Calculating Capacity With a Maha C808M Charger

[beamis]

As I posted before, I received 8 Maha 10Ah D cells from Thomas Distributing that were reading about 0.5V - 0.7V out of the bag. The first run they wouldn't even hold a charge for a minute in the Maglite. I have been running them on conditioning cycles on the C808M since Christmas. The last cycle's discharge portion lasted about 13 hours. My understanding from other threads is that the discharge current of the C808M is 360mA, and so I calculated 0.36A x 90% x 13 hours = 4.212Ah. Does this calculation seem about right?

What gives me pause is that the user manual says conditioning a D cell can take up to 30 hours. A 10Ah D cell should take that long just to discharge if the discharge current is indeed 360mA. Assuming a 2A charging current, the whole cycle should take about 35 - 40 hours.

 

[SilverFox]

Hello Beamis,

Your calculations look correct.

It appears that the cells are crap.

Tom

 

[beamis]

Thanks for responding. I contacted Thomas Distributing and they said I have to ship the batteries back and include a note that I would like to be refunded the price of shipping. They suggested I use USPS Priority Mail so they could see the shipping amount on the package. I'm going to request that they send cells reading 1.2V.

 

[rmteo]

You can get 8 of these 10000mAH cells for $44.12 ($5.51 each):
http://www.batteryspace.com/nimhrechargeablecelldsize12v10000mahrechargeablebattery8pcs.aspx

I use them and all 8 measure 10000+ mAH.

 

[beamis]

Thanks for the tip. I have to stay with Thomas Distributing this time, so I think I'm going to use this as an opportunity to try out the Accupower Evolution cells. I don't want to go another round with some possibly very old stock on the Mahas and I hear good things about the LSD on those Accupowers.

 

[WDG]

My experience has been that Thomas Distributing has top notch customer service.