a higher discharge rate for longer duration without overheating. This means the design is more reliable. A FET will more easily go into thermal runaway at higher voltages at the FET junction and the circuit fails sooner.

Tim Marks

#3 n808 Oct 07, 2012 07:06 PM

Thanks for the detailed explanation!

I'll just use another charger for this odd single cell.

#4 Capn_Crunch Jan 21, 2013 10:55 AM

3 volt discharge limit
 
Hi,

I am wondering if the same lower voltage discharge limit applies to the PL6? I couldn't find it in either manual.

#5 Tim Marks Jan 21, 2013 10:34 PM

Quote:

Originally Posted by Capn_Crunch (Post 23881250)
Hi,

I am wondering if the same lower voltage discharge limit applies to the PL6? I couldn't find it in either manual.

Hi:

Yes, PL6 and PL8 use same discharge technology so both have the same lower voltage limit. PL6 is still based around a bipolar transistor, it's just smaller so does lower current/wattage.

Tim Marks

#6 Capn_Crunch Jan 23, 2013 12:20 AM

Thanks!
 
Thanks for the prompt reply!


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