Strange battery behaviour - Page 1
Forum section: electronics / general

author: Mr Darkman
author_rank: Newbie
timestamp: May 24, 2016, 08:14:44 pm
content: Hi everyone. Long time subscriber to the associated youtube..... I now even like mailbag!A history (dates aprox)2000 A brand new safe (£2,000) is delivered. Four AA batteries inserted . Everything works fine.2007 Safe touchpad becomes sluggish red light flashes (battery warning light?)New batteries inserted. Safe completely deadNew batteries (another make) inserted. Safe still completed deadTry the new batteries in a second safe. The second safe works. Now have some "partially used" batteries from the second safe.Inserted "partial used" batteries in the first safe, and the safe springs into action.2012 (the same) Safe touchpad becomes sluggish red light flashes (battery warning light?)New batteries inserted. Safe completely deadNew batteries (another make) inserted. Safe still completed deadTry the new batteries in a second safe. The second safe works. Now have some "partially used" batteries from the second safe.Inserted "partial used" batteries in the first safe, and the first safe springs into action.2016 Safe touchpad becomes sluggish red light flashes (battery warning light?)New batteries inserted. Safe completely deadNew batteries (another make) inserted. Safe still completed dead.No longer a second safe. Safe dead.First thing.Why should brand new batteries not work but partial used do? <- This is my primary question, its really bugging me.Second thingWhat's the best way of quickly converting new batteries to "partially used". I don't have a monkey called probes, but I do have a multimeter.

author: kolbep
author_rank: Frequent Contributor
timestamp: May 24, 2016, 08:45:28 pm
content: Some times the outer insulation on the new batteries is too thick,This causes it to foul against the plastic in the holder (on the edges where the contacts are)and then the battery contact does not make proper contact with the positive terminal of the holder.Try put in the cells, and then check for voltage on the wires between the holder and the mechanism. No voltage means that this is the problem.Some times you can cut the edge off the insulation using a Stanley knife. But keep the Insulation on the sides of the battery.

author: suicidaleggroll
author_rank: Super Contributor
timestamp: May 24, 2016, 08:46:37 pm
content: What kind of batteries are you using? Lithium models have a higher voltage when new, it could be that that particular safe doesn't work well with the higher voltage.

author: TassiloH
author_rank: Regular Contributor
timestamp: May 25, 2016, 09:16:03 am
content: Are you sure the batteries cause this and not the time between battery removal and battery re-insertion? Sounds like the second step (remove batteries and try in another safe, than take used batteries and try in first safe takes way more time than just taking out the old ones and put in new ones fresh from the package).I am asking because I have seen something in a device before: When taking out the batteries the internal microcontroller runs for a short while from the remaining charge in a buffer cap until that voltage becomes too low. They saved the few cents on a proper reset circuit, so unless the buffer cap is completely drained (e.g. by waiting longer), no proper reset is generated when fresh batteries are inserted, so the microcontroller hangs.