Fluke 8506A completely useless for measuring Sanyo Eneloop - Page 1
Forum section: electronics / testgear

author: SharpEars
author_rank: Unknown
timestamp: October 05, 2014, 09:51:59 pm
content: I have a fairly discharged Sanyo Eneloop battery which has a voltage of around 0.394 V based on using a cheap but fairly accurate "one hung low" $10 multimeter. I try to measure it with my Fluke 8506A, and it cannot measure the voltage. The voltage keeps climbing by 90 uV at a time and is already at 0.422 V in both the 1xx millivolt setting and the 1.xxx settings. What is going on? Is the resistance of these Eneloops so high that the 8506A is useless to measure them?

author: electr_peter
author_rank: Unknown
timestamp: October 05, 2014, 10:07:12 pm
content: I would think I know how to describe voltage reading on a battery, it is normal behaviour.Normal multimeters have input impedance of 10MOhm, cheaper multimeters may have only 1MOhm input impedance.Fluke 8506A has >10GOhm (>10 000MOhm) input impedance on lower DC ranges.~0.4V of Eneloop battery is absolute rock bottom, there is no charge left in that poor battery. Thus any impedance, even few MOhm may discharge that battery even further. Then battery could "gain" some charge back via internal mechanism. Fluke just dislays this "charging up process" after previous discharge with cheap multimeter.

author: SharpEars
author_rank: Unknown
timestamp: October 06, 2014, 12:17:02 am
content: Quote from: electr_peter on October 05, 2014, 10:07:12 pmThe thing is that the battery didn't get charge back, it measured a constant 0.394 voltage on the "one hung low" multimeter, but kept climbing every time I hooked it back to the Fluke. It even remembered where it stopped climbing and just kept on climbing. The cheapo multimeter registered the same voltage each time I hooked it up.I am going to fully charge the battery this evening and see how the Fluke does then, but I was/am very disappointed with its inability to measure high resistance sources as this battery must have become.

author: Rufus
author_rank: Super Contributor
timestamp: October 06, 2014, 12:37:02 am
content: Quote from: SharpEars on October 06, 2014, 12:17:02 amSeriously, it is a problem with the nut holding the dial.The one hung low is loading the battery preventing voltage recovery, the 8506A loads it less and shows you the voltage recovering. Why don't you connect them both at the same time and see what happens.

author: SharpEars
author_rank: Unknown
timestamp: October 06, 2014, 02:00:50 am
content: Quote from: Rufus on October 06, 2014, 12:37:02 amArgh... I already put it on the charger. The next time I have a discharged Eneloop I'll certainly give that a shot (i.e., hooking it up to both meters).

author: BillW50
author_rank: Contributor
timestamp: August 13, 2015, 08:28:52 pm
content: So what ever happened with this battery? Did recharging ever bring the battery back to useful status once again? Or was it worthless? By the way, my UTI-T UT33B has a battery tester mode and will measure 1.5v (30 ohm), 9v (1.8k ohm), and 12v (240 ohm) batteries under load. My UT33B cost about 10 bucks shipped. I owned a few Flukes and none of them tested batteries under load.